Photographic Facts and Formulas

B o o ks o n Pho tography

ti cs for P oto r a ers Hans Harti n Ph. D . r ansl ated O p h g ph , by g, T by

F M . F. . P . S . 2 2 a es. Clot n Fra ri e S . r a k R. p , , R 3 p g h,

s i lli am li nt. nd i t emi str fo r P oto r a er W . F 2 ed i on. Ch y h g ph , by R

18 a es. Cl ot 2 p g h ,

i t ri al C om osi ti on i n P oto r a rt ur Hammond . 2 P c o p h g phy, by A h 34

a es i ll ustrati ons. Cl ot p g , 49 h, - P oto En r avi n P ri mer Ste en H . Hor an. Clot h g g , by ph g h,

. E i te r ank Fr a ri S M f amer a d d F . e . . F C as r om Y our C . . h by R p , , R r P . 8 . P ape , Pi ctori al L and sca e P oto r a the P oto Pi cto ri ali sts of B uf p h g phy, by h

i l str ti ns. Cl ot f alo . 2 2 a es l u a o 5 p g , 5 5 h,

P oto r a i c A musements W alter E . Wood u r . th edi ti on. h g ph , by b y 9

128 a es 100 i ll ustr ati ons. Cl ot p g , h,

r a E . W all . C . S . . . P . S . P r acti cal C ol or P oto . F F h g phy, by J , , R C lot h, “

The A i r B rus i n P oto ra G eo . F . Sti ne. 1 a es h h g phy, by 43 p g , 45

i ll ustrati ons. Clot h, r m i r ns r D r mi M r B m i P ri nti n nd B o o l a fe . E l a ro o l a e . g T , by y M P a s r nsl ated b F r an . Fra ri e S . . F . . S. 1 e . a . T y k R p , , R 99 p g Clot h, P r acti cal P oto ra Seri es eac 0 cents i n a er i n cl ot h g phy , h 5 p p , h ’ H o Th r t of Ex os r . i nners rou l es. . ow t 1. e u 2 e e S c e p e. B g T b 3

Ho to Mak P ri nts i n Colors. Ch oose and Use a Lens. 4. w e M r i ts ar . How to a Po tr a . How to Ma e Enl ements 6 . e 5 . k g k

M a antern li s 8 Th Elements of P oto ra . How to e S e . . e 7 . k L d h g phy

Ho t to a i . Ho M o P ri nts w o e uc e t es. 10 w to a e o . 9. R h N g v k G d

11. Mod ern D evelopment. ENGLI SH I MPO RTATI O NS

P oto r a Mad e E as as Eas as B C b . C i ld B a l e . h g phy y, y A , y R h y y

26 a es. P a er 4 p g p ,

The B arnet B oo of P oto ra . Clot k h g phy h , A rt of Retouchi ng Negati ves and P r acti cal Di recti ons for Fi ni shi ng and C olo ri n P oto r a i c Enl ar ements b o ert o nson g h g ph g , y R b J h ,

. S . B ruce and lf red B r ai t w ai te. B oard s T A h , i ro l i M t f i D rawi n b n H e c o r ree e od o L fe . . B rau . g yph G k h g, y A A B oard s ,

P oto r ams of the Y ear . P a er Clot h g p , h, ’ Penrose s Pi ctori al A nnual .

D e r sc iptiv e li st on r eq uest.

P ubli shed o r I mported by

A mer can oto ra c ub s n o i Ph g phi P li hi g C .

2 e b r M ss 8 w u St. s 1 us 4 N y , Bo ton 7, a ach etts PHO T O G R A PHI C F A C TS A N D FO R M U L A S

A L L F . F P . E . . R . . B W . C . S . 8 y J , ,

s i a E i r f A soc te. d to o AMERI CAN PHO TO GRAPHY “ A utlz or o P r acti cal C olo r P oto r a etc. f h g phy,

M E S A RICAN PHOTOGRAPHIC PUBLI HING Co .

M . S O . . BOST N , ASS U A 1924 o r i t 1924 C py gh , , by A E A A I N M RIC N PHOTOGR PHIC PUBLISH G CO .

E nter ed at Stati on er s Hall

r i n te an ound i n the U . S . A P d d b .

F i r st ed t on J u 1924 i i , ly ,

The i n r p e ess oston ass U . S . Al P , B , M , A R R A N

Foreword

idea k e t com ilation o The main x p in view in the p book has been to provide in condensed form Working formulas and instructions for the various processes of photography . There must necessarily be errors of

nd omission and commission , a the publishers will be

to an who grateful y reader , consulting its pages and _

to w failing ﬁnd hat he requires , will at once communi cate with them , in order that the omissions may be remedied in future editions . Forms for this purpose

of will be found at the end the book . The formulas given have not been selected in hap hazard fashion but , as far as possible , only from credit able sources .

Certain valuable information , received after the body of the book was made up into pages , will be found in the A ppendix at page 376 .

Contents

Foreword

Contents

Studio and Workroom Orthochromatic Photography Plate Backing Focus and _ Optics Exposure

Development Developers Fi xing and Clearing

I ntensiﬁcation

Reducers

Va rnishes

Silver Printing Processes

Printing-O ut Papers Salted Paper Bromide Paper

Developing-O ut Papers Toning Bromide and Gaslight Prints

S ulphide Toning The Carbon Process

The Gum-Bichromate Process CONTENTS

The Iron Processes

Platinotype

Ozotype and Allied Processes Oil and Bromoil Miscellaneous Printing Processes

Mountants Stereoscopic Work Lantern Slides Enlarging Flashlights

Colour Photography Photomechanical Processes Weights and Measures Chemical Tables Appendix Index Studio and Work room

-I t u WEIGHTS AND MEASURES . will be noted that form las in this work are usually given both in metric and duodecimal m i ? . ( or Brit sh and U . S ) weights and measures The etric weights and measures are not the exact equivalents of those in the other systems ; but the rati o of the ingredients in each

“ e u column is the sam . Readers m st therefore rigidly adhere

o one or an not out t the other system, d weigh solids in grammes and ' measure liquids by ounces or a hopeless muddle

on will result . In all cases the conversion has been made the assumption that photographic solutions are measured and not

out on weighed and , therefore , the ratios are based a uniform

6 0 . bulk of 16 oz . or 7 8 minims In many cases fractional parts have been omitted or rounded offto the nearest practical

too 1000 or 16 oz . quantity . In all cases , , the quantities , ccm , mean that these should be the total bulk of the solution when

h r i se to bf e w . made , unless stated Therefore , it is advisable dissolve the dry ingredients in some of the solvent and then

make up to the given bulk . B A CKG R O U N Ds — . Cloth is the best material , and can gener

u 96 . ally be obtained p to inches in width Calico , bleached or u to 72 nbleached , can be obtained up inches wide ; brown felt

u 60 . of u paper p to inches Small p ieces cardboard , abo t

u u . L a or V2 inch sq are , are req ired y the stretcher frame ﬂat on f r - the loor , and get a f iend to hold the right hand bottom corner of the material down to the corresponding corner of u u the frame , stretch the material q ite ta t , and nail down the _

- to of top left hand corner the edge the frame . Drive the tack or nail through a piece of cardboard and the material at 2 PHOTOGRAPHIC FACTS A ND FORMULAS

both corners . Then deal with the other corners in the same way . Then tack the center of the top and bottom edges , then

u u . the sides , p lling the material taut before p ttingin each nail u The result should be without any wrinkles . It m st then be

For rub one sized . this part of starch into a cream with

u u . three parts of water , and boil ntil a clear sol tion is formed ff Apply this with a sti brush to the material , and stand the use frame on end to dry . To make the paint , Whiting 24 parts Powdered glue 8 parts Treacle (molasses ) 12parts Water 160parts u Soak the gl e in the water for some time , add the treacle and e u m lt with heat , and stir in the whiting ntil a smooth cream is

For obtained . Divide into three parts . colours , obtain the

u : 2 following dry water colo r pigments ivory black parts , 1 u 1 . ltramarine part , red ochre part Mix the three pigments together and divide into six equal parts ; to one third of the

u u of gl e sol tion add one part the pigment , to another third of 2 of the glue add parts the pigment , and the remainder of the powder to the rest of the glue : this will give three dis ff e . tempers of di erent shad s Commercial distemper powders , u s ch as kalsomine, may be used .

Alternatively , dry canvas may be tightly stretched on a u wooden frame , then well wetted , a mixt re of dextrine and u u colo r sifted over the s rface from a ﬁne sieve, and the u ff u s rface then worked over with a sti br sh . The colours used may be as above or any powder colour used for house u decoration . The colours dry m ch lighter . For grey and u u u black backgro nds , do ble size , which is sed by paper u hangers , may be melted in a sa cepan , Slightly thinned down, u and drop black and whiting, previo sly mixed to the required

. c ff tint, added Two oats should be given with a sti brush, the STUDIO AND WORKROOM second being applied with the brush strokes in opposite direc tion to the ﬁrst .

PHOTOGRAPHING MACHINERY . Bright parts may be dulled by painting over with a thin cream of white lead and turpentine , darkened by the admixture of lampblack to give u f u of a grey . Freq ently , dabbing the sur aces with a l mp u ﬁ putty will be s f cient .

B E — s MEMORIAL STONES AND RA S S s. These often pre ent but of considerable trouble , if the surfaces the stones are u swept clean and strong Side lighting sed, the lettering and carvings will be thrown up into better relief . Wetting the stone frequently brings out indistinct lettering. In the case of u an brasses , r bbing with whiting, avoiding y deposit in the

u . u letters , is seful , as is also side lighting R bbings , obtained by placing a sheet of paper over the brasses and rubbing with

or a . a soft pencil charco l , may also be used

— I C SILVERWARE . Hollow ware may be ﬁlled with C or very cold water ; then in a warm damp room the outer surface u u will become dewed . Dabbing the s rface with p tty will

r i also kill all eﬂect ons . Or the object may be placed inside u t a tunnel Of tiss e paper , so hat the only light reaching it has to pass through the paper . — . or GLASSWARE This may be treated like silver , hollow

non- vessels may be ﬁlled with a actinic solution . — COINS . These may be smoked with burning magnesium

on ribbon , which leaves a delicate white film their surfaces . l Side ighting is preferable, so as to throw the figures , etc . , into relief . An impression may be taken in fine plaster of

Paris , and this photographed . Or the coins may be placed on a ﬁne white calendered card , slightly dampened, with a backing of blotting or other soft paper , and passed through

or . a copying other press This gives an intaglio of the coin, which, if lighted with a strong light from the bottom of the 4 PHOTOGRAPHIC FACTS AND FORMULAS

design , will when viewed in the usual manner give the impres sion of the relief of the original . —I f OBJ ECTS UNDER GLASS . it is desired to Show the glass

one of cover , give about fourth the whole exposure to the

Obj ect with the glass in position ; then remove the glass , and complete the exposure . T — o BLACKEN WOOD . Use 1oz Borax g . 1 Glycerine ccm oz .

2 z Shellac 125 g o .

16 oz Water 1000ccm . Boil until completely dissolved and add water to make up the

12 r 2 z u S 5 o o . original b lk, then add nigrosine W , g , stir u until thoro ghly dissolved , and paint the wood two or three times . This is not as satisfactory as the following, in which the aniline black is chemically formed in the wood u 3 C pric chloride 70g 5 8 gr . 0 53 Potassium bichromate 7 g 8 gr . 1 Hot water 000ccm 16 oz .

The u wood sho ld be freed from grease , then painted with this

to solution and allowed dry well , then painted with Aniline hydrochloride 140g

1000 16 oz Water ccm .

off Allow to dry, wipe any yellow powder that forms , and

u . A S u repaint with these solutions ntil black enough a r le,

ufﬁ u r two coats are s cient , as the colo r deepens in a day o two . rub Then well with boiled linseed Oil and leave to dry . To B RA ss — BLACKEN . Use Copper nitrate 208 g Water 500ccm Dissolve and add the following solution : Silver nitrate 208 g Water 500ccm STUDIO AND WORKROOM

u Clean the metal thoroughly, immerse in the mixt re , and then u : heat ; repeat if necessary . Or the following may be sed

Copper carbonate 50g 384 gr .

Ammonia 25 ccm 192min . 1 Water 1000ccm 6 oz . m Clean the metal and im erse until black, then wipe dry and f u . u o lacq er This attacks soft solder . Sol tion antimony

u e of on : (b tt r antimony) , brushed , gives bronze colours It has been stated that boiling the metal in a solution ofpotas

u of u u uf sium s lphide (liver sulph r) ntil s ﬁciently black , then

o rinsing, drying and smearing a little Oil ver it , gives better results than the above silver method . — FIREPROOFING FABRICS Soak in Alum Ammonium carbonate Boric acid Borax Water

Boric acid Ammonium phosphate Water

150 12 z Borax g o .

a Magnesium sulph te g 9 oz . W 1000 ater ccm 80oz . 25 Starch g 2oz .

Boil the starch with the water and add the salts . Immerse u the fabric until thoro ghly soaked , then dry and iron . Or a

u of u u s strong sol tion al min m acetate, p . gr . diluted

40 o u of with times its v l me water , may be used . The material s u 24 u ho ld be immersed for ho rs and then dried in the shade . 6 PHOTOGRAPHIC FACTS AND FORMULAS — FLEXIBLE LANTERN SCREEN . Take Glycerine 16 parts White glue 16 parts Zinc oxide 32parts Hot water 10parts u All are to be weighed . Dissolve the gl e in the hot water and

u u . add the zinc oxide , gro nd p with the glycerine Apply hot 10 u 160 to the screen . A screen feet sq are requires about ounces .

- TO BLACKEN ALUMINUM . Clean perfectly free from u grease by washing in soda sol tion , wash well , and immerse

I n Ferrous sulphate 1part Arsenious acid 1part Hydrochloric acid 12parts Water 12parts u u When the colo r is deep eno gh, dry with ﬁne sawdust, and

u . lacquer . This sol tion is intensely poisonous

A M ER A — u for BLACK FOR C s. This may be sed wood or or out : leather , inside

i rosine N g , spirit soluble Bismarck brown Denatured alcohol or

methylated spirit ccm 50min .

Aniline 29 ccm 1oz . u Heat the dyes with the alcohol ntil dissolved, and then add the aniline ; apply with a brush and dry before the ﬁre or in

sun the . Or , for a dead matt varnish, lampblack may be

u s s s O f rubbed p with gold ize or shellac varni h , u ing as little u u the liq id as possible ; then thin down with t rpentine . I N K B oTTL E — u FOR s. The following form la gives a water

r proof ink, and either black o white ink can be made by using

or lampblack zinc white . STUDIO AND WORKROOM

12 Copal , powdered g Oil of lavender 1000ccm i D ssolve by heat and stir in , for black Lampblack g Indigo g

for Or, white Zinc white

Apply With a ﬁne brush . — MATTING GLASS Dissolve by heat

Sodium or potassI um ﬂuoride 4 g 20gr . 2 Gelatine 4 g 0gr .

Water 1000ccm 1oz .

Coat on the glass and allow to set well and dry, then immerse in a 6 per cent solution of hydrochloric acid for 30to 60

u . seconds , and dry witho t washing The gelatine can be dis solved O ff with hot water and a ﬁne matt surface is obtained . Or the following may be used 0 0 u u 6 6 . A . Sodi m ﬂ oride g gr

s 12 12 Potas ium sulphate g gr .

Water 500ccm 1oz . 14 14 B . Zinc chloride g gr .

Hydrochloric acid 6 5 ccm 6 5 min .

1 z Water 500ccm o . Mix in equal quantities j ust before use and apply with a quill

r u u 30 u u pen O ﬁne br sh . In abo t min tes a ﬁne matt s rface is A obtained . nother plan , which is even more convenient , is to u or u paint a sq are rectangle with the above sol tion , when the whole surface will be matted . Titles may easily be writ

on u S ten the s rface with a oft lead pencil , and can be easily u removed at any time with r bber or soap and water . — SUBSTITUTES FOR GROUND GLASS Expose a dry plate to of of 3 the light a match at a distance feet , then develop until uniformly grey, ﬁx and wash . Immerse the plate in a solu 8 PHOTOGRAPHIC FACTS AND FORMULAS

or tion Of iodine in potassium iodide , a few drops of tincture u of iodine in water , until the grey fog t rns yellow ; then u u rinse , immerse in weak ammonia water ntil it t rns white , wash and dry . The longer the plate is developed in the ﬁrst

mattness. place, the more pronounced becomes the As a rule , e this gives a surface that is only us ful with a magniﬁer , the grain being too ﬁne for ordinary visual work . Or the follow ing may be used Rice starch 20parts Water glass 100parts Water 200parts The water glass is the ordinary commercial solution of

s sodium silicate of p . gr . Mix the above by ﬁrst rubbing the starch up with the water and then adding the silicate . Level the glass and pour enough of the solution on to cover u it , allow to dry , then coat with cell loid varnish . — To CLEAN GLASS Immerse the glass in the following

u 1 z Potassi m bichromate 50g o . Sulphuric acid 25 ccm 1 2 Water 000ccm 0oz . Immerse the glass and scrub with an Old toothbrush or mop u made by tying some rags on a stick , t rning the glasses over

u . with a stick , as the sol tion bites the ﬁngers Rinse in cold water , then in hot water and dry . Or make a thin cream of

Tripoli 500g 8 oz . Denatured alcohol or

methylated spirit 500ccm 8 oz .

500 z Ammonia ccm 8 o .

O f Rub well with a swab cloth and polish with a clean cloth ,

ﬁnishing with ﬁlter paper . CE ME N Ts — . Melt rubber and Shellac in equal parts on a sand bath and apply to the warm glass or metal . This is

for or useful cementing glass to glass , glass to metal . Or

10 PHOTOGRAPHIC FACTS AND FORMULAS

10 ing solutions are required : A . per cent silver nitrate solu 10 2 u . tion ; B . 5 per cent ammonia sol tion ; C per cent caustic

reducm u : potash solution ; D . g sol tion as follows

Sugar 90g 690gr .

Nitric acid 4 ccm 30min .

175 mm 2oz . 380 . Alcohol , min

Water 1000ccm 16 oz .

To make this , dissolve the sugar and acid in the water , boil

15 u . for min tes , cool down , and add the alcohol The longer u this solution has been made , the better it works . The act al silvering bath is made up as follows

A solution 20ccm 340min . 1 1 B solution (more or less ) 0ccm 70min .

C solution 10ccm 170min .

D solution 5 ccm 8 5 min . 2 100 3 oz . 50 . Distilled water ccm , min TO prepare the bath for about 700 square inches of glass

2 2 z 112 100 4 o . . surface , take ccm ( , min ) of A , and add B u u u ntil the sol tion nearly clears p, which will take about

1 z 2 00 21 z . 500 7 o . 87 6 o ccm ( , then add C ccm ( , 56 The mixture will again become thick ; then add cautiously more B until the solution clears . It should now be a brown colour but transparent . Then add

2 1 z 6000 1 o . 84 . Distilled water ccm , min

1 z . 2 u 300 0 6 . D sol tion ccm o , 8 min

° ° ° u 1 21 5 The temperat re should be from 8 to C . (6 to ° 70 With lower temperatures the D solution must be T u . O O low slightly increased temperat res give too thin ﬁlms , e u while with too high temp rat res the silver ﬁlm is too soft . u u The glass sho ld be covered with water , and , if the sol tions u ff are mixed beforehand, the water sho ld be poured O and the silvering liquid at once applied ; but good results are

u off u on u Obtained by po ring the water , po ring the D sol tion , STUDIO AND WORKROOM

- rocking the dish , and then adding the silver potash mixtures .

2or 3 u The action begins at once , and in min tes a light swab O f absorbent cotton should be lightly drawn over the surface so as to prevent the heavy sediment from settling down . As u nd the cotton becomes dirty , it sho ld be thrown away a fresh

u ex eri used . When to stop the action depends entirely pon p ence if too soon , the deposit is thin , and if too prolonged , it

' hi k n is t c a d requires much polishing . Wash with distilled

t dr water , lightly swab with co ton , and allow to y in a vertical

” f r position o at least an hour . Polishers are most satisfactorily made of the best Chamois leather stretched over a ball Of T cotton . wo polishers are necessary . First go over the

Whole surface with a plain rubber with light circular strokes ,

r u i dusting occasionally . Then ub a little ro ge nto the other pad , and polish in the same way . It has been stated that celluloid can be silvered with the above solution ; or the celluloid may be immersed in the sugar

u F r sol tion and then the others added in succession . o the above process the O ld fashioned sugar candy is the best form of u u u s gar to use ; if this is not proc rable , the best cane s gar must be used . R E . r t . C ow her gave a modiﬁcation of this process in which caustic soda is used and which seems not to be so dependent on u T of . 10 z o k 0 3 o . absol te purity the chemicals ma e ccm ( , 2 i f h r 50 n . o u t e a e u : 1 m ) sol tion , following req ired I . 0

u of per cent sol tion silver nitrate in distilled water ; II .

n u of u per ce t sol tion ca stic soda in distilled water ; III . 28 to 30per cent ammonia solution (strongest ammonia water)

- . u u u u of s IV Red cing sol tion eq al vol mes A and B , made a follows °

. u u 9 A S gar , l mp or white crystal g Distilled water 50ccm

Nitric acid , c . p . ccm 12 PHOTOGRAPHIC FACTS AND FORMULAS

Alcohol 28 5 min .

z 2 0 . 3 o . 5 Distilled water to , min

16 5 . B . Sugar gr

Distilled water 845 min .

Tartaric acid , cryst . gr .

f r Boil o 5 minutes , cool and add

Alcohol 18 ccm 304 min .

z 2 0 . 100 3 o . 5 Distilled water to ccm , min

For every 100ccm silvering solution take : 11ccm solution I . ( 186 remove 4 ccm (68 and dilute with 15 ccm m 250 . 7 c ( min ) distilled water ; add to the c , while shaking, 10 ammonia III . , until just clear ; then , while shaking, add

16 . . ccm ( 9 min ) solution II , and again , while shaking , add

u . enough ammonia to j st redissolve the precipitate Finally ,

u 4 of u I . add the dil ted ccm sol tion , Obtaining a sherry

. u 78 coloured , opalescent liquid Filter and dil te to ccm

2 z i 1 M x 11 . f . o . 358 86 o ( , ccm ( min ) IV with 11 - u ccm distilled water , add to the sherry coloured silver sol

on u tion , and pour immediately the glass , which sho ld be

° ° ° °

5 t 10 . . from 3 to 6 C . ( o F ) warmer than the solution u for Rock vigoro sly, and silver two and a half times the time Observed from pouring on the mixed solutions until deposi tion commences . Rinse twice in distilled water , swab under

off a tap , blot the surface water , allow to dry half an hour in ff a warm place, and polish o the slight bloom . — The R ochelle S alts Pr ocess Two solutions are required

for this 5

. v 10 A Sil er nitrate g 77 gr .

1000 16 z Distilled water ccm o .

. 2 B Silver nitrate g gr .

Rochelle salts g gr . 1000 1 Distilled water ccm 6 oz . u u In making this solution the water sho ld be bro ght to a boil , STUDIO AND WORKROOM

and ﬁrst the silver and then the Rochelle salts added, both being dissolved in as small a quantity of boiling distilled for u 25 water as possible . Boiling should be continued abo t minutes , until a grey powder has collected at the bottom of

’ the ﬂask . The liquid Should then be at once ﬁltered until t or quite clear , and it may be necessary o repeat this three

the e four times . The longer boiling the mor rapid the e of . deposition the silv r, and the more uniform it will be

for h Perfectly prepared solutions will keep about a mont .

of Equal volumes the two solutions are mixed just before use . — The F ormaldehyde P r ocess (L umi er e) Clean the glass

and . thoroughly with nitric acid , wash well with distilled water Pour on the surface a 25 per cent solution O f alcohol and leave for a few minutes . Prepare the following solution , which must not be made until required for use 40 24 24 s Formaldehyde , % solution drops drop 90 24 mi n 407 . Alcohol , % ccm 24 m Distilled water cc 407 min . 4 12 Silver solution 8 ccm 8 min .

f f r 100 m 1 This is su ﬁcient o 0qc 55 sq . and the tempera e 1 ° 20° 60° ° tur should be from 6 to C . ( to 68 The silver solution is prepared as follows : 10 Silver nitrate g 77 gr .

100 2 z Distilled water ccm o . Add solution of ammonia drop by drop until the brown precipitate first formed is redissolved ; but extreme care must be taken not to add too much ammonia . Then add 2 Silver nitrate g gr . 100ccm 2 Distilled water oz . Then add sufficient water to make the total bulk 1000ccm 16 ( and filter several times until quite clear . The glass should be drained from the alcohol bath and immediately c overed with the silvering solution . The deposition begins in 14 PHOTOGRAPHIC FACTS AND FORMULAS

about 90seconds and will be complete in about 2 minutes . d During the silvering, the bath should be gently rocke to

as u prevent striae. As soon the liq id begins to become cloudy O ff or show spicules of silver , it should be poured and a ma second quantity Of solution applied . Several coatings y be thus applied until the desired thickness is Obtained . At the close of the operation the surface has a slightly reddish u u brown appearance . It sho ld be washed with s ccessive lots

on of distilled water and dried , standing it white blotting d paper . When the ﬁlm is perfectly ry, it can be polished

C of with a soft hamois , enclosing a pad absorbent cotton and rouge ; the rouge used for gold is the best. The alcohol is u of u sed to prevent the formation a precipitate in the sol tion ,

u . and , if this forms , too much formaldehyde has been sed

too r u If little fo maldehyde be used, the ﬁlm has a prono nced reddish-brown colour and is punctuated with numerous pin u holes . In all cases , the formaldehyde m st only be added just before applying the mixture to the glass . If too high a

u u be temperat re be sed, the deposit forms too rapidly and

For comes powdery . small mirrors , the glass may be placed

or in a dish of porcelain glass , and the alcohol bath may be

. of u omitted If , instead using the silvered s rface as the mirror , the glass side is used, then the silver coat should be covered with : 10 Gum dammar g 77 gr . u 100 0 Bit men of Judea (asphalt) g 77 gr . 200 3 15 Red ochre g / oz .

1000 1 z Benzole ccm 6 o . The ammoniacal solutions of silver are dangerous to keep in u stock, as they may form f lminating silver which is explosive . DM WI N G S — LINE FROM PRINTS . Waterproof drawing ink should be used in drawing over any desired part of the print ; then immerse it in STUDIO AND WORKROOM

Iodine g gr .

Potassium cyanide g gr . 16 Water 1000ccm oz . u R ub the cyanide p with the iodine , add ﬁrst a very little

and u to u . water , then make p b lk Or the following may be used Thiocarbamide Nitric acid Water

Potassium bichromate S ulphuric acid Water

Then wash well . — ma NEGATIVES DIRECT . This method y be used for direct

n r or enlarged prints o paper o plates . The image should be developed with 45 Amidol g gr . u 120 Sodi m sulphite , dry g gr . u Ammoni m bromide g 36 gr . 2 15 Potassium metabisulphite g gr . 1000 16 Water ccm oz . Development should be stopped when the image is seen

f r r u . o 5 u th o gh at the back Of the plate Wash min tes , back

for with a piece of wet black paper , and expose to daylight 30seconds or to 6 inches of magnesium ribbon held one foot from the plate . Bleach in Potassium bichromate Nitric acid Water Then immerse in u u Sodi m s lphite , dry Potassium metabisulphite 16 PHOTOGRAPHIC FACTS AND FORMULAS

1 1 Water 000ccm 6 oz . This clears the bichromate stain ; after the plate has been u well washed , develop in the developer given above witho t the bromide .

A FEL I HTs — LIQUID S G . Sometimes cells ﬁlled with liquid but u are used in front of the light , they present no partic lar advantage . The following have been recommended Deep orange ( Farmer) Potassium bichromate 6 per cent solution in 94; inch thickness . This is only suitable for ordinary plates . Or ( Davenport) Mandarin orange Water Or ( Wordsley) Eosine Metanil yellow Water

for Or, a darker ﬁlter Eosine Metanil yellow Water Or ( Davenport) New coccin Water For deep red in 1inch thickness Tartrazine Violet Dahlia BO Water

Naphthol yellow 8 Violet Dahlia BO Water

18 PHOTOGRAPHIC FACTS AND FORMULAS

° 140° 60 . should be about C ( and the dye added , prefer i n u ou . ably, S l tion The glass sho ld be levelled, the necessary quantity of the dyed gelatine coated on it , allowed to set and

u for dried . Yellow screens , s itable bromide papers and lantern slide work : 2 Tartrazine 8 g 6 gr . 1 l u 8 000 16 . Ge atine sol tion , % ccm oz

7 to 10 100¢ cm or 750to 1000 Allow ccm to q , minims per 100 u sq . in . Two such glasses should be bound p together . Orange 3 23 Rose Bengal g gr . u 1 0 m 1 8 00 cc 6 . Gelatine sol tion , % oz

" u one of red Use the same q antity as above , and bind these screens with one of the yellow tartrazine ones . Bright red : 2 Xylene red 8 g 6 gr . u 8 1000 16 Gelatine sol tion , % ccm oz . Use the same quantity and bind with one of the tartrazine screens . Deeper red

4 sol . 8 Crystal violet, % ccm 8 1000 Gelatine , % ccm

Use as above with a tartrazine screen . Bright red ( Hii bl ) 5 3 Fast red g 8 72 gr . 5 38 Tartrazine g % gr . 1000 1 8 . 6 Gelatine , % sol ccm oz .

o 7 100 cm or 750 100 All w ccm per q , minims per sq . in . u out 600 This c ts all light to , and is safe for all ordinary plates . Deep red ( Hubl) Crystal violet Cupric sulphate S TUDIO AND WORKROOM

Glacial acetic acid 16 drops 8 drops

l 1000ccm 16 . 6 so . Gelatine , % oz u one Allow the same q antity as above , and bind up with of the bright red screens . Or

Tartrazine g 57V2 gr . r 120 C ystal violet g gr .

Cupric sulphate g 595 gr . Glacial acetic acid 15 drops 8 drops 1 1 1000 . 8 5 0 . 6 Gelatine , % ccm oz

Use the same quantity as above . This cuts out to 6 30and is

f r safe o orthochromatic plates . — GREEN SAFELIGHTS These are used for panchromatic

for plates , and are occasionally adopted instead of the red , with a green light it is possible to see better than with a faint Hii bl m red . recom ended a combination of ﬁlter blue with

u out naphthol green , which is the only green dye that c ts the u extreme red . The bl e was made into a stock solution of u Filter bl e g gr .

1000 16 z Water ccm o . 1 Ammonia ccm gr . For the screen use

a hthol 8 6 1 N p green g gr . u u 32 Bl e sol tion as above ccm oz . 1 8 . 000 1 z Gelatine , % sol ccm 6 o .

7 100 cm or 750 100 Allow ccm per q , minims per sq . in .

‘ Or ( L O wy ) u 2 New Bordea x R g 5 gr . T 6 4 artrazine g 6 gr . 9 6 9 Light green S g gr . 50 384 Glycerine ccm min . 8 1000 . 1 z Gelatine , % sol ccm 6 o .

10 er 100 cm or 1000 100 Allow about ccm p q , minims per sq . in . 20 PHOTOGRAPHIC FACTS AND FORMULAS

ﬁx ed-out or Old dry plates , negatives freed from their u o u images by red cti n , may also be sed by soaking in the u u u r above dye sol tions min s the gelatine , that is , sing wate

of for instead the gelatine solution , half an hour, then rinsing

one 3 u and drying . Or soak plate in per cent sol tion of

u of naphthol yellow, and another in per cent sol tion u n methyl violet for half an ho r , rinse , dry and bi d together . The following Was suggested by Haberkorn : Gelatine 60g Water 1000ccm

30 u on Soak for min tes , melt water bath , and add Blueish acid green 15 g Then add

Tartrazine g gr .

Naphthol green g gr .

100 cm . 7 Stir well and ﬁlter while hot To every q allow ccm ,

or 0 1 n . 75 00 . . u minims per sq i Bind two s ch screens together ,

' one use ti ssue a er w and coat with matt varnish , or p p bet een a sheet of ground glass placed between the light and the screen absorbs some of the heat . — NO N -ACTINIC PAPER Soak the paper in 10 Tartrazine g 77 gr .

Rhodamine 1g 7 .7 gr . 500 8 Water ccm oz .

z Alcohol 500ccm 8 o .

u O f The q antity rhodamine may be increased at will , when a u deeper colo red paper will be Obtained . The above paper is u safe for rapid ordinary plates . Transl cent vegetable parch e ment paper was also suggested . This was to be imm rsed for 5 minutes in a warm 10per cent solution of gelatine and u dried , then stained p in one of the following baths :

A . Tartrazine 2per cent solution

B . Chrysoidine per cent solution STUDIO AND WORKROOM

u C . Bl e carmine per cent solution C D . Methyl violet per ent solution

one u A gives a bright yellow paper , and thickness is s itable

" of one for development papers . Two sheets B and Of A T are suitable for bromide papers and slow plates . wo of C

ne f ‘A u for too and o o are s itable panchromatic plates , if not f bright a light be used ; another A makes it safer . One o A and one of C may be used for ordinary and orthochromatic i mi s plates ( Na a ) . —I n u ALCOHOL . several form las alcohol is recommended e u as an ingredi nt , altho gh under the prohibition act it is impossible for the average person in the United States to

Obtain this in any legal manner . In some cases ordinary u l ma u but for denat red a cohol y be sed, in others as , instance , u -sensiti sr u the colo r of plates , this is worse than seless

u it u ff on beca se has a very prej dicial e ect the emulsion . It is possible to obtain from chemical and bacteriological supply houses pure methyl alcohol under the names O f Eagle

or u or or methanol , Col mbian methanol spirits , methyl alco

. P . u u hol C , and these may be s bstit ted in nearly every case . O rthochromatic Photography

- WAVE LENGTHS OF THE PRINCIPAL FRAUNHOFER LINES . Fraunhofer line Wave-length Colour 7594

‘” 7 186 U U 6 86 7 O 6 56 3 Bright red U - 1 5896 Yellow orange U 5890 2 5270 Green 5 184 5 173 5 169 5 168 486 1 4308 4227 4101 396 8 3960 3934

3821-38 16 3728 358 1 3441 336 1 328 7 3180 3100 3021 2948

22 ORTHOCHROMATIC PHOTOGRA PHY

The wave-lengths in the above table are those gi ven by u u bu u Rowland, and are s ally employed , t for extreme acc racy i n spectroscopic work corrections must be used . The ’ f u i s u o ne unit O meas rement Angstrom s nit , ten millionth of

r . . a millimeter o A U . (called also tenth meter , t and u u u u only ro nd n mbers are given ; th s , taking the red cadmi m

u on 6438 line , it wo ld be called the above plan , while its \ corr ect ' measurement is It is frequently the u - un O f c stom to employ other its , for instance, the millionth

m u or u t a millimeter a is sed , the tho sandth of a millimeter p m u u (pronounced u) . Th s the cadmi m line may be expressed

: or or a . as x cm, a, j y

m r Hi or s o . . . . u u , A U or t It is s al in photo

u us 43 r e . U . 6 8 o graphic literat re to the abbreviated A , as the still briefer designation 644. The Greek lambda or A is u - sed to designate the wave length . It is very frequent also to designate a colour or position in u u the spectr m by s ch a term as D C , which means half way u 5 93 between the lines D and C ; this wo ld mean , taking 8 as

- the mean wave length of the D lines , that the stated position

u or ff O f - u wo ld be half the distance di erence wave lengths , th s 6 56 3— 5893 6 70 6 70 2 5 93 C , then divided by plus 8

22 - 6 8 . , the designated wave length

— l‘ i0us DISTRIBUTION OF COLOURS IN THE SPECTRUM . V a tables Of the distribution of the colours in the spectrum have but been given , the followingcompiled by Listing may be accepted as being typical : Colour

Deep red 24 PHOTOGRAPHIC FA CTS AND FORMULAS

Orange Middle 6 14 End 58 5 Yellow Middle 559 End 534 G reen Middle 5 12 End 491 Cyan blue Middle 473 End 455 Middle 439 End 424 Violet Middle 409 End 396 Lavender Middle 384 End 372

— - R TH O CH R O MA TI S I N G . or u O PLATES Ordinary , non colo r

orthochromatised u sensitive plates , may be by bathing in sol

of . u u tions dyes As a rule , s ch plates have a higher colo r sensitivity than those coated with an emulsion to which the

u but do not u dye is added d ring the mixing , they keep q ite aswell .

- — B lue r en and G reen S ensi tisers. g e Acridine orange NO ,

M hlheim ii u . made by Leonhardt Of , was the Old dye sed A saturated alcoholic solution was made and diluted with water ; but this dye stains the gelatine S O tenaciously that it cannot be removed except with an alcohol bath . It has been entirely replaced by pi naﬂavol ( Hoechst) or the new dye dimethyl i i st r l r d ne u . y y py methiodide , s ggested by Mills and Pope This

u u u u or is sed in an aq eo s sol tion , in

3 u . which the plates are bathed for min tes , rinsed and dried This gives very even sensitiveness from the bright blue to the 560 ff 6 20 u y ellow at , then falling o rapidly to , and witho t the

u u - e of us al gap in the bl e green , charact ristic the eosine dyes . n n Y l ts — G ree a d e low S ensi i ers. Erythrosine is the dye

26 PHOTOGRAPHIC FACTS AND FORMULAS

taken as to the use O f a green safelight . These dyes sensitise

2 For - 0. to about 7 the extreme red and infra red, dicyanine

u u . not for m st be sed This does sensitise green at all , and great care must be taken in protecting the dye and its solution from light . Only perfectly clean glass dishes S hould be used for bath ing plates ; Old porcelain dishes and metal tanks are to be o avoided , as , in the f rmer case , they are apt to contaminate

of u the dye baths from traces Old sol tions held in the cracks , u u f and metals tend to red ce the dyes and ca se og. Home u bathed plates will not keep well , and the sooner they are sed the better . The followmg method of hypersensitising plates gives u extraordinary colo r sensitivity and speed , but the plates will not keep more than about 36 hours . Three stock solutions of dyes are required 1 A . Pinaverdol g 90° 1000 Alcohol , ccm

B . Pinachrome g 90° 1000 Alcohol , ccm

C . Pinacyanol g 90° 1000 Alcohol , ccm u D . Sol tion A 405 ccm Solution B 405 ccm Solution C 210ccm

u of u u If absol tely correct rendering the colo rs is req ired , the u ratios Of these sol tions may have to be altered slightly . It

" u sensitol will be nderstood also that the English dyes , green

sensitol of and red , may be used instead the pinaverdol and pinacyanol with equally satisfactory results . Stock dye solu tion :

. u 12 400 oz . 9 E Stock sol tion D ccm 6 , min .

00 z . 2 6 9 o . Alcohol ccm , 88 min ORTHO CHROMATIC PHOTOGRAPHY

2 . F . Silver chloride g gr

° ’ 22 80 6 1 . Ammonia , ccm min

z Distilled water 920ccm 16 o . The ammonia should have a speciﬁc gravity of about S ensitl smg bath 2 u 100 1oz . 8 8 . G . Sol tion E ccm , min 2 u 100 1oz . 88 . Sol tion F ccm , min

c 800 13 . Al ohol , ccm oz

The This alcohol contains approximately 50per cent water . u u plates sho ld be bathed at as low a temperat re as possible , 3 u 1 u the dish rocked for min tes , the plates rinsed for min te , s and then dried as rapidly as po sible . It is possible to take snapshots with plates thus bathed in well -lighted rooms with a lens working at f 4. Various formulas have been given for panchromatising r a e . u plates , some Of which given here As a r le , the fastest

u not u on plates sho ld be sed , as they are more liable to fog keeping ; and a clean working plate should be chosen . ’ ll c B t Wa a e s a h.

Pinacyan ol 15 ccm . Pinaverdol 12ccm Homocol 12ccm Ammonia ccm Alcohol 410ccm 90 Water 5 ccm 9% oz .

4 u e s 30 . Bathe for min t s , rin e in alcohol for seconds , dry s 720 u - Sensiti es to , witho t any gap in the blue green . Dicyanine may be used instead Of the homocol with slightly greater speed . ’ — G r eenﬁeld s B ath This bath is specially intended for but u u tank work , the sol tion sho ld not be used more than twice 3 Pinachrome ccm 23 min . 28 PHOTOGRAPHIC FACTS AND FORMULAS

Pinacyanol 2ccm 15 min .

Water 1000ccm 16 oz . A s all the i socyani nes are decolourised by the carbonic acid dissolved in water, this bath would be rapidly decolourised , u and in this state would not give s ch good results . A small addition of ammonia or borax is essential . In the above baths the dyes are used in alcoholic stock solution . ’ G eorge s F ormula.

Pinaverdol ccm 105 min .

Homocol 9 ccm 69 min .

Pinacyanol ccm 88 min . 2 Ammonia ccm 5 8 min .

90 376 6 . Alcohol , % ccm oz

1 1 z Water to 000ccm 6 o .

This bath is too strong in ammonia . The dyes in the above bath Should be used in a alcoholic stock solution . ’ l Monpillard s F ormu a.

r Pinacyanol o dicyanine 5 ccm 38 min .

Homocol 5 ccm 38 min .

Ammonia ccm min .

1 1 z Water 000ccm 6 o . 750 With dicyanine the sensitiveness extends to , with pina

6 0. d e 1: 1 cyanol to 8 Stock y solution 000alcohol . —L ii O - DESENSITISING PLATES . pp Cramer found that by bathing plates in certain dye solutions both ordinary and colour-sensitive plates could be desensitised after exposure and thus be worked in a bright orange or yellow light without fog. Phenosafranine in a per cent solution may be used ’ one k or 10 O f with minute s bathing in the dar , per cent a per cent solution may be added to the developer with equally good results . Other dyes of this class that act well

dimeth lsafranine iroﬂé are y , amethyst violet , g , safranine M N ,

cresosafranine u phenosafranine and . Unfort nately, these ORTHOCHROMATIC PHOTOG RAPHY

dyes are very tenaciously retained by the gelatine and can s only be discharged by a nitrite bath , uch as

Sodium nitrite 1g 8 gr .

Hydrochloric acid 10ccm 80min .

Water 1000ccm 16 oz . or a 2per cent alum solution with an equal volume Of hydro

chloric acid . The Hoechst dye works have introduced two

e inakr tol inakr to new dyes for the sam purpose , p yp and p yp l

' green ; the latter is the more soluble of the two and may be

or used as a preliminary bath added to the developer , but the strength should be only Neither of these dyes e stain the gelatine so much as the safranines . Lumi re and S eyewetz have found that aurantia in a 1 1000solution acts desensi as a good desensitiser , and also toluylene red . This i - t sing process is also applicable to screen plates . — ORTHOCHROMATIC FILTERS Yellow ﬁlters are used to cut down the excessive blue and violet sensitiveness Of colour

u of d e u sensitised plates . The q antity y given is calc lated in

O f u or 1000 grams the dry dye per sq are meter , grains per u sq are inches . It is advisable to dissolve the dyes in distilled u u water and add to the gelatine sol tion , previo sly prepared and ﬁltered . 1 u 25 6 14 . To make the gelatine sol tion , immerse g ( gr )

l 500. 8 oz . soft ge atine in ccm ( ) distilled water , stir for

5 O ff . minutes , and pour the water Again add the same

to for 10 quantity Of water , allow the gelatine soak minutes

O ccasronal O ff. with an stir , and pour Repeat the operation ,

to 15 u ff allowing the gelatine soak for min tes , and pour o

. out u the water Drain as m ch water as possible , then melt

on the gelatine a water bath in the water that it has absorbed . Add sufﬁcient distilled water to make the total bulk 1000ccm ( 16 and ﬁlter through glass wool or absorbent cotton . 30 PHOTOGRAPHIC FACTS AND FORMULAS

u To make the dyed gelatine , the following q antities of ﬁlter yellow ( Hoechst) should be used ( Hii bl )

1 . NO . . Filter yellow g gr

2 . No . . Filter yellow g gr

3. . NO . Filter yellow g gr

4 . NO . Filter yellow g gr 2 4 9. . No . 5 . Tartrazine g 8 gr The above quantities of dye should be dissolved I n 50to 100 f 384 768 . u ccm ( to min distilled water , and added to s ﬁcient m z 5 i n . . 700 15 o . 43 gelatine solution to make ccm ( , ) in all m on 1 1 . . This quantity should be coated q or 000sq in . of glass The increase Of exposure with these ﬁlters varies with the

- e of but colour sensitiven ss the plates used , the following will be some guide 1 2 NO . . . Increase from V2 to , according to plate Can be for u u used instantaneo s work and portrait re in the studio . 2 O 2 6 . N . . Increase from to Can be used for distant u mountains and costume st dies . Yellow reproduced the same tone as blue.

. 6 . u NO 3. Increase from to 8 Gives yellow m ch brighter u than bl e .

. 4. 4 12 NO Increase from to . Correct luminosity ﬁlter . 5 NO . 1 . Increase from 4 to 5 . Contrast ﬁlter . Reproduces

u u f r bl e like black, yellow like white . S itable o cloud studies

I S in which the sky to be very dark, and furniture . KO nig recommended the following quantities Of ﬁlter yellow to the same areas as above . 1 NO . . Filter yellow g gr . 2 No . . Filter yellow g gr . 3 NO . Filter yellow g gr .

. 4. 1 No Filter yellow g 8 gr . u u l 3 2 The increase in expos res sho ld be . , , and 3 re s ectivel p y . Pl ate B acking — CARAMEL BACKIN G A non-actmrc coating is applied to the back of glass plates to prevent halation , or the reﬂection

O f brightly lighted Obj ects from the back surface of the glass . TO be effective the backi ng must be in optical contact with u the glass , and sho ld theoretically be Of the same refractive index .

or ur Caramel b nt sugar does not dry , but a crystal caramel

e . powd r , which dries hard , is obtainable commercially This can be made as follows : place some white sugar in a stewpan

u . and heat over the gas , stirring continuo sly until it melts 2 ° The u 2 2 . temperat re will , then rise very rapidly to C

° 4 0 u 15 u ( 3 F Contin e heating for min tes , stirring all the time ; bubbles of gas will be given off and a clear red ﬂuid

u . u not formed , which grad ally thickens The heat sho ld be

u 5 u or contin ed more than min tes longer at this stage , the

a u u f product will be spoiled . Then po r o t on a sheet O metal

or u . u slate , and it sho ld set hard and brittle Break p into - u u small pieces , place in a wide mo thed bottle , add water eq al

one to third the height of the fragments , and leave for three i days . Add ten t mes the volume Of wood or denatured alcohol or or 24 methylated Spirit , and shake well two three times in ff u . u o ho rs Po r the alcohol , which extracts the sticky part , and add sufﬁcient water to the residue to make a fairly thick

. u n liquid This dries hard b t brittle . If o e eighth O f the u original mixt re , before the addition Of the alcohol , be added , it loses its brittleness . Instead Of dissolving in water , it may

u out a be po red in a ﬂat dish , llowed to dry, and then powdered . A suitable backing mixture is 31 32 PHOTOGRAPHIC FACTS AND FORMULAS

Crystal caramel powder Gum arabic Water

Caramel powder Water Denatured alcohol (methylated 150 spirit) g 3 oz .

or Mix and strain through muslin . Ordinary caramel the above may be mixed with a thick gum arabic solution and u burnt sienna or lampblack in eq al weights . Or the follow ing may be used Dextrine Crystal caramel Ammonium chloride Water Alcohol Glycerine u ff Work p into a sti paste .

- ASPHALT BACKING . Dissolve powdered asphalt in ben

or zole , chloroform , preferably, carbon tetrachloride , to form u a dark brown liq id . Apply with a brush . This dries very rapidly . ’ CORNU S BACKING . Oil of cloves 6 parts Turpentine 7 parts

Lampblack q . 5 . u ff Use eno gh lampblack to form a sti paste . This takes a long time to dry and has a very strong smell .

STAINED COLLODIONS . Aurine Enamel collodion

34 PHOTOGRAPHIC FACTS AND FORMULAS

1 Erythrosine 0g 77 gr . 1 Aurine 8 g 6 gr .

Ivory black 8 g 6 1gr . This will dry in 10minutes and can be readily removed with a damp sponge .

- QUICK DRYING SOAP BACKING . 346 Soap gr . Denatured alcohol (methylated 1000 16 spirit) ccm oz . 14 10 Erythrosine g 7 gr . 14 10 Aurine g 7 gr .

Scrape the soap into ﬁne powder or shavings , digest in the alcohol for a week with occasional Shaking, add the dyes , and ﬁlter .

— or u or d BACKING S HEETS . Black red paper, g mmed coate

on one u but f with dextrine side , may be sed, is less e ﬁcient u than any Of the others . Sheets that can be repeatedly sed may be 'made by coating cloth or paper with Soft gelatine 1part Water 2parts Glycerine 1part

‘ Soak the gelatine I n the water and melt in a water bath ; add u the glycerine , then add lampblack, nigrosine, water sol ble,

r -ou o a red dye to colour . Or printing t paper may be exposed to light until dark, then washed , dried, soaked in glycerine ,

u f he and sq eegeed to the back o t plate . OXGALL ( BOLAS) u 1 Oxgall , p riﬁed part G um arabic mucilage 4 parts Red or black water colour 1part The water colour Should be Obtained in a tube ground up in

. ff u water This should be applied with a sti br sh, and a sheet O f r black celluloid o paper applied . Focus and O ptics — To FIND THE FOCAL LENGTH OF A LEN S Many methods

u for u have been s ggested ﬁnding the focal length, eq ivalent

u r u of u foc s , o foc s of a lens , and many them req ire a knowl

s edge O i the position Cf the nodal point O f emergence . Thi f u o but can be ound by calc lati n , it can also be determined by temporarily mounting the lens in a V -shaped groove on a

fro . small block Of wood , SO that the lens can be moved to and u Or take a large ﬂat cork and drive a nail thro gh the center , n SO thatthe cork will turn o this as an axis . Fasten the lens u to the cork by a r bber band , and focus some very distant

u sun or on u Object , s ch as the moon , a piece Of card or gro nd glass also temporarily held on a cork . When the image is u q ite sharp , rotate the lens , and , if the image moves , the nodal point Of emergence O f the lens is not over the point of rota u tion Of the cork . The lens sho ld be shifted to and fro and the image again focussed until it no longer moves with the

” f of rotation o the lens . Then the node emergence is exactly

O f over the axis rotation , and this is the point from which the focal length should be measured . The following method is accurate and calls for measure u ments which are easily made . Foc s a foot rule to a deﬁnite m u size, easure the distance between the r le and the image , and D u s . call thi Then foc s to a larger size , again measure the d distance as before , and call this . Then the followi ng ' formula will give the focus ( z ii hsa R O f being the ratio image to object in the ﬁrst case , and r 36 PHOTOGRAPHIC FACTS AND FORMULAS

: D . d . that in the second case . Example in in R = 4 and r = 5 ; then then ( 5 X 5 1) and (4 X 4 1) + 4 then 10i n 1 20 . 9/ ; and , the equivalent focus of the lens . — A nother Methods This method can be carried out in any

u on room . First foc s a very distant Object , and mark the extension of the camera ; then focus on a comparatively near

Object, that is to say, one in the length of an ordinary room , again mark the position Of the camera , and call the distance

x u on between the two marks . Again foc s a still nearer u ﬂbc Object , again meas re the distance beyond inﬁnity mark, B and call this distance y . Let be the distance between the

14 the distance Of one Object is 4 in . and that of the other 1 4 u 96 i n . B 44 96 8 . , then And s ppose the extension of the camera beyond the inﬁnity or distant mark for 1 1 in f . . 12 . . 8 t the object at ft was in and at , % , then

In this method , if the lens is moved in focussing, the distance

two B ascer between the Object at the positions , or , must be

ined f ta by measuring from some part o the camera front .

on If , the other hand , the focussing screen is moved and the lens remains stationary, we need only measure the distance f between the two positions o the Object .

A nothe M t — r e hod. u on Set up a foot r le a wall , and shift the camera until an image is Obtained on the ground glass u u u that is exactly the same size as the r le ; nat rally, how m ch Of the rule is included depends on the size Of the ground u glass . Then meas re the distance between the rule and the 4 image , divide this by , and the result will be approximately the equivalent focus .

Or set up the foot rule as in the previous method, and FOCUS AND OPTICS make the image not more than one-fourth Of the size of the t u Object ; then make a nega ive of the foot r le , and , calling the distance between the rule and sensitive plate D and the ratio

r u of reduction , which can be found by meas ring the length of the image on the negative and dividing into the length of

= D r r : the foot rule , then f X ( Example a rule 10 un of D Of 5 mm was fo d to give an image mm , was 800min r = 150 ==800 , then then f X ’3 l ) mm .

A t Method ; Focus on no her . a near Object , then move the D Object further away from the lens by a distance , refocus , note the distance through whichThe focussing screen has been

a. moved , and call this Again move the Object away from the u D lens another distance eq al to the ﬁrst distance , and u b call the distance the foc ssing screen has moved , then

D 96 a 2 b main stationary in this method . Let , ,

' A n th - th — I n u n o er Me od. o Reverse the lens its ﬂange , foc s

or b. inﬁnity, a very distant Object , and call this distance u Replace the lens in its ordinary position , and again foc s on

. O b D inﬁnity Now focus on a near ject at a distance , measure

of the extension the camera beyond the inﬁnity mark, and = — = = b . D 4 call this y ; then f ) y Let 8 , b 8 ,

P i nhol M th — u e e od. The foc s can also be found by means

. on u Of a pinhole Focus inﬁnity with the lens , and meas re of r the size the image o make a negative . Then place a u f pinhole in the position of the lens , and prod ce an image o the distant Object exactly the same size ; the distance Of the pinhole from the image is the focus . A simple thin lens may

u of . f be sed instead the pinhole Or , if a lens O known focus 38 PHOTOGRAPHIC FACTS A ND FORMULAS

is available , it is only necessary to measure the size Of the two on images , when both lenses are focussed the same distant object , and the focal lengths are proportional to the sizes of the two images .

- metri cal Method. A A G eo Focus two distant Obj ects , as 1 nd C D f . a o and B in Fig , let and be the images these

F i g. 1

= h+ a a A C Objects then f tan , being the angle between

B D u h s and . Meas re the length , the di tance between the

of s CL images the two objects , and al o , their distance from

-= = the lens ; then f h ( CD Let CD or h 4 in . = = — = L in . and C 8 ; then f 4 8 ) 8 . A — A nother G eometri cal M ethod. t a a distance , at least

100 u O ff s times the foc s , set at right angles to the axi Of the lens two marks a distant from the axis . The distance

two n between the images o the screen will be V2 f . ’ G rubb s t — A f Me hod. t each S ide O the focussing screen make a pencil mark equidistant from the center . Place the camera ﬂat on a sheet of white paper in front O f a window .

u so Foc s on a very distant Object , that its image falls exactly on w one pencil mark . Then dra a pencil line along the side of u the camera , sing the edge Of the camera as a straight edge . Shift the camera so as to bring the image O f the same

on on u Object to the other pencil mark the gro nd glass , and u again draw a line along the side of the camera , sing the same FOCUS AND OPTICS

u side as before . Prod ce these two lines so that they meet 2 B A D A . . C A in the point , Fig Bisect the angle by the line ,

F i g. 2

EF u and draw a line at right angles to this line , eq al to the separation O f the pencil marks on the ground glass ; the focal A length is then G . ’ — ‘ f mi t s A l eth d T. o S h o . Smith , the National Physical

of Laboratory, London , has given another method ﬁnding

u u s on uss of the eq ivalent foc s Of a lens , ba ed the foc ing the image of a distant Object on the lens axis upon the ground

O f the u glass camera , sing first the complete lens and then u each component separately . The optical r le that serves as a basis of the method is that the focus of a lens Of focal length f is at a distance equal to fF 1" from that of the combination Of focal length F formed by placing in fr ont Of the first lens ’ O f another focal length f . The method is carried out as w: u follo s fit the complete lens to the camera , and foc s sharply on a distant object . Mark the position of some part Of the lens front or moving baseboard against a fixed part of the

. NO W o u camera rem ve the front combination , and again foc s on d u the Object , noting the distance thro gh which the lens — ’ front requires to be racked out ; this distance is fF f in ’ which F is the focal length of the whole lens and f and f those Of the combinations . Now focus again with the whole 40 PHOTOGRAPHIC FACTS AND FORMULAS

on lens the same object, the lens being placed with the back

to . combination the front Mark the position as before , then refocus after removing the front combination , really the back d’ one now in front . The distance between the two positions 2 ’F edd’ F u is f f . Henc , that is to say , by m ltiplying \ the two distances d and d’ together and extracting the square root , we get the focal length .

’ L — A u ockett s Method. . Lockett s ggested the following method : First draw two short vertical lines at about the

u 1 center Of the foc ssing screen , exactly inch apart and 3 u n parallel with each other . Foc s sharply o a far distant

u or object , such as a remote ch rch spire factory chimney , and mark carefully on the camera baseboard the exact posi tion Of any convenient part Of the moving lens front . This

O ff 1 may be called the inﬁnity mark . Now measure inch in ' out until the advance Of this mark, and rack the camera same

- point Of the front is against this l inch mark . Fix up a foot rule at about the height Of the lens , and move the whole

fro u u u camera to and , witho t any other adj stment , ntil the u u u rule is in the sharpest possible foc s at f ll apert re , and with the commencement or zero of the graduations coinciding

ne u f of with o Of the pencil lines . Then the n mber o inches the rule seen on the ground glass between the two pencil lines u will be eq al to the focal length of the lens . This method is based on the following reasoning : let F be the equivalent

u r or foc s , and the ratio proportion between the size of the

. u u or image and the Obj ect Then the minor conj gate foc s ,

F F r u . the distance from lens to gro nd glass , is When 1 the camera front is set inch from the inﬁnity mark, then F r equals 1inch and must also be equal to F F ; there

o r F - f re equals . It is not essential to adhere to the 1inch extension , and a greater distance will eliminate errors in

42 PHOTOGRAPHIC FACTS AND FORMULAS will appear sharp in front of and behind the Object focussed 6 - for . The following table shows the distances for a inch

: 8 lens starting with f , though in the scales only the nearest whole numbers are given : - 450 . 6 . 100X f: 8 in 37 ft . in ’ - = 22 i n = 16 5 . 19 i 100 : . 9 X 6 f t in . ” - = i n = 2 24 150 . 1 100X 6 f: i t . 6 in . ° - = = 2 112 . 10 6 : 3 9 . 4 0 X f % in ft % in . 100X 6 ” E — TO u u FOCUSSING SCAL constr ct a foc ssing scale, draw a u u u line eq al in length to the eq ivalent foc s Of the lens , mark h off u . exactly the half , third , fo rth, sixth, eig th , etc , and add

1to each division ; this will give a scale as below . Multiply

u u of the n mbers below the line by the foc s the lens , and the result will be the distances in inches at which an Object will T S . O be harp , if the lens be placed at this point ﬁx this scale

u u or to a camera , foc s ﬁrst on the clo ds , a very distant obj ect , mark the baseboard at any convenient part Of the camera B front , and place even with this mark, the scale extending,

s f u O . Obvio ly , from this mark away from the rear the camera

4 5 7 9 13 3

F i g. 5

— u DEPTH OF FOCUS . Welborne Piper s ggests that , know ing the hyperfocal distance for the stop in use and the

s u u di tance Of the Object in sharp foc s , if we divide the prod ct of s two sum u the e distances by their , the res lt will be the distance of the nearest Object in focus ; if their product is

ff su divided by their di erence , the re lt is the distance Of the

s : u u n farthe t Object in focus . Example s ppose we are foc ssi g

- 6 . on 10 . with a inch lens an Obj ect ft away, taking in u as the circle Of conf sion . The depth constant for the lens is FOCUS AND OPTICS

00 . 100 6 3600 . 3 X in ft The hyperfocal distance , which is always equal to the focal length multiplied by the u diameter Of the apert re , and divided by that of the circle Of

u for 6 - : 6 300 - 6 or conf sion , is therefore a inch lens at f , 50 10 10ft. 50 . u on ft When foc ssing , the near depth is ( X ) 50 ( 50 10) ft . The limit Of far depth is ( X 2 10 50 10 . u ) ( ) 172 ft When foc ssing on inﬁnity, the O u i s nearest bject in foc s at the hyperfocal distance , and depth

" extends from that point to inﬁnity . When the hyperfocal

u on u distance is foc ssed , the nearest Object in foc s is at half

s a the hyperfocal distance , and the farthe t at inﬁnity, so th t depth extends from half the hyperfocal distance to inﬁnity . — FOCUSSING RULES FOR HAND CAMERA S The following two simple rules may be useful to hand camera workers .

1 u s : us . Applicable when the backgro nd is not very di tant Foc on a distance equal to twice the product O f the greatest and s s sum : u horte t distances , divided by their . Example S ppose u u 20 the s bj ect to be a street scene with a ho se yards away, a 5 u man yards away, and both are req ired to be sharp ; then 2 2 0 5 2 . 2 ( X ) 0) X 8 yards . Applicable when

‘ the background is inﬁnity or very distant : Focus on a point u u f j st do ble the distance o the nearest point . Example again suppose that the nearest point is 5 yards distant ; then n 2 the point to focus o is 5 X 10yards . The following rule may also be used : square the focal

O f u 100 length the lens in inches , m ltiply by , divide by the f u 2 n mber Of the diaphragm , and then divide by . Example :

cu z 8 ' 5 With a lens Of 5 in . fo s at f X 5 X 2500 8 312 2 156 and % in . Then every 1 1 3 . thing beyond 56 in . ( ft ) will be in focus if this plane u be foc ssed on .

— TO COMBINING LENSES . ﬁnd the focal length Of two u lenses separated by a short distance , m ltiply the focal lengths 44 PHOTOGRAPHIC FACTS AND FO RMULAS

of together , and divide by their sum less the distance separa ’ ” f tion . Let f and f be the foci and d the separation O the ’ ” two lenses ; then the final focal length will be (f X f ’ ” : 6 - 8 - (f f d) . Example a inch and an inch lens are to be combined with a distance of separation O f 1inch ; the focus will be (6 X 8 ) (6 +8 To find the focal length of a supplementary lens or magnifier to

u O f u red ce or increase the focal length a given lens , m ltiply the focal length F to be altered by the ﬁnal focal length the u desired , and divide prod ct by the original focal length

: i less the ﬁnal focus . Example it is des red to reduce the 10- 7 10 7 70 focal length of a inch lens to inches , then X , 10— 7 3 70 —3 23 TO u , and red ce the focal u u length, positive or convex lenses m st be sed ; to increase

or u us the focus , negative concave lenses m st be ed ; and , in of this case , the focus the lens to be added is preﬁxed by the minus sign in the formula Example : to lengthen a 7-inch 10 7 10= 70 7 -3 lens to inches , X , and , — — therefore 70 3 23 A very simple rule to re

for u member as to the focus of a magniﬁer red cing the focus , or , in other words , to take near Objects close to the camera , is that the focus of the lens must be equal to “supplementary the distance Of the Object . In this calculation the separation of the lenses has been neglected ; to take this into considera u tion is a reﬁnement that merely complicates calc lations . DI A P H RA M — r ff RATIO APERTURE OF G s. The ratio o e ective aperture O f the stops or diaphragms does not coincide with their actual diameters in consequence Of the condensation Of u the light by the front lens component in compo nd lenses .

To e u u f r d termine the correct ratio apert re, foc s the lens o parallel rays , that is , for a very distant Object ; then replace u s u f the foc s ing screen with an opaq e card , in the center o which is a pinhole . In a dark room place a light behind the FOCUS AND OPTICS

of u on pinhole , and a circle light will be fo nd the front glass O f the lens ; the diameter of this circle will be the true aper ture of the stop , and dividing the focal length by this gives f u the true ratio aperture . As it is sometimes di ﬁc lt to see the

on circle of light the glass , the latter may be dusted with talc , which makes it more readily visible . Or a small piece of bromide paper may be cut and placed inside the cap of the lens , and a fairly long exposure given to the light passing the through the pinhole and t he lens . On development diameter of the black circle is the diameter of the ratio u aperture . Another method is to foc s a bright Spot Of light u at inﬁnity or a great distance , and then move the foc ssing screen un til the spot Of light becomes a disk Of any deﬁnite

. u diameter , say, half an inch Then the distance the foc ssing screen was moved divided by the diameter O f the disk of light is the diameter Of the ratio aperture . To ﬁnd the diameter

Of the stops for a lens , the following approximate method : u u F may be adopted Find the eq ivalent foc s Of the lens , measure the distance between the two outer surfaces of the

call d O f front and back lens , this ; then the diameter the stop

4 — x F 2d x . : u 16 f will be ( V ) Example foc s Of lens , u or d 2 inches , distance between the s rfaces , inches ; if the : 8 16 2 —8 = 16 desired stop is f , then ( V2 X ) 1 : : 8 . 78 inches , the diameter for f ’ I E w — PIPER S TABLE OF ANGLES OF V . TO ﬁnd the angle u on incl ded any given plate, divide the diagonal of the plate

u of . T u by the equivalent foc s the lens The quotient , is eq al : t he of but to twice tangent half the angle , the value Of the angle can be found very nearly from the follow1ng table If Tis The angle If Tis The angle less than is less than less than is less than 17 8 1 20° 84 ° 46 PHOTOGRAPHIC FACTS AND FORMULAS

If Tis If Tis less than less than

5 1° 53° 116 ° 58 ° 119 ° 62° 122° 66 ° 124M° 70° 127 ° 74 ° 130° 77 ° 134 °

To determine the covering angle , the diameter is taken as equal to twice the distance from the principal axis Of the lens t f TO o the farthest corner o the plate . determine the view

n we of a . a gle , take simply the diagonal the plate as the di meter The diagonals O f ordinary plates and ﬁlms are : 6 i 5 x 7 8 . n .

5 . i n 9 0 . x 7M” .

6 x 8 . . . 10. i n M M 7 . 10 2 x l .8 i n .

1 x 12 0 1 . i 5 6 n .

4 x 5 16 x 2 2 i 0 . n 5 6 .

20 x 24 FOCUS AND OPTICS

- CORRECTION FOR NO N ACHROMATIC ( SPECTACLE) LENSES .

After focussing, the distance between the lens and plate must be decreased by approximately the focal length of

use of the lens , in the normal the lens when photographing

u . distant Obj ects . In portrait re , copying, etc , the correction is greater , as follows

n n fi n seme Ratio of r edu cti o I . S i z e Corr ecti on of focal l en gth ) 2 3 4 — E S M 1. e. T LEPHOTO FORMULA Let be the magnification , , the number O f times the image produced by the complete lens is larger than that produced by the positive lens alone ; ’ F the focal length of the complete lens ; f the focal length of ” the positive lens ; f the focal length of the negative lens ; s fi d E the camera exten ion from negative lens to plate . To n the magnification M : Divide the camera extension by the 1 M E focal length Of the negative lens , and add , or ( ” — 1 : u f ) l . To find the camera extension M ltiply the focal of n u 1 or length the egative lens by the magnification min s , E f” (M The focal length Of the whole lens for distant Objects equals the focal length Of the positive lens ’ u or F M O b m ltiplied by the magnification , f . For near ’ ects u N F mE mN j when red cing times , ( f ) ( ’ ” ’ ” m = the — in which ratio Of f to f , f f (Dall meyer) .

Assume the same notation as above . The separation of the v ’ — ” ” positi e from the negative lens (f f ) (f M) . : u u f in o . Example S ppose the positive lens has a foc s 7 , the

u of 3 ih . w u for negative a foc s , hat separation will be req ired

4 ? A ns — 3 3 —4 = . 4 magniﬁcations ) ( ) M. An alternative formula giving the separation necessary to Obtain ’ a telephoto combination of a desired focal length is (f ” ’ ” - u f ) f (f F ) . Example : s ppose the positive lens is

9 . u 4 i n . in foc s and the negative , what separation is required 48 PHOTOGRAPHIC FACTS AND FORMULAS

u 1 ? — 4 9 to make the combined foc s 6 in Ans . ) X - = 5 2 = (4 5 M +M 7M in . Where a on of scale of magnification is marked , as the ordinary type adj ustable mount , and another magnification is desired that ’ M for ma nifi is not marked, let stand any existing marked g ” M . M cation , the magnification desired Then f X ( ” M (M X M ) will be the increase of separation re : 5 quired . Example Suppose a magnification Of be wanted , 3 and the nearest mark is , the focus Of the negative lens 4 5 — 3 5 3 = 4 being 4M. Then MX ( ) ( X ) MX i 3 5 n . / , which is the necessary extra separation readily

for measured from the existing mark 3 magnifications . When the focus Of the negative lens is not known, it is easy to find it from the distance between any two magnification marks on u : the mo nt . The rule is multiply the two magnifications ff u uo together and divide by their di erence, m ltiplying the q ” tient by the distance D between the two marks ; (M X M ) — M D am : be (M X . Ex ple suppose the distance

8 4 on i a . tween the marks and a telephoto mount is M , then — = 8 4 8 4 6 in . ( X ) ( ) X M X M , which is the required focus (Lockett) .

E — PINHOLE EXPOSUR The correct exposure is , with the small pinholes used in practice, always greater than that cal

l ted on cu a a basis of relative aperture ratios . The inverse square law cannot be applied in calculating relative exposures at varying plate distances from one and the same pinhole . 12 NO . Using a pinhole made with a needle , the pinhole exposure factor by which the aperture ratio numbers must be multiplied varies from to as the plate distance 254 12 diminishes from to 8 mm ( Carnegie) . Watkins ﬁnds that it is better to expose with a pinhole for 50per cent longer than the exposure calculated on the ratio

u on apert re , and gives the following table based instead

50 PHOTOGRAPHIC FACTS AND FORMULAS

Then multiply the focus of the lens by the times of enlarge u 1 u e ment pl s , and the res lt will be the distanc between lens

of and sensitive surface . This distance divided by the times enlargement will give the distance between the lens and nega

: s 4 x 5 tive . Example to ﬁnd the di tances for enlarging a

16 20 of 20 5 4. negative to x , the times enlargement 4 1 2 2 6 . u 6 3 3 Using a Min foc s lens , MX ( ) V2 and M

4 8 Min . The greater distance is called the major con u u u u j gate foc s and the lesser the minor conj gate . In red cing or copying, these distances are reversed, that is , the major conj ugate or greater distance is between the subject and the lens and the minor between the lens and the sensitive surface . — How TO CARE FOR HIGH GRA DE LENSES The lens should u be capped when it is not in use. Avoid s dden and extreme u n temperature changes . The lens sho ld ot be exposed to u acid f mes . Avoid placing or leaving lens where dampness

' i D u on t. O or moist re may collect not permit lens to fall , or u s bject it to a sudden jar . Occasional cleaning is not only

but u O r u advisable necessary when d st , ﬁnger marks moist re

’ n For u Show o the lens surfaces . this a camel s hair br sh and

e : a clean , soft , linen cloth are desirable . Proc ed as follows

’ on Remove dust with camel s hair brush . Breathe lens u u s rface , and with cloth wipe lightly with a circ lar move

r u rub ment . If ﬁnger o d st marks cannot be removed, the surface gently with a tuft Of cotton moistened with clean warm

u . water . Dry the s rface with a piece of clean linen cloth Under no circumstances use abrasives or any kind of polish

use alcoholine ing or cleaning material . Never acids , alcohol ,

r or other solvents on the lens surfaces o on the mount . Only in extreme cases should lens elements be removed from their

u u . metal mo nts to clean inner s rfaces When replacing same, seethat they ﬁt evenly and ﬁrmly in the mount . Exp osure — TIMING S HUTTER SPEEDS Using a pendulum for this u p rpose , the speed Of the bob is in feet per second

2 ” 2x gz( si n sin ; O f in which g force gravity at the place Of experiment , uffi l O f u u being s ciently approximate , length pend l m

' B an ular di s lacement of bob in feet , the g p from vertical at its

. u of highest position , C the ang lar displacement from vertical

’ u s bob for position at which speed is req ired . From thi a table can be calculated Of the speeds Of the bob over each 5 degrees Of arc and also the total period Of the pendulum ( Collingridge) * TH E RA - AMERICAN PHOTOG PHY EXPOS URE TABLES . u u u Find n mbers for s bject , stop , light , month and ho r , and 60 u plate . Add them , refer to table (page ) and give expos re u indicated . When the expos re fails to correspond with speed

on u marking Shutter , use the nearest Sh tter speed, preferably the lower .

S ub ect j . Sea (only) and clouds M 1 Sea views , snow scenes , distant landscape Open landscape with unimportant foreground 2 Average landscape with foreground 3 u u 4 Landscape with dark foregro nd , gro ps in sunlight u u Street scenes , b ildings , gro ps 5 Portraits in shade 7 Indoor portraits 8 to 10 Interiors 8 to 16

o r i p t 19 06 F . un as o . o r i t 19 11 19 13 19 14 C y gh , , by D d T dd C py gh , , , , by

F R . F . r ap r i e . o r i t 19 12 19 15 19 16 m er i can oto r a i c C py gh , , , , by A Ph g ph u i s i n o P bl h g C . 52 PHOTOGRAPHIC FACTS AND FORMULAS

t S op .

L i ht g . Intense sunlight (inky-black shadows ) Bright sunlight ( strong shadows ) Faint shadow cast by sun Dull (no shadows ) Very dull (whole sky very dark) 2 u 0 i f If sunlight falls over one sho lder , add ;, straight across 1 2 u subject , add ; if sun is ahead, add . When sing back

of . . or s 2 combination only R R symmetrical len , add , unless u actual f val e of stop is known and used . L A TI TUDEs - LIGHT VALUES FOR VARIOUS . The following tables show the value of the light for each hour of the day and month for various latitudes and are calculated for use

A meri can P hoto ra h Ex osure T bl s with the g p y p a e . ° For 60 u N Southern Siberia , So thern Alaska , Northern a u Can da , Iceland, Norway , Sweden , and Northern R ssia .

A P May Apr . Mar . Feb . Jan . A u . . . v M M June July g Sept Oct No . Dec . 12 0 0 l 2 3 11 1 0 M 1 3 5 10 2 M M 1 4 6 9 3 1 5 8 4 7 5 6 6 5 7 4 8 5

. . . e A u Dec Nov Oct S pt . g. July June

Jan . Feb . Mar . Apr . May EXPOSURE

The months for latitudes north O f the equator are given at the t of for u op the tables , while those the so thern hemisphere are below .

° F r 53 S o N British Isles , Northern Germany, outhern u Canada , and Southern R ssia .

A P May Apr . Mar . Feb . Jan .

‘ . Nov. . M M June July Aug . Sept . Oct Dec 12 0 O M 1 2 3 11 1 0 0 M 1 3 4 10 2 0 0 M 4 5 9 3 1 5 7 8 4 7 5 6 6 2 5 7 5 4 8 6

. . . . u Dec Nov Oct Sept Aug . July J ne

Jan . Feb . Mar . Apr . May

For 40 Northern United States , Armenia , Spain , u Italy , T rkey , Japan , Greece , Pekin , and Central China.

P May Apr . Mar . Feb . Jan .

A u . v . M M June July g Sept . Oct . No Dec . 12 0 0 0 M 1 1 1 11 1 0 0 0 M 2 1 1

‘ 1 10 2 0 0 M 2 1 I I 9 3 V2 2 2 1 1 8 4 1 2 2 7 5 4 5 6 6 5 7 54 PHOTOGRAPHIC FACTS AND FORMULAS

° u For 30 N . Southern China , So thern United States ,

Northern Mexico , Northern Africa , Arabia , and Northern

India .

May Apr . Mar . Feb . Jan .

une July A ug. Sept . Oct . Nov . Dec . % 0 o o 0 M I

0 o o o yz l o o o 1 o 2 M I 3 2 3 4 6

v . . . . e Dec . No Oct Sept Aug July Jun

Jan . Feb . Mar . Apr . May

30 S . u u For ; So thern A stralia , Northern Argentina, Cape u Colony, and Urug ay .

2 ° x 3 N . u For ; India , Me ico , So thern Egypt, Central u Arabia , C ba , and Northern West Indies .

P May Apr . Mar . Feb . Jan . u u A u D . . Nov. ec. M M J ne J ly g Sept Oct . 12 M M 0 0 0 M 11 1 0 0 0 0 M M 10 2 0 0 0 M M 1 9 3 M M 1 1 8 4 1 1 1 7 5 2 2 6 6 3 4 6

. . A u u Dec Nov Oct . Sept . g J ly June

Jan . Mar . Apr . May 2 ° For 3 S . u ; Northern A stralia , Northern Chile, Bolivia ,

Madagascar, Rio Janeiro , and Transvaal . EXPOSURE

° °

20 S . 20 . Tropics , N to ; Northern Brazil , Canal Zone ,

u . Central Africa , Ceylon , Borneo , S matra and Paciﬁc Islands

A P May Apr . Mar . Feb . Jan .

. ov . . M M June July A ug. Sept . Oct N Dec 12 0 0 M —M —M 0 0 11 l 0 0 0 0 10 2 0 0 0 0 1 8 4 1M 1 1 1 1 1 7 5 3 3 2M 2M 2M 3 3 — PLATE SPEEDS The numbers in the ﬁrst column indicate the exposure factors for use with the A mer i can P hotography

T l s u E x p osur e ab e . The letters in the last col mn are develop u ment speeds for Thermo Development . The other col mns

use u u - contain factors for with the B rro ghs Wellcome , Wat u kins , Wynne and Harvey expos re meters .

A mer .

o B W . Wat. nn e Har . Ph t. . Wy A gfa fi l m 132 130 7 3 E A gfa Color p late n 1 A sco S p eedex fi lm 54. 76 25 0 100 D A M tr 35 0 1 0 . U a s ee P . . l p d 2 A M N i n 25 0 100 . o r e e P . . Sl M A M s eci a r i 1 18 0 8 . P . . p l ap d 7 M fi lm 1 1 1 A . 8 0 8 P . . /s 7 A E w r s n i n 1 18 . d a d E s g 0 8 7 A E w r n i n 3 5 0 . d a d s E s g sp eedy A 2 100 B ar n et O r di n ar y 4 M2 6 5 5 2 1 B ar n et Sp eci al r ap i d A 130 7 3 B ar n et self-scr een 1 18 0 8 7 ' n 25 B ar et R ed seal 94 M 0 100 B ar n et Stu di o 4 00 M M 25 0 100 D B ar n et S tu di o 5 00 Pr ess 35 0 120 D ar n et l 5 00 143 E U t . r a 85 S or B p . S tho 3 1 B ar n et S tu di O 4 00 ort o 25 0 100 E h 76. A B ar n et Pr ess M 35 0 120

au c et . . A D 35 0 120 B h B P .

auc et . . A C 25 0 100 B h B P .

au c et . . A 130 7 3 B h B P . B 1 au c et . A A 3 6 5 5 2 B h B P . . C ar bi n e r oll ﬁ lm 1 18 0 8 6 Cen tr al Col orn on 1 6 5 5 2 J

en tr a P an r t o . m 6 5 5 2 C l . O h Co H C en tr al Comet 130 7 3 G Cen tr al Sp eci al 18 0 8 6 Cen tr al Sp eci al XX 25 0 100 D 56 PHOTOGRAPHIC FACTS AND FORMULAS

Centr al E xcel all Cr amer Con tr ast Cr amer Slow I so r m r m a e o . 81. m C C Co . ISO Cr amer Sp ectrum Tr i chr ome m r n r r I o. C a e A cho med . s Cr amer B ann er X m n r a er st . O 8: I s ort. C I IS o. P r am r r wn ost C e C o . P Cr amer Sp eed-o-kr ome Cr amer Hi -Sp eed Cr i ter ion Pr ocess Cr iter i on Or di n ar y Cr i ter i on ISO or di n ar y Cr i ter i on E x tr a r ap i d Cri ter i on Ex tr a r ap i d I so Cr i ter i on Roll fil m Cr i ter ion Ci n e film r i ter i on S eci a E x r R C p l t a ap . Cr i ter i on P or tr ai t Cr i ter i on E n el i te E astman Pr ocess film E astman i n P fi lm C e os. E astman R api d p late E astman E xtr a r ap i d pl ate astman S l u tr a r i E p . l ap d E astman ortho E astman Sup er -sen siti ve p l ate astman P ar -s ee or i m E p d P t. F l man i n E ast e n e . r C g o d . m n i n E ast a e n e . u C g s p . sp eed E m n i n n ast a an . C e eg. p E astman S up . Sp eed P or t film E astman Commer ci al E astman Commer ci al or tho G em Pr ocess G em Uni ver sal Slow G em Uni ver sal G em Medi um G em Tr i col G em U tr a r a studi o l p . G em N osk r en e S R p . ap . G em Meteo r

G em Roll ﬁ lm G em p ortr ai t S alon ISO G em G old l ab el G em S al on XX I so G em S al on Fi lm G evaer t O rtho Process G evaer t Or di n ar y Gevaer t Or tho anti halo G evaert Fi lter ed ortho e aer t e r a i G v Sp c. p d G evaer t O r thochr ome G evaert Sp eci al sen si tive

58 PHOTOGRAPHIC FACTS AND FO R MUL A S

Illi n gwor th r oll film Pack Illi n gwor th P an chr o fast Illi n gwor th Hi gh r ap i di ty Illi n gwor th Ultr a r ap i d Illi n gwor th Studi o fast Illi n gwor th Fl eet i n r i o x ast Ill gwo th Stu d e . f Illi n gwor th Sup er Fl eet Illi n gwor th Or tho fast Imp er i al Pr ocess m r i r n I p e al P ocess P a . Imp eri al Lan d scap e m m r i a i n r i n r m I p e l F e g a O d. Imp er i al O r d m Imp er i al S over ei gn 1$ m i a r H I p er l Sp ec. ap m i a r ort H I p er l Sp ec. ap ho H Imp er i al Non -fil ter Imp er i al R oll fi lm 1 Imp er i al Imp er i al P an chr o B m er i a eci a sen I p l Sp l . m r i i s n or I p e al Sp ec al e . tho m r i a r i 72 s. es I p e l S . P s Fl ashl ght m i er a S . S . S r ess . I p l . P Imp er i al E cli p se M m er i a E c i se soft or t o or t o soft M I p l l p , h , h J ou gl a R ose l ab el 85 or tho A J ou gl a In ten si ve 1 J ou gla O rtho B C 1 J ou a P n r oc gl a . P ess 1M J ou a u e an r o gl Bl b d P f . 1 M J ou gl a Mauve M Kodak Sp eed fi lm M Kod ak fi lm p ack M o a cu t fi lm r K d k eg. M M Lumi er e Blu e l ab el 1 umi er im - e ex anti hal . L S pl , 1M mi er u e r t o A . L O h B . 1 Lu mi er e O r tho C 1 umi er e P n L a . Pr océ dé 1 L umi er e Rep r oducti on 2 Lu mi er e P ell i cu l ai r e 1M Lumi er e In stan tan é e 1M L u mi el e p an chr omati c m Lu i er e E x tr a r ap i d e 132 mi Lu er e Gr an de i n stan tan é e 1 mi Lu er e Portr ai t i n stan tan é e 1 Lu mi er e Maxi ma M Lumi er e S i gma M Lumi er e A u tochr ome 7 M—8 M Lumi er e P l avik fi l m 1M Lumi er e Ci n e fi lm 1M mi u er e N C . L . Sp eed fi lm 1 EXPOSURE

Lumi er e S i gma ortho ﬁlm Mar i on Pr ocess Mar i on Fi n e gr ai n Mar i on Or di n ar y Mar i on P an chr o n n I o Mar i o I st . s Mar i on B r i lli ant i n Mar o R ecor d I so R ecor d .

Mar i on P . S . Mar i on Por tr ai t

r i n . Ma o W B . w n ho om h Ma so P t ec . Maw son Castl e Mawson F el i xi Mawson Gl adi ator aw on r A P n M s O tho a . Mawson Wi z ar d Mawson Vi ctor y Mawson Sup er G l adi ator

N ew ecor ext . ast R d , f x x s e N ove e t . p e dy

N ov ex or tho stu di o x e Novex Ma . sp e d P aget Col or p late P aget XX P aget XXX a et r oce P n P g p ss a .

P a t . F . r ge S O tho o o o o o o o o o o o o 0 o

a S R rt o S . R . P get . . O h a M d r o e . P get P f .

a et r t x t ec. r a . P g O ho e . Sp p

a et or t . r R . P g P ext a S .

a et r o . xt. R P g P f e . P aget r oll ﬁlm

a et S . F ortho P g .

P aget P an . or d . Paget Hu rri can e Raj ar Or di n ar y

a ar S . R . 85 I so N R j . S . Raj ar r oll ﬁ lm a r r r 400 R j a Ult a ap . a ar tr 5 5 0 R j Ul a r ap . S eed Pr ocess S eed P an chr o S eed 23 S eed O r tho L ee 26 x Non - S d hal . S eed Gi lt E dge 30 S eed G r aﬂ ex

tan ar I m . r S d d p Po t. S tan dar d P ostcar d tan ar O r thon on S d d Poly . tan ar E xt m S d d . I p erial S tan l ey Commer ci al Stan l ey R egular A mer .

W at. nn e Har . o B .W Ph t. . Wy Vul can ﬁlm 1 18 0 8 6 Welli n gton Film 1 M 18 0 8 6 W elli n gton Ortho Process 9 1 32 8 5 M Welli n gton Or di n ary M 9 0 6 0 Welli n gton Sp eedy Por tr ai t 1 18 0 8 6 G ’ Welli n gton E x tr a Sp eedy M M 25 0 100 F - 1 18 0 8 6 F Welli n gton I so sp eedy A nti scr . Welli n gton Studi o an ti-scr een M 5 00 14 3 E n n extr a s eed 35 0 120 F Welli gto Pr ess Sp ec. p M Welli n gton Xtr eme M 35 0 120 E Welli n gton sup er Xtr eme V 5 00 143 C Wr atten P n hr o 1 130 7 2 a c . M M r t n an hr r ocess 5 6 5 5 2 W at e P c o. P M M 5 6 5 5 2 Wr atten P anchr o. M

— u E xp osure. The following table shows the expos re cor responding to the number found by adding the ﬁve factors . EXPOSURE

p EED — I n CO N TI N EN TA L PLATE S s. the following table the speeds given are those usually accepted) on the continent of “ ” Europe and are degrees Scheiner . A few plates , other than

’

f erm n make u . those o G a , are also incl ded These degrees are compared with those of other speed marking systems in a table on another page . Agfa Chrome Agfa Chrome Isolar Agfa Chromo I sorapid A gi a Extra-rapid Agfa Film pack Agfa Roll ﬁlm Agfa Color Plate Agfa Is’olar Agfa I sorapid Agfa O rthochrom Isolar A gfa Special Anker Apollo Elite

- Apollo Elite s Violet Bayer Roll and ﬁlm pack Berolina Landscape O rth m Berolina o at. Berolina Ultra -Record K Berolina Ultra - Record W u Colonia , bl e label

Colonia , yellow label ortho n ih l Colonia , yellow label ortho a t a .

Colonia , red label

Eastman E . R . Plates Eastman ortho Eastman rapid

Eastman S . S . 62 PHOTOGRAPHIC FACTS AND FORMULAS

Eastman S . U . R . Eastman Seed 26 Eastman Seed 27 ‘ Eastman Ortho Effwee Color Effwee Garantie

Effwee ntih l ortho . a a . Eifwee Special Efi wee Ultra rapid Eisenberger Extra Rapid Eisenberger Color Eisenberger Ortho antihal Eisenberger Reform Eisenberger Ultra rapid Elko Ultrarapid ntih l Elko Ultrarapid a a . Elko Ultrarapid ortho ntih l Elko Ultrarapid ortho a a . Ensign Filmpack Roll film Errtee Yellow label E rrtee lilac label Errtee White label Glock Fidelitas Glock Bona G oerz roll film and film pack — G uilleminot Radio brom G uilleminot Radio -Eclair Haake High speed portrait Haake Normal Haake landscape and Process Haake Ortho Hauif Extra rapid Hauff O rthochrom extra rapid EXPOSURE

h Hauﬁ O rthochrom anti al .

Hauﬁ Ultra - rapid Hauff Rontgen ' Hauﬁ Transparency Herlango Germania Herlango Ultra Herlango Ultra ortho A ntihal Herlango Tizian

rl n - ntih l He a go Ortho Vigor a a .

Herlan o u orthochrom antihal g L zo ,

Herlan o orthochrom antihal g Lirot , Herlango Process Herlango Germania transparency

Herz ka Chromodux

Herz ka Extra -rapid Herz ka Jotha a rapid Herz ka J otha b ortho Herz ka J otha c ortho antihal Herz ka Normal Herz k a P ressoplan ﬁlmpack Herz ka Reform Herz ka Ultra rapid Ica Ideal Extra rapid Ica Ideal antihal Ica Ideal ortho antihal Ica Lloyd Ica Max imar Ica National Ica Volta-Extra rapid Ica Volta -ortho Ilford Anti - screen Ilford Special rapid 64 PHOTOGRAPHIC FACTS AND FORMULAS

Ilford Versatile Ilford Zenith Imperial Flashlight

Imperial Ortho spec . sen

Imperial Ortho spec . rapid Imperial Special sensitive

ord Jahr Sigurd , all sorts

Jahr Sigurd ext . all sorts Jahr Blue seal Jahr Blue seal ortho

Jahr Red label , A , B , C , D Kirschten Reform red label Ki rschten Extra rapid yellow label

irs hen ntih l K c t Extra rapid a a . Ki rschten Extra rapid orthochrom Ki rschten Ultra Rapid Kraco Extra rapid Kraco ortho Kraco ortho antihal Kranseder Reform Kranseder ortho . moment Kranseder ortho . slow Kranseder Bromsilber extra rapid Kranseder Bromsilber antihal Kranseder Bromsilber extra rich Kranseder Imperial Kranseder Munchener Aerial L eonar Green label L eonar Lutar L eonar Red label L eonar ortho antihal Lainer Ala Lainer Ala ortho

66 PHOTOGRAPHIC FACTS AND FORMULAS

Perutz Perx anto Perutz Silver eoside Premo ﬁlm pack Premo ﬁlm pack Speed Sachs Extra rapid Sachs Color Sachs Antihalation Sachs Antihalation Color S chleussner Blue label S chleussner Yellow label S chleussner Yellow label Instantaneous S chleussner Inalo

S chleussner O rthochrom

S chleussner Red label S chleussner Viridin S chleussner A inalo Stock Extra rapid Stock Ordinary Talbot E rrtee Special rapid Talbot Errtee Ortho antihal Talbot Errtee Extra sensitive Talbot E rrtee Ultra rapid Unger Hoffmann V erax normal Unger Hoffman Kromal Unger 81 Hoffman V erax rapid Unger Hoffman V erax rapid with Star Unger Hoffmann V erax Bromide Unger 8: Hoffmann V erax I sok romid Unger Hoffmann V erax Transparency Westendorp Wehner Red Westendorp Wehner Green Westendorp Wehner Color EXPOSURE

Wiphot Extra rapid Wiphot Color antihalo Wiphot ortho antihalo Wiphot Ultra

- BROMIDE PAPER SPEEDS ( B uR RO UG H s WELLCOME) . Austral Star Austral Pearl Crayon

- Barnet Ordinary, Platino matt , Cream Crayon Barnet Tiger Tongue B arnet Verona Barnet Bromoil Coralyte Rapid Coralyte Ordinary Criterion Enamel - u Criterion Platino matt , Ro gh Cyko Enlarging Empire B romyta

Gevaert Normal Gevaert Vigorous Gevaert Partox

Ilford (all varieties except as below) Ilford Rapid Contrasty Ilford Ordinary Surface Illingworth Imperial Platino -matt Kentmere Ordinary K entmere F . C . K K K entmere . . K K entmere . Q . Kodak Royal

K - odak Rapid (Platino matt , Permanent) 6 8 PHOTOGRAPHIC FACTS AND FORMULAS

- Kodak Contrast ( Platino matt , Permanent) Kodak Slow K odak Nikko , Velvet Kodak Kodura Kosmos Kosmos V itegas

Lilywhite , Normal

Lilywhite , Rapid u e L mi re, A , C , F, L u e L mi re , B Marion Montauk Paget

Rajar

Standard Bromide P . M . C . Wellington

Wellington B . B . 6 Gaslight papers approximately 64

LANTERN PLATES . Austral Barnet

Cramer Lantern , Transparency Eastman Empire Gem Black

Hammer , Yellow label

Hammer , White label Ilford Special Imperial Special Imperial Slow Jougla Black Leto EXPOSURE

l re L um e Transparency , Black Lumiere Warm Magnet Marion Chloro -bromide Marion Vandyke Marlon Gelatino -chloride Mawson Paget Rapid Paget Slow 12 Paget Color Transparency 3 Raj ar 10 Royal Standard Black 8 Seed 3 Standard R egular 3 Standard Slow 4 Wellington 1 Wratten 20

In these tables the paper or plate with a factor number of 6

u u of one 3 u req ires twice the expos re with a factor of , nder like conditions .

S — u no COMPARISON OF PLATE SPEED Unfort nately , com mO n agreement has been arrived at as to the marking Of plate u u speeds , but the following table gives the s ally accepted ratios between the various systems 8 “3

. B m’ 8 70 PHOTOGRAPHIC FACTS AND FORMULAS

as; ss E as 34 12 4 52 42 13 5 54 52 14 6 57 66 15 7 60 82 16 8 63 103 17 9 66 8 8 130 18 10 6 9 105 154 19 11 72 140 206 90 20 12 75 175 257 100 21 13 78 228 335 115 22 14 80 280 410 128 23 15 84 350 575 144 24 16 88 455 6 70 164 25 17 92 560 825 180 26 18 95 8 700 1030 204 27 19 98 6 8 75 1280 228 28 20 100 5

To convert Hurter Drifﬁeld into the Watkins system

u . u 4. M ltiply the H D . n mbers by 50and divide by 3 TO convert Wynne into Watkins : Multiply the square root of Watkins numbers by TO u u convert Wynne into H . D . M ltiply the sq are root ’ of u Wynne s n mbers by 7 . 7 . This table gives an approximation O f the connection be

u s B ut tween the vario s sy tems O i determining plate speeds . absolute reliance can not be placed upon it as there is no standard system and plate manufacturers differ as to their use of u Drifﬁ l e d . . the H rter (H D ) method , therefore, these u speeds , as advertised by vario s makers , are not comparable . EXPOSURE

It should be recognized that the ﬁgures given are for use with particular exposure systems and will yield good well f exposed negatives . The character O the same may not agree

u and or with individ al Opinions , in this case higher lower numbers should be used until with a given developer the desired character Of negative is Obtained . All plates have

and more or less latitude , therefore , considerable variation in exposure may be given and good negatives be still Obtained . — ex osil res EFFECT OF THE STOP APERTURE . The relative p are as the squares O f the aperture Of the stops or diaphragms .

s u : 8 5 For in tance , if the expos re with stop f is seconds , with 16 u s but 4 ; u , f it is not twice as m ch , time beca se according 2 2

8 64 16 256 . to the above rule , and Therefore , the exposures are as or as This applies to all

" lenses irrespective Of their focal lengths . O F — VARIATI N OF VALUES . When copying and enlarging, u u the u the lens is not working at its eq ivalent foc s , act al working focus being more or less increased ; therefore the

u i val es Of the stops are altered . Mr . Alfred Watkins g ves the following- t able which shows the necessary variation Of the exposure due to the alteration of the f value of the stop u Lantern slide making Thin N eg. Medi m Dense

Neg . Copying Black and Photograph Coloured White Obj ect 15 times focus from lens M 1 10 M 1% 1

V2 2

Vs 2V2 M 3 2 1 4 ( Copying same size) 72 PHOTOGRAPHIC FACTS AND FORMULAS

The numbers in the table are multipliers Of the calculated exposure . VARI ATION OF ENLARGING EXPOSURES FROM TH EO R ETI

—Mr s for i A L . C . Watkins al o gives the table enlarg ng Enlarging

Diameters Medium Neg . Equal size 2 3 2 4% 2M 3 6 3 4 8 4 6 M 5 9 18

u u . These n mbers are m ltipliers , as in the last table The numbers O f diameters Of enlargement are found by dividing the length of one side O f the enlargement by the

~ length Of the same side Of the negative . — TH E EFFECT OF ALTITUDE ON EXPOSURE Variations in u due u expos re to variations in altit de , or distance above sea u level , are negligible in ordinary work , that is to say , nless f - u u 5000 t. the altit de exceeds , when three q arters Of the cal l f . cu ated u u . t expos re sho ld be given Over , half the

u . reg lar time would be sufﬁcient . This is for near objects Panoramic views from mountain tops require panchromatic

lates and to cut out u . p special ﬁlters haze , as in aerial expos res —T i SHUTTER SPEEDS FOR MOVING OBJ ECTS . he follow ng are approximately the slowest speeds O f the shutter which will

s u 25 give a sharp image . The Obj ect is a s med to be feet distant from the lens and to move diagonally across the ﬁeld of the lens People walking in street scenes Animals and people walking slowly People walking three miles per hour

74 PHOTOGRAPHIC FACTS AND FORMULAS

Illuminated buildings 2minutes Open streets with arc lamps 3 minutes Open streets with wet roadway or snow 2minutes Close street scenes 6 minutes Close street with wet roadway or snow 4 minutes — STOP APERTURE SYSTEM S Various systems have been suggested from time to time for numbering the diaphragms

or but u . stops , practically only two have s rvived In the one,

or ff and the more general , the F ratio system, the e ective

u O f u u apert re is expressed as a fraction the eq ivalent foc s , u : 8 F/8 or 8 th s as F , f , which means that the aperture of the ne Th stop is o eighth Of the equivalent focus . e other system

on 4 u u is based f as nity, and the stops are merely n mbered in fractions and multiples Of this . The following table shows O f the relation the two systems , the latter being known as the

. . or u U S system , the Uniform System n mbers

N . . U . S . O U . S . No 1 f : f : 12 9 f : M f : 16 16 fz 2 M f : 32 fz 28 28 M f : 28 49 f: 3 f : 32 64 f: 4 1 f : 36 8 1 f : 5 l 56 100 : 5 6 56 2 2 12 f f: 45 . 5 8 f: 6 f : 56 196 f: 7 f: 6 256 f: 8 4 f : 70 f: 9 f: 80 10 f : f : 5 12 f : 8 f : 100 625 : 10 u —— Stolze proposed . f as nit , and Dallmeyer ( 3 16 The : 10 u Paris Congress also adopted f as the nit . Zeiss adopted EXPOSURE

: 100 u f as nity , so that the larger stops were marked with the relative luminosity , which gave as a fraction the relative 256 for : 6 . 3 exposures ; instance , f was , and the exposure compared to that for f: 100was All these systems have practically fallen into disuse in England and America , the ratio system alone—being used . EXPOSURE METERS The Watkins , Wynne , Imperial , and Beck meters are based on the measurement O f the actinic ‘

‘ power O f the light by the dark enl ng O f a sensitive paper/ to a s x u r a standard tint . Scale bearing the f val e Of the diaph gm re u and speed of the plate a bro ght into coincidence , and the exposure I S then read O ff against the time taken by the paper to darken . These meters should be exposed to the light falling upon the shadiest part Of the subject in which f ull detail is re

‘ i s sun u . I f q ired there no important shadow , test the direct I f light . there is any important shadow , face the meter to the

sun or use . sky and not to the , the shadow Of the body

’ T u O j dge the matching of the tint , hold the meter at arm s

. r d, bse v u length an o e thro gh half closed eyes , and note the time when the paper is neither lighter nor darker than the

not u . tint . An absolute match is req ired — MAKING PAPER FOR EXPOSURE METERS I n order to make u u a paper s itable for these meters , bromide paper sho ld be immersed in the darkroom for 5 minutes in a to 5 per

u ss u u u cent sol tion Of pota i m metabis lphite or sodi m nitrite , rinsed and dried . The tint caused by the action Of light varies with the paper ; but a test should be made by burning 2grains

s u Of magne i m ribbon , coiled into a spiral , at a distance Of 4 M inches . The tint thus Obtained will correspond to the ’ correct exposure for a plate of Watkins speed 1exposed at 8 u u . u u f , midday in J ne s nlight The colo r sho ld be matched u with water colo r . Development — FACTORIAL DEVELOPMENT ( Watki ns) There is practi cally a ﬁxed relation between the time of appearance of the image and the total time of development to Obtain a given

or density, degree of contrast , gamma of a negative , which

of u holds good for all variations strength , amo nt Of alkali ,

or e u . bromide , t mperat re , within reasonable limits This is known as the factorial or time development method . The “ ” total time of development divided by the time of appearance u Of the ﬁrst signs Of the image , excl sive of the sky in lands

or scape work , a white collar in a portrait , gives what is “ ” f known as the factor o the developer . The following table gives the factors for various developers for a normal neg ative Adurol 5 Kodak portrait Amidol 10 Metol

A z ol 30 M etO l-hydrochinon Certinal 30 Ortol Diogen 12 Paramidophenol Edinol 20 Pyrocatechin Eikonogen 9 Pyro -metol

Glycin-potash 12 Metoquinone Glycin- soda 8 Rodinal Hydrochinon with bromide 5 Synthol Imogen -sulphite 6 The following are the factors for pe -soda or pyro potash DEVELOPMENT

Pyro Bromide Factor Bromide Factor

’ e oz . r . J I oz . gr . p g I lr /I Z 0 18 2 M 0 12 3 M 0 10 4 1 0 8 8 2 0 6 M Estimated factors for American pyro -soda developers 11 . . C . Seed A B , no bromide 11 Seed pyro , no bromide 10 Stanley , no bromide u 6 Cramer , maxim m strength M S 11 Cramer , minimum trength

e 11 Hammer , no bromid m 12 East an , no bromide Should the negatives Obtained by the use of the above factors a r u a seem too thin , the f cto s m st be incre sed ; if the negatives

o . are to dense , the factors should be decreased The factor for a combined developer with the reducing agents in equal ratios is the mean of the two ; for instance ( £3e 6 metol 30) 2 18 ff If the developing agents are in di erent ratios , the factor for u each is m ltiplied by the number Of parts , and the sum of the factors divided by the number of parts of developer agents r 4 2 . Fo used instance , pyro parts plus metol parts : 6 X 4 = 24 and 30X 24 +60== 84 and 6 4 1 then 8 6 4 the factor required . — THERMO - DEVELO PMENT ( Watki ns) VVhile the normal 1 ° temperature for development is assumed to be 8 C . 6 ( 5 F . ) it is not always convenient or possible to Obtain this u of temperat re exactly , and , as the rapidity development is 1ncreased u with a rise of temperat re , and decreased with a u u colder sol tion , allowance m st be made for the change of 78 PHOTOGRAPHIC FACTS AND FORMULAS

temperature . The variation in time Of development due to “ changes in temperature ofthe solutions is known as the tem

” ° ° - r fe c efﬁcient 10 . 18 pe atu o , and is calculated for C ( In practice it will be found convenient to draw up a table for 2 a developer for every degrees rise or fall , which is not a

one use difﬁcult matter , as can the developer factor and a table of logarithms . Expose a plate on a landscape , including

cut two or . a portion Of the sky , and into , make two exposures

It is necessary to have means for warming up the dish, devel oper and graduate , and also a thermometer must be handy .

The warming apparatus need be nothing elaborate , a deep i baking tin or a large developing dish . Fill th s with water at ° 90° u 32 . abo t C ( and place the dish, graduate and developer in it . As soon as the developer has reached the °

for 24 . desired temperature , which convenience may be C ° 2 ° ° ( 75 and should not be above 7 C . ( 80 place l te in h the p a the dish , flood wit the developer, and note the u for time ; watch caref lly the first appearance of the image , and again note the time . The plate is no longer any use and may be thrown away . It is really advisable to place the plate . in the dish at the same time as this is floated on the warm m a . water , so that the plate itself y be raised in temperature It can be easily covered with an opaque card to protect it from light . Then treat the second plate in the same way, only use f this time the developer cold , and note the time o appear ff ance exactly as before . If the di erence in the temperatures °

10 C . of the two developers is exactly , the temperature co efﬁci ent is found at once by subtracting the logarithm Of the “ lesser time of appearance from the logarithm of the greater time . Should there be a greater or less difference in the 10 temperatures than degrees , subtract the logarithm O f the of the lesser time from that greater time, and divide by the d ff i erence of temperatures . The result will be the log . factor DEVELOPMENT

by which a table can be drawn up for the developer used . An a example will make this clear . Suppose that we have developer which we know from practical trial gives just the negative which we want with a factor of 10. S uppose that ° - we make the above described trial with a developer at 90 C .

° ° ° 20 . 68 (48 F . ) and C ( and with the lower tempera t ture it took 50seconds for the ﬁrs appearance of the image , and at the higher temperature 22seconds ; then from a table l 50 t of logarithms we ﬁnd thatthe og. of is and tha for 22is then

22 log .

Now the difference between the two temperatures was 20 9 11 e 11 , therefor which is the

° o logarithm of the difference in time f development for 1 C . or the log . factor . As we know that the developer has a °

of 10 9 . factor , therefore , if the time of appearance at C was 50 the of 50 10 seconds , total time development will be X

500 . O f seconds Then , if we want to ﬁnd the time develop °

for 10 . lo . ment C , we subtract the g factor from the

. 50 b log Of , and multiply y the factor to ﬁnd the correct time 50 Of development . Thus log . Of l . o . from a table Of logs we ﬁnd that this is the g Of and , u 10 464 m ltiplying by the factor , we have seconds as the

500 9 . result , instead Of at degrees If the temperature is lower , then we add the log . factor ; thus , assuming that the u 2 ° 7 C . temperat re has dropped degrees to , then log . 50 x 2) from our f . O table we ﬁnd this to be the log and again, using our 10 factor , we have X seconds as the correct a at the dur tion of development lower temperature . The 80 PHOTOGR APHIC FACTS AND FORMULAS following are a few temperature co-efﬁcients that have been determined (Watkins) P - u e soda, witho t bromide (Watkins ) P - e soda , with bromide (Watkins )

- u Pe soda ( H . D . ) witho t bromide

- K Pyro soda , odak powders

- Pe soda tabloid ( B . W . ) P - o e soda tabloid , Ilford f rmula

A z ol V ictol Certinal Rodinal , , , Metol-hydrochinon Metol -hydrochinon tabloid Glycin R ytol Hydrochinon Paramidophenol Amidol Ortol — O f v STAND DEVELOPMENT . This is a method de elopment u u in which a dil te developer is sed in an upright grooved tank, r i n which the plates are placed and left fo a given time . In

he ut t early days , it was p forward as a cure for every error u u in expos re , and the sol tions used were so dilute that from u 12 to 24 hours were req ired to Obtain normal negatives . The only advantages Of stand development are that the grain of the negatives is ﬁne and the results uniform , if the devel

u u re oper be freq ently agitated , and no vis al examination is quired or possible . It has been stated that the duration of development with the diluted solutions can be calculated from u u their dil tion , that is to say , a developer that is dil ted 5 times e u 5 but will r q ire times as long in the tank, this is only true of r r tten one o two developers . W a Wainwright found by careful photometric measurements , that the increase in time depends to a great extent on the quantity Of air dissolved i n

82 PHOTOGRAPHIC FACTS AND FORMULAS

Pyr ocatechin (B othamley) c A . Pyrocate hin dr Sodium sulphite , y Water

u . B . Sodi m carbonate, cryst Water

° °

1 18 . 6 5 Time , hour at C (

- Pyro soda ( Handy) . Sodium sulphite Sodium carbonate Pyro Water Pyro-soda (Harris) Pyro 1g 3 Sodium sulphite , dry g 12 Sodium carbonate , cryst . g Potassium metabisulphite g Water 1000ccm 1 ° ° 0 15 16 . 60 Time , to minutes at C ( Pyro-soda (Munkmcm 100 A . Pyro g Potassium metabisulphite 25 g 1 Water 1000ccm 0oz . 1 dr 00 l oz . B . Sodium sulphite , y g 1 1 00 . Sodium carbonate , cryst . g oz 2 2 Water 000ccm 0oz .

use 1 1 8 . For , mix part A , part B and parts water Time 2 ° ° 6 5 ° ° 3 5 minutes at 18 to 21 C . ( to 70 0minutes at ° ° ° ° ° °

1 . . 1 5 to 18 C (60 to 6 5 F ) 40minutes at 3 to 15 C . ° ° 1 ° ° ° ° 0 1 . ( 5 5 to 60 F . ) 50minutes at to 3 C (50 to 55

If the developer be used at half the above strength, the times : 50 1 80 100 will be minutes , hour , minutes , and minutes respectively for the above temperatures . DEVELOPMENT

i n l Munkmcm — R od a ( ) . Dilution Sodium sulphite ,

l n 2 u e O f dry, Mper cent sol tion may be us d instead water to dilute the developer Temperature Development in minutes

. e Cent . Fahr Portrait Architectur Landscape 22 72° 14 21 70 15 20 68 16 19 66 18 64 17 62 60 58 56 2 1 .5 54

Metol~glyci n I eﬂcott) Metol Glycin

Sodium sulphite , dry Potassium carbonate Hot water A dur ol (Mortimer) S u odium s lphite, dry Potassium carbonate Water When dissolved add Adurol 50g 10 1 ° ° 8 . Dilute time , minutes at C (65 Edi n ol .

Edinol

u Sodium s lphite, dry Potassium carbonate ‘ Water 84 PHOTOGRAPHIC FACTS AND FORMULAS

- Edi nol Hydr ochi non. Edinol 5 g Hydrochinon 5 g 125 Sodium sulphite , dry g Potassium carbonate 20g 20 Sodium carbonate , cryst . g Caustic soda 4 g Potassium bromide 1g Water 1000ccm Pyr o for lantern sli des (Mor timer) Pyrogallol g u Sodi m sulphite , dry g S ulphuric acid ccm Acetone ccm Water 1000ccm ° 5 ° 5 10 18 . 6 Time , to minutes at C (

A midol (Harris) . u u Sodi m s lphite , dry Potassium metabisulphite Potassium bromide Amidol Water

Amidol

Sodium sulphite, dry u 27 Ca stic soda lye , % Potassium bromide Water 2 3 Time , to hours . G l ci n y . Glycin u Sodi m sulphite , dry Potassium carbonate DEVELOPMENT

Potassium bromide g gr .

l 2 Water 1000ccm 3 oz . — COMBINED DEVELOPING AND FIXING This process ft c quently crops up and numerous formulas have been given

s for its u e. The following are arranged in chronological order and the later ones do give some sort of satisfactory negatives .

’

P unnett.

u 2 r . A . Potassi m metabisulphite g 35 g

Ortol 3 g gr .

Water 400ccm 10oz .

. 4 B Caustic soda g 60gr . 4 Potassium bromide g 60gr .

00 z Water 5 ccm 16 o .

. 2 C Hypo 5 g 1oz . 00 2 Water 5 ccm 0oz . 1 1 B 2 For use mix part A , part , and parts water . H n (i nate.

. u u dr 200 A Sodi m s lphite , y g 1536 gr . c 3 Causti potash 9 g 714 gr . o i 93 1 Pyr catech n g 7 4 gr . 1000 1 Water ccm 6 oz .

. 200 B Hypo g 3 oz . 1000 Water ccm 16 oz . For use 12 20 mix parts A , parts B , and 30parts water B k a er . Hydrochinon Potassium metabisulphite Caustic potash Hypo Water

Edinol gr . 86 PHOTOGRAPHIC FACTS AND FORMULAS

S odium carbonate , cryst .

Sodium sulphite , dry Hypo Water

Hypo 30g Potassium metabisulphite 40g 12 u . 0 Sodi m carbonate, cryst g Potassium bromide 1g Water 1000ccm Add 2 per cent edinol just before use

Piggr Pyrogallol g Amidol g 240 Sodium sulphite, sat . sol . ccm 4 . . 80 Sodium carbonate , sat sol ccm u l 240 e .So . Potassi m cyanid , sat ccm m ' Cr é z er . Amidol

Sodium sulphite , dry Hypo Water

R mo ay nd. Hydrochinon 8 g Metol 4 g 0 Sodium sulphite, dry 3 g

u . 0 Sodi m carbonate , cryst 8 g Hypo 6 g Water 1000ccm ’ G r emler or lantern sli d r , f e wo k . dr Sodium sulphite , y Hydrochinon Caustic soda DEVELOPMENT

Potassium bromide g gr .

10 c m 1 Water 00 c 6 oz . u 4 8 The act al developer is parts of the above, parts water, and 2Mparts of 20per cent solution O f hypo .

Haysede.

Sodium sulphite, dry Hypo

o s . S dium carbonate , cry t Potassium bromide Hydrochinon

28 . Ammonia , % sol Water

Hydrochinon

Sodium sulphite , dry

‘

Sodium carbonate , cryst . Hypo Ammonia Water

<9 O tsuki S udz uki .

Meto uin ne A . q o 6 g 30 Sodium sulphite , dry g Water 600ccm

B . Hypo 60g Caustic soda 5 g Water 400ccm

Mix in equal volumes just before use . B a l rre . Amidol

Sodium sulphite , dry Acetone Hypo Water 88 PHOTOGRAPHIC FA CTS AND FORMULAS

Nmaids.

Metol g gr .

dr 30 230 r . Sodium sulphite, y g g

Hydrochinon g 34 gr .

Caustic soda 5 g gr .

Hypo 60g 46 0gr .

Water 1000ccm 16 oz . DEVELOPERS FOR DEEP TANKS FOR COM MERCIAL FINISH

ER —E stman Kodak Tank A B C P ro ormulas s. a y f

9 140 . A . Sodium bisulphite g gr

Or potassium metabisulphite 9 g 140gr .

Pyrogallol 60g 2oz .

Potassium bromide 1g 16 gr .

Water to 1000ccm 32oz . dr 105 B . Sodium sulphite, y g

Water to 1000ccm 32oz . ’ 5 C . S odium carbonate , dry 7 g

Water to 1000ccm 32oz .

5 oz . Take M each of A , B and C and add water to make one ' f gallon ( 162ccm to make 3785 ccm) . Time o development 1 ° 1 ° about 2minutes at 6 5 F . ( 8 Portrait Super Speed ﬁlm requires about 10to 15 per cent longer development than other ﬁlm . Metal-Pyr o tank develop er :

A . Sodium bisulphite Metol Pyrogallol Potassium bromide Water to

B . Sodium sulphite , dry Water to

C . Sodium carbonate , dry 2 Water to 3 oz .

90 PHOTOGRAPHIC FACTS AND FORMULAS

l dr Sodium su phite, y

Hydrochinon 2oz .

Sodium bisulphite 5 oz .

Potassium bromide 50gr .

10oz . Sodium carbonate , dry

Cold water to 9Mgal .

1 z 6 o . B . Cold water

45 . 1 z Pyrogallol gr o . Add B to A and develop 15 to 20minutes at 6 5 ° F accord °

. 65 F . one ing to density desired For each degree below , minute should be added to the time of development chosen . °

F r 6 5 F . one o each degree above , minute should be sub tracted from the chosen development time, provided the bath is fairly fresh . Renewer : Water Metol e dr Sodium sulphit , y Hydrochinon Sodium bisulphite

2 4 . e 5 . Sodium carbonat , dry / oz oz The renewer is added from time to time to keep the developer even with the top of the tank and at the same time to freshen u p the solution . A fresh bath should, however , be mixed u or p every two three weeks at least , according to the number of h rolls developed in t e Old solution . D evelop ers — A R O L . . C The Eastman name for amidol , which see

— bromh drochi non or ADUROL . This is either y ( Schering) chlorh drochinon H uff y ( a ) , gives softer negatives than aff hydrochinon , and is less ected by temperature

s l hi ’ r 12 . u u te d 5 A Sodi m p , y g Adurol g Water 1000ccm

B . Sodium carbonate , cryst . 350g

Water 1000ccm 16 oz . 3 s 2 B Mix part A with parts .

A . Adurol Potassium metabisulphite Water u B . Ca stic soda Potassiumbromide Water u Mix in equal vol mes .

. u 2 4 A Ad rol 0g 15 gr . u 1 Sodi m sulphite , dry 80g 6 5 gr .

1000 1 z Water ccm 6 o .

. u 12 B Potassi m carbonate 5 g 2oz . 1000 Water ccm 16 oz .

For studio and instantaneous work mix in equal volumes . For time exposures and landscape work mix equal volumes

A , B , and water .

-A AMIDOL . stable amidol developer Namias) u 25 Sodi m sulphite , dry g 192gr . 5 3 Amidol g 8 Mgr . 92 PHOTO GRA PHIC FACTS AND FORMULAS

r Metol 1g g . 2 Potassium bromide g gr .

z Water 1000ccm 16 o .

The metol exerts a protective action for the amidol .

e Desalme has suggested as a preservative stannous tartrat , which is made as follows Stannous chloride 50g Tartaric acid 70g Boiling water 350ccm To this add the following solution :

55 422 . Sodium carbonate , dry g gr

Warm water 300ccm 5 oz . M Filter the mixture and make up to 1000ccm ( 16 oz . ) ake the amidol developer stock as follows

Amidol 15 g 115 gr . 2 u Su 55 4 2 . Sodi m lphite , dry g gr

u ab 100 768 . Stanno s tartrate , as ove ccm min

Water 1000ccm 16 oz . For use dilute with 2parts of water and add 3 per cent Of sodium bisulphite lye . This stannous tartrate solution may A n also be successfully used with other developing agents . other method of making the stannous tartrate solution is as follows : Stannous chloride Tartaric acid Water And add Sodium carbonate 25 g Water 250ccm

Filter and make up the bulk to 1000ccm ( 16 Glycollic and lactic acids have also been recommended as preservatives and act well :

94 PHOTOGRAPHIC FACTS AND FORMULAS

— one DIOGEN . Generally used in solution

2 . 150 2oz . 37 Sodium sulphite , dry g , gr

z 19 . 5 1o . 6 Diogen 7 g , gr

Potassium carbonate 375 g 6 oz .

Water 1000ccm 16 oz .

Mix 1part with 4 parts water .

DI N L — E O . One solution

300 4 oz . 384 . Potassium metabisulphite g , gr

Water 500ccm 8 oz . Dissolve and add

100 1oz . 318 . Edinol g , gr Then add

2 . 2 0 3 oz 249 . Caustic potash g , gr

Water 1000ccm 16 oz .

Mix 1part with 10to 20parts water . One solution with carbonate 0 5 3 4 . Sodium sulphite , dry g 8 gr in Ed ol 50g 384 gr .

S 96 . odium carbonate, dry g gr

1 z Water 1000ccm 6 O .

1 u Mix part with 5 to 10parts water . The sodi m carbonate may be replaced by potassium carbonate 15 g ( 115 when the developer acts more rapidly . Gives very clean negatives . Two solution

. Edinol 10 A g 77 gr . 1 0 00 77 . Sodium sulphite , dry g gr

1000 z Water ccm 16 o .

. u 5 B Sodi m carbonate , dry per cent solution or Potassium carbonate 5 per cent solution

Mix in equal volumes . The potash works more rapidly and gives denser negatives . DEVELOPERS

Stock solution for Hammer Plates : Sodium sulphite 125 g Edinol 10g Sodium carbonate 50g Water 1000ccm

For use mix with an equal volume of water .

-A EIKONOGEN . slow acting soft developer

u 67 5 14 . A . Sodium s lphite , dry g gr 2 Eikonogen g 18 gr . z Water 1000ccm 16 o .

u dr 75 576 . B . Sodi m carbonate , y g gr z Water 1000ccm 16 o .

Mix 3 parts A with 1part B . A more rapid acting developer can be made by replacing the soda by an equivalent weight of 2 u o 98 75 . potassi m carb nate , namely g ( gr ) One solution

u 60 46 0 . Sodi m sulphite , dry g gr

Potassium carbonate 50g 384 gr .

Eikonogen 30g 230gr .

Boiling water 1000ccm 16 oz .

K l . eeps well . For use mix with an equal vo ume Of water

— u ELON . Another name for Metol , nder which heading the u Eastman Elon formulas may be fo nd .

FERR — O Us OXALATE . The use Of this developer has been u completely abandoned , mainly beca se plates are actually slower when developed with it than with the organic devel of of opers , and also because the deposition calcium oxalate and basic iron salts in the gelatine ﬁlm . On the other hand , it has the great advantage Of giving an image composed of but u u nothing p re silver which is a ne tral colour , that is , without selective absorption , and is , therefore, valuable in certain photochemical investigations . Ferrous Oxalate is a u yellow stable powder , insol ble in water, which can be pre 96 PHOTOGRAPHIC FACTS AND FO R MUL A S pared by mixing ferrous sulphate with oxalic acid or a soluble

Oxalate , as follows Ferrous sulphate Water Dissolve and add 184 Potassium oxalate , neutral parts Water 500parts

u Mix the two sol tions , ﬁlter and wash the precipitate with

u of . fo r or ﬁve lots distilled water , and dry The result 26 should be 180parts Of ferrous Oxalate . Oxalic acid 1 parts may be used instead of the potassium salt . Ferrous oxalate u x or is sol ble in excess of neutral potassium O alate , other

r alkaline oxalate . It is obvious that the developer may be p e pared in two ways : either by dissolving the dry salt in oxalate

or solution , by adding ferrous sulphate solution to excess of

u . Potas an alkaline Oxalate , when it ~ will remain in sol tion sium oxalate is used in preference to the corresponding u ammonium and sodi m oxalates , because it is more soluble . u Conseq ently , it will dissolve more of the ferrous oxalate ,

~ which is the active agent in development . The strongest developer can be made as follows Potassium oxalate Water Boil and add u 100 l 3 5 . Ferro s oxalate, dry g / oz

Allow to cool slightly and immediately bottle . This practi u of cally forms a saturated sol tion ferrous oxalate . This not so u u method is convenient as sing separate sol tions , for which the following stock solutions are required

A . Ferrous sulphate 330g Water 1000ccm Sulphuric acid 1ccm

98 PHOTOGRAPHIC FACTS AND FORMULAS

I . Potassium oxalate Potassium citrate

Water 16 oz .

This gives cold tones .

II . Citric acid Ammonium carbonate Water

Gives warm tones .

III . Citric acid Ammonium carbonate Water

Gives extra warm tones .

333 5 . IV . Ferrous sulphate g oz

Sulphuric acid ccm 96 min .

6 z Water 1000ccm 1 o .

1 3 . For use add part of IV to parts of I , II , or III Another modiﬁcation is Citric acid 250g Magnesium carbonate 157 g 1 16 Water 000ccm oz .

of or . This can be used instead I , II , III given above a Should any calcium ox late be precipitated in the gelatine , 1 a weak hydrochloric acid bath, about per cent , will remove the precipitate .

— - GLYCIN . This is a slow working very clean developer

O f u u giving images a ne tral grey colour, and is very s itable for stand development . G lyci n paste (Hnbl) dr Sodium sulphite, y Warm water DEVELOPERS

Mix well and add gradually Potassium carbonate 500g Water to make 750ccm

O ff Carbonic acid is given and a thin cream formed , which must be well shaken and mixed with 12times its volume of water before use .

l ci n-sod G y a. G lycm S u odium s lphite , dry u Sodi m carbonate , dry Water G lyci n-p otash (Hn bl) u u 15 2 7 oz . 84 Potassi m metabis lphite g , 3 gr .

“ u 175 2 z 3 4 o . 8 . Ca stic potash g , gr 120 22 Glycin g 9 gr . 1000 16 Water ccm oz . 1 25 Mix part with parts water . — u HYDROCHINON . One sol tion u Sodi m sulphite, dry Hydrochi non

Sodium carbonate , cryst . Hot water Two solution

. 25 192 A Hydrochinon g gr . u 50 Sodi m sulphite , dry g 384 gr . W 1000 1 ater ccm 6 oz .

B . Potassium carbonate 10per cent solution 2 1 Mix parts A with part B . One solution : Hydrochinon u u Sodi m s lphite , dry Formaldehyde Water 100 PHOTOGRAPHIC FACTS AND FORMULAS

fol Especially suitable for black and white line work . The lowing also is excellent for the same purpose :

A . Hydrochinon g Potassium metabisulphite g Potassium bromide g Water 1000ccm 17 B . Caustic potash g Water 1000ccm

Mix in equal parts .

50 300 384 . to For very ﬁne grained images , add to g ( gr

z O f 16 oz . O f 5 Mo . ) ammonium chloride to every liter ( )

normal hydrochinon developer .

Rapid acting , soft working developer (Lainer) 10 A . Hydrochinon g 77 gr . 20 1 S u 54 . odi m sulphite , dry g gr 120 922 Potassium ferrocyanide g gr . 1000 Water ccm 16 oz . B 50 3 4 . Caustic potash g 8 gr . 1000 16 Water ccm oz .

s 1 For u e mix 10parts A with part B . Development will be

u u . u u completed in abo t one min te If ca stic soda is sed , the

- ferrocyanide may be reduced to one ﬁfth. For general use it is better to mix the developer with an equal volume O f water . One solution developer (Lainer) u u 75 Sodi m s lphite , dry g Hydrochinon 50g Potassium ferrocyanide 175 g Caustic potash 16 5 g Water 1000ccm use 4 f For dilute with parts o water . t For Eas man Motion Picture Film, Negative and Pos

itive.

102 PHOTOGRAPHIC FACTS AND FORMULAS

B . Potassium carbonate Water

Mix 3 parts A with 1part B .

t l -s — u M e o oda. Replace the potassi m carbonate in B by

u 50 384 . Sodi m carbonate , dry g gr

s For use mix A and B in equal volume . One solution

Metol 15 g 115 gr .

u u 60 460 . Sodi m s lphite , dry g gr

u 75 576 . Sodi m carbonate , dry g gr

Potassium bromide g gr . 1 Water 000ccm 16 oz . u For studio work mix with an eq al volume of water . For 2 landscape work mix I part with parts water .

Metol oisoni n B e rs - p g ( e ) . The hands should be dipped into a saturated solution of parafﬁne in gasoline (petrol) s ev before u ing metol . Less s ere forms of the trouble can be treated with :

Carbolic acid 21g 160gr .

Powdered calamine g 240gr .

Zinc oxide 6 3 g 480gr .

Glycerine 6 5 ccm 1oz .

2 z Lime water 50ccm 4 o . 1000 1 Rose water to ccm 6 oz . R ub the zinc and calamine into a smooth paste with the glycerine , and add the carbolic acid and the rest Of the waters . This may be applied during the day . The following should be applied at night Salicylic acid Boric acid Starch powder Zinc oxide Petrolatum DEVELOPERS

Flexible collodion should be applied to all cracks during the day . Mawl-hydr ochi non Cramer A . Metol Hydrochinon u u Sodi m s lphite , dry Water u B . Sodi m carbonate , dry

Water 25 oz .

For use mix in equal volumes .

sc tol-H r hi no A n o Me yd oc n . Metol g Hydrochinon g

S odum u 9 s lphite , dry g u 6 Sodi m carbonate , dry g Potassium bromide g Water 1000ccm 5 6 u 1 ° ° 8 . 6 5 . Time , or min tes at C ( F ) m t P l M . . E ast an Mo i on i cture Fi m N e ative (9 P osi Q , g tive . Elon (metol)

u u dr Sodi m s lphite , y Hydrochinon Potassium bromide u Sodi m carbonate , dry Citric acid Potassium metabisulphite Water

° ° u 1 Temperat re 6 5 F . ( 8 o E astman P or trai t ( f Commer cial Films — - . Metol hydro chinon tank formula . Elon (metol) u u Sodi m s lphite , dry 104 PHOTOGRAPHIC FACTS AND FORMULAS

Sodium bisulphite g

Hydrochinon g Moz . u 3 Sodi m carbonate , dry g

Potassium bromide g 95 gr . 1 Water to 000ccm 5 12oz . 1 ° 6 5 ° 10 14 Temperature 8 C . ( Development from to u u minutes . The following strengthening sol tion may be sed to keep the volume and strength up to standard :

‘ Elon (metol ) 5 g 8 5 gr . ' 2 5 u 3. 6 . Sodi m sulphite , dry g oz

Sodium bisulphite g 55 gr .

Hydrochinon g 170gr . 4 Potassium bromide g 5 gr .

1 ‘ 2 Water to 000ccm 56 oz .

TO u u u give this stock sol tion greater keeping q ality, the sodi m carbonate is not added until the strengthening solution is 1 used . For use dissolve part of sodium carbonate , dry, in 32 parts Of the above solution .

t d rd P st Pl t S an a o car d a es. Elon (metol ) g u Sodium s lphite , dry Hydrochinon g 4 Sodium carbonate , dry 7 g Potassium bromide 195 g 10 12 Water 00ccm 8 oz .

use m f For mix with an equal volu e O water .

S tanle P lates —For y . these plates the following metol hydrochinon developer is recommended Elon (metol ) g u u Sodi m s lphite , dry g Hydrochinon g u Sodi m carbonate, dry g 1 Water 000ccm 16 oz .

106 PHOTOGRAPHIC FACTS AND FORMULAS

- Eastman X R ay Film. Elon (metol ) g 120 Sodium sulphite , dry g Hydrochinon 11g 60 Sodium carbonate , dry g Potassium bromide g Water 1200ccm

The above is for tray development ; for tank, use

240 . 42 1oz . Elon (metol) g , gr

u dr 2040 68 oz . Sodium s lphite , y g

18 5 6 oz . 96 . Hydrochinon g , gr

1020 34 . Sodium carbonate , dry g oz

Potassium bromide 36 g 550gr.

Water to 22000ccm 6 gal . — Hammer P ostal P late Stock solutions

1. Metol g Hydrochinon 10g Sodium sulphite 38 g Water 1000ccm 2 . S odium carbonate 78 g Water 1000ccm 2 f 1 . For use mix equal parts o Nos . and One solution developer Metol g Hydrochinon g Sodium sulphite 12g Sodium carbonate 4 g Potassium bromide g Water 1000ccm use u For mix with an eq al volume of water . — R ex o Film Dissolve the chemicals in the following order

20 . Metol g , gr u s 1 Sodi m ulphite , dry 4 g DEVELOPERS

Hydrochinon 4 g u 21 Sodi m carbonate , dry g

Potassium bromide 1g 15 gr .

Water 1150ccm 40oz . — F O L . N This is a ﬁne , white , crystalline powder , insoluble

O f u u in water except in the presence ca stic alkali , which sho ld

u the u be very p re , so that manufact rers recommend only the

of uff O in d use Ha alkali , which may be btained either soli

The or u . form in sol tion , in connection with this developer alkaline solution is prepared as follows

Hauff alkali (caustic soda) 400ccm 2oz .

Water 1000ccm 5 oz .

For The developing solution is compounded as follows . u tray development ; time , three to ﬁve min tes

10 1 z Water 00ccm 6 o . u u n u 40 5 . Sodi m s lphite , a hydro s g gr l 2 eO o u 0 13 oz . N lye s l tion , as above ccm e l 1 N O 4 g 3 gr . In case of over- exposure 10to 20drops of 10per cent potas u s u si m bromide ol tion may be added .

15 to 20 For tank development , minutes Water 100liters u u 300 Sodi m sulphite , anhydro s g N col lye solution 1200g Ne01 200g 10 1 . 5 Potassium bromide , % sol ccm Neol is claimed to work free from fog and therefore to for u be excellent nderexposed negatives .

- A u ORTOL . molec lar compound Of two molecules Of metol with one of hydrochinon

A . Potassium metabisulphite Ortol Water 108 PHOTOGRAPHIC FACTS AND FORMULAS

dr 60 460 . B . Sodium carbonate , y g gr

90 690 . Sodium sulphite , dry g gr

Potassium bromide g gr .

Hypo g gr .

Water 1000ccm 16 oz . The same weight Of potassium carbonate may be used instead 1 1 1 of the soda . Mix part A , part B , and part water ; for a more rapid developer mix A and B in equal volumes .

S tock soluti ons for Hammer plates

1. Ortol Water u 2. Sodi m carbonate Sodium sulphite Water

For use take 1 125 cm NO . solution c 2 u 12 NO . sol tion 5 ccm Water 750ccm ' PA RA I D P HE N L - solutiorl : M O O . One Paramido henol 4 31 p hydrochloride g gr . u u 40 310 Sodi m s lphite , dry g gr . u “ 40 1 3 0 . Sodi m carbonate , dry g gr 1000 1 Water ccm 6 oz .

for use. u Ready Does not keep so well as in separate sol tions .

r mid h . Pa a o enol 20 1 A p hydrochloride g 54 gr . 1000 1 Water ccm 6 oz .

. 60 460 B Sodium sulphite , dry g gr . u 120 2 Potassi m carbonate g 9 0gr . 2000 2 Water ccm 3 oz . 1 2 Mix part A with parts B . More suitable for papers and transparencies than negatives . u One sol tion, similar to rodinal (Ermen) 625 Water ccm 11oz .

110 PHOTOGRAPHIC FACTS AND FORMULAS

e u . images , s itable for transparencies The d veloper can only

be used once , as it spoils rapidly .

- Pyr ocatechin P otash.

200 z 22 A 3 o . 4 . . Pyrocatechin g , gr 00 u 4 7 . Sodium s lphite , dry g oz 1 Water 000ccm 16 oz . 120 2 u 9 2 . B . Potassi m carbonate g gr 1000cc 1 Water m 6 oz .

For use mix in equal parts . One solution Potassium metabisulphite Potassium carbonate Water Mix in a mortar and add

350 z Pyrocatechin g 7 o . — This forms a thick cream which must be stored in well corked 1 2 f bottles . Mix part with 0parts o water .

R a i d ne-soluti on develo r Ellon p o p e ( ) . u 250 Sodi m sulphite , dry g Caustic soda 35 g Pyrocatechin 50g Water 1000ccm

1 15 of Mix part with parts water .

Two-soluti on V o el ( g ) .

. 50 A Sodium sulphite , dry g Pyrocatechin 20g Water 1000ccm

B . Caustic soda 14 g Water 1000ccm 1 1 4 Mix part A , part B with parts water .

P r ocatechi n—acetone Hanne y ( ke) . Pyrocatechin DEVELOPERS

12 Sodium sulphite , dry g Water 1000ccm

Mix just before use 12parts with 1part acetone .

— - PYROGALLOL . Pyro ammonia was once the favorite de velo er on of p , but is rarely used now account its variability, due to the evaporation of the ammonia

50 384 . A . Sodium sulphite , dry g gr Sulphuric acid 6 drops 3 drops 1 Pyrogallol 4 g gr .

Water 500ccm 8 oz . u e 10 u B . Potassi m bromid per cent sol tion 2 00 4 z . s . . o C . Ammonia, p gr ccm

1000 2 z Walter ccm 0o . 1 5 5 50 a . For use mix parts A , part B , parts C , and parts w ter Pyr o-glyceri ne ( Edwards) A . Pyrogallol Glycerine Denatured alcohol (methylated spirit) 250ccm u 15 B . Potassi m bromide g Ammonia 40cc‘m Glycerine 40ccm Water 250ccm For 1 1 B 30 use mix part A , part , and parts water .

F or reat contrasts g , suitable for black and white line work or photomechanical or process plates ( Mawson)

A . Pyrogallol 7 g Ammonium bromide 7 g Potassium metabisulphite 7 g Water 1000ccm

. i s 2 B Ammon a , p . gr . 1ccm Water 1000ccm For o e use, mix in equal v lum s . 112 PHOTOGRAPHIC FACTS AND FORMULAS

P - d yro S o a.

A dr . Sodium sulphite , y Sulphuric acid Pyrogallol Water

B . Sodium carbonate , cryst . Water

For use mix in equal volumes .

“ ” - — Th B J . P ro S oda. b e . y Specially recommended y tis ur l P h to r h B ri hJ o na of o g ap y . It keeps well and does not stain

1 z . A . Pyrogallol g o

66 4 . Sodium sulphite , dry g oz

1 . 1 Potassium metabisulphite 6 6 g oz .

1 z Hot water 000ccm 60o . u Mix the sulphite and metabis lphite dry, and add to half the for one minute water ; boil , add the pyro , then the remainder of the water, and cool .

u 2 . 00 B Sodi m carbonate, cryst . g Water 1000ccm use 1 1 2 For mix part A , part B and parts water . ‘ Harter (5: Dri i eld tand rd D elo r — ﬁ S a ev p e . Recommended for plate testing : Pyrogallol 8 parts 40 Sodium carbonate, cryst . parts

. 40 Sodium sulphite, cryst parts Water 1000parts

P r o-Causti c Valenta -A y very rapid stainless developer, acting very much like metol

u A . Sodium s lphite, dry Pyrogallol Water

114 PHOTOGRAPHIC FACTS AND FORMULAS

dium bisul hit 3 A . S o p e 9 g ‘ u u 39 Sodi m s lphite, dry g

z Hot water 1000ccm 64 o . Boil for 5 minutes and add when cool

Pyrogallol 31g 2oz .

4 oz . B . Sodium carbonate, dry g

z Water 1000ccm 64 o . Potassium metabisulphite must not be substituted for bisulphite in the above formulas .

-s l r l t Pyr o oda deve op er fo Cramer p a es. A u 5 . Sodium bis lphite g Pyrogallol 30g Water 480ccm

. 60 B Sodium sulphite , dry g Water 480ccm

. u 30 C Sodi m carbonate, dry g Water 480ccm For tray use Solution A Solution B Solution C Water For tank use Solution A 250ccm Solution B 350ccm Solution C 250ccm Water 5800ccm °

6 . 2 Temperature 5 F Time 0minutes . / Cramer s P r o-A t — u y ce one. Stock pyro sol tion Sodium bisulphite g Pyrogallol g u 182 Sodium s lphite , dry g Water 1000ccm DEVELOPERS

: o 72 24 For tray , use Stock pyro s lution ccm, acetone ccm ,

r 3 928 o 1oz . water ccm ; pyro solution , acetone drams , water

14 oz .

use : For tank, Pyro solution ccm , acetone ccm , 5 1000 or 1 oz . water ccm ; pyro solution M , acetone drams , water 58 oz

° °

u 21 30 . Temperat re C: (70 F . ) Time minutes

A s P - n co yr o S oda.

1. Potassium metabisulphite g u Sodium s lphite , dry g Pyrogallol g Water 1000ccm

2. 0 Sodium carbonate, dry 7 g 1 2 Water 000ccm 3 oz . 1 1 . 2 1 2 . a a . For use mix No , p rt, NO , part , w ter , parts

° ° of 1 6 Time development 5 minutes at 8 C . ( 5

Kodak Film P ck P r l a y o formu a. 22 Pyrogallol g gr . u S l 5 0 Sodi m u phite, dry g 6 gr . 5 Sodium carbonate , dry g 7 gr . 1000 2 Water ccm 7 oz . ° °

u 18 . 6 5 20 Temperat re C ( Develop for minutes .

F or Eastman N - C (5' A uto ra hi F l g p c i m.

A . Pyrogallol g

. . 3 Sulphuric acid , c p ccm Water 1000ccm

B . u Sodi m sulphite , dry 107 g

Sodium carbonate, dry g Water 1000ccm For 1 1 8 use mix part A , part B parts water .

F or S eed and S tanle P lates — y . For tray developer 116 PHOTOGRAPHIC FACTS A ND FORMULAS

r u A . Sodium o potassium bis lphite g Pyrogallol g Water 1000ccm 94 B . Sodium sulphite, dry g 1 Water 000ccm 16 oz . 78 C . Sodium carbonate , dry g 1 m 1 Water 000cc 6 oz .

use 1 1 1 7 . For mix part A , part B , part C , and parts water For tank developer

or 9 A . Sodium potassium bisulphite g Potassium bromide g Pyrogallol g Water 1000ccm 109 B . Sodium sulphite , dry g Water 1000ccm

du r . c d 78 C So i m arbonate , y g

Water 1000ccm 16 oz . For use mix A solution 36 ccm B solution 36 ccm C solution 36 ccm to 1000 12 Water ccm 8 oz . °

6 5 . 15 Temperature F Develop minutes . For S eed 30and G raﬂex plates use A solution 47 ccm B solution 47 ccm C solution 47 ccm Water to 1000ccm 6 5 ° 15 Temperature F . Develop minutes .

- — Pyr o A cetone for Hammer P lates Stock solutions

1. u u 129 Sodi m s lphite g 3 oz .

r 1000 23 z Wate ccm Mo .

Hydrometer test,

118 PHOTOGRAPHIC FACTS AND FORMULAS

Pyrogallol 28 g 1oz .

Oxalic acid g 8 gr .

Water 225 ccm 8 oz . 1 2 Nos. For use make the following solutions , and and equal parts :

1. Pyro solution as above Water u 2. Sodi m sulphite , dry

Sodium carbonate , dry

z Water 20o . Tank developer 2 1 u 56 oz . No . sol tion ccm

2 56 2oz . No . solution ccm f For 15 minute development add 225 ccm ( 8 oz . ) o water at

° 6 5 F .

2 z For 30minute development add 560ccm ( 0o . ) of water at ° 6 5 F .

h m t P t s F or Wratten P anc ro a i c la e .

A . Sodium or potassium bisulphite 6 g Pyrogallol 30g Water 500ccm

. u 45 B Sodi m sulphite, dry g

500 16 z Water ccm o .

. o u C S di m carbonate, dry g 500 1 Water ccm 6 oz . 1 1 1 For tray development, mix part A , part B , part C, and

7 parts water . 1 1 1 For tank development , mix part A , part B , part C, and 25 500 2 parts water , to which add for every parts , parts of 1 o per cent soluti n of potassium bromide .

The times for development for the above tray and tank de velopers are DEVELOPERS

Temperature Tray

° 36 . 12 . 50 F . min min

18 . 6 . 6 5 F . min min ° mi 9 n. 80 F . 3 min .

- l t u . F or S tandar d P a es. The stock sol tions are as above

or TO develop Standard Extra , Imperial Portrait, Thermic ,

se 1 A 1 1 7 Polychrome plates , u part , part B , part C , parts

rthon n of A water . For O o plates use the same proportions ,

‘

C but 12 . B , , parts water

for For tank developer Standard Plates , use the same form ula for as Seed plates , except for the Standard Polychrome , for which the formula is A solution ccm B solution ccm C solution ccm Water 1000ccm °

u 6 5 . 15 u Temperat re F Develop min tes .

F or E astman P ortrai t omm i l “ , C erc a , Commerci al O r tho 6

Commer ci al P anchr ti F lm — u oma c i s. The form las for the tray developer are the same as for the Wratten Panchromatic

. For u plates the tank developer the same formulas are sed, in the following proportions : A solution B solution C solution Water to

P -rW t l e e o .

A . Pyrogallol Metol Potassium metabisulphite Potassium bromide Water 120 PHOTOGRAPHIC FACTS AND FORMULAS

c . B . Sodium arbonate, cryst 1 z Water 6 o .

Mix in equal volumes .

P l t s — c F or Hammer a e . Sto k solutions

e 156 1. Sodium sulphit g

1000 z Water ccm 16 o . 2 78 . Sodium carbonate g Water 1000ccm

3. Potassium metabisulphite g Metol g Pyrogallol g Potassium bromide g Water 1000ccm For tank take 1 NO . solution 2 NO . solution

NO . 3 solution Water 112Moz 10 ° Develop minutes at 6 5 F . For tray development

4. Pyrogallol Metol Water 2 Solution No . as above u Sol tion NO . 3 as above For use take

. 4 1 NO solution 00ccm 1oz .

. 2 u 100 NO sol tion ccm 1oz .

. 3 100 NO solution ccm 1oz . 800 1200 2 Water to ccm 8 to 1 oz .

Pyr o-Metal Tank (9 Tray D evelop er for Eastman P ortrai t 6 ’ Commerci al Films .

122 PHOTOGRAPHIC FACTS AND FORMULAS — A n a . u TO Z O L . E stman developer Form la will be found under developing papers . Fixing and Clearing

- FIXING The rapidity with which plates , ﬁlms , and papers

n ﬁx is dependent o the strength of the bath , its temperature ,

i 40 45 and the degree of exhaustion or previous use . A to ‘ per cent solution of hype is the strongest bath that should be

- r used and is the most apid in action . Plain , alkaline, acid, or acid and alum baths may be used . The ﬁrst two are generally

for -out and for used printing papers , the latter plates , ﬁlm ,

e d . and d velope papers In all cases , the temperature should be 1 ° 6 ° u 8 . 5 maintained abo t normal , C ( A bath should u not be sed too long, as the more it is used, the greater its u sat ration in silver salts , therefore , the longer it will take to ﬁx properly and the greater the chance for the formation of f insoluble , transparent silver salts which are di ﬁcult to wash

out.

u The easiest , way to make a sol tion is tie the hypo _to or crystals up in a cloth piece Of Canton ﬂannel , and suspend of in a vessel hot water . This obviates any necessity for

ﬁltering the solution .

P lain baths Hypo 400g 1000 Hot water to ccm 16 oz . — A lkali ne bath Generally used for silver printing-out images Hypo 125 g u Sodi m carbonate , dry 7 g Salt 7 g

1000 1 z Water ccm 6 o . u u Sodi m s lphite, dry, may be substituted for the carbonate . 123 124 PHOTOGRAPHIC FACTS AND FORMULAS

A ci d bath. Hypo 150g Potassium metabisulphite 25 g

z Water 1000ccm 16 O . This is about the correct strength for papers ; for negative work the hypo should be increased to 400g (6 M An equally efﬁcient bath is made as follows : Hypo 400g 30 2 Citric acid g 30gr .

u 35 270 . Sodium s lphite , dry g gr

1 0 1 z Hot water to 00 ccm 6 o . Dissolve the hypo in half the water and the acid and sulphite

- one u . in fourth, mix the sol tions and make up to bulk — A cid-alum bath The follow1ng l s typical of the formulas recommended by plate and ﬁlm makers Hypo 250g Water 1000ccm Dissolve and add u 31 Sodi m sulphite, dry g 1 No . 8 86 Acetic acid , g

' Alum 31g 12 Water 3 ccm 5 oz . i Dissolve the chemicals n this order . Some paper makers u recommend the same bath , but with do ble the quantity of u s lphite and alum, for developed prints .

A ci d-chr ome lum th a ba .

u Sodi m sulphite , dry Moz . 1 Water Moz . Stir well and add 20 Glacial acetic acid ccm 154 min .

Then add to the following, after the hypo is dissolved Hypo 400g Hot water 600ccm

126 PHOTOGRAPHIC FACTS AND FORMULAS

may be tested as suggested above . About three days is sufﬁ

u of . cient , as a r le , to throw down the whole the silver One of the best methods of regaining the silver is to

of procure a sheet brass , not too thin, and place in the barrel or so jar at an angle , that both sides are presented to the 4 . u 8 u liquid After abo t ho rs , the whole of the silver will be precipitated in the metallic form on the brass and can usually

or be removed by bending a corner sharply two three times , ff when the silver will spring o . The brass can then be put back into the vessel and allowed to remain another 24 or 48

of i lver will hours , when practically the last trace s be ex ffi e ma tracted . This thin coat is di cult to remov and y be left e on until the next batch of residues is to be treat d . u Paper and print clippings and waste prints sho ld be burnt , and the ashes collected and mixed with the silver sulphide from the old ﬁxing baths . — P lati num R esi dues The developer and acid ﬁxing baths from the platinotype process should be collected and prefer - ably boiled down to about one fourth the volume . Then some u u saturated sol tion of ferrous s lphate should be added, the

u ut. mixt re boiled for an hour, and the platinum ﬁltered o

l ths — G o d ba . Old gold toning baths may be treated in the same way as the platinum solutions , after acidulating with hydrochloric acid .

It does not pay a photographer to refine his ownresidues . u u All the silver resid es sho ld be mixed together , and the gold u and platin m kept separate, and sent to a refiner , who will allow market value of the metals minus a small charge for refining . —I t HYPO ELIMINATORS . is an open question whether the use of chemicals to destroy the last traces of hyposulphite of soda and the hyposulphites Of silver is j ustifiable if perma n nency of results be the aim . Their action is probably i most FIXING AND CLEARING

cases to convert these salts into tetrathionates ; and, as a nega tive or print can be practically freed from hypo in half an

use hour by proper washing , their is only allowable in cases of great pressure Of time or shortage of fresh water . The fol

e lowing have been recomm nded .

hl ri t H r t Z i nc hyp oc o e ( a ) .

Chloride Of lime 10g 77 gr .

W 500 8 oz ater ccm . R ub the lime into a cream wi th a little water ; then add the O f : rest the water, and add to 2 5 Zinc sulphate 0g 14 gr .

z Water 500ccm 8 o . Shake well and ﬁlter or allow to stand until the precipitate

u u u . For u s bsides , and decant the s pernatant liq id use dil te with 9 parts of water ; i mmerse the negatives or prints for h u 3 u . abo t min tes , and t en brieﬂy wash and dry Sodium or potassium hypochlorites may be made and used in the same

of way , employing the alkaline carbonates instead the zinc salt .

Potassiums erman anate l u p g , in per cent sol tion , may also be u to sed, enough being added to water give a pink tinge , and the negatives bathed in the solution until the colour is no u longer discharged , repeated baths being used . Potassi m percarbonate in 1per cent solution has also been sold com m r i ll u e c a y as Hypax or Hypono . Sodi m perborate can be in or used the same way . Potassium ammonium persulphate 1 u in per cent sol tion , made alkaline with ammonia , may also Thi x . o dant A nthi n be used The former has been sold as y , o , 5 u etc . A per cent sol tion Of hydrogen peroxide may also be used . B A TH — HARDENING s. Sometimes used for negatives and prints in hot weather . Thorough washing so as to eliminate all hypo must precede these baths : 128 PHOTOGRAPHIC FACTS AND FORMULAS

10 A . Alum per cent solution, or

2 or B . Chrome alum per cent solution , 10 C . Formaldehyde per cent solution

With the last bath, freedom from hypo is not so essential .

of Practically , the use these baths has been rendered obsolete u by the use of the chrome al m ﬁxing baths . T — CLEARING B A H s. These baths are not much used at the present day when the use of sulphite and the newer developers the elatine prevents the staining Of g , which was so prone to of occur in the early days the gelatine plate, when plain

- pyrogallol developer was used . The well washed negatives may be immersed in 1 Potassium permanganate g 7 .7 gr . 1 1 Water 000ccm 6 oz . for 5 1 minutes , then rinsed in water and immersed in a per O f or bi sul cent solution potassium metabisulphite , sodium hite : p , or in Alum Citric acid Water

Alum Citric acid Ferrous sulphate 1 Water 6 oz .

Chrome alum Sodium bisulphite Water

Thiocarbamide Citric acid Water

I ntensiﬁcati on — TH E MERCURY INTENSIFIER . This is probably the most

rs generally used of all i ntensiﬁe . The silver image is treated e with mercuric chloride or bromide until bleached , th n

. washed , and blackened by various reagents The mercuric halide solution is sensitive to light and should be kept in the u but dark . It is extremely poisono s when taken internally,

o the absorption by the skin , even in the case fcuts and abra o h . sions , is practically armless Make up the foll wing mer cury solution

Mercuric chloride 20g 154 gr .

Salt 20g 154 gr .

or Ammonium chloride 20g 154 gr . 2 or Hydrochloric acid 3 ccm 3 min . 4 or Potassium bromide 20g 15 gr .

z Water 1000ccm 16 o . The purpose Of these additions is to increase the solubility of u e the merc ry salt , and the bromide gives gr ater increase u of density than the others . The plate to be intensiﬁed sho ld

‘ be perfectly free from hypo , and if dry, soaked in water for 10 u u min tes , and then immersed in the mercury sol tion until the image seen from the back is white ; on no account should the action be stopped before this point is reached . It should then be well washed in water acidulated with hydrochloric u 5 u u acid , abo t min tes soaking in six s ccessive baths u u may be sed ; then , after washing in r nning water for 10 u min tes , it may be blackened . The acid bath removes the u merc ry salt , which is tenaciously held by the gelatine, and might otherwise give rise to stains . This acid treatment may be avoided by the use of the following bleach : 130 INTENSIFICATION

Mercuric chloride 20g 154 gr .

192 . 2oz . Ammonium chloride 150g , gr

Hydrochloric acid 10g 77 gr .

z Water 1000ccm 16 o . The large proportion of the ammonium chloride is said to facilitate the removal O fthe mercury salt . The blackening may be effected with one of the following reagents u 1 of ron s ha e A . Ferro s oxalate developer , using part i ulp t solution to 6 of oxalate ;

r, e a en s w h sul B . Amidol developer . Othe dev loping g t it phite may be used ; u u 5 O f u C . Sodi m s lphite , per cent solution the anhydro s or 10per cent solution of the hydrated salt ;

10 u of am D . Ammonia , per cent sol tion the strongest monia water . The bromide bleach does not give such satis factory results with this as the chloride ;

- — kh Monc oven . E . Silver potassio cyanide ( ) This is pre pared from 2 1 ﬁlt 0 54 . 1. S ilver rate g gr

0 z Water 5 0ccm 8 o . 20 154 . II . Potassium cyanide g gr 500 Water ccm 8 oz . Add three-fourths of I to II and shake thoroughly ; a thick curd white y precipitate will be thrown down, which dissolves on u 18 shaking . If a perfectly clear sol tion Obtained, add u more I ntil , after shaking and allowing to stand with occa sional 10 u agitation for min tes , there is a permanent white u u precipitate . The q antity Of silver req ired depends on the of strength the cyanide , which varies considerably ; in any u case , a permanent deposit m st be formed , even by adding more silver than above stated . This method of mixing is e t e b tter than adding the cyanide to h silver . If the negatives 132 PHOTOGRAPHIC FACTS AND FORMULAS

are allowed to remain too long in this solution , they are reduced ; u - - F . Merc ric iodo cyanide (Eder)

Potassium cyanide 5 g 38 gr .

Potassium iodide g 19 gr .

r Mercuric chloride g 19 g .

Water 1000ccm 16 oz . u The bleached image ﬁrst t rns yellowish , then dark brown ,

e and , if the plate be removed at this stage , it will gen rally be too dense for practical purposes ; if the action is allowed to

u brotvn e contin e longer , the image turns a lighter and becom s more transparent ; ’ chli e s or sul hantimoniate G . S pp salt sodium p i ’ 2 12 S chl ppe s salt 5 g 9 gr . 1 Ammonia 0ccm 77 min .

Water 1000ccm 16 oz . u use e - Make j st before and ﬁlter . Giv s a brownish red image which is too dense for ordinary work . This is useful for restoring negatives intensiﬁed with mercury, which have faded with course Of time ; 10 H . Sodium sulphide g 77 gr .

1000 z Water ccm 16 o . Usually gives too much intensiﬁcation for ordinary work

I . Formalin with caustic soda has been recommended for but blackening the bleached images , presents no advantage ;

’ J . Stannous tartrate ( Helain) Stannous chloride 20g Tartaric acid 20g Water 1000ccm This has also no special features to recommend it

assuml n Practically , it may be said that , g the original den sit of 1 y the negative to be , the intensiﬁcation given by A , B , 2 e C , E will be , by D bout Repeated bleaching with

134 PHOTOGRAPHIC FACTS AND FORMULAS

A nilinfabrikation . Germany by the Aktiengesellschaft f . A similarly acting solution can be made as follows Mercuric chloride 187 g Hot water 750ccm

2 2 u u 225 3 oz . 6 . Ammoni m s lphocyanide g , gr

Water 250ccm 4 oz .

For use dilute 1part with 10parts O f water . The negative u but too t rns black at once ; , if left long , the intensiﬁcation is u reduced . The images are not stable nless a developer is applied .

TH E E der Welborne P i er and CHROMIUM INTENSIFIER ( , p — Carnegi e) This method of intensiﬁcation has deservedly received considerable attention , being less liable to stain and u much less poisono s than many others . The negatives need not u i be absol tely free from hypo , as the bleach ng bath u u Oxidises this , tho gh , if m ch hypo be present , it may be

e necessary to apply the bleaching bath twic . Two stock solutions are required : u I . Potassi m bichromate Water

II . Hydrochloric acid , pure W' ater The bleaching baths are B C Stock solution I 32 64 64 parts Stock solution II 3 16 64 parts Water 128 80 32parts Immerse the negative in the solution until the image on the u glass side appears bleached , then wash ntil the yellow stain is removed , and develop with amidol in white light . Other us but developers may be ed , without bromide , the image u u ffu req ires expos re to di sed daylight , and they are less INTENSIFICATION

intensiﬁ satisfactory . A gives the strongest and C the least cation . The process may be repeated as Often as required . As a variant the following may be used

Chromic acid g gr .

Salt g gr .

Water 1000ccm 16 oz .

The procedure described above should be followed . The acid

10 cent and and salt may be kept in stock solutions , say per f mixed as required .

chlorochromate ma A convenient form Of a dry salt , the , y be prepared as follows (Lumiere S eyewetz )

A mmonium bichromate 82g 126 5 gr . a Hydrochloric cid ,

12 z . 1 . s . 364 o 60 p . gr ccm , min

Place the acid in an evaporating dish, add the ammonium u u 100 salt , and evaporate ntil dry . The res lt will be g

14 hl r hrom te m 5 3 . c o oc a a ( gr ) Of ammonium , which y be kept in a dry state or in a 10per cent solution by dissolving in

10 0 2 z 0 3 . 21 . o . 30 0 ccm ( ) distilled water Of this , ccm ( min )

u bea diluted 1 0 1 z sho ld to 00 ccm 6 o . ) to form a convenient u bleacher . The eq ivalent weights Of the potassium salt may

1 r 4 00 o 15 3 . be used , that is , g gr TH E - — COPPER SILVER INTENSIFIER . This intensiﬁer is par ticularl u for or y val able black and white line negatives , and

s give great intensiﬁcation . The bleaching solution is pre pared from

. u u 115 2 I C pric s lphate g oz . 500 cm Hot water c 8 oz .

. u 115 2 II Potassi m bromide g oz . Hot water 500ccm 8 oz

Mix and allow to cool . The negative should be bleached in 2 u e this , washed no longer than min t s , and blackened in S ilver nitrate 10per cent solution 136 PHOTOGRAPHIC FACTS AND FORMULAS

still reater densit If g , y be required , the negative should be well

' washed after bleaching and redeveloped with any ordinary

r developer , the silver treatment being omitted . Or , afte e washing , the negativ may be blackened with a per cent solution Of sodium sulphide .

on As an improvement the silver nitrate , which may cause

s . stain , Namias recommends silver oxalate To prepare this , take : Silver nitrate Water

Dissolve , and add

6 46 . Potassium oxalate , neutral g gr 0 1 Water 5 ccm oz .

Allow the silver oxalate to settle down , decant the water, and

1 z . add the precipitate to 000ccm ( 16 o ) water . Shake the solution every time before applying to the bleached negative .

The process is applicable to papers as well as plates , and it is advisable to subsequently immerse in a 10per cent solution of hypo for a few minutes and wash well .

TH E -TI N - I n COPPER INTENSIFIER . this the ﬁnal image of consists Of a mixture tin and silver compounds , and the intensiﬁcation is due to a great extent to the non-actinic colour of the deposit , which is a warm brown . Bleach the negative in Cupric chloride 30g Hydrochloric acid 3 ccm Water 1000ccm Wash thoroughly and immerse I n the following Stannous chloride 40g Water 400ccm To which is added Caustic soda Water

138 PHOTOGRAPHIC FACTS AND FORMULAS

erric anide 40 307 . I1. Potassium f y g gr

Potassium oxalate 10g 77 gr .

Glacial acetic acid 40ccm 300min .

Water 1000ccm 16 oz . oh If mixed in equal volumes , a reddish brown image is tained ; 1part I and 2parts II give a reddish image ; 5 parts I u o and 1part II give a brown . The colo r is also dependent t some extent on the duration Of the action of each bath . The negatives should be washed in a 2per cent solution of citric

1 or . acid , or per cent oxalic glacial acetic acid If plain water of 5 are be used , about ﬁve changes at intervals minutes enough . Prolonged washing in running water will com

letel . p y remove the intensification , generally first in patches — TH E LEAD INTENSIFIER This gives very great intensifi cation and is only suitable for black and white line work 3 Lead nitrate 46 g 35 gr . 3 Potassium ferricyanide 70g 5 7 gr . 2 1 Glacial acetic acid 0ccm 54 min .

z Water 1000ccm 16 o .

This will keep in the dark . The lead salts are rather tena ciously retained by the gelatine ; it is advisable to immerse the 5 u of for 5 negatives in a per cent sol tion nitric acid minutes , u and then wash . If the negative be s bsequently developed , B rather less intensiﬁcation is given . y applying a 10 per

u of C a cent sol tion hromic cid to the bleached negative, an

non- orange image is obtained , which is very actinic , and the 2 lines remain clear . Treatment with a per cent sodium u u s lphide sol tion gives the greatest increase .

L umi r — n QUINONE INTENSIFIER ( e e) . This has ot come

use into general , and the intensiﬁcation is practically depen dent on a change of colour Of the image into a more non actinic one ; but some compound O f silver and bromine is present . INTENS IFICATION

u A . Q inone Potassium bromide Water Or

S odium uinone u 10 77 . B . q s lphonate g gr

Potassium bromide 25 g 192gr .

Water 1000ccm 16 oz .

The negative after treatment may look muddy . It should be , n 10 " briefly ri sed with water , and immersed in a per cent u solution Of ammonia . The colo r given by A is reddish o brown , by B yellowish br wn . Ammonia , with short action , gives great intensification , bothimages becoming dark brown ; ’ e 10~ u u aft r min tes action , the original colo rs are again formed with less intensification . The carbonates Of sodium and

u u l vm i n potassi m also t rn the images brown , g g also great iﬁ tens cation . Hypo reduces the image without altering the u of e colo r plates tr ated with A , but with B the ﬁnal colour - u r is a reddish yellow . S lphites o bisulphites convert the

e - of image Of A into a gr enish brown ; in the case B , into a

. u on dark brown An amidol developer acts like s lphite A ,

‘ —“ but e - i gives y llowish black images W th B . - nn BROMO IODIDE OF COPPER (J e ey) . u s C pric ulphate 37 . 5 g Water 500ccm

When dissolved , add m 9 9 Potassiu iodide g 6 gr . u 23 1 Potassi m bromide g 77 gr . 500 Water ccm 8 oz .

O f A slight precipitate copper iodide is formed , which should be ﬁltered out. The negative should be immersed in the solu

" u u tion ntil bleached to a bright yellow colo r , which takes 5 15 from to minutes , and then well washed and immersed in a saturated solution of sodium sulphite to which a few 140 PHOTOGRAPHIC FACTS AND FO R MUL A S

w grains O f silver nitrate have been added . This gives a bro n

- ish black image . By applying a hydrochinon developer, a i reddish image is obtained, and rod nal gives a brown . After or intensiﬁcation , the negative print should be well washed u r in water . Both bleaching and redevelopment sho ld be ca ried out in bright daylight . This is very rarely used and presents no particular advantages . DYE - a INTENSIFICATION . Partially ble ch the images in u Potassi m ferricyanide g gr .

Ammonium bichromate g gr .

Glacial acetic acid ccm 64 min . 1 Water 000ccm 16 oz . e Then wash, and immers in

Victoria green g gr .

Safranin g gr . ccm Glacial acetic acid 64 min . 1000ccm Water 16 oz . 30to 120 5 Dye for seconds and wash for minutes .

142 PHOTOGRAPHIC FACTS AND FORMULAS

Chloride of lime 6 g add to Make into a paste with a little water, and

34 . Sodium carbonate, dry g gr 2 4 z Water 50ccm o .

Shake thoroughly , filter, and wash the filter with successive portions of water to make the total bulk of the filtrate 1000ccm ( 16 then add

Chrome alum 4 g 30gr . Immerse the negative and rock the dish for a few minutes then gently pass a pad of absorbent cotton , well wetted , over the surface .

BICHROMATE . 2 Potassium bichromate 0g 154 gr . m Sulphuric acid 40cc 308 min .

Water 1000ccm 16 oz .

Dissolvethe bichromate , and add the acid . This has nothing particular to recommend it , and requires rather long washing to remove the yellow stain from the negative . i PERMANGANATE (N om as) . u Potassi m permanganate g 4 gr . u 10 Sulph ric acid ccm 77 min . 1 1 Water 000ccm 6 oz . or It is preferable to mix this just before use, stock solutions can be prepared by dissolving the permanganate in half the water , and the acid in the other half the stock permanganate u i sol t on must be kept in the dark . This reducer acts evenly

u for and can be sed prints as well as negatives . Should any brown stains appear , they may be removed by immersing the plates or prints in u Sodium s lphite, dry Oxalic acid Water

Wash well after this bath . REDUCERS

-A n IODIDE AND HY PO (L ai ner) . extremely slow acting of reducer , which is useful in the case negatives generally f ogged

Potassium iodide 10g 77 gr .

z Hypo 250g 4 o .

Water 1000ccm 16 oz . The negative should be immersed in this solution for from

1 r i u 8 to 10hours , o unt l the desired red ction is attained , then

ma wa . well washed . Prints y also be reduced in the same y CERIC SULPHATE (L umi er e) Sulphuric acid Water

Ceric sulphate

Stir until dissolved, then add 10 1 Water to 00ccm 6 oz . f u For use mix 1part with 9 parts O water . This red ces the contrasts , and the negatives should be well soaked in water

u F r prior to immersion in the sol tion . o overexposed dense mtx u u u negatives , the above stock sol tion with an eq al vol me

u ex er of water , and Immerse the negative dry ; care m st be

cised . , as the action is very rapid There is no liability to stain ,

u u for and the sol tion may be sed still more dilute prints .

- - I O Do . u CYANIDE Extremely poisono s , but clean acting 6 46 Iodine g gr . u 18 1 Potassi m iodide g 38 gr . Water 30ccm Rub the iodine and the iodide together in a mortar or graduate

rod u with a glass , add the water , and stir ntil complete solu tl on 18 obtained ; then add : Water Potassium cyanide 144 PHOTOGRAPHIC FACTS AND FORMULAS

This forms an excellent non-staining reducer for developed prints if diluted with 10times its volume of water — MERCURY AND CYANIDE ( Eder) A n extremely poisonous but non-staining reducer Mercuric chloride Water

Dissolve , and add 1 Potassium iodide g 9 gr . u Red merc ric iodide is precipitated , \which is dissolved by the addition of 5 r Potassium iodide g 38 g . u This acts rapidly . It is s itable for developed prints if

diluted with 10parts of water . A variant Of this is to replace u f u the iodide with a like q antity o sodi m carbonate crystals . i ller CUPRIC CHLORIDE ( S p ) .

A . Alum Cupric chloride Salt Hot water

Dissolve , and ﬁlter when cold . u B . Saturated sol tion of salt . For use u mix in equal vol mes . When the negative is nearly uf u s ﬁciently red ced , wash . This cannot be recommended, as u u u the red cing action contin es too m ch during the washing . A variation of the above ( Fourti er ) has been suggested u c 5 3 C pri sulphate g 8 gr . 100 Water ccm 2oz . u u Dissolve , and add sol tion Of potassi m carbonate until no u f rther precipitate is formed . Collect the precipitate on a

of ﬁlter, wash with several changes water , and then dissolve in Hydrochloric acid Water

146 PHOTOGRAPHIC FACTS AND FORMULAS

the silver into silver ferrocyanide , which dissolves in the hypo . Homolka suggested as a stable reducer

Potassium f erricyanide 50g 384 gr .

- z 224 . 200 3 o . Sodium amido acetate g , gr

Water 1000ccm 16 oz . 5 10 For use dilute with from to parts Of water , and, when u the desired red ction is attained , immerse the negative in an acid ﬁxing bath . ’ Another modiﬁcation of Farmer s reducer is the following of (Haddon) , which has the advantage keeping well 1 Potassium ferri cyanide 0g 77 gr . 1 Ammonium sulphocyanide 20g 54 gr .

1 1 z Water 000ccm 6 o . u The negative sho ld be soaked in water before immersion . — AM MONIUM PERSULPHATE . The particular value of this reducer is that it attacks the densest parts Of a negative more u u but than the shadows , th s considerably red cing contrasts ; its action is much complicated by intentional or accidental u additions , s ch as acid , chlorides , and iron salts , which may occur by keeping the solution or the use of ordinary tap 5 water . A per cent solution in distilled water should be

to 3 4 u r 1 made , and allowed stand for to ho rs , o 5 ccm

105 . of 10 u ( min ) per cent solution of sulph ric acid, or 1 f ccm (8 min . ) o 5 per cent solution of ammonia iron alum added per liter ( 16 The following solution has been

for advised ( Bennett) , and can be kept a considerable time in stock 125 Ammonium persulphate g 2oz . 10 Sodium sulphite , dry g 77 gr .

u c 10 S lphuric a id g 77 min . 1000 1 Water ccm 6 oz .

u 4 8 of For use dil te with from to parts water, according to REDUCERS

s 5 the rapidity of action desired . Immer ion in a per cent solution Of sodium sulphite has been recommended as a stop

but . bath, this is liable to cause red stains The best plan is to wash rapidly . The following mixture ( Puddy) acts on the shadows be fore the high-lights

Ammonium p er sulphate 50g 384 gr . ’ A mmonium sulphocyanide 25 g 192gr .

Water 1000ccm 16 oz . The following solution acts on all densities nearly alike

u . A . Potassi m permanganate g gr

u u 10 solutiO n 15 115 . S lph ric acid , % ccm min

Water 1000ccm 16 oz . 2 12 u 5 9 . B . Ammoni m persulphate g gr

Water 1000ccm 16 oz . 1 For use mix part A with 3 parts B . The separate solutions m but u . keep well , should not be mixed until req ired The ti e u 1 3 Of red ction varies from to minutes , and greater control is Obtained by diluting the mixture with an equal volume of s water . As oon as the desired reduction is reached , immerse the negative in a 1per cent solution Of potassium metabisul hi te 5 . p for minutes , and wash

L umi er e — QUINONE REDUCER ( ) . This acts like ammonium

- persulphate , that is , reduces the high lights more than the shadows 5 Quinone g 38 gr . u u 20 154 S lph ric acid ccm min . 1000 1 Water ccm 6 oz . u As soon as the desired red ction is reached , the plate should

2 u u h be immersed in a per cent sol tion Of sodium bis lp ite, washed , and dried . — HARMONISING HARSH NEGATIVES . This method of re ducing the over -dense parts of negatives has been replaced by 148 PHOTOGRAPHIC FACTS AND FORMULAS

Th u . e the use of the pers lphate , but it is still valuable nega tive should be immersed in

Hydrochloric acid 25 ccm 192ml n .

Potassium bichromate 8 g 6 1gr .

Alum 40g 307 gr . 1 1 Water 000ccm 6 oz . u u Leave ntil bleached thro gh to the glass , then thoroughly wash until all traces of yellow disappear . It should then be developed with a slow acting developer, such as hydrochinon , u - u u u abo t one fo rth the s al strength, and development con tinued u of ntil , on examination the negative from the glass side , it is seen that the shadows and half tones are fully developed, while the high lights still show white silver chlo ride . The negatives should then be ﬁxed and washed . This u h l method is also usef l for a ated negatives. The following modiﬁed bleacher may be used

Chromic acid 5 g 38 gr . u 1 Potassi m bromide 0g 77 gr .

100 1 z Water 0ccm 6 o . u or The method of sing is as above , , to hasten the removal Of of the yellow stain , apply a per cent solution potassium u r u u metabis lphite o sodi m bis lphite .

— e MECHANICAL REDUCTION . This is a method but littl

s u ex ert hands. practiced and rather dangero s , except in p It

s consi ts in local attrition of the gelatine , preferably with a chamois leather moistened with denatured alcohol (methylated spirit) . Another abrasive has also been suggested ( Baskett) ,

u f u of il and consists of a mixt re o eq al parts terebene , olive O ,

s u and metal poli h . This is also sed with chamois leather , and

u use acts more q ickly than the alcohol . After its , the negative should be rubbed two or three times with benzol to remove the grease . Some commercial metal polishes may be used u u witho t any admixt re , but , after shaking well , should be

V arnishes

H — V A R N I S Es. The increasing use of bromide and develop f -out ment papers instead o printing papers , and , in a minor of degree, the general adoption films by amateur workers , has rendered less Obligatory the use of negative varnishes for the protection of the gelatine surface . In the case of celluloid u films , it is Obvio s that the solvents used in the varnishes must e not attack the celluloid ; ther fore , the aqueous varnishes are u not preferred , tho gh they do give so much protection as the “ ” m h t” others . Varnishes ay be classified as o and cold varnishes , the former being applied to a heated negative , while the latter may be applied to the cold negative . In the

ﬁrst case , the negatives should be warmed in front of a ﬁre or over a gas or spirit burner until the glass is as hot as the r back Of the hand can comfotably bear . H T O VARNISHES .

Orange shellac 75 g 576 gr . ‘ 5 Gum sandarac 7 g 576 gr .

96 1000 1 z Alcohol , % ccm 6 o . 2 1 Castor Oil ccm 5 min . Allow the mixture to stand with frequent shaking until the

I S resins have dissolved ; then filter . There frequently some u tro ble in clarifying varnishes , as the fine insoluble particles u will not easily filter o t. The remedy is to add about 2per ei u cent by w ght of some inert powder, s ch as finely powdered

u or l p mice stone tripoli , shake well , and ﬁ ter . Another formula Orange shellac G um elemi Alcohol VARN IS HES

1 Gum mastic 8 g 6 gr .

250ccm 5 oz . Ether .

z Gasoline 750ccm 11O .

Not advisable, as the vapours are very explosive when mixed

: with air . Another G um sandarac Camphor Venice turpentine Oil Of lavender Alcohol

Orange shellac 200g 1536 gr .

G um sandarac 50g 384 gr .

‘ Gum mastic 5 g 38 gr .

G um dammar 5 g 38 gr . m Castor Oil 5 cc 38 min .

Alcohol 1000ccm 16 oz . — 0 COLD VARNISHES . Aque us shellac varnish (Water house) 0 14 Orange shellac 8 g 6 gr . 20 Borax g 154 gr . 20 u . 154 . Sodi m carbonate , cryst g gr

Glycerine 5 ccm 38 gr .

1000 1 z Water ccm 6 o .

Dissolve the borax and soda in half the water, add the u shellac , and boil ntil dissolved ; then add the glycerine and u eno gh water to make the total bulk, and ﬁlter when cold . Or Bleached shellac B orax u Sodi m carbonate , cryst . 152 PHOTOGRAPHIC FACTS AND FORMULAS

Glycerine 3ccm Water 1000ccm : The method Of making is as above . Or Bleached shellac 150g Alcohol 300ccm

Dissolve , and add z Ammonia 225 ccm 4 o .

Glycerine 7 ccm 54 min .

Warm water 1000ccm 16 oz .

' u for The above are particularly s itable ﬁlms . When using bleached shellac , it is essential to procure freshly bleached lac , n or that which has bee kept under water , as , when exposed to

. Dichl r the air , this loses its solubility to a great extent o

e o hydrin is an exc llent s lvent for bleached shellac, when warmed, but this varnish cannot be used for ﬁlms , as it dis solves the celluloid . A h excellent varnish (Valenta) is made as follows r 75 Gum damma g 576 gr . 60 or Gum mastic g 460gr . c 1000 Carbon tetra hloride ccm 16 oz .

If the mastic is used , it is necessary to heat to obtain perfect

. B solution oth varnishes give hard surfaces, which take retouching well . E i hl p c orhydrin and dichlorhydrin have also been recom

for mended (Valenta) as solvents varnishes , but have found use little . The following are suitable formulas Copal 20g

Epichlorhydrin 70ccm

Digest on a water bath until dissolved, and add Alcohol 770 ccm 11oz . Epichlorhydrin 160 ccm 4 oz .

. a Then ﬁlter This gives a very hard ﬁlm th t dries quickly,

154 PHOTOGRAPHIC FACTS AND FORMULAS

u of dissolve , the sol tion sinks to the bottom the bottle and fresh solvent takes its place . This also frequently obviates the necessity of ﬁltering . Another plan is to mix the resins

or with coarse glass grains beads , about half the size Of a grain of wheat . N E A TI V E - o neces DEVA R N I S H I G N G s. S metimes it becomes sary to remove the varnish from negatives and this usually can be accomplished by soaking in strong alcohol , and then using gentle friction with a pad of absorbent cotton . It is preferable to use only j ust enough alcohol to cover the surface successwe Of the negative , and to apply two or three alcohol 2 baths . A more energetic solvent is a per cent solution of u or ca stic potash , or soda , ammonia in alcohol , which may be u sed for the ﬁrst bath , and then followed by clean alcohol . — PRINT VARNISH . Sometimes used for brightening up matt surface papers G um sandarac Benzol Acetone 90 Alcohol , %

G um 60 dammar g 1oz .

500ccm z Ether 8 o .

500 z Benzol ccm 8 O . These may either be applied with a brush locally to the o shadows or the prints ﬂ ated face downwards on the varnish .

BLACK VARNISH . Shellac 200g Denatured alcohol 1000ccm 1 Aniline black, spirit soluble 5 g ALCOHOLIC COLD VARNISHES Valenta G um sandarac 180g 96 1 Alcohol , % 000ccm VARNISHES

Oil of lavender 10ccm 77 min .

Gum sandarac Benzol Acetone 96 Alcohol , %

CELLULOID OR ZAPON V ARNISH .

‘ Pyroxyline or celluloid scraps 20g 154 gr . Amyl acetate 1000ccm 16 oz . Allowto stand for some time with frequent shaking until or solution take place , and then allow to stand three four days

to . to settle . This takes a very long time dry Or

P yroxyline or celluloid scraps 12g 92gr .

z Amyl acetate 400ccm 6 o .

Benzol 400ccm 6 oz .

Acetone 200ccm 3 oz . 5 u This is also suitable for prints . A per cent sol tion of pyroxyline in equal volumes Of amyl acetate and alcohol can

u to be sed protect metal work , can be applied either with a

or u brush spray , and is q ite invisible ; sometimes butyl acetate is used instead of the amyl compound . Greater adhesion is obtained with the following

37 . 5 2 Pyroxyline g 88 gr . 2 Shellac g 88 gr . 00 Amyl acetate 5 ccm 8 oz .

250 z Benzol ccm 4 o . 250 4 Methyl alcohol ccm oz . The ﬁlm thus obtained is not so lasting as the plain pyroxyline varnish . Black varnish may be made by incorporating lamp

or r black , when the varnish will be more less matt, o by the

of - use spirit soluble nigrosine , when glossy surfaces will be

Obtained . Any coloured varnish may be made by dissolving oil- u sol ble aniline dyes in the solvents . 156 PHOTOGRAPHIC FACTS AND FORMULAS — CRYSTAL VARNISHES . These are sometimes used for lan tern slides and transparencies G um dammar Benzol

Fused amber Chloroform

Fused amber 200g Gum sandarac 300g

G um elemi 50g 384 gr . 1 Alcohol 1000ccm 6 oz .

Camphor 6 g 46 gr . — RETOUCHING VARNISHES . Since the gelatine ﬁlm , as well u as many of the varnishes , will not take kindly to the reto ch u u ing pencil , it is c stomary to apply locally a reto ching varnish or medium which leaves a surface with a slight tooth .

u u or These sho ld be applied in very small q antities , a drop two u i u ﬁ , gently r bbed w th a circ lar motion with the nger tip u over the part to be reto ched, and then allowed to dry um 2 G dammar 0g 96 gr .

u 100 1 . T rpentine , reﬁned ccm oz

Powdered resin

Turpentine , reﬁned

G um dammar u T rpentine , reﬁned Benzol Oil of lavender

G um dammar Venice turpentine

158 PHOTOGRAPHIC FACTS AND FO R MUL A S

2 . Water 37 . 5 ccm 88 min 2 Hydroﬂuoric acid 37 . 5 ccm 88 min . z Denatured alcohol to 1000ccm 16 o . of Spread the solution with a brush or spill paper, and allow to soak for about 5 minutes . Then try and strip the narrow cut edges ; if these can be easily removed, the work may be proceeded with ; if not , the plate should be left a little longer . O ff When the ﬁlm is loose , as shown by the above test , pour

not to . the liquid carefully, taking care let the ﬁlm slip Pour f u u for 2or on some o the above sol tion witho t the acid, leave

3 O ff. minutes , and then drain this Gently place a piece of or u smooth waxed paper thin cell loid over the negative , and u lightly sq eegee into contact ; on lifting the paper , the film to will be removed with it , and can be transferred another support . Great care must be taken in the use of the above solution, as it attacks the fingers and all glass . It is better either to make up the stock solution without the hydrofluoric

' u acid and add this j st before use , or to omit the acid alto gether, and use instead Sodium ﬂuoride or Potassium ﬂuoride Add just before use : 75 5 Nitric acid ccm 76 min .

If the gelatine skin is to be kept as a ﬁlm , it should ﬁrst be

a coated rather thickly with enamel collodion , m de as follows 30 2 Pyroxyline g 30gr .

500ccm z Alcohol 8 o .

500 z Ether ccm 8 o . oil 20 15 Castor ccm 4 min . u Allow to dry thoro ghly before applying the stripping ﬂuid .

use of In order to obviate the the ﬂuorides , the following may also be used with success : Potassium carbonate VARNISHES

Formaldehyde Glycerine

Denatured alcohol (meth . spirit) 300ccm

1 z Water to 1000ccm 6 o . u The carbonate sho ld be dissolved in the glycerine , and the water and other ingredients added . This solution is rather slower than the hydroﬂuoric acid ; it can be used in a dish 2 h and allowed to act for 0 to 30 minutes . When t e ﬁlm

to u O ff u proves be loosened , po r the sol tion , replace with a u 4 of 6 mixt re Of parts alcohol and parts water , and leave

5 to 10 u out for min tes ; then lift the plate , drain , and strip he t ﬁlm as outlined above . Silver Printing Processes

- - — va COLLODIO CHLORIDE PRINTING OUT EMULSION . The ri ous formulas have been calculated for a total bulk Of 1000ccm 16 The correct method of making the emul sion is to prepare the collodion by dissolving the pyroxyline

on' in the alcohol and ether , by ﬁrst pouring the former to the pyroxyline and shaking until it is thoroughly saturated, and then adding the ether . Absolute alcohol should be used, and u ma p re methyl alcohol y replace ordinary ethyl alcohol , but u the alcohol m st be free from pyridine bases , which cause dis coloration O f the coated paper . As little water as possible u sho ld be used to dissolve the chlorides , acid , and silver , and such solutions should be mixed with alcohol prior to addition

- l to the collodion . It is often necessary to allow the raw cO lodion to stand for some time for any impurities or undis solved ﬁbers to settle down ; but the best results are Obtained with the specially prepared pyroxylines , sold under the name

r li of celloidin or py a n . The best chlorides are those Of

u O f strontium and lithi m , and only the crystalline salt stron “ u ti m should be used . The lithium chloride should be u e weighed out and dissolved in alcohol as soon as p rchas d, 10 u so as to make a per cent sol tion , as it is very hygroscopic f u and absorbs varying quantities o moist re . These two chlorides are the most satisfactory in practice . Taking a

u the typical form la ( Hanneke) , following is the best method of mixing Pyroxyline Alcohol Ether

162 PHOTOGRAPHIC FACTS AND FORMULAS

Ether 400ccm

Citric acid 5 g gr.

5 . Strontium chloride , cryst . g gr 20 1 Silver nitrate g 54 gr . 4 c m Castor Oil c 31min . 20 14 Water ccm 5 min .

When castor Oil is advised , which is used to keep the paper supple and prevent it from cracking , it should be mixed with e u an q al volume of alcohol before adding to the emulsion , and should be added last . ll Wa . Pyroxyline Alcohol Ether Citric acid Lithium citrate

Lithium chloride , cryst .

Strontium chloride, cryst . Silver nitrate Water Glycerine

M n hove o ck n. 15 Pyroxyline g 115 gr .

662cc 10 z m o . 3 m Alcohol , 88 in.

500ccm Ether 8 oz .

r Citric acid g 8 Mg .

. 2 r Magnesium chloride, cryst g 4 g . 10 7 Silver nitrate g 7 gr . 10ccm Water 77 min .

Ammonia ccm 5 min. f Add the ammonia to the solution o citric acid . This was

m for an a e specially recom ended tr sp r ncies . SILVER PRINTING PROCESSES

Valenta. Pyroxyline Alcohol Ether Citric acid

Lithium chloride , cryst .

Strontium chloride , cryst . Silver nitrate ‘ Water Glycerine

Pyroxyline 169 gr .

9 oz . 38 . Alcohol , 8 min Ether Citric acid dr Lithium chloride, y

Strontium chloride , cryst . Silver nitrate Water Glycerine

oll n ruch V e b . Pyroxyline Alcohol Ether Citric acid

Lithium chloride , cryst .

Strontium chloride , cryst . Silver nitrate Water Glycerine

A o n n. Pyroxyline A lcohol 162 PHOTOGRAPHIC FACTS A ND FORMULAS

Ether 400ccm r Citric acid 5 g g .

u . 5 . Stronti m chloride , cryst g gr 2 1 Silver nitrate 0g 54 gr . m m Castor oil 4 cc 31 in. 20 Water ccm 154 min .

oil When castor is advised , which is used to keep the paper supple and prevent it from cracking, it should be mixed with

e u u an q al vol me Of alcohol before adding to the emulsion , and should be added last .

Wall . Pyroxyline Alcohol Ether Citric acid Lithium citrate

Lithium chloride , cryst .

t. Strontium chloride, crys Silver nitrate Water Glycerine

M n khoven o c . 15 11 Pyroxyline g 5 gr .

2 10 z 66 ccm o . 3 m Alcohol , 88 in.

500ccm Ether 8 oz . Citric acid g

u c Magnesi m chloride, ryst . g Silver nitrate 10g 10 Water ccm 77 min.

Ammonia ccm 5 min.

a of Add the ammoni to the solution citric acid . This was s e m for ran e s p cially recom ended t spar ncie .

164 PHOTOGRAPHIC FACTS AND FORMULAS

Ether 500ccm Citric acid g

u e . Calci m chlorid , cryst g Silver nitrate 35 g r Specially recommended fo transparencies .

Moss . Pyroxyline Alcohol Ether Citric acid Zinc chloride Silver nitrate Water Glycerine

B olt on . 177 Pyroxyline gr .

7 oz . 400 Alcohol , min .

7 oz . 400 Ether , min . 31 Citric acid gr .

. 2 Lithium chloride , cryst 6 gr . 13 Silver nitrate 8 gr .

H nne a ke. Pyroxyline Alcohol Ether Citric acid u Calci m chloride , cryst . Silver nitrate Water Glycerine Castor Oil H n k an e e. Pyroxyline S ILVER PRINTING PROCES SES

Alcohol Ether Citric acid

u . Lithi m chloride , cryst Silver nitrate Water Glycerine Castor Oil

I fanneke. Pyroxyline Alcohol Ether Citric acid u Lithi m chloride , cryst . u Stronti m chloride , cryst . Silver nitrate Water Glycerine Castor Oil H n an eke. Pyroxyline 24 g Alcohol 500ccm Ether 440ccm Citric acid 5 g

u . 4 Calci m chloride , cryst g Silver nitrate 25 g Water 37 ccm Glycerine 4 ccm Castor Oil 4 ccm

This is intended for matt surface paper . H annek e. Pyroxyline Alcohol 166 PHOTOGRAPHIC FACTS AND FORMULAS

Ether 575 ccm Citric acid g

u . Calci m chloride , cryst g S ilver nitrate 30g Water 20ccm

Specially suitable for transparencies .

Cobenz l . Pyroxyline Alcohol Ether Citric acid

Lithium chloride , cryst . Ammonia Silver nitrate Glycerine

Cobenz i . Pyroxyline 40g Alcohol 500ccm Ether 500ccm Citric acid g

Lithium chloride, cryst . g

Ammonia 7 .5 ccm ' Silver nitrate 20g Water 10ccm

for u This is intended matt s rface paper . S ul t an. Pyroxyline Alcohol Ether Citric acid

dr Lithium chloride , y Silver nitrate

168 PHOTOGRAPHIC FACTS AND FORMULAS

A shman . Pyroxyline Alcohol Ether Citric acid

u . Stronti m chloride , cryst Silver nitrate

Cr onenberg. Pyroxyline Alcohol Ether Citric acid u Lithi m chloride , cryst .

u . Stronti m chloride , cryst Silver nitrate Water

L in r a e . Pyroxyline Alcohol Ether Citric acid u Lithi m chloride , cryst .

S e trontium chlorid , cryst . Silver nitrate Water Castor Oil N th Van ora . Pyroxyline Alcohol Ether Citric acid A mmonium chloride Silver nitrate S ILVER PRINTING PROCESSES

Water Glycerine

Eder . Pyroxyline Alcohol Ether Citric acid

u i . Lithi m chlor de, cryst

u e . S tronti m chlorid , cryst Silver nitrate Water Glycerine l t Vaen a.

Pyroxyline g 173 gr .

z Alcohol 500ccm 8 o .

Ether 500ccm 8 oz . 1 1 Citric acid 8 g 38 gr .

u . . Calci m chloride , cryst g gr 1 Silver nitrate 8 g 138 gr . 1 Water 0ccm 77 min .

Glycerine ccm 19 min . — to FLATTENING . Collodion papers when toned may need be ﬂattened by immersing them one by one face down in a

- smooth bottomed tray containing a very little water . As

off soon as all are in , drain the water and let the tray stand in a slanting position for ten minutes before toning . If this is

s u u . u mani u not done , the print may c rl p badly Subseq ent p l i t ns f r . . a o are the same as o P . O P — SILVER PHOSPHATE PAPER These are very rapid -printing u papers with long scale of gradation . The phosphate em l sions can be used alone or mixed with citro -chloride emulsions to increase the speed ' 170 PHO TO G RA PHI C FA CTS ' A ND FORMULAS

4 Collodion, % Ether

10c m s . . c Phosphoric acid, p gr Then add : i Citric acid 6 14 m n. Alcohol

Shake well , and add Silver nitrate Hot water Alcohol

Shake thoroughly, and add Lithium carbonate g

no ff Till there is longer any e ervescence, and add 1 11 Glycerine 5 ccm 5 gr . 1 115 Alcohol 5 ccm gr . 1 l u 0 m . . Calci m chromate , % ccm gr

or This paper may be toned in the ordinary way , if treated

u i with per cent sol tion of citr c acid , till the yellow colour

on disappears and then washed, it gives rich brown tones ma ﬁxation in a hypo plus sulphite bath . Or the following y be used 3 Collodion , M% Phosphoric acid Citric acid Alcohol

Shake well , and add 100 Silver nitrate g 770gr .

Ammonia q . s . q . s. u Coarsely powder the silver , add very ca tiously enough u monia to form a clear sol tion , and add : Alcohol 320ccm

172 PHOTOGRAPHIC FACTS AND FO R MUL A S some O f the strontium bromide with anhydrous calcium chloride , thus using in the above

u . Stronti m bromide , anhydrous g gr

u . Calci m chloride , anhydrous g gr u If a still harder working paper is req ired , replace the calcium 1 u 0 76 8 . salt by ranyl chloride , g ( gr ) All these papers tone

u but . well in the sual baths , and lose little in the ﬁxing bath l ti - Manipu a on . The phosphate and bromide papers are

- u out . B ut sed in the same way as ordinary printing papers , u of u in conseq ence their high sensitiveness , they sho ld be u manip lated in a yellow light , and extreme care should be u taken when examining the prints d ring printing , otherwise a tint will be Obtained over that portion Of the paper exam i ned . They both tone well either in the separate or combined u b baths , but are specially s itable for sepia tones y platinum toning . P rintin g-O ut Pap ers

- - —~ i GELATINO CHLORIDE OR PRINTING O UT PAPER . Th s paper , also called P . O . P . in England , is coated with an emulsion of silver chloride with an organic salt Of silver and o of excess Of silver nitrate in gelatine . The greater the rati

or nl c u . ga salt , the more vigoro s the prints Many formulas u s have been s ggested , some Of which either give poor re ults o erti es or the paper has poor keeping pg p , and they are , there fore , omitted . The following will be found reliable . A n b ey . u A . Sodi m chloride g Citric acid g Potassium citrate g Water 500ccm Gelatine 54 g

B . Silver nitrate 5 1g Water 400ccm C.Chrome alum g Water 100ccm

° for 30 u 50 . Soak the gelatine in the water min tes , melt at C 122° ( and add B at the same temperature , stirring slowly ; ﬁnally , add C . This gives a slow printing paper with very long Scale of gradation and is most suitable for the combined bath . B ar ker .

A . Ammonium chloride Rochelle salts Citric acid Alum Gelatine 174 PHOTOGRAPHIC FACTS AND FORMULAS

z Water 500ccm 8 o .

32 245 . B . Silver nitrate g gr

Water 500ccm 8 oz . f Mix The gelatine should be equal parts o soft and hard . as above . Vigorous printing, suitable for sulphocyanide and combined baths .

Wade. A . Ammonium chloride g gr .

Rochelle salts g gr .

Citric acid g gr .

Alum g 40gr . 32 Gelatine g 245 gr . 500 Water ccm 8 oz .

. 96 B Silver nitrate g 737 gr . 500 Water ccm 8 oz .

. u Mix as above Vigorous but rather slow printing, s itable for both baths .

B dle ea . A . Ammonium chloride g gr . 5 3 Rochelle salts g 8 gr . 20 154 Citric acid g gr . 5 38 Alum g gr . 500 Water ccm 8 oz .

B . Silver nitrate 288 gr . 500 Water ccm 8 oz .

Mix as above . Vigorous and fast printing, suitable for both baths .

A shm n a . A . Ammonium chloride Tartaric acid

Sodium carbonate, cryst . Citric acid A mmonium citrate

176 PHOTOGRAPHIC FACTS AND FORMULAS

1 Yellow resin 4 g 3 gr .

Then heat the mixture until the resin is dissolved , adding more ammonia if necessary . Allow to cool , and add 1 Gelatine 4 g 3 gr . 0 Water 4 ccm 307 min . li u u N eutra se with hydrochloric acid , and add sat rated sol tion of citric acid until the mixture has a distinct acid reac u u tion . This sho ld be added to the em lsion , allowance being made for its bulk by reducing the quantity of water used in making up the emulsion .

of To Obtain hard , contrasty printing papers , add to any the above emulsions from to per cent of the following solution : Chromic acid Water

When dissolved , add

u . Calci m carbonate , pure q . s u with constant stirring until the mixt re remains turbid , then

ﬁlter, and wash the ﬁlter with 250 4 Water to make ccm oz . This forms approximately a 10per cent solution of calcium chromate . The more of this is added to the emulsion , the harder it works . PRINTING should be carried on until the high lights show a decided tinge ; then the prints should be immersed in : Salt 100g

u o 50 Sodi m carb nate , dry g 1000 Water ccm 16 oz .

5 u for 5 Bathe for min tes , rinse minutes , and tone . ff l TONING may be e ected either with an alkaline , a su pho

or ﬁrs - cyanide, a combined bath . The t named does not give PRINTING- OUT PAPERS

such satisfactory results as the others . following typical formulas Chloride Of gold

u or Sodi m acetate , borax or Sodium tungstate or phosphate Boiling water

Borax Sodium acetate Boiling water

Chloride of gold g gr .

Chalk g gr . 5 Chloride of lime g gr .

1 z Water 000ccm 16 o . For this bath the printing must be carried much further than u u 5 s al , and the prints should be merely washed in water for minutes prior to toning . Or

’ Chloride of gold 2g 15 gr . u Sodi m bicarbonate 30g 230gr .

z Water 1000ccm 16 o . This bath is very rapid in its action and gives blueish to

- A n Violet black tones , according to the depth of printing . other bath that gives very rich tones is

' of Chloride gold g gr . u 60 0 Sodi m formate g 46 gr . u Sodi m carbonate g 6 gr . 1000 1 Water ccm 6 Oz . u u The s lphocyanide bath gives better tones , as a r le , than the above . A normal formula is Chloride of gold 178 PHOTOGRAPHIC FACTS AND FORMULAS

Ammonium or potassium

sulphocyanide g 30gr .

0 z Boiling water 100ccm 16 o . i n u Dissolve the gold half the water, add to the s lphocyanide use dissolved in the remainder, and when cold . A very con veni ent stock solution can be made as follows Potassium sulphocyanide 24 g Water 400ccm ° 2 ° Heat to 98 C . ( 08 and add slowly with constant stirring Chloride of gold 8 g Strontium chloride 80g Water 400ccm

This should be heated to the same temperature . Allow to h cool , ﬁlter , and was the ﬁlter with

Water 200ccm 2oz . use 1 f For mix part with 19 parts o water . The stock solu u tion m st be kept in the dark . Sulphocyanide baths are - rather apt to give double toning, that is , blueish high lights with brown shadows . The following bath is free from this defect 1 Chloride of gold g gr . 2 Salt 0g 154 gr .

r . Sodium sulphite , dry g g 1000 1 2 Water ccm 6 0 .

for This should be allowed to stand an hour before use . Red tones can also be obtained by the use of the following

Ammonium sulphocyanide 5 g gr . u Potassi m iodide to g to gr .

Gold chloride g gr .

Water 1000ccm 16 oz .

Combined toning and ﬁxing baths have found much favour , the e as the ﬁnal tone is easily determined, which is not cas

180 PHOTOGRAPHIC FACTS AND FO R MUL A S

f with the character o the print , that is to say , the area of the dark parts of the image . The following will give a rough idea Of the quantity of gold to be used for every 645 qcm

00324 for for 0. 100 . ( sq red , g reddish

for . brown , g gr . ) brown , g gr )

- u . for warm p rple brown , g gr ) for cold purple - 025 c u 0. brown , g for old p rple black , g

gr . ) — PLATINUM TONING The tones obtained with gold range from reds to purples and browns . Colours ranging from u of u or O b sepia to black , witho t any trace p rple red , are u tained with platinum as the toning agent . A s itable bath is 2 Potassium chloroplatinite g gr . 2 Dilute phosphoric acid 30ccm 30min .

1 z Water 000ccm 16 o . u The phosphoric acid may be replaced with dil te lactic acid ,

u or or acetic , tartaric , citric , oxalic acid in like q antity ; 1 m . 0 77 . a sulphuric acid , ccm ( min y be used The above baths keep well and give pure whites . The following acts well when freshly prepared Platinum perchloride g Sodium formate g Formic acid ccm Water 1000ccm The following is also an excellent bath (Valenta) u 1 Potassi m chloroplatinite to g to gr .

Meta hen lendiamine 1 p y to g to 7 .6 gr .

1000 1 z Water ccm 6 o . For nu all plati m baths , the prints must be ﬁrst immersed in

10 O f 5 a per cent solution common salt for minutes , then rinsed ; after toning, the prints should be immersed in : 100 2 Salt g oz . S u 50 1 odi m carbonate, dry g oz . PRINTING-OUT PAPERS

2 Water 1000ccm 0oz . 5 u 10 u Bathe for min tes , and then ﬁx in per cent sol tion Of hypo . i N om as.

Platinum perchloride g gr .

Stannous chloride 1g 7 .7 gr .

z Water 50ccm 1o . r Dissolve the platinum in half the wate , the tin salt in the

two u : remainder , and mix the sol tions ; then add 4 Hydrochloric acid 5 ccm 38 min .

Oxalic acid 10g 77 gr .

z Water to 1000ccm 16 o .

The u and prints sho ld be washed in salt and water, then in

r nl n plain water befo e to g. — COMBINED PLATINUM AND GOLD TONING The use of

u u or - gold and platin m gives p re black blue black tones , the blue tinge being dependent on the depth of toning with the gold . Print deeply , and immerse the print in Salt 25 g

u c Sodi m arbonate , dry g Water 1000ccm 5 Leave for minutes , wash well , and tone in Borax 10g u 10 Sodi m acetate , fused g Gold chloride g Water 1000ccm

Then wash, and tone in

s u Potas i m chloroplatinite g gr . 1 Citric acid 0g 77 gr . 16 123 Salt g gr .

1000 1 z Water ccm 6 O . u u - Tone ntil the prints look p rple black then wash , and ﬁx . 182 PHOTOGRAPHIC FACTS AND FORMULAS

u Another process with a merc ry salt , which is open to ques tion as to permanency, is to tone with

Potassium chloroplatinite 3 g 23 gr .

Salt 20g 154 gr .

Water 1000ccm 16 oz .

- Tone until a blue violet colour is obtained ; then rinse well , and tone again in : Mercury sulphocyanide Citric acid Gold chloride Water

Wash well , and ﬁx as usual .

RA — GOLD AND U NIUM . This also gives blackish prints

Gold chloride g gr .

Uranium nitrate g gr .

Salt 4 g 31gr .

Sodium acetate 4 g 31gr .

Water 1000ccm 16 oz . ffi Dissolve the gold and uranium , and add su cient sodium carbonate to neutralise the solution ; then add the other i n

r ie u g ed nts. Printing m st be rather deep ; a salt bath should be used prior to toning, and an alkaline bath for ﬁxing .

G — or URANIUM TONIN This gives more less red tones , so- r u the called red chalk o Bartolozzi colo rs . Print rather deeply , immerse in a salt bath , wash well , and tone in 2 Uranium nitrate g 15 .4 gr . 10 Thiosinamine g 77 gr . 1000 1 Water ccm 6 oz .

Wash thoroughly, and ﬁx . — PALLADIUM TONING This gives sepias and warm blacks but is not generally used . Potassium chloropalladite Salt

184 PHOTOGRAPHIC FACTS AND FORMULAS

Paramidophenol may also be used (Hanneke) 4 Paramidophenol hydrochloride 7 g 5 gr . 1 Citric acid 8 g 6 gr .

25 192 . Sodium sulphite , dry g gr

Water 1000ccm 16 oz . ’ Liesegang s aristogen for the same purpose was said to be

Hydrochinon 10g 77 gr .

Sodium acetate 10g 77 gr .

Citric acid 10g 77 gr .

u . . 500 8 . Sodium s lphite , sat sol ccm oz

Water 500ccm 8 oz . It was discovered by Wilson that an alkaline developer could u be sed , if the print were ﬁrst immersed in potassium bro

u so of mide sol tion , as to convert the whole the silver salts u into bromide . After expos re the print should be immersed , u 10 u witho t washing , in a per cent sol tion of potassium for 5 10 bromide to minutes , then well washed , and treated with the following

. 140 A Hydrochinon g gr .

Sodium sulphite, dry g 35 gr . u “ 9 0 S lphurous acid ccm 7 min .

Potassium bromide g 35 gr .

Water 1000ccm 16 oz .

B . Caustic soda 9 g 70gr .

Sodium sulphite, dry 9 g 70gr . W 1 ater 000ccm 16 oz .

C . Ammonium carbonate g 280gr . u Ammoni m bromide g 280gr .

1000 z Water ccm 16 o . u Mix in eq al parts before use . The following is simpler

A . Hydrochinon g 175 gr . u Sodium s lphite , dry g gr. u u S lph rous acid g 87 .5 gr . PRINTING -OUT PAPERS

Water 1000ccm 16 oz .

u 1 . B . Potassi m bromide g oz

Ammonia 9 ccm 70min .

350 . or Sodium carbonate , cryst . g gr Water 1000ccm 16 oz

For use mix 1part of each with 1part water . Or the follow ing may be used :

o 28 . A . Hydrochin n g gr

”

u u 28 r . Sodi m s lphite , dry g g

Water 1000ccm 16 O z .

F r 4 4 B 8 o use , mix parts A , parts , given above, and parts to water . Greater contrasts can be Obtained by decreasing A 3 can u to parts , while ﬂatter prints be sec red by increasing A

or u 7 parts , the water in each case being increased red ced , so u as to make the total b lk Of the solution the same . Another formula (Kodak) is the following

A . Hydrochinon g u Sodium s lphite , dry g Potassium bromide g Ammonium bromide g 1000 Water, ccm

B . Caustic soda g Water 1000ccm

C . Tannin g Water 1000ccm

For 150 4 30 . use mix parts A , parts B , parts C W hichever developer be used , it is important to Observe the greatest care not to expose the paper to white light , as the slightest light action is developed . It is , therefore , advisable

e b to manipulat the paper y yellow light entirely . The image ou A sh ld only be faintly visible after exposure . fter the bromide bath, the prints should be washed at least 3 minutes . The developed image is a pale yellow or orange colour ; care 186 PHOTOGRAPHIC FACTS AND FORMULAS

too must be taken not to develop far , and development should be stopped when the details in the high lights just begin to

of 10 or show . A stop bath per cent of potassium bromide 1 per cent glacial acetic acid should be used , the prints thor

ususal wa . oughly washed , and then toned in the y — DISCO ( DEFENDER) PRINTING-OUT PAPER Print two or three shades darker than is desired in the ﬁnal print . Wash

or of in ﬁve six changes water before toning , and tone in the following, keeping the prints moving

Gold chloride solution 25 ccm 1oz .

z Water 1000ccm 40o . u Add eno gh borax to turn red litmus paper blue . The above gold chloride solution is made by dissolving a 15 -grain tube

f z o 1 . 42 gold chloride in 5 o or 5 ccm of water . When the 4 desired tone is attained , transfer prints direct to a per cent u f sol tion o hypo . — 8 EASTMAN SOLIO PAPER . Wa h prints in 5 or 6 changes of e u wat r before toning . Tone in a plain gold bath, sing 044 1 . 1 . 000 4 . g ( gr ) to ccm ( 8 oz ) water . Neutralise bv u adding a few drops at a time of sat rated solution Of borax ,

u or u . sodi m bicarbonate sal soda . Test with red litm s paper

u or : When toned , immerse prints in r nning water , Common salt 8 g Water 1000ccm Fix not less than 10minutes in Hypo 100g Water 1000ccm Solio hardener 4 ccm The Solio hardener is made as follows Aluminum chloride 250ccm Sodium bisulphite 208 g

2 z Water 1000ccm 1 o . Or the following may be used

188 PHOTOGRAPHIC FACTS A ND FORMULAS

u . darker than the ﬁnished prints are req ired to be Place , without washing , directly in the baths , which should be at

° ° 6 5 . 18 C . ( and keep constantly in motion For sepia tones : immerse for 10minutes in a 10per cent solution of hypo . For brownish-black tones : immerse for 10minutes in a 10per cent solution of common salt ; then transfer direct to the same strength hypo solution . For dark brown tones : immerse in

Hypo 100g 2oz .

Salt 100g 2oz .

Water 1000ccm 20oz . Variation in tones from light to dark brown is obtained by decreasing or increasing the quantity of salt in the above bath . n As soo as the desired tone is Obtained , the prints should be u b of or run caref lly washed y repeated changes water , in f ning water for 30minutes . The most satisfactory method o

“ drying is to place the prints between clean blotters .

- — GEVAERT R O N I x SELF TONING PAPER This is a collodio chloride paper . Print a little darker than the ﬁnished print is desired to be . For sepia and brown tones , wash prints for

2 or 3 three to ﬁve minutes in changes of water , immersing

f r 1 1 them face down to prevent curling . Fix o 0to 5 min utes in 1 Hypo 00g 2oz . 1 2 Water 000ccm 0oz .

for one u off u u but Wash ho r , blot s rpl s water , do not dry

. u between blotters For dark brown and bl e tones , wash as before and then immerse for 5 to 10minutes in :

Salt 100g 2oz .

Water 1000ccm 20oz .

Rinse , ﬁx and washas for sepia tones . Baths should be used only once . Salted Pap er

-I n PLA IN OR SALTED PAPERS . this process the original surface of the paper is practically preserved , the sensitive

r in salts being more o less the ﬁbers Of the paper , in contra distinction to thoseprocesses I n which they are suspended

- ' n u s . C u e in a em l ion In all ases , however , a size sho ld b used us to prevent too deep penetration into the paper . Vario

u u . sizes may be sed ; starches , s ch as arrowroot , etc , tend to

s give browni h tones , while gelatine tends rather to more blueish tones . The size may be applied to the paper ﬁrst , “ but it is frequently more convenl ent to incorporate the salts with it 4 Arrowroot 20g 15 gr . 2 Water 750ccm 1 oz . R ub the arrowroot into a cream with a little O f the water e bring the r mainder Of the water to the boil , add the arrow o u e root cream slowly with constant stirring, and c ntin e h at ing until a translucent liquid is formed . Then add 14 10 Ammonium chloride g 7 gr . 23 17 Sodium carbonate , cryst . g 7 gr .

Citric acid 7 g 54 gr .

250 4 z Water ccm o . ff n lu As e ervesce ce takes place when mixing this latter so tion , i t is advisable to make it in a fairly large beaker before add

. u ing it to the arrowroot It is as well , tho gh not necessary , to u 5 boil this sol tion for minutes to expel the carbonic acid . The salted arrowroot mixture should be strained through u ﬁne m slin while hot . Immerse the paper in the warm solu for 2 u u tion min tes , and hang p to dry . When nearly dry, again immerse for the same time , and hang up hy t he oppo 189 190 PHOTOGRAPHIC FA CTS AND FORMULAS

to site corners to those previously used . As an alternative this , the paper may be pinned by two corners to a ﬂat board , and the salting solution freely applied with a broad ﬂat brush . re The solution is allowed to dry , and the operation is then wr 50 peated. Increase Of the arro oot by per cent increases ne brilliancy Of the surface . For a gelatine size o of the following may be used : Gelatine Ammonium chloride Sodium citrate Water

Gelatine Ammonium chloride u dr Sodi m citrate, y Salt Water

7 54 Gelatine g gr . 14 10 Ammonium chloride g 8 gr .

1000 1 z 6 o . Water ccm .

The more gelatine used , the higher the gloss Of the resultant

. u prints The more citrate sed, the more rapid the paper , with

. n less contrast Soak the gelati e in the water, melt by heat . and add the salts .

- L A C — ‘ MATT AND SEMI MATT PAPERS . Wil ll these bleached

shellac with gelatine is used as a size . Unfortunately, e u u bl ached shellac is quite insoluble in aq eo s mediums , and its solubility is very variable, unless freshly bleached : 83 Bleached lac g 637 gr . 42 2 Borax g 3 3 gr . 750 Water ccm 12oz . u The lac sho ld be broken up small , added to the borax solu

192 PHOTOGRAPHIC FACTS AND FORMULAS

Dissolve the silver, add enough strong ammonia to form a clear solution , and then add

Silver nitrate 32g 245 gr .

Water 250ccm 4 oz . If necessary add a little more ammonia to clear up any precipitate formed . Papers thus prepared will not keep more u but e than a few ho rs , they print very rapidly, and giv very use vigorous prints . It is better to the plain silver solu

u . tions , and f me the paper with ammonia just before use This can be effected by cutting the paper to size and pinning

O f on f to the inside the lid of a plate box , the bottom o which is a sheet of blotting paper wet with a 10per cent solution '

u 10 15 uf . of ammonia . Abo t to minutes will be s ﬁcient In

of u a stead the liq id ammonia, coarsely powdered mmonium ma carbonate y be used , and then the paper should be fumed for 30minutes . Printing should be carried rather deep and the prints washed with repeated changes Of water until no milkiness is or 5 u ma u seen in the water , a per cent sol tion of salt y be sed , 1 and the prints then washed for 0minutes . Toning may be f r ef ected with either gold o platinum . Weak baths give the u best results , s ch as B orax 7 g 54 gr .

e Gold chlorid g gr .

1 cm Hot water 000c 16 oz . Sodium phosphate or acetate may be used instead of the borax , and the tones vary from sepia to purple, according to u the d ration Of toning . As the prints always dry a little

or u colder , bl er , in tone than when wet , allowance should be made for this . A suitable platinum bath is Potassium chloroplatinite g Citric acid 8 g Salt g SALTED PAPER

1 Hot water 1000ccm 6 oz . 1 After toning , the prints should be immersed in a per cent t solution of common salt o stop the toning action , ﬁxed in a

5 per cent solution of hypo , and well washed . - b o If resin sized paper e used , the f llowing will give black and sepia tones direct . For black tones

‘ Sodium phosphate 40g B orax 20g Sodium carbonate 10g Sodium chloride 5 g Potassium bichromate g Water 1000ccm FO r sepia tones 20 14 Sodium phosphate g 5 gr . 07 Borax 40g 3 gr . u 5 Sodi m chloride g gr .

Potassium bichromate g gr . 000 1 Water 1 ccm 6 Oz . 20 40 r d . Immerse the paper for to seconds , and y Sensitise on S ilver” ni trate 50g Lead nitrate 50g Water 1000ccm u Neutralise this with sodi m carbonate before use . The f ollowing method is given by Namias 25 19 Gelatine g 2gr .

- . 6 4 Zinc chloride , cryst g 6 gr . 5 38 Citric acid g Mgr . 6 46 Ammonia ccm min . 1000 1 Water ccm 6 oz . a Soak the gelatine in h lf the water , and dissolve with heat ; dissolve the acid in the remainder Of the water, add the

z 1nc two o ammonia and then the , mix the s lutions and ﬁlter . 194 PHOTOGRAPHIC FACTS AND FORMULAS

Tartaric acid may be used instead Of the citric , and darker brown tones are obtained . Immerse the paper in the warm u solution and dry . Sensitise by br shing over with either of the following solutions Silver nitrate Citric acid Glycerine Water

120 922 Silver nitrate g gr . 5 Ammonia q . s . q . .

z Water 500ccm 8 o . u u Use eno gh ammonia to form a clear sol tion , and then add 50 3 4 u u 8 . Lactic acid , p re syr py ccm mm

1000 1 z Water to ccm 6 o . Greater contrasts can be obtained by adding a little 5 per cent solution of potassium bichromate . A more rapid paper is Obtained with the following : 100 6 Silver nitrate g 7 8 gr . 50 3 Uranium nitrate g 84 gr . 50 3 Lactic acid ccm 84 min . 1000 1 2 Water ccm 6 0 .

e i s l i ' The following gives s p a tones , but the stock o ut on will not keep

- of Ammonio citrate iron , green g Water 333ccm Potassium bichromate g

: Dissolve , and add 2 Silver nitrate g 56 gr . 667 Water ccm 11oz .

After printing, this paper should be immersed in a 1per cent u o a a 2 sol ti n of ox lic acid , then w shed , and ﬁxed in a per cent hypo bath.

196 PHOTOGRAPHIC FACTS AND FORMULAS .

After printing , the material should be immersed in salt solution , washed and toned as usual , if desired . Thin veneer wood can be sensitised ; maple and plane give u the best results ; pear is less satisfactory . The wood sho ld be immersed for at least 5 minutes in : 5 Soft gelatine 37 . g Water 1000ccm

Soak, melt by heat , and add

Formaldehyde ccm 58 min . 5 Dry with moderate heat , and immerse minutes in 2 12 Hard gelatine 5 g 9 gr .

Soluble starch 100g 768 gr . 1 Ammonium chlori de 0g 77 gr . 1 m 1 Water 000cc 6 oz .

Again dry, and sensitise in 100 Silver nitrate g 768 gr . 3 6 3 Citric acid 8 g 7 gr . 1 1 Water 000ccm 6 oz . l tiick . Dry q y Print deeply from contrasty negatives , wash and tone as usual . of u The sensitising leather , s ch as split calfskin , is an easy matter , but it will not keep after sensitising . It is advisable to coat it ﬁrst with plain collodion and then with a collodio u chloride em lsion . Or the following may be used 19 Hard gelatine g gr . u 10 Sol ble starch g 77 gr .

Potassium bromide g 67 gr . u 5 Cadmi m bromide g 67 gr . u 1 Cadmi m iodide g 9 gr .

i u Ammon m chloride g 19 gr . 1000 Water ccm 16 oz . u Sat rate the material , dry quickly , and sensitise in : 40 Silver nitrate g 307 gr . SALTED PAPER

4 Citric acid 50g 38 gr .

z Water 1000ccm 16 o . Clean brilliant negatives and short exposure to a bright light

are required ; enlargements may also be made . After expo sure the material should be immersed in a 5 per cent solution u : of ammoni m chloride , and developed with 1 Pyrogallol g 9 gr .

Hydrochinon 7 . 5 g 58 gr . f Citric acid 10g 77 g .

u e 34 260 . Sodi m sulphit , dry g gr

Water 1000ccm 16 oz .

° ° u Temperat re 35 C . (95 As soon as the image has well

appeared, ﬁx in an acid bath , and tone with gold .

For an emulsion for fabrics , either Of the following may be used :

12 2 z 0 o . 47 . Hard gelatine g , gr 1300 2 Water ccm 3 oz .

Dissolve, and add

Zinc bromide , cryst . Cadmium iodide Cadmium chloride ° 15 ° 70 . 8 Next , add at C ( Alcohol 500ccm Then add in the darkroom Silver nitrate Water i dd F nally , a 100 Alcohol ccm 770min .

° ° for 2 0 1 Digest M hours at 8 C . ( 76 and then cool

° u u 1 down with constant stirring ntil the temperat re s 15 C . ° ( 59 when the emulsion will sink to the bottom of the u vessel ; this sho ld be collected , washed , and melted with the addition Of 198 PHOTOGRAPHIC FACTS AND FORMULAS

Sodium carbonate g gr.

Ammonium bromide g gr .

2400 z Water ccm 38 Mo . ° ° Melt at 30 C . ( 86 and saturate the fabric . This can u and s also be sed for paper , gives from red to black tone , u according to expos re and developer .

200 PHOTOGRAPHIC FACTS AND FORMULAS both gelatine and paper and its tendency to give rusty black

- tones . Amidol and metol hydrochinon , also called M . Q . , u u - are the favo rites ; the former tends to give bl e black , and the latter pure black tones . A m l — i do . This developer will not keep more than three d u 5 ays , and the most convenient method is to make p a per

u of u e cent sol tion dry sodi m sulphite , add per c nt of

u . potassi m bromide ( Mgr to the ounce) , add per cent u u f 4 . u O amidol ( gr to the o nce) , and dil te with an eq al bulk water just before use :

Sodium sulphite, dry Potassium bromide Water

When dissolved , add

Amidol g 40gr .

’ M tol-H r i n n — f e yd och o . The mean o the maker s formulas

Metol g Hydrochinon 3 g u dr 21 Sodium s lphite , y g u 16 Sodi m carbonate , dry g Potassium bromide g Water 1000ccm

Eastman Metol—h dr chin n D l y o o eve op er . Elon (metol) 5 g u 75 Sodi m sulphite , dry g

20 2 z ~ Hydrochinon g o .

u 105 1O z o . Sodi m carbonate , dry g M

s u 20 Potas i m bromide g 1 gr . 1 Wood alcohol 30ccm 13 oz . 100 Hot water 0 ccm 100oz . 1 21 For use mix part with 6 parts water . Temperature ( 70° BROMIDE PAPER

A i d l D v l Eastman m o e e op er . u Sodi m sulphite , dry A crol (amidol) 12 Water Moz . For use mix Stock solution 157 ccm 1 u 0 ol . 8 Potassi m bromide , % s ccm drops

Water 843 ccm 6 oz . Time O f development should be not less than a minute and a quarter .

O R TH O B RO M A N D N VA B R M GEVAERT O O BROMIDE PAPERS . Developer for Vigorous prints : Metol Hydrochinon

u u Sodi m s lphite , cryst . u n Sodi m carbo ate, cryst . Potassium bromide Water For soft prints 5 40 Metol g gr . ochn 12 Hydr i on g gr . u u 2 . 6 1 z Sodi m s lphite , cryst g o .

s um 1 Potas i carbonate g 50gr . u 1 Potassi m bromide g 8 gr .

1000 1 z Water ccm 6 o .

Dissolve in order given . Prints Of any required degree O f vigour may be made by mixing the two solutions in suitable o ° ° . 3 u s 1 8 . 6 5 pr portions Development time , min te at C (

: After rinsing , ﬁx in Hypo Potassium metabisulphite Water 202 PHOTOGRAPHIC FACTS AND FORMULAS

10 u 1 2 u Fix min tes , wash to ho rs , and do not dry between blotters .

HAM MER OPAL PLATES . Metol 5 g

Hydrochinon 20g 1oz .

Sodium sulphite 75 g 3Moz . Sodium carbonate 125 g

2 1 . Potassium bromide to . 5 g Mto dr

Water 1000ccm 50oz .

z to Add from 120 to 200ccm (6 to 10o . ) wood alcohol For use 1 6 prevent precipitation . mix part of above with parts water . — FACTORIAL DEVE LOPMENT FOR BROMIDE PAPER Dr . B . J . Glover puts forward a strong case for the application of the ’ Watkin s factorial system for bromide papers , which, how u ever , is not applicable to development papers on acco nt of the very short time of appearance . The developer he adopts ° he K 1 d t of 7 C . an is odak amidol formula at a temperature , he ﬁnds a remarkable coincidence between the exposure multi of plied by the time development , in seconds , for prints showing practically the same result . This forms a constant , which is Three cases are cited in which the exposures , 30 15 10 10 were , and seconds respectively and the factors , 1 22 u i n is in ish 5 and Mused . The res lts were practically d t gu

of 60 120 180 able ; and the total times development were , and seconds respectively , which , as will be seen , when multiplied u u u by the expos res , eq al He formulates his ﬁrst r le as follows : development must not be for a shorter time than u that req ired to produce the maximum black of the paper . u Accepting this , it will be obvious that it will be nnecessary to calculate both exposure and development ; one only need be c determined and the other is at on e deduced therefrom, which

s n practically forms his co d rule . As he puts it : a knowledge

Developing-O ut Papers — DEVEL OPMENT OR GASLIGHT PA PER sL These are com ar tivel w p a y slo papers , which can be manipulated in not too use bright a white light , though it is safer to a yellow or

- bright orange safe light . — EXPOSURE The exposure is much longer than with bro - in mide paper, and it is advisable to use a high candle power

- s u 50 . cande cent lamp , s ch as a watt Mazda The distance

' 2 r from the lamp should not be more than 1 inches . O mag

‘ nesiurn 1 12 ribbon may be used , inch at a distance of inches uf being s ﬁcient for an average negative for cold tones . The r longe the exposure , with corresponding increase of bromide in the developer , the warmer the tones . — . rac DEVELOPMENT Any developer may be used, and, p u tically , negative developers , with bromide , may be used f ll strength . mi l A do .

o S dium sulphite , dry Potassium bromide Water

When dissolved, add 4 Amidol g 0gr .

For of u notes as to the keeping this , see nder Bromide Paper . ’ Metol-H dr hi — y oc non . The mean of the maker s formulas

Metol Hydrochinon u u Sodi m s lphite , dry

Sodium carbonate , dry Potassium bromide DEVELOPING-OUT PAPERS

1 z Water 1000ccm 6 o . All formulas given under Bromide Paper are applicable to development papers .

- — N O N ABRA SION DEVELOPERS . Glossy development papers - of are likely to show black hair like lines , due to abrasion the o u sensitive surface . The f llowing has been s ggested as obviating these ° 2 Metol g 7 gr .

Hydrochinon 6 g 46 gr . r 12 92 Sodium sulphite, d y g gr . r 20 14 d 5 . Sodium carbonate , y g gr m Potassium bro ide g 3 gr . o 2 P tassium iodide g gr . 1000 1 Water ccm 6 oz . The iodide is the active agent and may be added in about the above ratio to any developer . Or add per cent of hypo 12 1 . 6 oz . to the developer , that is , g per liter ( gr per ) PYRO DEVELOPER FOR WARM BROWN TONES ON DEVELOP

MENT PAPERS .

A . 5 Potassium metabisulphite g gr .

ﬂ P ro allO l 22 1 y g g 69 gr . 15 11 Potassium bromide g 5 gr . 1000ccm Water 16 oz .

. u 87 .5 B Sodi m sulphite, dry g 672gr .

c dr 87 .5 2 Sodium arbonate, y g 67 gr . 1000 1 Water ccm 6 oz . For mm 10 20 0 use A , B , water 7 parts . The image appears 30 40 in from to seconds , and development is complete in 3 4 or minutes . The prints should be ﬁxed in an acid bath e without intermediat washing . K VITAVA ( ODAK) PAPER . 1 . Elon (metol) u u Sodi m s lphite , dry 206 PHOTOGRAPHIC FACTS AND FORMULAS

Hydrochinon 23g 46 Sodium carbonate , dry g Potassium bromide g Wood alcohol 138 ccm z Water to 1000ccm 32o . 46 2. Sodium carbonate , dry g

1 2 z Water 000ccm 3 o . 1 - u In preparing No . , dissolve each chemical in three fo rths of ° 12 ° a 53 . 5 the w ter, heated to about C ( before the next u 1 2 is added . Normal development should req ire from Mto

minutes . 12 1 : 5 . to For Etching Brown , use ccm of No , water make 1000 7 10 u of ccm , and add ccm of per cent sol tion potassium

f 1 1 z 2 . f o No . 6 o . 60 . o bromide ( oz , water to , and min

potassium bromide solution) . 1 12 : . 5 For Athena Old Master and Glossy , use No , ccm , 2 1 f No . 000 o 10 , ccm , water to ccm, and add ccm

s mm o 1 z u ot s 2 . . 2 a N . o NO per cent sol tion p bromide ( , , ,

1 z 1 z . 6 o 0 f o 3 . o , water to ., and add min potassium bromide

° ° u 21 0 solution) . Temperat re C . (7 F) .

ARTURA . 1 . Elon (metol) u Sodi m sulphite, dry Hydrochinon

Sodium carbonate , dry Potassium bromide Water to Then add Wood alcohol 2 . Elon (metol)

Sodium sulphite , dry Potassium bromide Water to

208 PHOTOGRAPHIC FACTS AND FORMULAS

Hydrochinon 2. 9 g u u Sodi m s lphite , dry g u 35 Sodi m carbonate , dry g Add 2 drops of 10per cent potassium bromide solution to

z f each 30ccm ( 1o . ) o developer . Use full strength at 1 ° 6 ° 8 C . ( 5

F r for u o professional use ; soft developer Art ra Iris , Azo and other professional papers . Dissolve in order named

1000 z Water ccm 40o . K d l n 1 o e o g 0gr . 2 40 Hydrochinon g gr . 5 u u 9 . 180 Sodi m s lphite , dry g gr .

9 . 5 1 u 80 . Sodi m carbonate , dry g gr Add 1drop of saturated solution of potassium bromide to

2 z f . each 60ccm ( o . ) o developer Use full strength at ° 6 5 ° 18 C . (

T z l D v l — o o e e o er . p Stock solution for developing papers . Dissolve in the order named Hot water 1000ccm Toz ol 33 1/3 g u u 100 Sodi m s lphite , dry g

u . 75 Sodi m carbonate , dry g u 3 Potassi m bromide . g Wood alcohol 150g For portraiture on Artura and Azo use 100ccm of stock

u 0 1 z sol tion to 70 ccm water ( o . to 7

For u Velox , bromide , and amate r ﬁnishing grades of Azo , 6 2 f add 7 ccm ( oz . ) o dry sodium carbonate to the above quantity of stock solution and for use dilute 1to 2for Velox 1 ° 6 . 21 and Azo , and to for bromide papers Use at C . ( 70°

HALOID PAPERS . Metol DEVELOPING-OUT PAPERS

u u Sodi m s lphite , dry g Hydrochinon g u Sodi m carbonate , dry g

4 z Water 1000ccm 0o .

Add one drop saturated potassium bromide solution to every f f 1 . o 2oz . o developer ( ccm to every liter) Times develop ° ° d s r 1 o 1 . r r 1 2 I n u t o t 8 . 6 5 Po t a a ment at C ( F ) y Mto , M 1 1 1 K 1 1 i 1 1 M, Rito Mto M, alo to M, Enlarg ng M to M use K r s minutes . The of alo (slow speed) o Rito ( fa t speed) u - with the following developer gives cold, neutral or bl e black toneS ° Metol 5 g o u u 5 S di m s lphite , dry 7 g

2 2 z Hydrochinon 0g o .

dr 125 12 z o . Sodium carbonate , y g M u e 2 Potassi m bromid g 100gr .

1000 O O z Hot water ccm F o .

For use 1 mix part stock solution with 3 parts water .

K — u HALOID ALO RITO . For ne tral black tones : 1 Metol g 5 gr . u Sodium s lphite , dry g 0 Hydrochinon g 6 gr . u 22 2 Sodi m carbonate , dry g 4 0gr . 1000 40 ccm oz . Add one drop saturated solution potassium bromide to each

u of 1 two o nces developer ( ccm to every liter) .

A N S CO CY KO PAPER . Metol

Sodium sulphite , dry Hydrochinon

Sodium carbonate , dry Potassium bromide 210 PHOTOGRAPHIC FACTS AND FORMULAS

40 Water 1000ccm oz . ° 6 5 ° Temperature 18 C . (

A N S CO NOKO PAPER .

Metol gr . Hydrochinon g 25 Sodium sulphite , dry g

Sodium carbonate , dry g Potassium bromide g Water 1000ccm

Time of development 45 to 60seconds .

Y K ENLARGING C o. Metol 8 g u Sodi m sulphite , dry g Hydrochinon g

Sodium carbonate , dry g 1 20 60 u . . 3 . Potassi m bromide , sat sol to ccm to min

1000 z Warm water ccm 40o . 1 ° 6 5 ° Temperature 8 C . (

K EL ox ODAK VELVET GREEN AND V PAPERS .

Metol g 7 gr . u u 7 110 Sodi m s lphite , dry g gr . 2 3 Hydrochinon g 0gr . u 13 15 0 . Sodi m carbonate , dry g gr e 10 40 40 Potassium bromid , % drops drops 300 10 Water ccm oz .

V ERO TY PE R —For u MIMOSA PAPE p re black tones , use u 50 1 Sodi m sulphite , cryst . g 94 oz . 2 3 Metol g 0gr . 6 2 Hydrochinon g 9 gr . u 135 4 Sodi m carbonate , cryst . g Moz . 1 1 u 0 . 0 1 Potassi m bromide , % sol ccm 80min .

1000 3 z Water ccm 5 o . Or the following separate solution developer

212 PHOTOGRAPHIC FACTS AND FORMULAS

u 4 drops saturated solution potassium bromide . Temperat re

° ° 21 u C . ( 70 Prints m st be exposed so that the time of 1or development will be not less than 45 seconds for NO .

2. For u 30seconds for No . commercial and amate r print : ing , the following is recommended Elon (metol) g u u 13 Sodi m s lphite , dry g Hydrochinon g u 18 Sodi m carbonate, dry g

u . . Potassi m bromide , sat sol ccm Hot water 1000ccm 21° 0° Temperature C . (7

DEFENDER COM MERCIAL PAPER . Metol g u u 25 Sodi m s lphite, dry g Hydrochinon 3 g u 1 Sodi m carbonate , dry 8 g

“

sol . 8 Potassium bromide , sat drops Water 1000ccm

° ° u 1 Temperat re 8 C . (6 5 F ) .

DEFENDER VELOUR BLACK . Metol g u Sodi m sulphite , dry g Hydrochinon 4 g u Sodi m carbonate , dry g u 12 . . 5 600 Potassi m bromide , sat sol drops drops 1000 Water ccm 40oz . For commercial use Metol u u Sodi m s lphite , dry Hydrochinon u Sodi m carbonate , dry Potassium bromide DEVELOPING- OUT PAPERS

z Water 1000ccm 40o .

DEFENDER PR FESSI NAL PAPER . O O ) Metol g u u Sodi m s lphite , dry g Hydrochinon 3 g u Sodi m carbonate , dry g 4 Water 1000ccm 0oz .

Potassium bromide, 25 to 0 30 80 s sat . sol . 7 drops to drop

” The quantity of bromide determines the tone ; with thesmall est quantity a comparatively cold tone results with from 1to

1Mminutes development for correctly exposed prints . Alternative developer for black and white prints 1 2 1 . . Metol g 50gr

u 5 oz . Sodi m sulphite , dry g Hydrochinon g Water 1000ccm

2. u 100 Sodi m carbonate, dry g Water 1000ccm For use mix u 1 n . 10 Sol tio No ccm oz . u 2 N o . 2 Sol tion ccm oz .

625 z Water ccm 20o . 2 2 Potassium bromide g 3 gr . 1 Develop from Mto 3 minutes . Special stress is laid on the necessity of increasing the quantity of bromide with increase of u of the temperat re the developer .

E V I TTE x - — G VAERT (rapid gas light paper ) . For vigorous prints :

A . Metol u Sodi m sulphite , cryst . Hydrochinon

Potassium carbonate, cryst . 214 PHOTOGRAPHIC FACTS AND FO RMULAS

Potassium bromide g 8 gr .

Water 600ccm 20oz . 40 60 . c Dissolve in order indicated Development, to se onds

° ° at 16 C . (60 For soft prints 2 5 . B . Metol g gr

2 . u . 8 Sodi m sulphite , cryst g Moz

Hydrochinon g 8 gr .

1 z u . 35 o . Potassi m carbonate , cryst g

Potassium bromide g 8 gr .

Water 600ccm 20oz . f Time and temperature as before . Prints o any desired vigour can be obtained by mixing A and B in appropriate : proportions . After development , rinse and ﬁx in Hypo 250g Water 1000ccm PotassI um metabisulphite 25 g

for 10 one u . Fix minutes , wash to two ho rs Dry ﬂat , but not between blotters . This paper gives warm black tones by

o simple development , and is not intended for sepia t ning in u s lphide solutions .

- - GEVAERT NOVA GAS (commercial gas light paper) . 1 1 Metol g 5 gr .

r 4 60 Hyd ochinon g gr .

u 1 z . . 35 o Sodi m sulphite , cryst g

u 2 . Sodi m carbonate , cryst . oz u 30 0 10 . 6 Potassi m bromide , % sol to drops

Water 600ccm 20oz .

° °

1 . . 6 5 Dissolve in order named Develop at 8 C . ( F ) If 15 10 u whites are not clean , add drops per cent sol tion of u u A potassi m bromide to each o nce ( 30ccm) developer . fter development, rinse thoroughly and ﬁx in Hypo 150g

Toning B romide and G aslight Prints — COPPER TONING . Various shades from red to violet i a brown are obtainable by this process , wh ch is b sed on the deposition of red cuprous ferrocyanide on the image with the simultaneous formation of white silver ferrocyanide . It is actually an intensiﬁcation process ; therefore , the primary image must not be developed too far . Single solution ( Ferguson)

1 . 1 z 0 06 1o . 5 . Cupric sulphate , % sol ccm , dr 1 1 u 0 . 800 3 . Potassi m citrate , % sol ccm oz u Potassi m ferricyanide, 1 1 4 z . t 0 . 9 o 3 (i . % sol ccm , This solution will keep and does not stain plates or papers ; I ed the colours are dependent on the length of mmersion . S lacz ek fo gives the following rmulas for various tones , and , not u as the baths will keep well , they should be mixed j st

. O f before use In all these formulas , the quantities the solu tions should be added to the stated amount of water in the order given : u 10 250 Potassi m citrate, % sol . ccm u 1 40 2 0 . 90 . C pric sulphate, % sol ccm min u l 100 . so . Ammonia al m, sat ccm

Potassium ferricyanide, 10 30 21 mi % sol . ccm 8 n.

750 12 z Water ccm o . - r This gives red or Violet brown tones with clea whites . u 200 Ammoni m oxalate , sat . sol . ccm 3 oz . u 10 0 . 4 2 C pric sulphate, % sol ccm 90min . u Ammoni m carbonate , 10 . 10 2 % sol ccm 7 min . TONING BROMIDE PRINTS

u Potassi m ferricyanide ,

l 30 218 . 10% so . ccm min z Water 800ccm 12o .

This gives cherry red tones with a faint tinge in the whites . 1 l 0 0 so . 10 Potassium Oxalate , % ccm 10 s 40 u ol . C pric sulphate , % ccm l 10 so . 10 Tartaric acid , % ccm

Potassium ferricyanide ,

1 3 216 . 0% sol . 0ccm min

Water 800ccm 1202. red- f 100 1 This gives brown tones. The addition o ccm ( M f oz . ) saturated solution o ammonia alum gives browner tones . l 2 . so . 0 Ammonium oxalate, sat 0ccm u u 1 l 40 0 so . C pric s lphate , % ccm

. . 10 Oxalic acid , sat sol ccm u Potassi m ferricyanide , 1 0 . 30 m 21 % sol cc 6 min .

00c m Water 8 c 12oz .

- This gives a reddish Violet tone . The following bath gives

so- e or the call d red chalk Bartolozzi tones , but the whites are tinged u Ammoni m carbonate ,

sat . sol . 570ccm 1 0 . 12 Cupric sulphate, % sol 7 ccm u Potassi m ferricyanide, 10 . 304 % sol ccm 5 oz . 1 A weak ammonia bath , per cent , will clear the whites . The following gives reddish-brown tones with clear whites ( Crab tree) Cupric sulphate Potassium citrate Ammonium carbonate 218 PHOTOGRAPHIC FACTS AND FORMULAS

2 2 Potassium f erricyanide 1 g 9 gr .

Water 1000ccm 16 oz . With all the above baths much more transparent images may be obtained by immersion for about 5 minutes in a 5 per cent

- hypo solution . A violet red tone is obtained ( Somerville) by treating a copper-toned image with - u Ammonia iron al m , 100 10% sol . ccm Hydrochloric acid 10ccm

u 10 . 80 Potassi m bromide , % sol ccm Water 1000ccm Bleach the print i n 1 Cupric sulphate 00g 76 8 gr .

Potassium bromide 100g 768 gr . 1 1 Water 000ccm 6 oz . Then immerse in a 2 per cent solution of nitric acid for 5 5 u minutes , wash well , and immerse in a per cent sol tion of

- s . sodium sulphite , which give a brown tone Bleach the print in

u erri nid 14 Potassi m f cya e g 0 gr .

s u 2 Pota si m bromide g 7 gr .

z Water 1000ccm 16 o . Wash for 10minutes ; then immerse for 1minute in 2 Acid potassium oxalate 7 g 208 gr .

Water 1000ccm 16 oz . Then bathe for a few seconds in a 6 per cent solution of ammonia , and immerse in :

° u u 1 C pric s lphate 0g 77 gr .

Hydrochloric acid ccm 12min .

Water 1000ccm 16 oz .

Until the desired colour is obtained ; then wash and ﬁx . Immerse the prints in ( Namias) Rochelle salts

220 PHOTOGRAPHIC FACTS AND FORMULAS

Rochelle salts Tartaric acid Potassium ferricyanide Water

This gives rich brown tones . Uranium nitrate Rochelle salts

u sol . Ammonia al m , sat . Tartaric acid Potassium ferricyanide Water

- This gives reddish brown tones . A simpler formula is

u e 5 3 r . A . Urani m nitrat g 8 g

Water 500ccm 8 oz .

5 3 . B . Potassium ferricyanide g 8 gr

Glacial acetic acid 14 ccm 96 min .

z Water 500ccm 8 o .

Mix just before use . Or the prints may be immersed in u u B ntil bleached, well washed , and then soaked in A ntil the u desired colour is obtained . In this last form la , the salts are

10 u u . dissolved as given ; that is , per cent sol tions are not sed Olive green tones ( Namias ) Tone the prints in the usual

u : urani m bath , then wash, and immerse in Ferric chloride 5 g Hydrochloric acid 10ccm Water 1000ccm - u Fix in the acid hypo sodi m acetate bath . — IRON OR CYANOTYPE TONING I n this process the colour on f u n is dependent the deposition o Pr ssian blue o the image , u and this is sol ble in alkalis ; therefore , long washing in ordinary water is inadvisable . Immerse the prints in a 5 per cent solution of potassium TONING BROMIDE PRINTS

ferricyanide with the addition of a little potassium oxalate , 2 u wash well , and treat with a per cent sol tion of iron to ammonium oxalate . This salt is the best use for all iron

a of . toning baths , as it is st ble and uniform composition ’ k s u S edlacz e form las are as follows , and all the quantities 10 u apply to per cent sol tions of the salts , unless otherwise stated Ammonia iron alum PotassI um citrate l n . so . Ammo ia alum , sat Hydrochloric acid Potassium ferricyanide Water

This gives a deep blue tone . 2 1 Ammonia iron alum 5 ccm 75 min . u 60 440 Potassi m oxalate ccm min . 100 u 00 . . . 7 Ammonia al m , sat sol ccm min 35 Hydrochloric acid 5 ccm min .

erri ni 20 m Potassium f cya de ccm 240 m. 1000 16 Water ccm oz .

“ “ ol This gives a c d blue . If the hydrochloric acid and alum be

10 70 . of 10 f omitted , and ccm ( min ) per cent solution o r u u ta taric acid be sed , a grey blue colo r is given Ammonia iron alum 100ccm Potassium bromide 60ccm Hydrochloric acid 10ccm water 1000ccm

i This g ves a bright blue . The following was specially recommended by Pfenninger - m for the blue constituent image in three colour work . I

or merse the print transparency in the following solution, made by weight

erric anide Potassium f y 230gr . 222 PHOTOGRAPHIC FACTS AND FORMULAS

10 77 . Sodium carbonate , cryst . g gr

Ammonium nitrate 10g 77 gr .

Salt 10g 77 gr . 1 Water 1000ccm 6 oz .

The image bleaches to a bright greyish brown , and should be then well washed , and immersed in 2 Potassium bromide g 4 gr . 12 Glacial acetic acid ccm 7 min . 42 Ammonium iron alum g gr . 1 1 Water 000ccm 6 oz . s a e A soon as the prints have ssumed a st el blue colour, they

u 5 cent , sho ld be well washed , ﬁxed in a per I solution of hypo 2 1 again well washed , and immersed for minutes in a per ul cent solution of sulphuric acid . The prints sho d be rather u u darker than us al , as this process red ces the density slightly . — VANADIUM TONING . This gives green tones which vary according to the ratio of iron to the vanadium salt and the f “ u n duration o the washing . The colo r is dependent o the u e - deposition of vanadi m ferrocyanid , which is yellow orange , in combination with Prussian blue ; with prolonged washing some of the latter dissolves ; therefore , the green becomes

Nami s brighter . a recommended separate baths :

u erric anide 50 3 Potassi m f y g 84 gr . 1000 1 Water ccm 6 oz .

Ammonia q . s . q . 5 . Add enough ammonia to make the solution smell distinctly after shaking well . Immerse the bleached and well washed prints in a bath compounded of the following stock solutions :

. u 2 l A Vanadi m chloride , per cent so ution 2 . o B Ferric chloride , per cent soluti n For use take A solution B solution

224 PHOTOGRAPHIC FACTS AND FORMULAS

Water 500ccm 17Moz . Mix into a cream and add slowly with constant stirring pure 70 118 3 s . . sulphuric acid, p gr ccm ( min) then follow the directions given above . The actual toning bath is A mmonium oxalate or sulphate solution as above 50ccm 50 Oxalic acid, sat . sol . ccm 0 u . sol . 5 Ammonia al m , sat ccm

2 . . 0 . Ferric oxalate, % sol q s Glycerine 50ccm a Pot ssium ferricyanide, 1 10 0 7 . % sol . ccm 7 min m 1 Water 1000cc 6 oz . Mix the oxalic acid and vanadium solutions with half the water ; then add the alum solution and the ferrl c oxalate ; mix the ferricyanide solution with the glycerine and the

of u . remainder the water , and add to the ﬁrst sol tion The

' the bl uer u 10 more ferric oxalate used , the colo r ; with ccm

(77 min . ) in the above bath a bright emerald green tone is u obtained . Toning takes from 10to 15 min tes ; the prints should be immersed in a 10 per cent solution of sodium

5 for 10 u sulphate for minutes , and then washed min tes . Namias suggests the following method of making van adium chloride : 10 Ammonium vanadate 0 g 768 gr . 2 m Hydrochloric acid 50cc 4 oz .

250 m z Water cc 4 o . S 60 80 460 6 1 . odium bisulphite , dry to g to 0gr Heat until the solution turns blue and dilute to 1000ccm 1 6 . ( oz ) with water . For green tones bleach the prints in the usual ferricyanide bath, wash well , and immerse in

s o 25 1 Vanadium chloride , a ab ve ccm 92min . c Ferric hloride g 19 gr . TONING BROMIDE PRINTS

Ammonium chloride 100g 768 gr .

z Water 1000ccm 16 o .

More ferric chloride gives bluer tones . Wash and ﬁx in an

- acid hypo sodium acetate bath . — LEAD TONIN G Various colours may be obtained by bleaching prints with a lead salt and ferricyanide , and sub sequent treatment with various reagents . The results are not very satisfactory ; there is a very great tendency for the he whites to be stained , and great intensiﬁcation is given . T bleaching bath may be :

Lead acetate or nitrate 40g 307 gr .

Glacial acetic acid 100ccm 770gr . 4 Potassium ferricyanide 60g 60gr .

1 z Water 000ccm 16 o . u u When thoro ghly bleached , the prints sho ld be washed with 10 three successive baths of per cent nitric acid, then washed for W one a short time with ater , and treated with of the

: following baths ammonium sulphide , for black ;

’ S chli e s 2 u - pp salt , per cent sol tion , for reddish yellow ;

u 2 for potassi m chromate , per cent , yellow ; ferric chloride for green ; c upric chloride for red ; uranium nitrate and ammonium chloride for red-brown ; cobalt or nickel chloride f r u - o green ; merc ric iodide for orange yellow . L ead-ir on for gr eeni shtones (Maquenne - This is a com plicated process , which is open to the same Objections as but u above , the prints m st be rather denser than normal , as

no . there is intensiﬁcation Four stock solutions are required , which Will keep in the dark :

A . Lead acetate Glacial acetic acid

Ferric chloride , dry Water B . Lead acetate 226 PHOTOGRAPHIC FACTS AND FORMULAS

Glacial acetic acid 100g 768 gr .

Water 1000ccm 16 oz .

100 768 . C . Potassium ferricyanide g gr

Water 1000ccm 16 oz .

D . Ferric chloride g gr .

Glacial acetic acid 10ccm 77 min . 1 Water 1000ccm 6 oz .

‘ To make A , dissolve the lead salt in the acid and water , add u - the iron , shake well , and ﬁlter . Bl e green tones are obtained by immersion of the prints for 5 minutes in a 2 per cent solution of glacial acetic acid and then in the following for 6 minutes

A solution 100ccm 1oz . 1 1 C solution 00ccm oz .

1 1 z Water 000ccm 0o .

u for Again immerse in the dil te acetic acid bath a short time , of wash well , transfer to a per cent solution citric acid ,

e ru and wash for an hour . Th n b the surface gently with a

of : pad absorbent cotton , and immerse in 5 10 3 Potassium chromate to g 8 to 77 gr . 1000 1 Water ccm 6 oz .

- The colour turns brownish green ; wash the prints , immerse u in the citric acid sol tion , as above , and wash for a short time . Bright green tones are obtained by preliminary treat ment with an acetic acid bath and immersion in : 80 6 14 A solution ccm min . 20 154 B solution ccm min . 100 C solution ccm 768 min .

1000 1 z Water ccm 6 o . u Then the prints m st be treated with the acetic acid, chromate u and citric acid baths . P re green tones are obtained by treating the prints to a preliminary acid bath, then im mersing in :

228 PHOTOGRAPHIC FACTS AND FORMULAS

z Water 1000ccm 16 o . Or the following (Eder) Uranium nitrate 5 g Ammonio -citrate or iron 5 g Glacial acetic acid 200ccm 1 Water 1000ccm 6 oz .

— - COBALT TONING (S omerville) Greenish or green blue but unsatis tones are obtained by this process , they are very

I factory . Bleach the mage in 60 4 Potassium bichromate g 60gr .

z Potassium ferricyanide 300g o . 1000 6 Water ccm 1 oz .

Then wash until free from any yellow stain , and immerse in 25 12 Cobalt chloride g 9 gr . 6 Ferrous sulphate g 46 gr . Hydrochloric acid 200ccm

1000 1 z Water ccm 6 o . Replacement of the hydrochloricby glacial acetic acid gives u brighter green tones . The prints sho ld be ﬁxed in :

250 4 z Hypo g o . 45 345 Boric acid g gr .

1000 16 z Water ccm o .

use . Dissolve by heat , and when cold Wash the prints well . Or bleach the image in Potassium ferricyanide 60g Lead nitrate 40g Water 1000ccm u Wash thoro ghly, and immerse in : 100 Cobalt chloride g 768 gr . 30 23 Hydrochloric acid ccm 0min . 1000 1 Water ccm 6 oz . — GOLD AND PLATINUM TONING (S omerville) Gold toning i s some e re o e to mo e to m ro e the tim s s rt d , r i p v colour ofprints TONING BROMIDE PRINTS than to Obtain warm tones ; and greenish or rusty prints can u be improved by placing them face p, as they come from the on of washing after ﬁxing , a sheet glass , dabbing into ﬂatness

of u with a clean pad linen , and br shing over with 14 Ammonium sulphocyanide 20g 5 gr .

Gold chloride 1g gr . H 1 ot water 1000ccm 6 Oz . s hen *A U e w . u cold soft ﬂat br sh , without metal binding, u u Sho ld be sed . When the desired improvement is reached , i s u - k that , when the image becomes black or bl e blac , wash u well , and dry . P rple blacks can be obtained by bleaching the prints ﬁrst in : u u 2 12 C pric s lphate 5 g 9 gr . P otassI um 25 12 bromide g 9 gr .

1000 1 z Water ccm 6 o . for 5 u 5 Rinse , and immerse min tes in per cent nitric acid , wash , and tone in. u Ammonium s lphocyanide 8 g 6 1gr .

Ammonia 3ccm 23 min . 1 Gold chloride g 8 gr .

“ e 100 Wat r 0ccm 16 oz .

10 20 u s Toning takes from to min te , and the more ammonia u sed , the deeper the tone .

Platinum toning gives warm sepias , but the results are not permanent . The following may be used ( Heatherly) s u 160 122 Pota si m oxalate g 8 gr . u 13 1 Merc ric chloride g 00gr . P um 20 14 otassi citrate g 5 gr . 40 Citric acid g 307 gr .

1000 16 z Water ccm o .

Mix , and add just before use Potassium chloroplatinite Hydrochloric acid 230 PHOTOGRAPHIC FACTS AND FORMULAS

Water 1000ccm 16 oz .

When the desired tone is obtained , wash well , and dry slightly darker tones are Obtained if the print is immersed in a 2 per cent solution of sodium carbonate . The following is stated to be suitable for bromide but not development (gaslight) prints :

Mercuric chloride 2g 16 gr .

Potassium chloroplatinite 4 g 32gr .

Citric acid 18 g 138 gr .

1 z Water 1000ccm 6 o . u u This sho ld be made p fresh , and gives warm sepias with

" of . For slight staining the high lights cold sepia tones , with of o u absence staining of the whites , add p tassi m bromide

1 . . g ( 8 gr . ) to the above Wash well after toning — SELENIUM TONING This gives various shades of sepia to purplish-red tones ( Miliani )

Powdered selenium 2to 10g to 77 gr .

Sodium sulphide 100g 768 gr .

z Water 1000ccm 16 o . u u u Heat the sol tion till the seleni m dissolves , and dil te as

u use. m req ired for The weaker the bath , the ore sepia the

u . u u colo r On dil ting the bath , some seleni m is thrown down ,

u or and the solution sho ld be ﬁltered , the prints after toning passed through two or three baths of 1per cent solution of u u sodi m s lphide . Another (Valenta) u 12 Seleni m g 7 gr . u u 200 3 Sodi m s lphide g oz .

1000ccm 1 z Water 6 o . u 5 6 Heat until dissolved , dil te with to times the volume of l 20 40 water , and add pyrocatechin , per cent solution , to ccm

154 30 1 z 6 o . to every liter or to 7 min . to If the whites are u tinged , pass the prints thro gh weak baths of acid sulphite of soda .

232 PHOTOGRAPHIC FACTS AND FO R MUL A S

When dissolved , pour into Nitric acid Water To make the bath use 4 Molybdate solution above 250ccm oz .

Water 1000ccm 16 oz .

Potassium metabisulphite 50g 384 gr .

This should be used in artiﬁcial light, and the prints well washed . TONING BY REDEVELOPMENT (Manly) -Various tones can be obtained by bleaching prints with the following baths and redeveloping with the given developers

u 3 2 0 . A . Potassi m ferricyanide 3 g 5 gr 4 10 Ammonium bromide 0g 3 gr .

1 1 z Water 000ccm 6 o .

B . Cupric sulphate 50g 384 gr . u 5 Sulph ric acid ccm 0min . 4 Common salt 50g 38 gr .

1000 16 z Water ccm o . P u . o 2 1 C tassi m bichromate 0g 54 gr . 5 min Sulphuric acid 0ccm 384 .

: 100 Salt g 768 gr .

1000 1 z Water ccm 6 o .

A one of fter bleaching in the baths , the prints should be

for 20 to 30 washed minutes , and redeveloped in the fol lowing :

I . Metol u Sodi m sulphite , dry

Sodium carbonate; dry Water

II . Hydrochinon Potassium metabisulphite Water TONING BROMIDE PRINTS

100 768 . III . A mmonium carbonate g gr

1 z Water 1000ccm 6 o . n f The tones are somewhat dependent o the make o paper, but the following will give a general idea of the tones Obtain of able . Bleach in A ; develop in equal parts II and III , diluted with more or less water ; rich purplish-brown tones

. 1 are Obtained Bleach in equal parts A , B , C ; develop in ;

s i I n . result , good black slightly want ng depth Bleach in B ; u - o I ; i , develop in splendid , velvety bl e blacks n the shad ws

’

C . 4 11 6 like arbon paper Bleach in C ; develop in parts , parts III and 2parts water ; distinct intense brown with pure

B h/ in . leac 1 1 1 whites C ; develop in part II , part III , part w l u . ater ; a good sepia , like s phur toning Bleach in C ; 2 1 2 develop in parts II , part III and parts water ; result , a bright brown .

l B ﬂ A 'R Sulphide Toning

There are two principal methods of obtaining warm brown or sepia to purplish brown tones : the direct and the indirect . u In the former , the image is converted into silver s lphide direct , while in the latter process the silver is ﬁrst converted

or e u . into chloride , bromide iodid , and then into s lphide — A lum n h B l DIRECT PROCESSES a d yp o ( aeke and) .

Hypo 200g 3 oz .

Potash alum 46 g 354 gr .

Water 1000ccm 16 oz .

u of u Dissolve the hypo , keeping the temperat re the sol tion u a near the boiling point , add the al m gradually with const nt 5 ° ° 122° . u 0 60 stirring, and allow to cool Heat p to to C . ( 14 ° 0 . to F ) each day for three days , and then add 1 I 0 . 5 7 40 55 . Silver nitrate , % sol to ccm to min u The bath m st not be ﬁltered .

A lum-su r—h B l n ga yp o ( aeke a d) . 2 2 Hypo 5 g 19 gr . u White s gar 40g 307 gr . u 2 2 Al m 5 g 19 gr . 1 1 Hot water 000ccm 6 oz .

s Mix a above . It is advisable to wash the prints thoroughly after ﬁxing , and with some papers it is advisable also to

m s for 5 u u s im er e min tes in an al m bath , then brieﬂy wa h and

° °

. u 44 110 tone The bath sho ld never be above C . ( the ° ° u u 2 u best res lts being obtained at abo t 3 C . (90 tho gh u 0 u toning at this temperat re takes 3 min tes .

A lum and h o A r tur — yp ( a) . Specially recommended for but u for development (gaslight) papers , eq ally suitable bromide prints

236 PHOTOGRAPHIC FACTS A ND FORMULAS

° ° ° 20 5 u 2 6 5 . 3 0 . 68 C ( to F ) for to min tes , and apparently

but for 1 u no change takes place ; , if washed Mho rs , the sepia tone makes its appearance . L iver of sulphur or p olysulphide process Woodman

Wash the prints free from hypo , harden by immersion in u formaldehyde sol tion , and place at once in a solution of liver of sulphur (sulphurated potash) made by dissolving

z a piece about the size of a pea in 200ccm ( 7 o . ) water .

l ul — A mmoni aca liver of s phur ( V ero) . The prints must be free from hypo and must not have been dried . Harden by

’ 10minutes immersion in a 10per cent solution of formalde hyde , wash , and immerse in

Liver of sulphur 7 g 54 gr .

Water 1000ccm 16 oz . Ammonia a few drops

- Toning is very rapid and purplish brown tones are obtained .

A mmoni um sul hid Kr p e ( opf) . u 2 12 A . Ammoni m sulphide 5 ccm 9 min . 1 1 Water 000ccm 6 oz .

2 . B . Ammonium carbonate g 9 gr 2 Water 15 ccm 2oz . 1 C . Ammonium persulphate g 0gr . 2 Water 15 ccm 2oz .

Mix in the above order . The colour of the mixture should - u u be greenish yellow, and , in abo t half an hour , t rn to

use. u golden yellow, when it is ready for Prints sho ld be

s wa hed for a short time after ﬁxing , and then immersed in the bath at normal temperature ; toning takes about 15 min

° ° u . 30 86 10 tes If heated to C . ( toning is complete in minutes .

S odi um sulphide-ferri cyanide B r own u 20 400 Sodi m sulphide, % sol . ccm S ULPHIDE TONING

Potassium ferricyanide ,

200ccm 4 oz . 20% sol .

e . The mixtur turns milky , but clears up on stirring well Then add 10 200 Potassium bromide, % sol . ccm Glacial acetic acid 50ccm u Stir until the precipitate dissolves . The prints sho ld be f rom 10 15 well washed , and, in to minutes after immersion

b u . in the ath , ass me a very pleasing brown tone S ulphi de~ ferri cyani de (B lake-S mi th) -Three stock solu tions are required .

. l 00 A Sodium sulphide , pure g Water 400ccm 2 . 5 B Sulphuric acid, pure ccm Water 250ccm u C . Potassi m ferricyanide 50g Water 500ccm For use mix A solution Water Then add 180 2 oz . 6 . B solution ccm , dr

And , ﬁnally, add C solution 500ccm u 2 5 Toning sho ld be complete in from to minutes .

A mmoni um sul hide- erri c nid p f ya e.

A . Potassium bromide Potassium ferricyanide Water

To this , add

. u 25 B Ammoni m sulphide ccm 192min . Water 100ccm Ths a o on s b i l st s luti hould e mixed just before use . 238 PHOTOGRAPHIC FACTS AND FORMULAS

Thi ocar bamide-sulphi de ( Tri epel)

Potassium bromide 10g 77 gr . 1 Potassium ferricyanide 15 g 15 gr . 31 Sodium sulphide 4 g gr .

Thiocarbamide 2g gr . 2 Caustic soda g gr . 1 Water 1000ccm 6 oz . — INDIRECT PRO CESSES . The bleaching bath may be made

or . either with a bromide , chloride iodide The correct formula for the bromide is Ammonium bromide For the chloride Salt For the iodide Potassium iodide Each should be added to

u erri c nide 35 269 Potassi m f ya g gr . 0 Water 100ccm 16 oz . u u If the halide salts be sed in the above q antities , there is no

of f loss in the intensity the images , which will be the case i u they are sed stronger . The above may be kept as stock solutions . The following gives a somewhat colder sepia than the above Potassium ferricyanide 6 g Ammonia 15 ccm Water 1000ccm u u Vario s modiﬁcations have been s ggested, as Potassium ferricyanide 23 g Potassium iodide 14 g Ammonium persulphate 14 g Water 1000ccm

Potassium iodide

240 PHOTOGRAPHIC FACTS AND FORMULAS

print and cause blisters . A stock solution that will keep ( Blake-Smith) can be made as follows z Sodium sulphide 330g 5 o . 1 z dr 50 6 5 . o . Sodium sulphite, y to gr Mto z Water 1000ccm 15 o . u For use dilute with 9 volumes of water . The bath sho ld not be used too long . Ammonium or barium sulphide may be used instead O f the sodium compound

Ammonium sulphide 10to 20ccm 77 to 154 min . 1 Water 1000ccm 6 oz .

2 Barium sulphide g 5 gr .

1 z Water 000ccm 16 o . Shake the latter solution for a few minutes and allow to stand for any precipitate to settle , and then ﬁlter . The barium salt is more stable than the sodium and therefore preferable in practice .

For chlori sin or g bromising the image , quinone has been recommended (Lumiere S eyewetz ) ' 5 3 r Quinone g 8 Mg .

‘ Sodium chloride (salt) 6 g 46 gr .

Sulphuric acid 3ccm 23 min . 1000 1 Water ccm 6 oz . 11 5 Potassium bromide g ( 8 gr . ) may be used instead of the sodium chloride . The bleached images are amenable to exactly the same treatment as all other bleached images . u Molybdenum and tin sulphur compo nds , called sulpho or thiomolybdates and stannates have been proposed ( Smith) “ ” the former was introduced commercially as Cubrome and gives excellent results . This solution can be made as fol lows Ammonium molybdate SULPHIDE TONING

1 z Hot water 1000ccm 6 o .

When cold, add in small quantities with constant stirring,

‘ ammonium sulphide sufﬁcient to form a deep orange solu

: tion . For use mix

Stock solution 100ccm 770min .

Ammonia 10ccm 77 min .

Water 1000ccm 16 oz . f the If the whites o prints are stained yellow, immerse for a 3 u a short time in a per cent sol tion of ammonia, and w sh e o thoroughly . This gives xcellent results with the bichr mate bleaches . Sodium sulphostannate may be prepared as follows e 2 0 u u 30 3 . Sodi m s lphid , pure g gr

. 1 z Water 1000ccm 6 o .

Stannic sulphide 70g 538 gr .

u u one- of t Dissolve the sodi m salt in abo t fourth the wa er , add the tin salt , and heat gently with constant stirring until u dissolved ; then dilute to bulk . Stannic s lphide is known

u or u or . also as tin dis lphide , bis lphide , mosaic gold One part of the above solution should be diluted with 9 parts of

s water for u e.

S ul hi d s lus l — p e p deve op er . This method gives somewhat darker tones , as some black metallic silver is probably formed u with the sulphide . The prints sho ld be bleached as usual

G reenall ( ) , and then treated with the following : 1 Metol g 7 . 7 gr . P otassium carbonate g 100gr . 3 u 1 . 5 2 3 0 . Sodium s lphide , % sol to ccm to 4 min 100 Water 0 ccm 16 oz . a f This gives warm black , which varies with increase o the sulphide . ’ Valenta s method requires three stock solutions

. 20 A Pyrocatechin g 154 gr . 242 PHOTOGRAPHIC FACTS AND FORMULAS

50 384 . Sodium sulphite , dry g gr

Water 1000ccm 16 oz .

200 3 . u . B . Sodi m carbonate , cryst g oz 1 Water 1000ccm 6 oz . ’ 1 chli e s 0 77 . C . S pp salt g gr 1 1 Water 000ccm 6 oz . us 2 1 for For e mix parts A with part B , and sepia tones add 4 2per cent C ; for warm brown tones add percent C .

sul i s — I Toni ng wi thmercury phde . n this method the varia tion of colour depends on the addition of more or less mer cury salt to the image ( Bennett) . Two stock solutions are required for the bleaching bath u 11 A . Ammoni m bromide g Potassium ferricyanide 35 g Water 1000ccm 28 B . Mercuric chloride g Potassium bromide 28 g Hot water 1000ccm And two stock solutions for the toning bath

1. u 330 Sodi m sulphide g 5 oz . u 50 6 5 38 5 Sodium s lphite , dry to g to 500gr . 1000 1 Water ccm 6 oz . ’

. S chli e s 10 II pp salt g 77 gr .

1000 1 z Water ccm 6 o . The following table gives the colours obtainable with the various baths B leacher Black Brown black Deep brown Dark brown Deep " warm brown Reddish brown

244 PHOTOGRAPHIC FACTS AND FORMULAS

’ — S ulphide and S chlippe s salt Variation of colour may be obtained by combining sodium or ammonium sulphide with ’ u u S chlippe s salt ( Bishop ) . Ten per cent sol tions of sodi m ’ S chli e s u or sulphide and pp salt sho ld be made , the com u mercial solution of ammonium sulphide may be sed . For red-brown tones mix S ulphide solution ’ S chlippe s salt solution Water For warm brown S ulphide solution ’ S chlippe s salt solution Water For brown tones e u 75 6 Sulphid sol tion ccm 57 min . ’ chli e s u 2 1 S pp salt sol tion 5 ccm 92min . 1000 1 Water ccm 6 oz . — Carmi ne or r ed chalk tones: These can be easily procured by treatment of a sulphide toned print with gold sulpho cyanide Gold chloride g Ammonium sulphocyanide 23 g Water 1000ccm The following ( Blake- Smith) acts better

. 1 1 A Gold chloride g 5 gr . 225 Water ccm 7 oz .

B . 2 Thiocarbamide g 3gr . 1000 1 Water ccm 6 oz .

. u 10 C S lphuric acid ccm 77 min . 1000 Water ccm 16 oz . For 1 1 use mix part each Of A , B and C with 0parts water . Allow the action to continue until the deepest shadows are toned . SULPHIDE TONING

l hi - t ri nts — u R educi ng su p de oned p . S lphide toned prints may be reduced by treatment with most of the usual negative

r u reducers o with chlorine and bromine water, sol tions of

u u . iodide , permanganate , and s lph ric acid The most satis

u u or factory are sol tions Of c pric chloride bromide, the latter for preference ( Smith) . The chloride reducer is equal parts of a 5 per cent solution o f cupric chloride and a

r u n of u : 15 pe cent sol tio common salt . The bromide red cer is

5 5 . Cupric bromide 7 . g 8 gr

u r Sodi m bromide g 480g .

1 1 z Water 000ccm 6 o . The cupric bromide in this bath may be replaced by using

6 5 . u u u g ( gr ) c pric s lphate , and increasing the sodi m bromide by 8 g (6 1 After reduction the prints should be immersed for 2minutes in a 5 per cent solution of hydro

f r u 1 o u . chloric acid , and washed abo t 0min tes

P ar ti al develo ment and sul hi di n — p p g. Bleach the prints in

u u for the us al ferricyanide and bromide mixt re , wash 90 u seconds in r nning water , and immerse for various times in 30 the following developer ; rinse for seconds , and treat with u u - the s al sulphide bath .

Metol g 14 gr .

Hydrochinon g 35 gr . u u Sodi m s lphite , dry g 70gr . 140 Borax g gr . Water 1000ccm 16 oz The following table shows the various tones obtained 246 PHOTOGRAPHIC FACTS AND FORMULAS

- m B m o v o 5 " m m m ? a o o a o s m a m u c m 9 m s m o s a 8 u t “ 2e g o 2 " e u 9 s B H t o o e o w m

8 8 S m 5 E o 3 B 5 5 E S E 8 8 E O N N ~ G o

. . . . v m o N w

248 PHOTOGRAPHIC FACTS A ND FORMULAS

: used . The ﬁnal conclusions are that excessive bromide in the bleach leads to loss of image ; too long washing after u bleaching sho ld be avoided, as well as weakness or too long u of use of the s lphide bath , and presence hypo in the latter . The C arbon Process

— MAKING THE TISSUE The gelatine mass is prepared with

3 : 1 or hard and soft gelatine in the ratio of , the ﬁnest pale ’ u a u of u carpenter s gl e m y be sed , with an admixture s gar candy ; in very hot dry climates a little glycerine . The latter addition is not advisable under ordinary circumstances . A typical formula is Gelatine 200g

S ugar candy 50g 384 gr .

Water 1000ccm 16 oz .

i i Colour ng p gment 4 to 10g 30to 77 gr . Soak the gelatine and candy in the water for about 30minutes u and melt on a water bath . The pigment sho ld be the ﬁnest

u u . u powder colo rs , as sed by artists It sho ld be worked up with a muller on a sheet of glass with a little of the gelatine

u to re u sol tion , and added the mainder of the sol tion , well stirred and strained through linen

THE — urs n COLOURS . The colo ca be mixed in various pro so ma u portions , that any shade y be obtained , and these sho ld be judged by their appearance when mixed with a little of the u gelatine sol tion and dried .

Chocolate br own — 6 4 1 Indian ink , English red , alizarin , u u 1 dissolved in a little soda solution , p rp rine part .

E n r avi n black — 19 1 g g Lamp black , carmine lake 0, indigo 10 parts .

Warm black — 6 Lamp black , carmine lake 6 , burnt umber 4 2 , indigo parts . D ark brown — 2 6 1 Indigo M, Indian red , carmine M, Van 4 dyke brown , lamp black 30parts . 249 250 PHOTOGRAPHIC FACTS AND FORMULAS

— 6 8 8 R ed br own Indian ink , carmine , Vandyke brown parts . — i 4 35 . S ep a. Lamp black , sepia parts — 15 2 P ur e black Indian ink , Vandyke brown , Venetian red 2 parts . — 20 2 1 . Vi olet black Indian ink , indigo , carmine part l — 10 5 R ed cha k English red , Italian red , lamp black parts .

Trans arenc tissue or enlar ed ne atives and osi tives. p y f g g , p — 2 3 5 . Indian ink , Indian red , carmine lake parts — To COAT B Y HAND Strain the warm mi xture into a ﬂat u O ff dish standing in warm water , and clear the b bbles the surface with a strip of paper or thin card . Hold the paper to u u be coated pright at the f rther end of the dish , its lower u u edge j st to ching the liquid, and gently lower it on to the

u . 2 s rface Float for minutes , and raise with a steady mo tion ; allow todrip and hang up to dry . — SENSITISIN G Either ammonium or potassium bichromate may be used : u 21 1 4 0 Potassi m bichromate to 6 3g 60to 8 gr . 1 Water 1000ccm 6 oz .

Ammonia q . s . q . s . Enough ammonia should be used to make the solution smell distinctly . For weak negatives use the weakest bath, for normal negatives the mean , and for harsh negatives the

. 3 u strongest bath Immerse the tissue for min tes , and dry in

° . u f u 1 the dark The temperat re O the sol tion should be 5 C .

° (60 F . ) The following gives a tissue that will keep better 2 2 Potassium bichromate 0g 40gr . 5 Citric acid g 60gr .

Ammonia q . s . q . s .

252 PHOTOGRAPHIC FACTS AND FORMULAS

u or paper is sed , either matt glossy , which may be prepared as follows : 1 1 Gelatine 00g Moz . 230 Barium sulphate 30g gr . 3 Glycerine 5 c 8 min .

1 z Water 940ccm 4 o .

Soak the gelatine in water, dissolve by heat , and add the

baryta rubbed into a cream with the glycerine . Add very carefully , almost drop by drop , with constant stirring 1 Chrome alum g 3 gr .

z Water 60ccm 2o .

or Paint the mixture thickly over the paper, else ﬂoat it u twice , hanging up by opposite ends each time . Obvio sly ,

single transfer or commercial baryta paper may be used .

S — u WAXING OLUTION . The temporary s pport has to be f u waxed prior to use, and the ollowing may be sed 15 Beeswax 20g 4 gr .

Powdered resin 20g 154 gr . 1 Turpentine 1000ccm 6 oz .

Melt the wax in a water bath, add the resin , and stir until dissolved ; then add the turpentine gradually with constant

stirring . This takes from 12to 24 hours to dry ; if ether be

u u u . s bstit ted for the turpentine , it will dry in a few min tes — Cauti on; u The water in the bath sho ld boil , and then the

u out f u gas be t rned , as the vapours o both t rpentine and ether

are explosive . This should be applied to the paper with a

off u pad , polished with a dry pad , and then hung p to dry .

ALUM BATH FOR DISCHARGING BICHROMATE STAIN .

Alum g 1oz . 1 1 Water 000ccm 6 oz . —T COLLODION FOR DOUBLE TRANSFER FROM OPAL . his ﬁne u u gives an extremely matt s rface , witho t any glaze, if THE CARBON PROCESS

u matt surface glass be sed ; if polished opal be used, a high gloss is obtained :

Pyroxyline g 6 5 gr .

Alcohol 500ccm 8 oz .

Ether 500ccm 8 oz . — A s . OPAL GLASS, IVORY OR WOOD FINAL SUPPORT Coat with the chrome gelatine - mixture given above under single

FO r u u transfer paper . canvas , the s rface paint sho ld be

u hot u 1 removed by scr bbing with soda sol tion , about 0per

u but . cent , ntil nothing the priming is left Paint freelywith

- u u the chrome gelatine mixt re , dry thoro ghly, rub down

' ﬁne sand a er a u smooth with p p , nd repeat the operations abo t u four times . The print sho ld be ﬁnally soaked in the gelatine

u u . sol tion , and sq eegeed into contact

TRA N S PA RE N CI E s — SUBSTRATUM FOR . Either of the fol lowing may be used : 40 30 Gelatine g 7 gr .

1000 1 oz Water ccm 6 . u 4 31 Potassi m bichromate g gr .

t e 30 Coat h glass thinly , dry , and expose to light for minutes ; then wash and dry . Or the glass may be coated with the following, which keeps well Gelatine Glacial acetic acid Water

Dissolve by heat , and add slowly A lcohol Phenol (carbolic acid)

i i Then add , with constant st rr ng Chrome alum 5 g 14 10 Water ccm 7 min .

TO TR A N S PA R E N CI E — INTENSIFY CARBON s. Immerse in 254 PHOTOGRAPHIC FACTS AND FORMULAS

38 Potassium permanganate 5 g gr . 1 1 Water 000ccm 6 oz . u of e Rinse and dry . Weak sol tions acid anilin dyes may also

u . of be used, abo t per cent By the use the latter it is n possible to alter the colour in a y desired manner .

256 PHOTOGRAPHIC FACTS AND FORMULAS

2 1 Dark red: Peach black , parts ; alizarin lake, part 1 Indian red, part .

B lack or encil drawi n s : . , f p g Graphite

B lack : Peach or blue black .

Warm black : Ivory black . — ARABIN G U M -BICHROMATE PROCESS The best Soudan e: gum arabic should be sifted through a 40mesh sieve . Tak 2 Hydrochloric acid 7 . 5 ccm 17 min . Water 150ccm

° ° 1 um 122 00 3 . 50 . Heat to C ( sift in g ( Moz ) of the g , 600 and stir until dissolved ; then add methyl alcohol , ccm

(21 and stir until the arabin is precipitated . Filter

u u out u h . thro gh linen , and sq eeze as m ch alco ol as possible u u ut Then break p the l mp , p in jar , and cover with fresh alcohol ; leave for some hours with constant stirring until

all . the water has been absorbed by the alcohol Squeeze dry ,

out u . spread to thoro ghly dry, and powder To make the : coating mixture, take 20 300 Arabin g gr . u 20 3 Magnesi m carbonate g 00gr . 40 5 1 2 Water to 7 ccm Mto Moz . The quantity of water depends on the thickness of the solu u tion desired . Mix the pigment of the desired colo r with the u u u above ntil a thick cream is formed , add an eq al vol me of 15 u u per cent sol tion of ammoni m bichromate , and spread ff on paper . Development is e ected in the Usual way with

° °

u 35 . water at abo t C (95 F ) . — u FORMULA FOR PURE WHITES . Freq ently pure whites are f u di ﬁc lt to Obtain with this process , and the following is said to obviate this trouble Potassium bichromate 72g Water 450ccm u Dissolve by heat , add eno gh ammonia to make the solution THE GUM - BICHROMATE PR OCES S

ff to o . smell distinctly, and then heat drive excess of ammonia to Beat the whites of several eggs a froth , and allow to 24 u u stand for ho rs to liq efy . The pigmenting solution is :

sol . 450 Bichromate , above ccm Cupric sulphate 90g G um arabic , powdered 800g Pigment 600g Albumen 200ccm Glycerine 100ccm u Mix well , and apply as sual to the paper . The I ron Processes — FERROPRUSSIATE OR CYANOTYPE PROCESS . This process is much used for the preparation of engineering and ’ on u draughtsman s plans , giving white lines a bl e ground ,

u of . that is to say, a bl e image is formed by the action light The sensitive solutions can be made as follows u 250 A . Ferric ammoni m citrate (red) g Water 1000ccm

Filter .

200 3 z o . B . Potassium ferricyanide g

1000 1 z Water ccm 6 o . u - Filter . The ferricyanide m st be in perfectly clear ruby red

advis crystals , free from any adherent yellow powder ; it is

‘ re out able to allow a little mo in weighing , and place the u u crystals in a ﬂask ; po r in some distilled water , shake , po r off the water , and repeat this operation ; then add the water

u . for the sol tion , and heat until dissolved Mix the two solu tions in equal volumes and ﬁlter . Either ﬂoat the paper on

l u for 3 or u the so tion minutes , paint the sol tion on freely u u with a broad ﬂat br sh , and dry as q ickly as possible , prefer

” ably by heat . A much more sensitive paper is obtained by using the green ammonio -citrate of iron ; then the solutions should be

A . Ferric ammonium citrate green) Water

Filter , and add

B . Potassium ferricyanide Water

260 PHOTOGRAPHIC FACTS AND FORMULAS

It is important that the paper base should be free from u wood p lp , preferably sized with starch, and with a hard u to surface . It has been s ggested add white dextrine to the

but u . sensitiser , this lowers the keeping q ality The paper u should be exposed preferably to sunlight until the gro nd ,

s of e or corre ponding to the whites the negativ plan , appears a dark olive-green ; it should then be thoroughly washed with u u on r nning water , and the lines sho ld appear white a deep u or or blue backgro nd . With stale paper with excess of

u or . imp re ferricyanide , the lines will appear more less tinted r ri in u 15 r Fre With unde p nt g the colo r more o less pale . quently , by somewhat prolonging the washing, the lines will clear up ; or this can be much curtailed by using a per

r cent solution of ammonia o sodium carbonate . This gives u subse a violet tinge to the bl e, and this can be corrected by

5 of quent treatment with an acid, per cent hydrochloric, u u or u of oxalic ( or s lph ric acid, al m solution the same u e strength . A m ch more stabl and contrasty image is ob tai ned if the print is developed with a per cent solution of u for r potassi m ferricyanide, and well washed four o ﬁve minutes . Numerous methods have been suggested for toning blue but u u prints , , as a r le, the res lts are extremely unsatisfactory . Immerse the dry print in

i s . . 897 6 Ammon a ( p gr ) ccm 9 min . 1000 1 Water ccm 6 oz .

u for As soon as the bl e color disappears , wash a few minutes , and then immerse in a 2 per cent solution of tannin ; this

s u u gives a blacki h colo r , but the o tlines may become blurred

i of from spread ng the colour into the whites . Or the print may be well washed in distilled water, and bleached in yellow light in S ilver nitrate THE IRON PROCES SES

Water 1000ccm 16 oz . u Wash with distilled water , and f me with ammonia , expose O to light , and develop with ferrous xalate ; then wash thor oughly . The cyanotype process may be used for making lantern

or u u slides transparencies , tho gh , nat rally , the colour is suit able for but few subj ects . The sensitising solution is rather weaker than used for paper : A.Ferric ammonium citrate

’ 4 z (green) 250g o . 1 z Water 1000ccm 6 o . 1 u 00 768 . B . Potassi m ferricyanide g gr 1 z Water 1000ccm 6 o . u out Mix in eq al volumes and ﬁlter . Gelatinised glass (ﬁxed for 5 dry plates may be used) should be immersed minutes ,

i d. and rapidly dried . The sensitiser will not keep when m xe

The plates should be exposed like the paper , and washed in the same way . ’ — PELLET S OR G U M -IRON PROCESS This process gives blue

on i u of lines a wh te ground , th s the reverse the cyanotype

r or . process , f om a drawing plan The paper has very poor u keeping q alities . Originally patented by Pellet . Three stock solutions should be prepared ( Pi z z ighelli )

. 200 A Gum arabic g 3 oz . 10 Water 00ccm 16 oz .

- . f 500 z B Ammonio citrate o iron (red) g 8 o . 1000 1 Water ccm 6 oz .

. 500 C Ferric chloride g 8 oz . 1000 1 Water ccm 6 oz .

u I n These sol tions will keep indeﬁnitely the dark, with the

u For exception of A , which becomes acid in abo t a week . use mi x in the following order : A solution 200parts 262 PHOTOGRAPHIC FACTS AND FORMULAS

B solution 80parts C solution 50parts

to It is important to adhere to this order , for , if A be added

u . C , the mixture becomes l mpy and useless The mixture is u but u at ﬁrst thin and ﬂ id , soon becomes more visco s , and in u f a few hours clo dy and o the consistence of soft butter . It should be used in this condition and will keep in the dark for

H u k : several days . a g recommended

u 1 5 300to 350 Gum arabic sol tion , parts

u : 10 100 Ammonium ferric oxalate sol tion , 6 parts u 20 30 Ferric chloride sol tion , to parts

n u Float the paper o this mixt re . Another excellent formula (Waterhouse) is G um A . arabic Water

B . Tartaric acid Water

C . Ferric chloride solution , 2 s . 1 10 14 1 p gr . 00to g 5 3to 8 5 1gr .

u or of Filter the gum sol tion through a sponge pad cotton , and mix with the acid ; then add the iron solution , which

u . sho ld be weighed , not measured , with constant stirring u 24 u Allow the mixt re to stand in the dark for ho rs , and add

- water to make the speciﬁc gravity Well sized paper,

- preferably gelatine Sized , should be fastened by pins to a

not ﬂat board , and the mixture applied too thickly with a ﬂat

. u brush As soon as the br sh begins to drag, the coating should be evened out with a round brush with circular strokes . l This operation should be performed by artiﬁcia light , and u the paper rapidly dried in the dark . The paper sho ld be u 15 40 kept nder pressure . The exposure will be from to

sun ff seconds in the , or proportionately longer in di used

264 PHOTOGRAPHIC FACTS AND FORMULAS

u . heat . Filter the mixt re through ﬁne linen Or the follow ing may be used

Gum arabic 100g 768 gr . 2 1 Ferric chloride 328 g 5 9 gr . 1 Tartaric acid 220g 690gr . 1 u 220 690 . Ferric s lphate , basic g gr

1 z Water 1000ccm 6 o . i Dissolve in the above order and ﬁlter . The follow ng ( Fisch) is only suitable for heavily Si zed or gelatinised papers

Ferric chloride 100g 768 gr .

Water 500ccm 8 oz .

Dissolve , and add

r i r Ta tar c acid 30g 230g .

“ z Water 500ccm 8 o . Or the following ( Shawcross) may be used for any paper

Gelatine 137 g 1052gr . 22 55 4 . Ferric sulphate , basic g gr u Sodi m chloride 87 g 668 gr . 1 1 Tartaric acid 7 g 30gr . 1 2 Ferric chloride 37 g 105 gr .

Water 1000ccm 16 oz . The solutions should be applied with a broad ﬂat brush or pad by artiﬁcial light , and rapidly dried . The paper will keep

2 r su for o 3 weeks . Expo re should be made under a drawing for 10 u u u about min tes in s nlight , or ntil the lines appear n yellow o a white ground . Development is effected on :

Gallic acid 6 g 46 gr . 1 Oxalic acid g 7 .7 gr .

1000 1 z Water ccm 6 o . THE IRON PROCES SES

The image should become black in from 3 to 5 minutes . The print may be completely immersed in the developer or ﬂoated

on u . u its s rface As soon as the image is intense eno gh , wash

off u with repeated changes of water , gently blot the s rface

u a . water , and hang p to dry in a warm pl ce It should be noted that the ferric sulphate used i n this process is the basic ’ M n ell u u or o s s . variety , also known as s bs lphate , salt

’ " I —I n GREASY OR PRINTER S N K PROCESS . this process the solubilisation of a colloid by the action of light on the iron

of u s for salts , and the capacity the insol ble colloid taking greasy ink i s employed ; it was suggested by Fisch G um 320 24 1 arabic g 5 gr .

z Water 1000ccm 16 O . e Dissolv , and add Tartaric acid Water

: And add , with constant stirring u Ferric chloride sol tion, 4 ° 5 . 22 5 3 z . 2 o 88 . Be g , gr Then add u 10 Manganese s lphate g 77 gr . 25 12 Water ccm 9 min .

o u All w to stand in the dark for several ho rs , and then ﬁlter

u s h u . t e u u thro gh ﬁne m lin Coat the paper in s al way , and 5 ° 4 ° 95 ° 113° dry at 3 to 5 C . ( to Or the following may be used G um arabic 325 g Water 1000ccm

Dissolve , and add Tartaric acid or Citric acid

Then add , with constant stirring

Ferric sulphate 200gr . 266 PHOTOGRAPHIC FACTS AND FORMULAS

or Ferric nitrate And add in the same way Uranium nitrate or Uranium chloride : Finally, add

Ferric chloride solution ,

s 210 3 oz . p . gr . ccm %

- Filter through muslin and coat well sized paper therewith .

The expo sure will be from 3 to 6 minutes in sunlight . Place

on of the print face up a sheet zinc or glass , and with a roller lightly charged with printer ’s ink roll up the surface until u niformly grey . Immerse the inked print in cold water ,

or u and transfer to a metal glass plate s pported at an angle , allow a S pray or stream of water to play over the surface ; with a pad of absorbent cotton gently rub the print . The exposed parts will be gradually dissolved , leaving only the inked parts .

- - PR CE s —A TRUE TO SCALE O s . f cheap and ready process for ’ u 25 u obtaining a few , abo t , p lls in printer s ink from line A drawings , etc . good black original is the best . Ferro prussiate or cyanotype paper should be exposed under the

or u on plan drawing, and witho t development laid down a ” or graph jelly , gently rubbed into contact , and immediately stripped . The jelly is now rolled over with a good letter press ink with a composition roller and it only takes on the A f lines . piece o paper is now laid on the jelly and rolled

on over lightly with a light roller , and, lifting, the impression u n u will be fo nd o the paper . Inking m st be done before each pull . The j elly can be made as follows

u 500 z Gl e g 8 o .

to 1000 z Water make ccm 16 o .

for u Allow to soak some ho rs , melt with heat , and add

1 z Gelatine g o .

268 PHOTOGRAPHIC FACTS A ND FORMULAS

dry plates in a 2per cent solution of tartrazin . The exposure 30 2 u n varies from seconds to min tes , according to the se si i s f f h t vene s o the paper and the strength o t e light . The developer should be preferably hydrochinon well restrained

- for . with bromide , as generally used line work Printing out u paper may be sed in the same way . And also the following (Albert) Albumen ’ u Fish gl e, Le Page s Ammonium bichromate Water

u 2 . Fish gl e 37 . 5 ccm 88 min

Ammonium bichromate 3 g 23 gr . u 2 Grape s gar g 5 gr .

om 1 z Water 1000c 6 o . Dissolve the sugar in about one-fourth of the water before u adding the other ingredients . Glass sho ld be coated with a whirler and exposure is best effected with a half -watt lamp at a constant distance , the glass being placed with the coated f h t side down on the drawing . Development is ef ected with o u u water , and the print can then be stained p with a sol tion of u u or b a dye , s ch as chrysoidin , water sol ble nigrosin , y immersion in a 4 per cent solution of potassium permangan

a of . ate , which gives deep brown image manganese dioxide

- PR I TI N B urian — COBALT IRON N G ( ) . This process seems more suitable for line drawings than prints from ordinary photographic negatives . Oxalic acid Water u Heat ntil dissolved , and add u Ammoni m oxalate , neutral

When dissolved , add THE IRON PROCES SES

Cobalt carbonate 8 g gr . u Effervescence takes place , and the mixt re should be digested until it turns red . The cobalt carbonate can be made by 16 adding 39 g gr . ) crystallised sodium carbonate to g of s ( 123 gr . ) cry tallised cobalt chloride , and washing and drying the precipitate . To the above red liquid, cooled down ° ° 95 : to 35 C . ( add

Lead peroxide 5 g gr . 2 Glacial acetic acid 3 ccm 3 min .

u . On shaking, the solution t rns a deep green From this point all further operations must be conducted by yellow light . Add

Lead peroxide 5 g gr . 2 Glacial acetic acid 3 ccm 3 min . out Pour the solution into a ﬂat dish, and allow to evaporate 10 until crystals form and it is dry . Add ccm ( 77 min . ) of 1000 16 water, ﬁlter , and make the bulk up to ccm ( b 20 14 The iron salt is obtained y mixing g ( 5 gr . ) of ferric u s lphate with ammonia , washing the precipitate, and adding

of . 36 g gr . ) acid ammonium oxalate This can be 2 0 f made by addi ng 30ccm ( 3 min . ) o ammonia to l 00g

768 . of ( gr ) oxalic acid, gently heating, adding more am monia until the solution smells distinctly of ammonia , then

off of 1 heating to drive excess ammonia , adding 00g

768 . u l ( gr ) of oxalic acid, heating ntil dissolved , and a lowing to crystallise . The actual sensitising solution is made by

2 of 1 mixing parts the cobalt solution with part of the iron . Paint on the paper with a brush and dry rapidly ; the paper u sho ld be a green colour . Exposure may be to daylight or an arc, and the image should show a bright yellow on the ff green ground . Development is e ected in a 1per cent solu tion of potassium ferricyanide until the whites appear white ; then brieﬂy wash and immerse in 1per cent hydrochloric 270 PHOTOGRAPHIC FA CTS A ND FORMULAS acid ; again wash and immerse in a solution of sodium sulphide until the paper turns grey ; then wash until white .

The sensitised paper will only keep about 6 hours . If the u c to ordinary ferric oxalate be sed , the pro ess is said be suitable for ordinary negatives . — - KA . LLITYPE This is a silver iron printing process , based n - u o the light sensitiveness of ferric salts , which are red ced to the ferrous state . The ferrous salts dissolve in the devel u s oper, and red ce ilver nitrate to the metallic state at the b points where the ferric salt has been reduced y light . l ’ F l Ha l s ormu as.

A . Ferric oxalate 200g Gum arabic 20g Water 1000ccm

B . Ferric potassium oxalate g Water 1000ccm 125 C . Oxalic acid g

52 cm 100 Ammonia c min .

1000 z Water ccm 4 o .

. a 12 D Pot ssium bichromate g 0gr . 1000 4 Water ccm oz . mi x 480 240 B 30 4 For use parts A , parts , parts C, and parts

. dr 3 . 5 . 7 . For D Then add silver nitrate , y , parts thin and soft negatives , increase the proportion of D from 30to 50 u f b - per cent , and red ce the proportion o C y one half or more . Developer

c 125 1 z Sodium a etate g o . 2 Tartaric acid g 1 gr . 5 50 10 Solution D , above to ccm to 100min . 1000 Water ccm 8 oz . Clearing bath S odium citrate Citric acid

272 PHOTOGRAPHIC FACTS AND FORMULAS

- 12 6 . 2. Ferric ammonio citrate , brown g gr 60 30 Ferric oxalate g gr .

Potassium oxalate 60g 30gr . 12 6 Cupric chloride g gr . 20 10 Gum arabic g gr . 1000 1 Water ccm oz . - 2 3 50 5 . . Ferric ammonio citrate , brown g gr 1 Ferric oxalate 30g 5 gr .

Potassium oxalate 70g 35 gr . u 16 C pric chloride g 8 gr . 30 1 Oxalic acid g 5 gr . 30 1 Silver nitrate g 5 gr . 20 10 Gum arabic g gr .

1000 1 z Water ccm o . u desn d Add potassi m bichromate solution , as e . u In preparing these sol tions , mix in the above order , leave for 24 u ho rs in the dark, and ﬁlter through cotton . Print faintly, and develop in S 80 40 ilver nitrate g gr . 20 1 Citric acid g 0gr . 16 Oxalic acid g 8 gr .

1000 1 z Water ccm o . 3 1 - Add sodium phosphate g ( % gr . ) for blue black tones . 1 For use mix part with 7 parts water . Fix in 3 4 24 32 Hypo to g to oz . 1000 1 Water ccm 6 oz . u - For brown , bl e green , and other colours

- . 0 A Ferric ammonio citrate , green 7 g Ferric oxalate 16 g Potassium oxalate 12g Oxalic acid 44 g Uranium nitrate 40g Gum arabic 20g THE IRON PROCES SES

Water 1000ccm Potassium bichromate ‘ 1 48 6 12 3 6 o solution , to ccm to dr ps

Allow to stand 24 hours in the dark ; then ﬁlter .

nitr te 100 50 . B . Silver a g gr l

Citric acid 60g 30gr . 10 Tartaric acid 20g gr . 1 1 Water 000ccm oz . o dr h First c at the paper with A , and allow to y ; then coat wit i n n su . B . Pr nt in the until the half tones are slightly ti ted For sepia tones wash and ﬁx in Salt 4 g Hypo 4 g Water 1000ccm For green tones immerse the print in 3 Potassium ferricyanide g 4 gr . Nitric acid 3 ccm 4 drops r 1000 Wate ccm 4 oz . Remove from this solution j ust before the green tone is reached , and ﬁx in weak hypo . Platinotype

This process is based on the light-sensitiveness of ferric u u oxalate, which is red ced by the action of light to ferro s oxalate , which dissolves in the alkaline oxalate used as a u u u developer , thus red cing the platin m salt , sed in the sensi

u of . tiser , in sit ; the iron salts form no part the image It is important that the ferric oxalate should be free from u ferrous salt , and the most satisfactory way to ens re this is u a : to prepare it . The following method sho ld be dopted

0 oz . 56 u 52 9 . Ammonia iron al m g , gr

Water 500ccm 8 oz .

Heat until dissolved , allow to cool slightly, and add Ammonia 200ccm

u 5 u . u Stir well for abo t min tes Then filter the sol tion , and wash the filter with repeated lots of water until the filtrate i s no longer alkaline to litmus paper . Then dissolve in : 2 1 1 15 6 5 . Oxalic acid , pure g gr

12 z Hot water 800ccm o . Pour this solution over the filter repeatedly until all the ferric hydroxide is dissolved ; wash the filter with sufficient water to make the volume of the solution 1000ccm ( 16 filter An alternative method, which obviates the necessity of

but to u ing, takes longer , is powder some iron al m, and out weigh the above quantities . Place the powder in a tall graduate ; the tall metric cylindrical graduates are the most convenient . Pour on the powder the above quantity of am e u u monia mix d with an eq al vol me of water . Stir for a few u 10 u e u min tes , and allow to stand for min t s . Fill p the u graduate with water, shake or stir well , allow to stand ntil

off the precipitate has somewhat subsided , and syphon the 274

276 PHOTOGRAPHIC FACTS AND FORMULAS

o 15 u All w to soak for min tes , dissolve by heat , and add

u 24 . Oxalic acid, p re g gr There will be further required a 10 per cent solution of l l 6 P .6 H u u aCl . tC O sodi m platin m chloride ( N ) 2 4 z , and a in solution of potassium chloroplatinite . All stock solutions must be kept in the dark . The best results are obtained with pure linen papers ; cheap

- wood pulp papers will not give good results . While it is not u absol tely essential with good papers , a preliminary sizing is desirable , and for this purpose gelatine, arrowroot , or of tragacanth may be used . The disadvantage gelatine is a d that it is very prone to form air bubbles , n arrowroot is To 2 preferable . prepare the gelatine size, make a per cent

u of 1 f . sol tion gelatine in water , and add per cent o alum To make the arrowroot rub 20g ( 154 gr . ) into a thin cream with

1000 16 oz . water , add to ccm ( ) boiling water with constant

u 5 . stirring , and contin e boiling for minutes Allow to cool , r and remove the skin which fo ms on top . The gelatine size must be used warm .

To apply the size , the paper should be pinned to a drawing

or u board , other flat s rface at the corners and the size applied with a broad flat brush in straight strokes , first across and u u u u then p and down the paper , ntil the s rface is niformly

. u wet Then a round soft br sh , a perfectly clean shaving

u work ed all u brush being excellent , sho ld be over the s rface u ntil it appears even and begins to lose its gloss . It may u u then be h ng up to dry . For ro gh drawing papers the sheets u 5 0 sho ld be immersed in the size for from to 3 minutes ,

of u according to the thickness the paper , and the ro ghness of su the rface . The paper should be drawn over the edge of

so off u the dish, as to wipe as much sol tion as possible , and then hung up to dry with the end that leaves the dish last at the top . PLATINOTYPE

PR Ess —To TH E COLD BATH O C . sensitise the paper it - u should be fastened by glass headed push pins to a ﬂat s rface . with a sheet of blotting paper underneath . As it is important that the sensitising solution should not come into contact

to u with the pins , it is advisable provide the latter with g ards , which can easily be prepared by cutting small squares of u n u cardboard , t r ing p the edges , and passing the pins l n through the midd e . As the paper expands and crinkles o

' of u application the liq id , the pins may be removed , and the s paper restretched and again pinned down . The sensiti er is i . 3 50 . A Potass um chloroplatinite sol . ccm min

- Lead iron sol . ccm 75 min .

u 5 . 5 Sodi m chloroplatinate 7 . drops 7 drops 3 1 Water to 8 ccm 50to 30min .

l u s . 3 Potassi m chloroplatinite o ccm 50min .

- Lead iron sol . ccm 75 min. - 1 Oxalic gelatine sol . ccm 17 min . u Sodi m chloroplatinate 7 . 5 drops 7 . 5 drops 3 8 0 1 Water to ccm 5 to 30min .

u . 3 50 Potassi m chloroplatinite sol ccm min .

- sol 3 Lead iron ccm 50min . u 2 Sodi m ferric oxalate sol . ccm 33 min .

u n 7 . 5 Sodi m chloroplati ate drops 7 . 5 drops 3 8 50 130 Water to ccm to min . The quantity of water in each formula is dependent on the u of the u u s rface paper ; smooth s rfaces req ire less , rough u ones the greater q antity . Increase of the water to 2 to 14 1ven times that g above gives grey prints . The above quantity of uf for 3750 cm 580 sensitiser is s ﬁcient q ( sq . in . ) of paper . Increase of the sodium chloroplatinate gives increased con trasts u u , or an eq al vol me of a 10 per cent solution of 278 PHOTOGRAPHIC FACTS AND FORMULAS

f potassium bichromate may be used instead . Omission o ff these naturally gives softer e ects . Sensitiser A with arrow

to - but root sizing tends brownish black tones , with plain , not

- arrowroot sized, drawing papers , black tones ; with gelatine

- sized papers blue blacks are given . A and B give too hard

s u u prints with contrasty negatives ; then C ho ld be sed , as this gives softer results . After printing until the image is faintly visible in greyish u u violet against the p re yellow nprinted parts , the print should be rapidly and evenly immersed in either of the following developers Neutral potassium oxalate Water

Neutral potassium oxalate 100g 770gr . u Potassi m phosphate 50g 384 gr . 1 Water 000ccm 16 oz .

of f I o , im t is preferable to take hold _ _ both ends the paper

one merse end in the developer , face down , draw right u u u thro gh the sol tion and then t rn face up. Development is comparatively slow and takes from 1to 2 minutes ; the

u soon x s f dish sho ld be gently rocked . As a su ﬁcient depth is attained , immerse the print , without washing , in 2 1 Hydrochloric acid 0ccm 54 min .

Water 1000ccm 16 oz .

u . face downwards . The dish sho ld be rocked After 5 min

of utes , remove the print to a second dish water acidulated 15 u as above , and , after min tes , remove to a third dish of f 15 u half the above strength o acid . At the end of min tes ,

u 30 off place the print in r nning water for minutes , then blot

. of between blotting papers , and dry Dilution the developer gives more brilliant prints ; or the same result may be ob tained by adding 2to 5 per cent of a l per cent solution of

280 PHOTOGRAPHIC FACTS AND FORMULAS

should be developed for not less than 5 minutes . The acid baths should not be stronger than from to 1per cent ; the acid treatment with the three baths should not last longer u u than 30minutes in all . The smaller q antities of the merc ry solution give the best colours . For this process the best

- results are obtained with paper sized with agar agar , which may be prepared as follows

- Agar agar 10g 77 gr .

Water 1000ccm 16 oz . 24 u u off Soak for ho rs with an occasional stir , then po r the u water , and add enough fresh water to make the total b lk

u . a u to to the above q antities He t ntil boiling , and allow boil f r 10 u w - o minutes ; ﬁlter thro gh a piece of ell washed linen , and allow to cool until a ﬁrm jelly is obtained . This jelly u u u sho ld be sq eezed twice thro gh coarse canvas , so as to u u divide it up into little nodules . A small q antity sho ld be

on f u placed the paper , worked all over with a fairly stif br sh ,

u u . u then eq alised with circ lar strokes with a softer br sh , and u n dried . The q antity used depends o the surface of the

u not . paper, but this sho ld be strongly glazed when dry TH E HO T — I n BATH PROCESSES . this process a hot devel oper is used and the sensitiser should be

sol 2 Ferric oxalate . 6 ccm 4 mm . u 4 Potassi m chloroplatinite sol . ccm 28 min .

- . 1 Gelatine oxalic sol ccm 7 min . Greater contrasts in the prints may be obtained by the addi tion of 5 to 10drops of sodium chloroplatinate solution or a l u of u per cent sol tion potassi m bichromate . The sam e", " developers as used for the cold bath papers may be used at a?

° u 50 ° 122° ° temperat re of to 75 C . ( to 167 For sepia tones the sensitiser should be

Ferric oxalate sol . 6 ccm 100min

u . 4 Potassi m chloroplatinite sol ccm 67 min . PLATINOTYPE

u Merc ric chloride ,

l 1 3 17 . 5 % so . to ccm to min Sodium chloroplatinate 2to 10drops 2to 10drops

Water 2to 4 ccm 33 to 67 min . The quantity of water is as before regulated by the surface u of the paper . The sol tion should be applied in the manner for : already described . The best developer this paper is

Potassium oxalate 100g 770gr .

Potassium phosphate 50g 380gr .

Citric acid 20g 154 gr .

Potassium ct ride 10g 77 gr .

z Water 1000ccm 16 o .

° ° ” 158 Use at a temperature of 70 C . ( L i ner COLD BATH PAPER ( a ) . A u 50 . Ammoni m ferric oxalate g

z Water 58 ccm 2o .

150 . 10 . 8 Oxalic acid , % sol ccm mm

u 2 30 . B . Potassi m chloroplatinite g gr

Water 10ccm 150min .

2 : The sensitiser for 3352q cm ( 5 0sq . in . ) should be

A solution 4 ccm 6 8 min . 1 B solution 8 ccm 36 min .

136 . u 4 . 8 Potassi m bichromate , % sol ccm min Immerse the exposed print for from 1to 3 minutes in the u u u developer , special salts being s pplied for this , ntil f lly

u of developed ; then clear in fo r acid baths hydrochloric acid ,

r u and wash fo a short time in r nning water . For

° ° s sepia print the developer should be heated to 66 to 8 8 C . ( 150° to 190° and the prints cleared in three acid baths

i f h s o half t e above strength . Development hould be effected in a feeble white light . The addition of 2 10 4 drops of a 10per cent solution of potassium bichromate to the developer f increases the brilliancy o the prints . 282 PHOTOGRAPHIC FACTS AND FORMULAS — PA L L A DI O TY P E PAPER This paper gives a very visible

and u u on printing image , expos re sho ld be carried until all details are visible . Immerse the prints face up in

Sodium citrate g 10oz .

1 z . Citric . acid g o

z Water 1000ccm 43 o . ° For black prints the temperature should be kept between 7

° ° ° 4 to 60 For use and 16 C . ( 5 sepia paper

Sodium citrate 50g 6 oz .

Citric acid g 150gr .

Water 1000ccm 120oz . ° 100° 38 . Heating the developer to C ( not beyond , gives

for r : warmer tones . Clearing bath both pape s

Sodium citrate g 10oz .

Citric acid 93 g 4 oz .

1 z Water 000ccm 43 o .

For use mix 1part with 7 parts water . Three baths should u 10 15 20 u the be sed , with , , and min tes in ﬁrst , second , and

F r 6 third baths respectively . o brilliant prints add from 4 to drops of a 10per cent solution of potassium bichromate to

r the developer . Wash the prints in running water for 10o

15 or 1 u minutes in several changes of 0min tes each . S A TI STA R — u and PAPE Print ntil a faint image appears , develop in 2 Potassium oxalate 00g 8 oz .

Oxalic acid g 100gr .

Water 1000ccm 40oz .

° °

u u 21 0 . Temperat re abo t C . ( 7 F ) for warmer tones heat ° °

38 . 100 to C F ) . Clear the prints in Sodium citrate 4 g

Water 1000ccm 75 oz .

f 10 15 u res ec Three baths are advisable o 5 , , and min tes p tivel b 10 u y , followed y a short washing for min tes , not

284 PHOTOGRAPHIC FACTS AND FORMULAS

allow the paper to dry at normal temperatures . The devel oper should be

Potassium oxalate l g 16 gr .

Potassium chloroplatinite l g 16 gr .

Potassium phosphate g 8 gr.

Water 12ccm 192min .

Glycerine 6 ccm 96 min .

u on s Place the print face p a heet of glass , and paint with u n the above , using a broad ﬂat br sh , and worki g as quickly e u 20 as possible . For the abov area of paper abo t ccm

f u . ( 154 min . ) o developer will be req ired r For line work o black and white work, this process is ' u very suitable , and the following sensitiser should be sed

- 120 . l 7 .5 Lead iron so . ccm min Potassium chloroplatinite

6 . sol . ccm min u Ne tral potassium chromate ,

6 . l % sol . ccm min 2 5 10 . Water 7 . ccm min u f m The above q antity is su ﬁcient for 5940qc ( 870sq . The best developer for this work is 12 4 Potassium chloroplatinite ccm 8 min .

Glycerine 50ccm 350min . 4 0 Water 5 ccm 8 oz .

1 z u Thirty ccm ( o . ) should be sed for the above area . Actu

O r ally, this process is as cheap as cheaper than any silver printing process . The acid baths must be used with all papers as already described . — PLATINUM PRINT-OUT PAPER I t is possible to prepare u out platin m paper that will print in the printing frame, but u it does not keep well , and the res lts are greatly dependent on u f r the h midity of the paper at the time o p inting . If too dry , only the shadows will appear ; while if too damp , ﬂat PLATINOTYPE

r u : foggy results a e obtained . The stock sol tions are A , the u u u normal potassi m chloroplatinite sol tion ; B , sodi m ferric 50 4 100 8 oxalate g ( water ccm ( C , gum arabic 50g (4 water 100ccm (8 The sensitiser is :

u 4 6 5 . Potassi m chloroplatinite sol . ccm min

98 . Sodium oxalate sol . 6 ccm min

6 5 . G um sol . 4 ccm min Increased contrast may be Obtained by the addition of sodium chloroplatinate or potassium bichromate solution as in t he u x other processes . The paper must be dried q ickly . E pos ing the paper to steam after printing, if the image appears of uf s ﬁcient depth only in the shadows , is of some assistance , but e a , at the b st , it is not a satisf ctory process . — SEPIA TONES BY DEVELOPMENT . Ordinary hot bath paper may be developed to sepia by the use of the following devel oper ( Hii bl ) u 100 Potassi m oxalate g 768 gr . s 50 Pota sium phosphate g 384 gr . 20 154 Citric acid g gr . u 10 Potassi m chloride g 77 gr . 10 7 Mercuric chloride g 7 gr .

a 1000 1 z W ter ccm 6 o . 0° 16 ° Use at a temperature of 8 C . ( 7 Or the following may be used u 65 Potassi m oxalate g 500gr . m 11 Potassiu citrate g 8 5 gr . 16 12 Citric acid g 3gr . u 52 Merc ric chloride g gr . 1000 1 Water ccm 6 oz .

° ° to 3 Heat 5 C . ( 95 Or the following (Jacoby) may be used u 250 Potassi m oxalate g 4 oz . 100 125 800 1 Zinc oxalate to g to 000gr . 286 PH OTOGRAPHIC FACTS AND FORMULAS

z Water 1000ccm 16 o . ° ° 69 ° 8 3° Heat to 21 to 28 C . ( to The larger the : quantity o f zinc oxide the warmer the tone . Or Potassium oxalate 200g

Acid ammonium phosphate 25 g 200gr .

Cupric sulphate l g 8 gr .

Water 1000ccm 16 oz . The following complicated developer has also been recom mended

250 4 oz . A . Potassium oxalate g

Water 1000ccm 16 oz . 12 32 5 . B . Cupric chloride g gr

Water 1000ccm 8 oz .

u 1oz . C . Merc ric chloride g 16 oz Water 1000ccm . 1 32 6 . D . Lead acetate g gr

4 z Water 1000ccm o . 1 4 4 1 Add 2parts of A to parts B , then parts C to part D , and heat until the preci pitate ﬁrst formed i s redissolved .

° ° of 176 Use at a temperature 80 C . —B LOCAL DEVELOPMENT . y thickening the developer with

- glycerine , it is possible to develop cold bath prints locally, ff ” a so as to obtain various e ects . Paint a sheet of gl ss larger than the print with glycerine , thinly and evenly . Use four

u or u teac ps saucers ; ﬁll A with p re glycerine ; B , with

10 u s u u glycerine parts , sat rated ol tion of potassi m oxalate

1 10 u O f part ; C , with glycerine parts , sat rated solution

u 5 u of potassi m oxalate parts ; D , with sat rated solution

u on l rined potassium oxalate . Lay the print face p the g yce glass , and dab into contact with a pad of clean linen . Paint u the whole of the print with the pure glycerine , sing a long s u 3 handled oft br sh , and allow to soak for minutes . Sat urate the brush with the B mixture and paint over the whole

288 PHOTOGRAPHIC FACTS AND FORMULAS

I n nsiﬁcation u 15 . parts B . te will be complete in abo t minutes

old D ollond — I ntensifyi ng wi th g ( ) . The print should be on of u placed face up a sheet glass , and , if previo sly dried , must be soaked in water ﬁrst . Dab into ﬂat contact with a clean linen pad , and paint the surface with glycerine , using

s on u O f a soft bru h . Then pour the s rface a few drops a per cent solution of gold chloride and paint rapidly over with the brush . As soon as the desired intensity is reached , rinse u a nder the tap , and sponge back and front with normal metol u f developer diluted with an equal vol me o water . There is some danger of the white assuming a pink or blueish tint with this process . l PL A TI TY E — u n TONING NO P s. Platin m prints can be to ed u e with urani m, iron, and catechu . The ﬁrst giv s brownish red tones , the second blue , and the third browns . For the uranium toning the following stock solutions are required u 1 A . Urani m nitrate 00g 76 8 gr . 1 Glacial acetic acid 00ccm 768 min .

Water 1000ccm 16 oz . m . 100co B Potassium ferricyanide 76 8 gr .

1 1 z Water 000ccm 6 o .

A mmom m u 3 40 C . u s lphocyanide 500g 8 gr . 1 1 Water 000ccm 6 oz .

use 10 1 1 z For add ccm A to 000ccm water ( 77 min; to 6 o . ) 10 10 77 . 7 . then add ccm ( min ) C and , ﬁnally, ccm ( 7 min )

. 10 u 5 35 . of B Instead of the s lphocyanide, ccm ( min ) a u per cent sol tion of sodium sulphite may be used . The well washed print should be placed in a dish, well ﬂooded with of u plenty the solution , and the dish rocked ntil the desired tone is Obtained . On the slightest sign of the solution becom ’ u oﬂ ing cloudy, po r and apply fresh ; otherwise the whites will be stained . The iron toning requires PLATINOTYPE

u 100 768 . C . Ammonia iron al m g gr

Hydrochloric acid 100ccm 768 min .

1 z Water 1000ccm 6 o .

1000 16 oz . use 5 35 . For add ccm ( min ) A to ccm ( ) water ,

5 35 . . 2 14 . then ccm ( min ) B , and , ﬁnally, ccm ( min ) C u u u Both these baths , partic larly the rani m , intensify the prints . The catechu toning process ( Packham) gives warm brown tones, but it is difﬁcult to keep the whites pure ; on the other ff a hand, this is rather e ective than otherwise , as the print p n o u pears as if prepared o t ned paper . A stock sol tion is prepared o f

Catechu 78 g 600gr . r 1 Wate 000ccm 16 oz . 5 m s or Boil for inute in a glass porcelain vessel , and add

200 z Alcohol ccm 3 o . For use mi x 20 Stock solution ccm min . 1000 16 Water ccm oz .

s u When used cold , this take some ho rs to tone , but , by rais

° ° ° ° l u u e 55 64 130 g the temperat r to to C . ( to 147 only

u 15 s u abo t minutes is neces ary . Sho ld the whites be stained,

e : and it is desired to r move this , soak in Castile soap 9 g u 1 Sodi m carbonate, cryst . 8 g Water 1000ccm e s u Wh n the tain is red ced, wash and dry . — COPPER TONING (Menk e Four stock solutions are re quired

A . Cupr1o sulphate Water

B . Potassium ferricyanide Water 290 PHOTOGRAPHIC FACTS AND FORMULAS

u . . C . Potassi m citrate , sat sol

100 768 . D . Potassium sulphocyanide g gr z Water 1000ccm 16 o . : 140 140 For use mix in the following order A parts , B parts ,

50 . C 24 parts , D parts As this is nothing more than a for modiﬁcation of the copper toning process bromides , pre f sumably the same class o tones will be obtained . BLUE PRINTS BY DEVELOPMENT ( Waverl ey)

. 22 Potassium oxalate, sol . ccm u Potassi m ferricyanide,

1 9 ccm 0 . 10% 5 0 . 7 mm

Glycerine 55 ccm 42min .

Water 1000ccm 16 oz . u Printing must be carried deeper than sual . The prints as

' sume a green tone in the developer and only turn blue in the acid baths . — PRINT-OUT SEPIA PAPER Another method of Obtaining pure brown tones is by the admixture of some palladium salt

chloro alladite 10 with the sensitiser , potassium p in per cent u u sol tion being used . The paper sho ld preferably be sized with arrowroot , and the sensitiser is :

u hl r ll di c o o a a te s l 4 6 5 . Potassi m p o . ccm min u Sodi m ferric oxalate 6 ccm 97 min .

- . 2 2 Lead iron sol ccm 3 min . 3 6 45 Water to ccm to 96 min . The image is so slightly visible that an actinometer should be u sed . Development should be effected with steam or by pressing the prints between damp blotting papers . Another method is by the use Of mercury ( Piz z ighelli )

. u e 10 A Potassi m chloroplatinit g 70gr . 60 42 Water ccm 0min .

. u 40 B Sodi m ferric oxalate g 280gr .

40 2 r Gum arabic g 80g .

292 PHOTOGRAPHIC FACTS AND FORMULAS

chloric acid until there is a faint smell Of chlorine . Or mix 1part Of chloride of lime with 1part of sodium carbonate or u and 10parts water, stir well , ﬁlter decant the clear sol

90 u . I m tion , add parts water , and faintly acid late as above merse the stained print in either O f these solutions until ff bleached ; then wash and dry . This treatment cannot a ect the image . PR I T - u VARNISHING PLATINUM N s. Freq ently platino types appear rather dull and sunken-in compared to their r appearance when wet . Application of p int varnishes will then brighten them up ; but the surface should not appear ’ u glossy . Artist s size, diluted with warm water , may be sed ; or megilp may be used in the same way ; or [the print may be sprayed or lightly painted with 1 part of mastic varnish ff diluted with 8 parts alcohol . For stronger e ects ordinary negative varnish may be applied locally or generally with a u of u 4 brush . Or a sol tion gelatine , abo t per cent , may be made , the print bodily immersed in this while warm , and

u en hung p to dry . Or the print may be rubbed with caustic paste .

R ES I DUE s — of u PLATINUM . The high cost platin m makes u it well worth while to save all platinum resid es . Scraps of paper , if unexposed , should be exposed to daylight and u u “ developed in the s al way . Print trimmings should be u b rnt , the scraps of the paper previously dealt with being u mixed with them . The developer sho ld be mixed with one

u of u of u u fourth its vol me sat rated solution ferro s s lphate , boiled, and the platinum precipitate allowed to settle or be u ﬁltered o t. The ﬁrst and second acid baths should also be

of l saved , boiled down until convenient bu k, at least one u u fo rth their original vol me , and scrap zinc added . Black u platin m is precipitated, and may be collected on a ﬁlter .

not o to e the r o It is w rth while mak esidues int platinum salts, PLATINO TY PE

but the residues should be sent to a reﬁner , who will allow

of reﬁn cash for them , with the deduction , a small fee for ing . An alternative plan is to mix the developing and acid

of baths , and immerse sheets clean copper therein , when the platinum will be deposited on the copper as a precipitate . off The platinum deposited on the copper can be scraped , and mixed with the precipitated metal .

- — - TY P E A u ld . PL A TI N o UR A N O . little sed process ( Reyno s )

‘ Two stock solutions are required

u i . A . Urani m chlor de , sat sol u 4 B . Potassi m chloroplatinite g Water 48 ccm u u - Mix in eq al vol mes , paint over well sized paper , and

u to rapidly dry . Potassi m chlorate may be added increase contrast . Print until only a faint trace of an image is visible , and develop on a ferrous oxalate developer . Wash the prints u u 1 in three s ccessive baths of hydrochloric acid , abo t % per cent , wash , and dry .

- — MER CUR o UR A N O TY PE Very little used (Reynolds ) . Two stock solutions are required :

u u of u u A . Sat rated sol tion rani m chloride

u u of r u B . Sat rated sol tion me c ric chloride

use 1 For mix 8 parts A with part B and apply to paper . Ex u u pose ntil the image is seen in f ll strength , then ﬂoat on a dil ute solution of chloride of gold or potassium chloro platinite . Wash in water acidiﬁed with hydrochloric acid ,

s wa h and dry . The toning may be omitted when warmer tones are obtained .

PA L L A — DI O TY P E . u Coat paper with ranium chloride , ferric

or u or u oxalate , sodi m ferric Oxalate , a mixt re of all three . Expose until the image is faintly visible ; then ﬂoat the print on 294 PHOTOGRAPHIC FACTS AND FO R MUL A S

hl r ll di e 1 r Potassium c o opa a t g 1g .

Water 500ccm 1oz . u Or paint this over the print , wash in acid lated water, then in water, and dry . The image is somewhat similar to platino

but . type , Of a warmer colour T I o DISTINGUISH A BROMIDE FROM A PLAT NUM PRINT . Touch a small corner of the print with a saturated solution of u 10 u of u merc ric chloride , or a per cent sol tion potassi m

s cyanide . In the ﬁrst ca e , the bromide image is bleached , u and, in the second , the bromide image is dissolved ; platin m u ff images are na ected .

296 PHOTOGRAPHIC FACTS AND FORMULAS

2 14 Alum 0g 5 gr . 0 30 Boric acid 3 g 2 gr .

z Water 1000ccm 16 o . u It is as well to add to this a few drops of ﬁsh gl e . A piece of linen or Canton ﬂannel should be wrapped round a reason u ably large pad Of absorbent cotton , some of the above sol

u on to of u tion po red the middle the paper , evenly distrib ted

u . with the pad , and then the paper h ng up to dry in the dark u 3 5 u The expos re will be from to min tes in summer , and u from 15 to 25 minutes in winter . The paper sho ld then be

too u . washed in water, but long washing m st be avoided

A piece of pigment tissue , the same size as the paper , should be immersed in the following : — Hydrochloric acid 2ccm 15 min . 2 Ferrous sulphate g 7 gr .

Water 1000ccm 16 oz . This is suitable for normal p ictures ; for contrasty prints reduce the iron salt to -g ( 19 and for soft prints 35 u u increase to g ( When the tiss e is q ite limp , u immerse the print in the bath , bring the two s rfaces into

out u contact , lift together , sq eegee into close contact , and 30 60 u leave for from to min tes , the longer time giving ff greater detail in the prints . Development may be e ected

or o at once , delayed for s me hours if more convenient . A later procedure required the following stock solutions

. 2 z A Hydrochloric acid 8 ccm 1o . u u 31 4 C pric s lphate ccm 80gr .

0 2 z Water 56 ccm 0o . The working solution was composed of

Hydrochinon g 9 gr .

1130 z Water ccm 40o . u 1 2 Sol tion A 4 to 8 ccm V2 to 1oz .

u use For soft pict res of small size from hard negatives , the OZOTYPE AND ALLIED PROCES SES 297 lesser quantity of A ; for normal negatives use 21ccm oz and for large prints from soft negatives use the full

The u hu quantity of A . pigment tiss e s o ld be immersed in 30 the above for seconds , the print also immersed therein

u to out u and bro ght into contact face face , lifted , thoro ghly

u or . sq eegeed , and left in contact as advised f the ﬁrst bath 1 u If the two are left in contact for more than % ho rs , they should be afterwards immersed in cold water for from 30to

mI es f carbO n 45 nut . Development may be ef ected as in the ° ° 109 ° 115 ° process with water from 43 to 46 C . ( to As rI nt im soon as development is complete , the p should be mersed in a 5 per cent solution of alum or Alum 28 g Hydrochloric acid ccm Hydrochinon g Water 560ccm for the same time , and then washed . —I n OZOBROME . this process , pigmented tissue impregnated with a bichromate and ferricyanide is brought into contact u with a bromide print . The metallic silver red ces these com

“ i s pounds , and the gelatine hardened in contact with the u u silver , so that it becomes insol ble in hot water , j st as u tho gh it had been exposed to light . Practically , it is a

of carbon process , in which chemical action does the work

out light ; it is , therefore , possible to carry the process at

t ne nigh , and many carbon prints may be obtained from o

u . bromide , if tho ght desirable Any good bromide print may be used ; but the best results

- are obtained with those not on baryta coated paper . The

' print should be ﬁrst hardened by 1mmers1on for 5 to 10

u 5 u of u or min tes in a per cent sol tion al m , formaldehyde , 4 u or a per cent chrome alum sol tion , washed, and dried . The ozobrome or sensitising solution is as follows ( Manly) 298 PHOTOGRAPHIC FACTS AND FORMULAS

Potassium bichromate Potassium ferricyanide Potassium bromide A lum Citric acid Water Or ( Schmidt) Potassium bichromate Potassium f erricyanide Potassium bromide Alum Citric acid Water Or ( Faworski )

Potassium bichromate g 64 gr .

Potassium ferricyanide g 5 1gr .

Potassium bromide g 5 1gr .

Chrome alum 3 g 23gr .

Citric acid 1g 7 .7 gr .

Water 1000ccm 16 oz . In hot weather the addition of 1per cent of magnesium sulphate to the above baths is advantageous ; or of ( Namias)

Chromic acid 5 g gr . 2 Potassium bromide 0g 154 gr .

Water 1000ccm 16 oz . The bromide print should be immersed in cold water for 10

u n t . min tes , and placed face up o a shee of glass The pig ment tissue should be soaked in 1part of the ozobrome solu tion diluted with from 4 to 5 parts of water for 2to 3 min

r utes , and then transfer ed to an acid bath . This is preferably kept as a stock solution : Chrome alum

300 PHOTOGRAPHIC FACTS AND FORMULAS

B . Glacial acetic acid

Hydrochloric acid, pure Formaldehyde The working solutions are 1 First bath . A solution part Water 3 parts 1 S econd bath . B solution part Water 32parts

The ﬁrst bath may be repeatedly used , but the second should u be made fresh every time . The temperat re is important , ° °

1 . . and 8 C . (6 5 F ) is convenient The bromide print must u u be thoroughly and evenly soaked in water . The tiss e sho ld 3 be immersed in the ﬁrst bath for minutes , and transferred f to the second bath . The length o stay in this determines f u the character o the res ltant print . If the ﬁnal print is to be 20 u like the bromide , seconds wo ld be correct ; a shorter time gives increased contrasts , a longer time softer prints . u ff The act al time varies with di erent makes of bromide paper , bu u u t the above r les apply to all . The soaked tiss e is removed u from the second bath , sq eegeed into contact with the wet u 15 bromide print , and the two left in contact for abo t min u tes . A longer time gives a darker print . The tissue , after the lapse of the necessary time , is stripped from the bromide

of . print , and the latter put into a dish water to wash The tissue should be brought into contact with a well-soaked sheet of u u transfer paper , thoro ghly sq eegeed , allowed to remain 30 minutes , and then developed as in the carbon process . A lower temperature of the developing water should be started

u neces with ; hotter may be sed as development proceeds , if

’ sary . Almost any kind of bromide paper may be used ; but l development (gas ight) papers are less satisfactory . After the bromide print has been well washed , it can be developed in white light with any developer . It is advisable for the OZOTYPE AND ALLIED PROCES SES 301

bromide print to have a white margin . Critical sharpness of not the carbro print is attainable , as the chemical action is a ffu di sion process , and this takes place sideways as well as downwards . O il and B romoil

— u for BROMOIL . The most s itable bromide papers this pro cess are those with fairly thick emulsion ﬁlms , with smooth or half matt surfaces which have not been hardened in the

e for s o . manufacture . Many firms make special pap rs thi w rk ut A method of testing paper is to c a strip , fix , wash, and dry ° as usual ; then immerse in water at 25 C . ( 77 gradually raise the temperature , and note when the film begins to feel ° °

30 35 . slimy or slippery . This should be between and C

° °

86 95 . n ( and F ) if higher than this , the gelatine has bee u u u u e hardened d ring manufact re , and is ns itabl for the pur

O r u u pose , will req ire higher temperat res for the solutions 24 ° 2 ° ° u u to 8 . 75 than the s al ones , which range from C ( to 2° 8 F Any developer can be used, though the least suit is e u able pyrogallol , and the b st temperat re for development 1 ° 6 5 ° is 8 C . ( The prints should be well exposed and t - u developmen carried to the limit , that is to say, ntil there f is no longer any further accretion o density . The print should be rinsed two or three times with water and preferably 30 u 3 ﬁxed in a per cent sol tion of hypo , containing per cent

u u u or u potassi m metabis lphite . Al m chrome al m hypo baths

u out u u . are unsuitable . Washing sho ld be carried as s al Some adherents of this process insist on the absolute neces

sit of r . y drying the prints , while others consider it det imental

s or of on The neces ity, otherwise , this step depends the

of s u character the gelatine ; soft gelatine req ire drying, while harder ones can be worked up at once .

As will be seen from the following tables , there is a wide

- choice of bleaching and relief forming baths . Those contain u ing copper salts are the most favo red . The most convenient 302

304 PHOTOGRAPHIC FACTS AND FORMULAS

2 3 4 6 2 2 Chr omi c aci d 1 18 30 Potassi um br omi de 4 28 33 30 18 Cup r i c sulphate

- m R ei tma er 6 . u er . A n on . 4 . c r ott 5 . ur 1 Nami as 2. mi t 3. ; ; y ; . ; S h ; S h W D vivi 1 2 3 4 5 6 7 8 9 10 11 12 12 4 0 43 40 22 30 10 Cupr ic su lp h ate 20 Cup r i c br omi d e 0 3 20 20 30 1 P otassi um br omi d e 10 8 4 4 2 1 2 15 P otassium bi chr omate 10 2 1 10 Potash alum 1 Chr ome alum

0. S ulphur i c aci d Gl aci al aceti c aci d Potassi um chr omate

n mi m n m de m r 3 rme 4 . Na as 5 . ee a 6 ru 2 orti e . . 1 A . W . . . . B ; M ; E ; ; S ; B

n 8 Wei ssermel 9 . eat er ston e 10. eat er ston e 11. n e or . Ca to ; 7 . B d f ; ; F h ; F h ;

i i n 12 e n ton ar . G ll ; . W lli g W d

1 2 3 4 Cup r ic sulph ate 29 23 30 24 15 i s 10 25 27 s um r om e 29 32 30 20 5 10 18 8 25 P otas i b id _ Potassi um bi chr omate 4 6 3 7 5 7 3 1 5 Ammon i um bi chr omate 4 5 10 1 2 1 5 5 Hydr ochlor i c aci d . . Sulphu r i c aci d 5 P otash alum . S alt 6 9

k i k k i 5 i mi n o i lk m t. 1 r i n s 3 . To ows 4 Sw t ows . r a Ma 2. ar . . ye ; K p k ; y ; ; B gh Ph n omi as 9 S tur n bur 10 ar n er 11 w t o 6 . n i e . a er 8 . N . e . S ; R e ; 7 M y ; ; g ; . G ; i S sk ow i .

The quantities of the ingredients given in the above tables

( Mebes) are for a total volume of 1000parts of solution . 2 The dried print may be soaked either in water , or a % to

5 of u u 5 u per cent solution sulph ric acid for abo t min tes , and

u u off then washed . The s rface moisture sho ld be blotted

u u ma and inking proceeded with . Dil te alkaline sol tions y also

u u 1 or be sed , abo t per cent caustic potash, soda ammonia ,

5 of or 10 or per cent the carbonates , per cent salt calcium chloride . The print should be placed face up on a sheet or of u two wet blotting paper , s pported on a sheet of glass , and a d bbed with a linen pad . Special brushes and inks are ob tainable or for this process , the ink may be applied with a velvet roller . The inks may be Obtained in almost every OIL AND BROMOIL

u or or colo r , and either the special inks , lithographic , photo

’ gravure inks may be used . Artist s powder colours may also u u be sed , and worked p on a slab with a palette knife with ’ u oil medi m , boiled linseed , or raw oil with a little j apanner s

su gold size . The inks dry very slowly, and it has been g gested to treat the completed print with certain solvents for u u the medi m , s ch as benzol , benzol and alcohol , petroleum d u ether , gasoline , etc . These are angero s , and the best is ' r hl ride r th carbon tet ac o . The print is rinsed once o twice wi

“

v . w the sol ent , and then dried This treatment gives a some hat dead appearance in the shadows ; then ordinary celluloid

s u 2 3 varni h , dil ted with to parts of amyl acetate may be used,

, u the prints immersed therein for a min te, and dried . —T— I L out . O PRINTING . his is a process worked by G . H

on Rawlins , which is practically based the Older processes of

M ri Poitevin and a ot. Gelatinised paper is sensitised with a d u bichromate , exposed un er a negative , thoro ghly washed ,

for u soaked in water an ho r , and then inked up , either with u a roller or br shes , charged with greasy ink, which only takes n o the exposed parts .

i moil oil Special papers , p g or printing , can be obtained commercially ; or paper may be ﬂoated on a 6 per cent solu tion of soft collotype gelatine for a few minutes and hung up u to dry . It sho ld be sensitised with the following 60 Ammonium bichromate g 460gr .

1000 1 z Water ccm 6 o . For use mix 1part stock solution with 2 parts denatured u alcohol . Place the paper face p on a ﬂat board or sheet of glass , and apply the sensitiser freely with a pad Of absorbent or u u cotton soft linen , a ﬂat br sh or a Blanchard br sh . The u alcoholic sol tion will not keep . The paper may also be immersed in a 5 per cent solution of ammonium bichromate 306 PHOTOGRAPHIC FACTS AND FORMULAS

o u for ﬁve minutes and dried . After exp s re the image should be seen I n a brown colour on the yellow ground of the

u u of paper , and sho ld be rapidly washed ntil all trace the

u to sensitiser is removed . Then it sho ld be allowed soak in

° ° ° ° 10 u 2 7 2 . for 25 8 . 7 8 water at to C ( to F ) min tes , placed u face up on a damp pad or sheet of glass , the s rface moisture

. a removed, and the ink applied The further tre tment is as for the bromoil process .

— of AQUARELLE PRINTING . The preparation the prints is

x for but of e actly the same as Oil printing , , instead using Oil

u u . pigments , thick water colo r pigments are sed

I RA H — f r O L O G P . o o This is a modiﬁcation "the bromoil p ‘ s ce s , in which a plain gelatine paper is used . A good bromide 5 u print is soaked in water for min tes , then squeegeed into

for contact with the gelatinised paper , which has been soaked

° ° 2 2 1 ' u 6 60 . to % min tes at C . ( F ) in the following u 11 Potassi m bichromate g 84 gr .

s u e . Potas i m ferricyanid 7 5 g 58 gr . u u Potassi m bis lphate g 3 gr .

i u Potass m bromide g 58 gr . u 1 Chrome al m g 1 gr .

' 1 1 z Water 000ccm 6 o . The print and the paper should be allowed to remain in con u u 20 u tact nder slight press re for min tes , then separated, and

u . the print washed, when it can be redeveloped and sed again

- The gelatine coated paper , after stripping, is placed in water 32° ° . u at C (90 F . ) for a few min tes ; then a relief begins to u u show , and it can be inked p as sual . Either single or double u transfer carbon paper may be sed for the gelatinised paper .

TRA FER — MAKING BROMOIL N S s. Presses are obtainable f commercially , which practically consist o two superimposed u rollers , with ﬂat beds on each side for s pporting the transfer

308 PHOTOGRAPHIC FACTS AND FO R MUL A S

e u just around these holes , painted with c ll loid varnish . This u is to prevent the absorption of water aro nd the holes , so that they will not be deformed and thus cause non-reg1stration in subsequent printings . u Any paper may be sed to transfer to , but the soft copper

r plate o collotype papers are the best , as they absorb the ink

i slightly and g ve a more velvety appearance. It is important u that the paper be lightly sized, otherwise the s rface may 2 tear in patches . A good size can be made by boiling per f cent o starch in water , and this can be painted over the

To u u . o surface with a ﬂat br sh m ch size prevents transfer .

be Hard , thick papers may be soaked in waterand placed tween thick ﬂufﬂess blotters under light pressure . for a little time to even the dampness . 7 Fig . shows the laying of the transfer paper on the marked

Fi g. 7

f . A B . 7 bromoil and the method o ﬁtting the pins , in Fig show the correct way to hold the tool and C the correct angle

. A for this The strokes may be either elongated ovals as in , OIL AND BROMOIL

- or B . u Fig . 8 , zig zag lines as in While r bbing , the paper should be held ﬁrmly down with the other hand close to the tool . It is preferable to use a normal relief and a soft ink rather than a hard one and high relief . When two transfers are to be made on the same paper it is advisable to dust the

Fi g. 8

first with talcum powder . Care must be taken in fitting the paper on the registration pins ; one should be fitted first into the hole and a cork slipped over it to prevent the paper slip ff ping o and then the other fitted into place . In using this transfer process for three-colour work care must be taken to keep everything at as even a temperature as possible . It is advisable also to mark around two corners of the bromoil with pencil lines , which with the pins facilitates registration . A sheet of thin celluloid should be placed over the print and the outlines Of a few prominent objects traced on the cellu 310 PHOTOGRAPHIC FACTS AND FORMULAS

u loid, and without shifting the cell loid the registration pins u on driven through it . Then the cell loid should be laid the u -in second colo r print , the sketched outlines made to coincide u and the pi ns driven thro gh the print . The third print is treated in the same way . r Anothe simple method was suggested by Bohm, as shown 9 a on in Fig . , in which is a sheet of plate glass which is

F i g. 9

o f ﬂuﬁi ess on placed a sheet , smooth blotting paper , then this

b of the freshly inked bromoil , and then a sheet smooth, hard drawing paper c. The latter is preferably fastened at one s end to the gla s plate so as to prevent it shifting . As a roller

of - a knitting needle one eighth inch diameter is used , which r can be seen as the little ound circle between the boards .

Pressure is obtained by means of the top board . The transfer u can be examined after it has been rolled , and if nsatisfactory can be rolled again in the same direction . For prints larger than 5 x 7 it is preferable to use a rather more elaborate

1 . 10. 6 20 arrangement, shown in Fig . This acts well up to x

F i g. 10 On each of its longer sides a U-shaped iron strip is fastened by two or three screws ; the holes must be about two-ﬁfths

312 PHOTOGRAPHIC FACTS AND FORMULAS

u . tion , otherwise a smear will be ca sed At first very light pressure should be used and with each passage of the block through the machine it should be increased . The transfer can easily be examined by removing the top pack , lifting one corner of the bromoil , while holding the main part down with ff u a sti card or straight edge , and the rolling contin ed if the u u advi s transfer is not eno gh . If a second p ll is desired it is able to free the bromoil from any trace of the ink by swab bing with a solvent , such as carbon tetrachloride . It must be again immersed in water before inking up again . The num ber Of pulls possible from one bromoil varies with the hard -five ness of the gelatine film and may be from five to twenty . —A ANOTHER BROMOIL TRANSFER PROCESS. direct print or enlargement should be developed with a non-tanning devel u oper, s ch as amidol , fixed in a plain hypo bath , well washed, and then bleached in the following u 10 Potassi m bromide g 77 gr . 1 11 Cupric sulphate 5 g 5 gr .

Potassium bichromate 5 g gr . 1 Water 1000ccm 6 oz . f Dissolve in the above order , and add su ﬁcient hydrochloric u acid to form a clear sol tion . After complete bleaching, 1 u wash well , and treat with a per cent s lphuric acid bath to 2 o u . 0 remove any yell w colo r Again wash, ﬁx in a per cent u 1 . 0 sol tion of hypo , and wash Immerse the print for min utes in :

33 z Glycerine 3 ccm 5 o .

Water 667 ccm 10oz .

on Place face up a clean glass plate, and roll down with a u roller sq eegee . Now fasten the edges down to the glass with

of strips gummed paper . Ink up with a roller with a greasy

or ink , litho collotype . If the paper is too much hardened , the ink will take on the parts which should be white ; then it OIL AND BROMOIL should be immersed again in the glycerine solution at a tem

° ° r u u peratu e of 30 C . (86 or ntil the gro nd shows a distinct relief then stick down again to. the glass and ink up . 100 u It is stated that at least p lls can be taken from this , and ,

of u . to co rse , in any colour The process is also applicable

- three colour work . Miscellaneous Printing Processes — TH E POWDER PROCESS This process is based on the fact that colloids lose their tackiness on exposure to light i n

. for contact with a bichromate It is rarely used paper prints , and its chief application has been for the preparation of t e

u e for - versed and d plicate n gatives photo mechanical work , F r or for making ceramic enamels . o the latter process the image was produced on collodionised glass to facilitate strip

u . ping , and the image transferred to the enamel plaq es The following are typical formulae

Dextrine 40g 307 gr . u White s gar 50g 384 gr . u 2 Ammoni m bichromate 0g 154 gr .

Water 16 oz . Glycerine 80drops 10to 40drops

Gum arabic 154 gr . u 12 White s gar 9 gr . 1 Ammonium bichromate 54 gr . Alcohol Water The alcohol should be added other ingredients are dissolved . Or : Dextrine Grape sugar Potassium bichromate Water Or ( Miethe) Gelatine Rock sugar candy

316 PHOTOGRAPHIC FACTS AND FO R MUL A S '

. of yellow stain , then rinsed and dried Instead using the collodion , the plate may be treated with

z Sulphuric acid 75 ccm 1o . 4 Water 300ccm oz .

Methyl alcohol 600ccm 8 oz . u until all yellow colo r disappears , then gently washed with water , and dried . The image is very tender and very liable

not to damage . If it is to be stripped from the glass , it is advisable to give the glass a preliminary coating of a 2per cent solution Of sodium silicate .

- THE PEPPER DUSTING O N PROCESS .

A 400 . . White pepper g 8 oz n 2 Benzole 1000ca 0oz . Allow to stand for 24 hours with frequent shaking ; then

ﬁlter .

z B . Gum dammar 50g l o .

m z Benzole 1000cc 20o .

C . Solution Of rubber in benzole ; bicycle tire cement will do . For 10 1 1 use mix parts A , part B , part C , ﬁlter , coat any u s rface , and dry in the dark . Expose under a transparency for or a few minutes in the sun , dust over with any dry litho

u or e. u other colo r , bronz Finally br sh clean with a soft brush .

EG RO G RA P H I t — - N C PROCESS (I t erheim) . Smooth well sized paper should be rather thickly coated with : G um 2 arabic 50g 4 oz . 1 Water 000ccm 16 oz . The gum should be in clear small lumps and preferably sus in u pended a ﬁne m slin bag in the water , which may be warm .

When all has dissolved, add u 4 Potassi m bichromate 38 gr .

When this has dissolved , add

A c l ohol 10ccm 77 min . MIS CELLANEOUS PRINTING PROCESSES 317

u u . u u The paper should be h ng p to dry The expos re , nder a

5 to 10 u ffu or line drawing , is from min tes in di sed light , until the image is distinctly visible . Immerse in water , not

u of . too cold , ntil the lines the drawing show a distinct relief of It should then be surface dried with a soft pad cloth , and

u dr : hung p to y . Then coat with

Shellac 50g 384 gr . Lampblack 150g

z Alcohol 1000ccm 16 o . u The shellac sho ld be dissolved first , filtered , and then the / u be lampblack worked in . A flat brush or soft pad sho ld u sed for applying this to the print , which, after complete u u 2 3 coating of the s rface , sho ld be immersed in a to per

u of u or on cent sol tion sulph ric hydrochloric acid , until gentle application of a soft brush or pad the black pigment comes away from the ground leaving the lines of a good intense black .

A N THRA P o — - CO TY E (S bacchi) . Well sized paper should be coated with a gelatine solution 33 2 Gelatine g 58 gr . 1000 1 Water ccm 6 oz . A

' ° ° ° to soak for 15 40 50 104 Allow minutes , melt at to C . ( to 122° and ﬁlter . Immerse the paper for 10minutes in

u of water , then place face p on a sheet glass , and lightly

or squeegee into contact , a soft linen pad may be used . The edges of the paper should be turned up to the height of about 1 cm . (94; in . ) so as to form a dish, and the gelatine solution

u 620 m 2oz po red in , allowing ccm per q ( . per sq . As u soon as the gelatine has set , hang p to dry . This paper will keep indeﬁnitely . To sensitise immerse for 2 minutes in a

4 u of u per cent sol tion potassi m bichromate , and dry in the dark ; this paper will keep for about a week . Expose under a drawing from 12to 60seconds in sunlight until the image is 318 PHOTOGRAPHIC FACTS AND FORMULAS

or a faintly visible . Immerse in running frequently ch nged

of . water, until all trace yellow disappears Then immerse in ° ° 2° ° 2 o 30 . 8 86 . water at 8 t C ( to F ) for one minute, imme di tel u on or d a y place face p a sheet of glass flat boar , and remove surface moisture with fluffless blotters or a soft linen pad. Finely powdered lampblack or other powder should be dusted over the surface through fine muslin ; a small sieve u can easily be made from a lidless box . Then a soft ro nd badger brush should be used with circular strokes to di stribute u the powder, which sho ld only adhere to the unexposed parts . u When the image is fully visible , the print sho ld be exposed °

sun r 60 . to the o in a moderately warm oven, not over C

° r he ( 140 until completely d y . At this temperature t

o . gelatine softens , and the powder sinks Slightly int it When u thoro ghly dry , immerse in cold water until it lies quite ﬂat, u rub u then place face p on a board, and the s rface gently with a soft pad until the ground is white . Should the powder uf not adhere s ﬁciently to the lines , the powdering operation may be repeated as often as necessary, a warm water bath u being used each time , and, if necessary, the temperat re raised a few degrees to thoroughly soften the gelatine . The print u then only req ires drying .

TH E Willi s — ANILINE PROCESS ) . The basis of this pro cess is the reduction of a bichromate by the action of light and the formation of an aniline colour on the exposed salt

or by the vapour of aniline like compound . Well-sized paper should be ﬂoated on (Reynolds)

Potassium bichromate,

sat . sol . 16 oz . 3 Sulphuric acid 45 min . Or ( Dawson) 104 Ammonium bichromate g 798 gr .

42to 126 323 Glacial phosphoric acid g to 968 gr .

320 PHOTOGRAPHIC FACTS AND FORMULAS

The image should appear in a few minutes and will be a dirty - u a n blackish green . The colo r is somewh t dependent o the duration of the aniline fuming ; the shorter this is the bluer the ﬁnal print ; the longer the time the more blue-black the

u on . colour . The f ming time is dependent the exposure u When the image is intense eno gh , immerse the paper in u u water, running or freq ently changed, ntil the whites are pure . If the whites will not clear , immerse the print in a 1per cent solution of sulphuric or 3 per cent hydrochloric acid then wash, and the green will be formed, which can be converted into blue by treatment with a 1per cent solution of ammonia . ’ E N DE MA N N S — ANILINE BLACK OR PROCESS . This is also u sometimes called vanadi m printing . Aniline black is formed by the action of a vanadium salt . The sensitiser is 31 3 Salt g 2 8 gr . 1 Potassium bichromate 3 g 238 gr .

Sodium vanadate g gr . 6 5 Sulphuric acid ccm 500min . 1000 Water ccm 16 oz . - 2 u Well sized paper , preferably sized with a per cent sol tion u of gelatine , is ﬂoated on the above or the sol tion may be applied with a brush and dried . Exposure should be about 7 ffu t u minutes in di sed ligh , and the print sho ld then be exposed to the vapour of a 2per cent solution of aniline in warm water , which should be heated in a dish . The image will appear in a brown colour and the paper should then be 24 ° 0° 75 ° exposed in a very damp room or box at to 3 C . ( °

86 . for 2 r o u . to F ) about hours , ntil quite black Finally , it u u sho ld be washed with dil te ammonia , and dried . FEERTY PE Z , PRIMULINE AND DIA OTYPE PROCESSES . These processes are but rarely used and are more applicable

- to fabrics than to paper . They are based on the light sensi MISCELLANEOUS PRINTING PROCESSES 321

ess f u u tiven o complex organic compo nds , which nder the u action O f light form coloured dye images . Feer s ggested the following

u toluoldi saz osul honate 25 A . Sodi m p g Beta-naphthol 25 g Caustic soda 8 g Water 1000ccm

Gives scarlet red images . u ditol ltetra O sul honate 25 B . Sodi m y z p Metaphenylendiami ne 20g Water 1000ccm

Gives brown images .

. ditol ltetraz osul honate 25 C . Sodium y p g Resorcine 22g Caustic soda 16 g Water 1000ccm

Gives orange images .

ditol ltetr z osul h n te 0 2 D . Sodium y a p o a 3 g 30gr . 20 15 Resorcine g 4 gr . 15 11 Caustic soda g 5 gr . 1000 1 Water ccm 6 oz .

. ditol ltetraz osul honate 30 2 E Sodium y p g 30gr . - 25 12 Alpha naphthol g 9 gr . u 7 54 Ca stic soda g gr .

1000 16 z Water ccm o .

. ditol ltetraz osul honate 30 230 F Sodium y p g gr .

Para hen lendiamine 20 14 p y g 5 gr .

1000 1 z Water ccm 6 o . u A , B , C can be sed alone ; D and E mixed in equal volumes for or u u violet tones ; E and F in eq al vol mes for blue tones . u u 5 u After expos re , which is abo t minutes in s nlight, the prints should be washed in water acidulated with hydro chloric acid . 322 PHOTOGRAPHIC FACTS AND FORMULAS

u The prim line process was patented by Green, Cross and : Bevan . The process is as follows 33 253 r Primuline g g .

1000 1 z Hot water ccm 6 o . Filter and immerse the fabric in the warm solution for about 10 u u 5 min tes , wash thoro ghly , and immerse for minutes in u 5 1 Sodi m nitrite (not nitrate) g gr . 15 11 Hydrochloric acid ccm 5 min .

1000 1 z Water ccm 6 o . u u Dry in the dark . Expos re m st be made under a positive , u if a positive print is req ired . Then the print is thoroughly

of washed , and treated with one the following developers . For red tones : Beta-naphthol Caustic soda Water For orange tones Resorcine Caustic soda Water For purple Alpha-naphthylamine Hydrochloric acid Water For blacks Eikonogen Water For brown 12 Pyrogallol g 92gr . 1000 16 ' Water ccm oz . u The prints m st be well washed after development, and if on . u fabric ironed before quite dry Unfort nately, it is almost a b impossible to obt in pure whites y this process.

324 PHOTOGRAPHIC FACTS AND FO R MUL A S

1 Sodium nitrite 0g 154 gr .

- Filter into an ice cold dish . Paper should be ﬂoated on the u u out cold sol tion , or fabric immersed , wr ng , and dried in u 8 12 the dark . Expos re under a negative will be from to u ffu min tes in di sed light , and the image shows in a brown u ff colour on the yellow gro nd . Development should be e ected 10 u of u with a per cent sol tion f sed sodium acetate , which - e - gives brownish red ton s . If alpha naphthylamine be used,

- brownish grey tones are Obtained . Better colours are O b tained by adding a little of the sensitising solution to the developers . The prints should be subsequently washed, and dried . Schoen patented the use of diazotised ortho -amido -salicylic acid and its compounds for obtaining coloured prints on paper r and fabrics , red tones being given, which can be alte ed by u treatment with vario s compounds , such as ferric chloride, or t lead acetate, cobalt nitrate , lime bary a water . Mountants

—A n DEXTRINE excellent preparation , when properly made , which keeps well and adheres ﬁrmly White dextrine 1000g Alum 40g S ugar 156 g z Water 1200ccm 19% o .

Phenol (carbolic acid) 3 ccm 22min . for 5 the Mix the dextrine with the water, boil minutes , add u u s gar and the alum ; stir ntil dissolved , allow to cool slightly,

- add the phenol , and cast into wide mouthed bottles . Inferior dextrine gives a coloured paste ; the alum is preferably left

out u u of . , as it may s bseq ently cause fading the prints If the bottles ﬁlled with the paste are cooled for several days in e a refrigerator , the paste s ts to a white ﬁrm mass . A simpler formula is White dextrine Water Wintergreen or clove oil

1000 1 White dextrine g lb . 1500 2 Water ccm 4 oz . il o f 2 12 O Wintergreen ccm min . of 2 12 Oil cloves ccm min . t Place the water in a vessel s anding in a water bath , and keep ° ° e u 1 160 the temp rat re at 7 C . ( stir in the dextrine slowly, and , when it has all dissolved , add the oils . S et in a for cool place several days , when it will congeal to a ﬁrm white paste . M —A DEXTRINE AND G U . very adhesive paste 326 PHOTOGRAPHIC FACTS AND FORMULAS

Picked white gum arabic g 290 Dextrine g. Ammonia 1ccm 4 drops 15 Phenol (carbolic acid) ccm 60min .

1 ‘ Water 000ccm 8 oz . I Powder the gum , and mix with the dextrine nto a smooth paste with one-fourth of the water ; then add the rest of the

10 . water , and boil for minutes Strain through linen , and add the phenol and ammonia when cold . — u u . GELATINE . This m st be sed hot A piece of ground u u glass sho ld be dipped in hot water , drained , and the mo nt n ant brushed over . The print is then laid face up o the u c of pasted s rface , rubbed gently into conta t with a piece t: paper, and is then pressed on to its moun

Soft gelatine g 3 oz .

12 z Water 750ccm % o .

Soak the gelatine in the water, melt in a water bath, and add Slowly with constant stirring

22 4 z Methyl alcohol 5 ccm o .

Glycerine 25 ccm 96 min . or u It is preferable to omit the glycerine, and use corn s gar

or . syrup , add sugar in the same proportion I LIQU D GELATINE .

1 z Gelatine 100g o .

Water 600ccm 6 oz . 1 Chloral hydrate 100g oz . of Soak the gelatine in the water , melt by the aid heat , add the 15 u o u chloral , heat for min tes , and then add s di m carbonate u u ntil the mixt re is neutral to litmus paper .

- STARCH GELATINE . u A . Berm da arrowroot Water

B . Soft gelatine Water

Stereoscopic Work

—T SEPARATION OF THE LENSES . his should be equal to the u interp pillary distance of the eyes , which is approximately 2 u i u u 6 5 mm ( 9/ 16 b t 76 mm ( 3 n . ) is s ally adopted

. e for normal work When taking n ar obj ects , the centers of

u u to the lenses m st be bro ght nearer one another , and the rule for ﬁnding how much is : if the additional extensI O n of the camera beyond the inﬁnity mark or focus is equal to the

u 1 r u focal length m ltiplied by , then the separation m st be reduced by an amount equal to the maxi mum separation multiplied by 1+ (r in which 7 is the ratio of image

- o . be one u to bject Example , the image is to made q arter

u s 1 r l 15 the nat ral ize , then ( ) , so that the separa u tion m st be 3 inches .

PR I N T —TO ’ secure MOUNTING s. correct conditions of con u u of vergency, each print m st be seen nder the same angle u view as that at which it was prod ced , and the two prints must be mounted in accord with the following rule Let P separation of any pair of corresponding points on prints N separation of same points on negatives E separation of eyes (average is 64 mm) L f separation o camera lenses . A non - prismatic stereoscope being used

1 s . If image points represent inﬁnitely di tant objects , Make P E 2 . o If only near objects are Sh wn , and an ordinary single

u e u plate do ble lens ster o camera has been sed, Make P E L N

3. for u or If a single camera is used two separate expos res , 328 STEREOS COPIC WORK

e N if two separate similar cameras are used together , measur

to with negatives placed edge edge , and in the same relative positions that they occupied during exposure ; then — Make P E N length of one plate . o If a prismatic stereoscope , ﬁtted with pr perly centred half

one lenses , is used, add the width Of prism to above values of P

ut Frequently, if the prints are c apart , errors may arise ,

o . and they may be wr ngly mounted To avoid this , place the u . o prints face down on the table , with the top away from y , and across the central dividing line draw a faint pencil line,

one . cut about inch long Then the prints in two , and , after u t the u trimming, mo nt hem so the pencil lines fall on o tside margins of the prints . In order that the picture shall be viewed as through a dark ff i frame , which is the most e ective way, tr m the prints as

: u 2 but follows the prints sho ld be % inches wide , mounted

of with an eighth an inch between them , and trimmed so that there is one- eighth of an inch more subj ect shown on the right -hand side of the left -eye print than on the right of - one- of u the right eye print , and eighth an inch more s bj ect shown on the left of the right-eye print than on the left of

- the left eye print . L antern Slides

— 3 i n . i 4 . 3 STANDARD SIZES British, % x % ; Amer can , x

u e f u 3 3 . . 3% in . Maxim m siz o pict re x in in both cases — t SPOTTING . The standard spo ting in Britain and the Col oni es is with two round spots of colour distinct from that u u sed for the binding , placed at the top of the pict re , when u o viewed as it appears in nat re . These spots g downward, and next the condenser when proj ecting . The American “ ” standard method is to spot with one tlfumb-spot at the - of u e bottom left hand corner the pict re , as vi wed in its proper direction . This spot is covered by the thumb of the n right ha d , when the lantern is fed from the right hand side , u - c and is at the pper right hand corner, next to the ondenser , u d ring projection . B ADHESIVE FOR INDING STRIPS .

Sugar candy 240gr . Water

Dissolve by heat , and add to

Fish glue 400ccm 2oz .

on cut . Brush thin needle (black) paper , dry, and into strips The strips may better be purchased when only small quantities are needed .

DI RA M — on LANTERN S LIDE A G s. Draw with a hard pencil u u um ﬁne gro nd glass , and varnish with a strong sol tion of g dammar in benzole . Or coat plain glass with : Sandarac g Mastic g Ether 800ccm Benzole 16 5 ccm

S ee S tan l e an d Stan ar D r l ates d , y d d y P

u I 1 2 S S S Dr P After J ly , 9 4, the eed , tanley and tandard y lates listed below will be distrib uted by the D efender Photo Supply m . ui E m K d Co pany, Inc , which has acq red from the ast an o ak u a Company , by p rchase , the brands , tr de marks and trade names together with the right to use the formulas for their manufacture u u and the excl sive right to sell them througho t the world,

Seed 27 (Gilt Edge) 26X

23 L O rtho L antern Slide (Yellow L abel) Panchromatic Non-Halation L O rtho Process Stanley Regul ar Standard Extra Imperial

O rthonon Regular L antern Slide Post Card LANTERN SL IDES

This gives a ﬁne grain and takes the pencil well . To make it again transparent , coat with Sandarac Mastic Ether

DIAGRA M LANTERN SLIDES . Canada balsam 4 parts Pure turpentine 8 parts Liquid siccative 1to2parts u I t Mix thoroughly, and add as m ch lampblack as will give the consistency of an ointment . Coat glass evenly with a : badger hair softener . Or Syrian asphalt 50parts Yellow Venice turpentine 10to 12parts Linseed Oil or varnish 15 parts Pure turpentine 15 parts Melt the asphalt and Venice turpentine in the turpentine by

oil . heat , and add the linseed with continual stirring Add enough lampblack to make it as thick as ointment . Well u cleaned glass should be coated with this until Opaq e, and allowed to dry ; then rubbed over with a little lampblack u u um r bbed p with g water . This will be repelled at ﬁrst but

- with continual working will take . A good sized darning needle mounted in a wooden handle may be used as the u graving tool . Broad s rfaces may be scraped out with a

. n . sharp knife . The above give white lines o a black ground E — u D VELOPMENT . N merous formulas have been proposed ’ for lantern slide plates . A few American manufacturers formulas are given , and are adaptable to other brands .

H mmer Tr s l t a an par ency P a es. Metol Sodium sulphite Hydrochinon 332 PHOTOGRAPHIC FACTS AND FORMULAS

Sodium carbonate 78 g Potassium bromide 2g Citric acid 2g Water 1000ccm

v l H mm r Pl t Extr me D ensi t D e e o er . a e a es e y p . Hydrochinon g Sodium sulphite 100g Sodium carbonate 150g Potassium bromide g

1 2 z Water 000ccm 0o . ° Use full strength at 6 5 F .

B l k Ton Tr ns r n P l t S eed L antern ac e a a e c a es. , p y

4 30 . A . Elon (metol ) g gr 4 Hydrochinon g 30gr . 1 u 7 130 . Sodi m sulphite , dry g gr

Water 1000ccm 16 oz . 2 1 u 5 . B . Potassi m bromide g gr 1 u 13 00 . Sodi m carbonate , dry g gr 1 0 1 Water 00 ccm 6 oz .

° u For use mix in equal volumes . Temperat re about 70 S eed Hydr ochi non D evelop er for Warm Tones

A . Hydrochinon g u Sodi m sulphite , dry g Potassium bromide g Citric acid g Water 1000ccm u B . Sodi m carbonate , dry g

Caustic soda g 30gr .

Water 1000ccm 16 oz .

u use For use mix in eq al volumes . For still warmer tones more B . ’ Cramer s Hydr ochi non-Pyrocatechi n D evelop er

. 10 A Sodium sulphite , dry 8 g

Enlargmg

TABLE FOR ENLARGING AND REDUCING .

B —1 4 —1 5—1 —1 —1 —1 . 3 % % 7 8 9 % 10 11 12 A . 9 10—1 11—1 12—1 1— B . 3 1 To ﬁnd the number of linear times of enlargement or redue of tion, divide the longer side the enlargement by the longer

of . side the negative Then ﬁnd this number,in the top row A , and multiply the lens focus by the numbers in the lower row

B . The greater distance is that between the lens and sensitive paper, and the lesser that between the lens and negative . e T 5 4 2 1 : o 0 6 . 20 5 4 Exampl enlarge x to x As , if 6 - a inch lens be used , the distances will be respectively

- 6 5 30 6 7 in. X and X % For reducing, the relative positions of the sensitive surface and negative or copy are u 20 16 u - reversed, thus to red ce a x fo r times with a 6 inch 30 lens , the latter will be inches from the subject and inches from the plate . ENL A R G I NG

RELATIVE EXPOSURES WHEN ENLARGING (WITHOUT A CONDENSER)

n exposure i s know .

To u se thi s tabl e ﬁ n d i n the top hor i z on tal li n e the nu mb er of ti mes of en r m n f r i x u r i n n n n l a ge e t o wh ch e p os e s k ow . U d er thi s umber the r el ati v e time of exp osur e for di ffer en t d egr ees of en l ar gemen t wi ll b e foun d Opp osi te the n ew ti mes of enl ar gement i n ﬁr st ver ti cal column B J RELATIVE EXPOSURES WHEN COPYING OR REDUCING ( . A lmanac

S cal e of reducti on for w i c ex osure i h h p s k nown .

To u se t i s ta e ﬁ n d i n h r i z n a i n h bl t e top h o o t l l e the scal e of r edu cti on for whl h x r c e osu e 1s n own . n r i h p k U d e th s scal e t e r el ati ve ti me of ex p osur e for iffer en t e r ees O f r e u cti on wi b e oun o i d d g d ll f d pp os te the n ew scal es of r edu c ti on mar k e I n r st er ti ca co umn d ﬁ v l l . 336 PHOTOGRAPHIC FACTS AND FORMULAS — SOLAR PRINTING Frequently used for making enlarge u -u ments with plain s rfaces for working p with crayon , water colour and Oils Potassium iodide g 3 Ammonium bromide 7 . g Ammonium chloride 2g Gelatine g Albumen 110ccm

1000 16 oz Water ccm . Soak the gelatine in three-fourths of the water for 30min u to tes , melt in a water bath , add the salts , cool down about ° 100° 38 . C ( add the albumen , which should have been u e previo sly whipped to a froth and allow d to liquefy, and e u add enough wat r to make up to b lk . Apply to the paper with a sponge or Blanchard brush, and dry . Sensitise with Silver nitrate 100g 50 Glacial acetic acid g oz .

1000 1 z Water ccm 6 o . h or . Apply with sponge brus , and dry The exposure with a good light will be about 60seconds . The developer is

Gallic acid g 96 gr . 2 1 Lead acetate g 6 gr . 1 1 Water 000ccm 6 oz .

' ni Add just before use a little of the silver trate solution .

Apply with brush or sponge . Or Milk 1000ccm Glacial acetic acid 38 ccm

Stir well , ﬁlter , and add to the ﬁltrate u 112 Potassi m iodide g gr . u Potassi m bromide g 27 gr .

Paint over the paper, and dry quickly . To sensitise, ﬂoat on or paint with S ilver nitrate

338 PHOTOGRAPHIC FACTS AND FORMULAS

Hydrochloric acid ccm 88 gr . 4 Citric acid 7 g 5 gr . 12 Water 800ccm Moz . u Allow the mixt re to cool , remove the skin , press through a

ﬁne cloth , coat the paper , and dry . This will keep any length

on Of time . The paper is salted by ﬂoating Ammonium bromide 20g Magnesium iodide 48 g Magnesium chloride 8 g Water 1000ccm This should be sensitised on 100 6 Silver nitrate g 7 8 gr . 40 cm Glacial acetic acid c 307 min . 1000 1 Water ccm 6 oz .

Small sheets may be ﬂoated, and large ones can be painted with the solution . Expose while damp until the details are e : visibl , and develop with 20 154 Gallic acid g gr . 10 Lead acetate g 77 gr . 5 5 Glacial acetic acid 7 ccm 76 min . 1000 1 Water ccm 6 oz .

’ After development immerse the print in weak soda solution , and fix . Flashlights — METHODS OF US E Flashlights may be divided into two : u classes A , pure magnesium powder blown thro gh a flame ; u and B , magnesi m mixed with some substance , rich in Oxy b r - e ca o gen , which can fired with a p, electric pyrophoric m etc. spark, The first na ed are less used at the present time than the second class , and they require no comment , as

. benz olene . special lamps to burn alcohol , gas , etc , can be

Obtained commercially . Gunpowder was one of the firstcompounds used for firing the second class o f flashlights ; but it soon gave place to gun or u u cotton pyroxyline , the s al proportions being pyroxyline

1 u 2 . out part , magnesi m parts The cotton should be pulled to a loose long tuft and the magnesium sprinkled over it . u e Strips of thin cell loid may be used in the sam way , ﬁring being effected by a long taper or match tied to the end of a u f stick . The man facture o ﬂashlights is exceptionally dan erous b an g , and should not be undertaken y y but experienced chemists . I TRA TES —I n MIXTURES OF MAGNESIUM WITH N . all cases , the weight given should be mixed with 1part of magnesium °

1 . . 0. 5 00 powder Thorium nitrate, ; this must be dried at C °

212 . u 1. . 5 ( F ) before mixing Stronti m nitrate , ; must also

1. . 2 . 5 be dried Potassium nitrate , Ammonium nitrate , ; 1 not advisable as the salt s hygroscopic , and the mixed powder 1' . 3. will not keep well Sodium nitrate , Cadmium nitrate , basic cadmium nitrate must be used , which can be made as : s u follows dis olve 100g ( 3% oz . ) cadmi m nitrate in 100ccm

3 oz . f ( % ) hot water in a porcelain dish , add a few drops o 10 per cent solution Of caustic soda , until a precipitate is 339 340 PHOTOGR APHIC FACTS AND FORMULAS

t dr dr 105 . formed . Evapora e until y, y for some time at C ° 1 220 u . ( and red ce to powder Lithium carbonate , ; u or one alone with magnesi m mixed with Of the above , gives u a red light . Potassi m permanganate , does not explode when struck ; gives brown smoke and more sparks than others .

1 . Manganese dioxide , should be very ﬁnely powdered Per

fectl u . y safe , b rns fairly rapidly with little smoke — 2 ETC . a u CHLORATES, PERCHLORATES, Pot ssi m chlorate , 2 1 . u or ; must be powdered Potassi m perchlorate , ; also in of u powder . Sometimes a mixture the two is sed , as chlorate ,

perchlorate, 94 . Both the salts must be in ﬁne powder i before mixing, and Should preferably be m xed with a feather on of is u a sheet paper , as strong friction apt to ca se an explosion . These compounds cannot be sent through the

or u 2. a post . Potassium ammoni m persulphate , Pot ssium 2 u or a m u . m oni m bichromate , ; b rns rather slowly Chrome

u u 1 . al m, anhydro s , ; a perfectly safe mixture — FLASH S HEETS . Flash sheets may be prepared by sus pending magnesium powder i n celluloid or pyroxyline solu

on u . tion , casting glass and stripping before q ite dry The following mixture has also been proposed Magnesium 1part Potassium chlorate 2parts Celluloid varnish 3 parts

To be used in the same way . Another method proposed is to

rub coat paper with starch paste, magnesium powder into it ,

. u f o s and dry Thin blotting paper , soaked in sol tion o p ta u u si m bichromate and dried, is th s pasted and dried . CA N DL E —S - FLASH s. low burning mixtures can easily be

SO - - made , and the called time light candles are small tubes of

r s paper, imp egnated either with pyroxyline solution or pota

u u . si m nitrate , and ﬁlled with a magnesi m compound Or

a of u u the cont iners may be made thin al mini m foil, to

342 PHOTOGRAPHIC FACTS AND FORMULAS oxide 5 ; magnesium cerium oxalate manganese oxide The chromates or tungstates Of thorium may also be u u used, and the mixt res keep well and give little smoke , s ch u e m nesI um 1 2. as ag , thorium chromate L mi re patented the

“ of of u use the chromates iron , manganese, chromi m, nickel , u u u cobalt, al mini m , ceri m, lead, copper and antimony, as B giving little smoke . oric and silicic acid have also been n u pate ted when added in eq al quantity to the magnesium , and u non- these mixt res are explosive , give little smoke and almost as much light as the permanganate mixtures . ma Aluminium y be used in place of magnesium , but it does not give quite so actinic a light . It may also be mixed with ' A - u " lu magnesium . slow burning alumini m mixture is a 6 u 6 6 2 minium , potassi m nitrate , barium nitrate , dextrine , sulphur The aluminiumpowder is sometimes greasy and clumps together ; in this case , it should be mixed with benzole , t u pe role m ether , gasoline , or as these are dangerous , carbon u t t i . i t o e rachlor de may be used _ The m x re sh uld be well

O ff shaken , the powder allowed to settle, the liquid poured , and the powder allowed to dry .

— rostini AMOUNT OF FLASHLIGHT POWDER NEEDED . O gives the following table of the quantity of magnesium and stop to be used : Distance ofobject Quantity ofmagnes ium in grams

‘ from light f: 7 f: 9 f: 12 f: 18 f: 25 1meter 2meters 3 meters 4 meters ‘ —M MAGNESIUM FOR UNDERGROUND WORK . artel divides the subjects into two classes : ( 1) short distances from 15 to 20 t 2 1 r . me ers , and ( ) long distances from 5 to 60mete s F or the Shorter distances he recommends three or four strips FLASHLIGHTS

3 Of magnesium ribbon , mm broad and meters long, wound into a spiral torch which gives an exposure of from

I V; to3 minutes ; from three to six of these spirals will give exposures from 15 to 20minutes ; up to 10meters one spiral u e u is enough ; up to 15 meters three or six sho ld b sed . Placing magnesium powder in 5 g lots and firing with a tuft f one u to 10 o pyroxyline , charge will be eno gh up meters ; for greater distances successive charges should be fired . Flash powders are not satisfactory; they are dangerous and - u give more smoke . For longer distances blow thro gh lamps a 8 u to 60 40 should be used , using bout g p meters ; up to meters 5 g . — d . L on e states of DURATION OF FLASH , that the duration h b ut a flas is dependent on various factors ; , calling the

of unknown ingredients a powder X , the following table u 1 X 100 15 : . 0 gives the d ration , magnesium , duration Of 2 X 100 u 1 . 75 u o f flash , seconds ; , magnesi m , d rati n o X 0 3. 10 225 f flash, seconds ; , magnesium , duration o X 100 u 2 4. 50 flash , seconds ; , magnesi m , duration of

ﬂash , seconds .

e Old powder ﬁr s more slowly than freshly mixed . The w weight Of the charge plays a part in the duration : 1g burns

2 for 3 for for seconds , g seconds , and g seconds . The particular manner in which the powder is laid also ff : 1 u 1 a ects the ﬂash g in a heap b rns for seconds , while g

: out u s spread b rn for seconds .

of ff : The method ﬁring also a ects the duration Electric ,

u ercuss1on d ration seconds ; p cap , seconds ; match, u seconds ; to ch paper, seconds . Any ﬂash longer than seconds will show movement of the eyes . Colour Photography

- L TER — u of THREE COLOUR FI s. The q antity dyes is given in grams per square meter and grains per 1000square inches . An 8 per cent solution o f gelatine should be prepared (see O rthochromatics) Red filter : Rose Bengal Tartrazine Green filter : Naphthol green Patent blue Tartrazine Blue-Violet filter

A cid rhodamine g gr .

Toluidine blue g gr .

u 700 m 15 oz . The us al quantity of dyed gelatine is ccm per q ( ,

1 . 435 . 00 min , per 0 sq — ADDITIVE FILTERS These are used for additive projection or with the photochromoscope . The gelatine should be pre pared as previously described . Blue-violet ﬁlter

Crystal violet g gr . M ethylene blue g gr . A few drops of glacial acetic acid should be used to dissolve the above . Allow the same quantity of dyed gelatine to the S ame area . Green ﬁlter Tartrazine Patent blue Naphthol gr een

346 PHOTOGRAPHIC FACTS AND FORMULAS the number of seconds from the moment of entering until

of u of the appearance the ﬁrst o tlines the image , exclusive of the sky in landscapes . The number of seconds elapsing before the appearance of the image is the guide to the further f u development o the plate, which sho ld be carried out accord ing to the following table Qu an ti ty of ammon ia so uti on i u te to 1 ota t m of l B d l d A . T l i e Time of ﬁr st app ear str en gth to b e add ed d evelopment i n cludi n g an ce of i mage after i mage app ear s time of app ear an ce S econ d s ccm MI nutes S econ d s 22to 24 None 2 0 25 to 27 2 2 15 28 to 30 8 2 30 31to 35 15 2 30 36 to 41 20 2 30 42to 48 25 2 30 49 to 55 30 2 45 56 to 64 35 3 o 6 5 to 75 40 4 0 over 75 45 5 0 The additional quantity of B solution must be added when u the o tlines begin to appear . u but Almost every developing agent has been s ggested , the following are satisfactory : u u Sodi m s lphite, dry

s . Ammonia , p gr . Potassium bromide Metol Hydrochinon Water to

Metol Hydrochinon u u Sodi m s lphite , dry Potassium bromide COLOUR PHOTOGRAPHY

Sodium hyposulphite g gr .

s 20 154 . Ammonia , p . gr . ccm min

Water to 1000ccm 16 oz .

For use dilute with an equal volume of water . The small u quantity of hypo causes the image to reverse in this sol tion , and development should be carried on until the highlights or

ﬂesh tones just begin to Show reversal , when viewed against

of the light . Instead using hypo , an excellent developer is a u 4 31 obtained by using pot ssi m ferrocyanide , g ( The following is stated to commence the development from the bottom of the ﬁlm : 1 Amidol g 5 gr .

19 145 . Sodium sulphite , dry g gr 19 1 Sodium bisulphite lye ccm 45 min . 2 Potassium bromide to g to 5 gr .

1 1 z Water 000ccm 6 o . Reversing solution a 2 1 A . Potassium permangan te g 5 gr . 5 Water 00ccm 8 oz . u 10 B . S lphuric acid , c . p . ccm 77 min . 500 Water ccm 8 oz . u l V u Mix in eq a olumes j st before use. The A solution must be kept in the dark . The following is preferable, being free from some disadvantages of the permanganate :

5 r Potassium bichromate g 38 g .

. 1 . 0 Sulphuric acid, c p ccm 77 min .

1000 1 z Water ccm 6 o . — . SECOND , DEVELOPMENT Any developer may be used for the second development after reversal ; the makers recom mend : u u Sodi m s lphite , dry Amidol Water 348 PHOTOGRA PHIC FACTS AND FORMULAS

—The INTENSIFICATION . following silver intensiﬁer was recommended by the makers 3 A . Pyrogallol g Citric acid 3 g Water 1000ccm 5 B . Silver nitrate g Water 100ccm 10 100 For use add parts B to parts A , and immediately apply u to the plate . The mixed sol tions rapidly turn cloudy ; then

u . the sol tion should be poured away, and fresh applied This u 30 should not take more than abo t seconds , as a rule ; then 2 the plate should be well washed , immersed in a per cent

‘

of . solution the clearing bath , well washed , and ﬁxed The following intensiﬁer may also be used :

Cupric sulphate 20g 154 gr .

Potassium bromide 20g 154 gr .

Hydrochloric acid 5 ccm 38 min .

z Water 1000ccm 16 o . ah As soon as the plate is ble c ed , rinse rapidly, and treat with a 5 per cent solution of silver nitrate ; then clear in a neutral

r permanganate bath , and redevelop with amidol o treat with a

5 per cent solution of sodium bisulphite . — VARNISHING . The makers recommend G um dammar 200g

Benzole 1000ccm 16 oz . The following is preferable as being less dangerous as regards ﬁre risks G um dammar 20g 154 gr .

50 384 . Manilla copal , powdered g gr

10 z Carbon tetrachloride 00ccm 16 o . u u As soon as the resins are dissolved , the mixt re sho ld be

h . heated to the boiling point , and then ﬁltered while ot — TH E PAGET PLATE With this a separate panchromatic

350 PHOTOGRAPHIC FACTS A ND FORMULAS

u the s lphite and bromide . When the solution is cold add the 1 u ammonia . For use mix vol me with 3 of water and use at 1 ° ° 8 . 6 5 3 . C ( Development time, minutes Then rinse S lightly and immerse in the following reversmg bath : Potassium bichromate 5 g 38 gr u 10 in Sulph ric acid ccm 77 m .

1000 16 z Water ccm o . The plate may now be handled in daylight and after about 3 minutes in this bath it should be washed for 30seconds and o 2 reimmersed in the developer for ab ut minutes . Then wash in running water for 3 minutes . Drying should be ff bu t . m e ected in a warm place , not by heat plate ay be [ The varnished by gently heating ﬁrst and then coating with 3 per u f cent sol tion o gum dammar in benzole . Photomechanical Processes

u The wet collodion process , collodion em lsion , lead , copper ,

i ntensiﬁers u and acid silver , and red cers are dealt with in

other sections . See index . , A N D - e r CLEANING ZINC COPPER . For lin wo k very ﬁne pumice powder should be applied with a felt pad or soft scrubbing brush and water and applied in the same direction - on as the original lines of the polish . For half tone work zinc or copper well washed whiting made into a paste with water and a little ammonia ShO tﬂd be used with a swab of absorbent cotton . Or, for copper , American polishing char ma u coal , with rounded end , y be sed in straight lines with plenty of water . G PASSING OR GRAININ BATH FOR ZINC . Powdered alum g Nitric acid ccm Water 1000ccm G R A I N I N G B A TH FOR COPPER . 23 1 r Chromic acid g 75 g . 1000 16 Water ccm oz .

ALBUMEN SENSITISER FOR LINE WORK ON ZINC . u of 23 15 Alb men (white egg) ccm 7 min . 0 ( Or dried albumen) g 5 gr . o u P tassi m bichromate g 40gr .

1000 1 z Water ccm 6 o .

- FISH GLUE S ENSITISER .

u ccm Fish gl e 36 5 min .

Ammonium bichromate g gr . 1000 1 Water ccm 6 oz . u Add eno gh ammonia to give a bright yellow colour . This 35 1 352 PHOTOGRAPHIC FACTS AND FORMULAS

u ﬁlm m st be burnt in after development .

- P Z I N — - INKING U LINE PRINTS ON c. Use photo transfer u ink, thinned down with very little t rpentine, and apply with compo or ﬁne nap leather roller . S — DEVELOPING LINE PRINT Immerse the plate in water , to which a few drops of ammonia have been added, and rub with swab of absorbent cotton .

HARD ENAMEL FOR ZINC .

1 z Fish glue 6 50ccm 0% o .

1 z Fresh white of egg 30ccm 2o .

(Or dried albumen) g 70gr . u 15 11 Ammoni m bichromate g 5 gr . Ammonia 15 drops 10drops

Water 1000ccm 16 oz . Beat the albumen to a froth and mix in the glue and again u beat p, allow to stand eight hours , then dissolve the bichro mate , then add the ammonia and ﬁlter through absorbent u cotton . The following gives a m ch tougher ﬁlm Fish glue ccm ’ Belting cement , Le Page s ccm Ammonium bichromate g Albumen ccm

Ammonia 7 .8 ccm Water 1000ccm Or ’

. z A Le Page s belting cement ccm 5 o .

Chromic acid g gr . 11 Ammonia ccm 87 gr . 1000 1 Water ccm 6 oz .

. 6 524 B Pure rock candy 8 g gr . 34 262 Ammonium bichromate g gr .

Add the acid to the water, then the ammonia and ﬁnally B with constant stirring .

354 PHOTOGRAPHIC FACTS AND FORMULAS

dr The exposed image is not burnt in, only heated to y and harden .

SCUM REMOVER FOR COPPER .

Acetic acid 100ccm 698 min .

z Common salt g 3 o .

z Water 1000ccm 16 o . The same quantity of hydrochloric acid may be used instead f o the acetic . — 10 e MACHINE ETCHING . Levy machine , ﬁrst etch, per c nt for 30 40 15 1 acid to seconds ; second etch, per cent for to 2 1 0 4 5 . % minutes ; third etch , per cent for to minutes Air

u for . secon and press re ﬁrst etch , to 94 lb d third etches , 1 10 e f r 30to 40 lb . A single etch with per c nt acid o seconds F r is generally enough except for extra deep work . o Holt i machine and line work on zinc , per cent w th three bites for 1 u . 8 and rolling p between Total time full depth , about For - minutes . half tone on zinc , use the same solution as for I line work, for VZ minutes ; then roll up and powder, and etch f r 2 o minutes . For half -tone on copper use perchloride of iron solution 5 f 35 B é . or 3 o a per cent solution anhydrous ferric chloride .

lb. for 30 Air pressure V2 to , time ﬁrst bite seconds and 3 4 total time % to minutes after stopping out. If the iron solution is very acid, add a little ammonia until a Slight pre ' ci itate p is formed, then boil and ﬁlter .

— G ri ndi n N w P l t s COLLOTYPE . g e a e . Sift over the surface

ﬁnely Sifted emery powder, wet well with water and grind with another plate with circular motion . Wash well after grinding .

Cleanin O ld P l tes S g a . oak in 5 per cent caustic potash solution for 4 days or place in hot 10per cent solution of

. S off sodium carbonate crape old ﬁlm with hard brush . R e use grind before . PHOTOMECHANICAL PROCES SES

S ubstratum.

Whites of fresh eggs 312ccm 5 oz .

2 z Sodium silicate 15 g 2o . 1 1 Water 000ccm 6 oz .

Beat the whites to froth and allow to settle , ﬁlter and add the u h other ingredients . Po r a little on the plate , drain slig tly

and place on leveled stand to dry . Or

15 11 . A . Gelatine g 5 gr

5 00 z Water ccm 8 o . 10 B . Alum g 80gr .

Water 500ccm 8 oz .

Dissolve the gelatine by heat , add the alum solution warmed up , and add um sol 4 Sodi silicate . 6 g The plates should be warmed and the solution applied with - m a broad camel hair brush and dry . A stock of plates ay be thus prepared, but they should be rinsed in water and again dried .

S ensi tive S oluti on . Hard gelatine 46 g Water 1000ccm Allow to soak for 30minutes and melt and add u 126 Potassi m bichromate g gr . 0 44 . 10 . . 6 2 and ﬁlter Allow min to every sq in . ( 8 ccm per u sq are meter) . Place the plates in the drying box and warm 4 ° 12 ° 8 . 0 up to C ( carefully level and coat . The tem

° ° er ture of u 54 130 p a drying m st not exceed C . ( After ° ° u 15 60 expos re wash in water at C . ( F . ) until all trace of yellowness has disappeared , then dry . hi n th P l t u E tc e a e. u g Act ally a moistening sol tion , there

. u being no etching action The plate Sho ld be rinsed in water , blotted off and covered with a mixture of 3 parts glycerine 2 f r and parts water o about half an hour . Or equal parts of 356 PHOTOGRAPHIC FACTS AND FORMULAS glycerine and water plus 2per cent of ordinary salt may be used . — u PHOTOGRAVURE . Negatives should be f ll of detail and without hardness and preferably carbon transparencies u sho ld be made , showing all details in the high lights , with out great density . The thinner these are kept , providing details in the high lights are visible, the better . Special

u or transparency tiss e is issued by the makers , standard brown may be used . t r P l t 5 Cleani ng he Copp e a e. Rub over with per cent solu

of u tion potassi m carbonate with cotton swab , rinse well and treat in the same way with 5 per cent solution of sulphuric and acid . Wash well polish with whiting made into paste u s with 3 per cent sol tion Of ammonia . Rin e plate with hot water and dry with clean cloth . i th P l t u u G rai n ng e a e. The us al d sting boxes should be used and the longer the time between setting the powdered asphalt in motion and the insertion Of the plate the ﬁner the

F r W 2 . o 0 grain a coarse grain alt for seconds . Allow the

2 F r plate to remain for from to 5 minutes . o very ﬁne grain

t o r it may be necessary to shake box and grain w o three times . Resin may be used but does not give such good results in unskilled hands .

tti n th r S e g e G ai n . Grip the edge of the plate with a hand u Vice , sing card to protect the copper , and heat over a gas u ﬂame , with contin al movement so as to even the heat , until a steel blue colour shows .

° unti n R si st Mo g e . Place the grained plate in water at 21

° 0 u u C . ( 7 slip in the tiss e and br sh the face with a soft brush to remove air bubbles . Bring the two into contact and u lift from the water , sq eegee well , and place between blotters

° ° r 10 u . 3 1 fo 8 . 00 r min tes Develop with water at C ( F . ) o ° ° ex e r e m e a re to 49 if under pos d ais te p r tu C . ( 120 F

358 PHOTOGRAPHIC FACTS AND FORMULAS

u 3 ﬁlm with a velvet roller . Place in water for abo t minutes and then roll up again with the roller ; this removes the ink

and any Slight veil can be removed with a wet swab of cotton . Free from water drops by lightly touching with blotting paper

and pin to board to dry . — DIRECT PRINTING ON ZINC AND ALUMINIUM . Sensitise with White of egg ccm Fish-glue ccm

Ammonia bichromate 7 . 8 g 60gr .

Ammonia q . s . q . 8 . 1 1 Water 000ccm 6 oz . Enough ammonia should be added to make the solution a clear lemon yellow . For large plates the volume of the solu - u tion may be increased by one fo rth with water . — VANDYKE OR REVERSE PROCESS . Zinc plates should be grained with the graining bath given for line work and coated with the following - u 111 Fish gl e g 8 53min . 22 Ammonium bichromate g 170gr . 1 Chromic acid g gr .

1000ccm 1 Water 6 oz . u After expos re , under a line copy , develop with plain water d and dye up with aniline ye. The plate should then be passed into a bath of 31 . 2 Ferric chloride , % sol ccm 16 min . 1000 Water ccm 16 oz .

Leave the plate until the colour disappears , then rinse and

. u dry Treat the plate with asphaltum washo t tincture , and ink up with the following

Bitumen, powdered Litho chalk printing ink Litho writing ink PHOTOMECHANICAL PROCES SES

Burgundy pitch 1part f Mix with heat and thin with the minimum o turpentine .

There must be but a very thin ﬁlm of ink on the plate .

Allow the plate to dry, and develop with water , plain or very slightly acidulated with hydrochloric acid . Weights and Measures

RULES FOR THE CONVERSION OF WEIGHTS AND MEASURES . t Weighs.

: 6 8 . Grains to grams Take per cent, and add per cent : 15 Grams to grains Multiply by , then increase result by

3 per cent . to : b 28 Ounces grams Multiply y , then increase result by 1 % per cent . t : 3 a Grams o ounces Take per cent , and incre se it by ( 5 per cent of : 40 n Pounds to kilos Take per cent , and i crease it by 1 r 10 0pe cent Of per cent) . K to : 2 ilos pounds Multiply by , then increase result by 1 2 0per cent ( per cent of 10per cent) . L t s eng h . : u l 2 u Inches to centimeters M ltip y by , then increase res lt 2 2 by 5 per cent ( 8 per cent of 5 per cent) . : 40 Centimeters to inches Take per cent, and diminish it r by 1% p e cent . : 70 Yards to meters Take per cent, and increase it by 2 30per cent ( per cent of 30per cent) . Meters to yards : Add 9 per cent and 4 per cent of 9 per cent . Fluid Measures .

: 40 40 er Pints to liters Take per cent , and increase it by p 5 f cent ( per cent o 40per cent) . : M b 2 Liters to pints ultiply y , and diminish result by 12 per cent . Example : Required the number Of grams equal to grains

362 PHOTOGRAPHIC FACTS AND FORMULAS

2 15 7 .

1 6 7 .68

20 A pproximate rule to convert English weights and measures into metric :

1 . 1. Call the new volume of solvent 000ccm 2 . of run If any the ingredients to ounces , take their ratio to 1000 the solvent, and write down the same ratio to in grams .

3. Divide each grain item by half the number of ounces , u and write the res lt down in grams . — u PERCENTAGE SOLUTIONS . Some disp te has prevailed as “ ” x u I n to the exact meaning of per cent sol tion , but photo graphic practice it means x parts in 100parts of the total bulk of u sol tion . As most chemicals are sold by the avoirdupois u u a o nce of grains , and liq ids are me sured by the ounce of 480 u minims , some conf sion has arisen . The following WEIGHTS AND MEASURES tables S how : (a) the accurate quantities of solids to be dis solved i n sufﬁcient liquid to make a total bulk of 100parts for the various percentages ; (b) the number of grains to be dis solved in sufﬁcient solvent to make 1ounce of any given percentage .

1per cent gr . 2 ( C M 3 4 5 6 7 8 9 10

The number of grains of which must be dissolved in sufﬁcient liquid to make ounce for the various per centages :

1per cent gr . 2

J O ~ P-

1 U \ O \I

O O O \ 10

These tables are sufﬁcient to calculate any percentage or

u or . R e volume , by merely m ltiplying adding Example :

to 15 u quired make a per cent sol tion , how many grains are required : 364 PHOTOGRAPHIC FACTS AND FORMULAS

10per cent 5 5 per cent

r g .

z f 10 16 o . o Required per cent solution , how many grains requir ed : 4 8 X 16 568 gr . The following tables are suffi cient to enable anyone to read u u ily convert the metric into the c stomary nits , and are based

u . . f on those p blished by the U S Bureau o Standards . L n th e g s. Inches

I I

A reas. Square Inches

366 PHOTOGRAPHIC FACTS AND FORMULAS

3 3 4 4

5 5 . 6 6 7 7 8 8 9 9 COMPARISON OF THERMOMETER SCALES - Equivalence of t ls us nd F ahr enhei t Thermomete s Cen igrade ( Ce i ) a r . O en ti Fahr en Cen ti F ahr en Cen ti gr ad e h ei t gr ade hei t gr ade 0 35 70 1 36 71 2 37 72 3 38 73 4 39 74

5 40 75 6 41 76 7 42 77 8 43 78 9 44 79

10 45 80 11 46 8 1 12 47 82 13 48 83 14 49 84

15 50 85 16 5 1 86 17 52 87 18 53 88 19 54 89

20 55 90 21 56 91 22 57 92 23 58 93 24 59 94

25 60 95 26 6 1 96 27 62 97 28 63 98 29 64 99 WEIGHTS AND MEASURES Chemical Tables

TABLE OF SYMBOLS AND MOLECULAR WEIGHTS OF THE MORE IM PORTANT COM POUNDS USED IN PHOTOGRAPHY 1 M0 . Name Wei ght 58 Acetone C: Ho 0 sulphite C: H. OH 8 03 Na 162 ci ace ic C2 H4 02 60 A d, t H 122 benzoic Co o G OOH bori c Hz B 03 62 carbolic Ca H5 OH 94 ' chlorochromic C1Cl 02 O H ‘ chromic ( anhydride) Cl 08 100 citri c C6 H8 0 H20 210 dithionic Hz S : O 162 formic H : CO , 46 allic C CO O H H 0 188 g 8 H: ( OH ) ; , 2 hydrobromic H B r 8 1 hydrochloric H CI hydroﬂuori c H F 34 lacti c CH: CH ( O H) G OOH 90 nitri c HNO; 63 ox alic Ha C2 04 126

pentathionic Hz S t 06 258 perchromic H Cr 04 117 phosphoric He P0; 98 picric C. H, ( N02) : OH 139 pyrogalli c Ca H: ( OH ) , 126 li sa cylic C. H4 ( OH ) G OOH 138 H2 8 0; 98 sulphurous H2 8 0 82 tannic C14 H10 09 322 r i ta tar c C2 H2 ( OH ) : ( COOR ) a 150 r i tet ath onic Hz S; 011 225 trithionic Hz S S 08 194 A l h co ol ( methyl ) CHs OH 32 l ( ethy Ca H5 OH 46 lum ammoni a A I NH 2 6 A , 2 ( 4 ) 2 ( S 04 ) ; 4H20 90

‘ chrome Cl a K2 ( S O 4 ) 4 24H20 998 i n ro ammonia Fez ( NH4 ) : ( 5 004 24H 0 964 A la K, 24H30 948 368

‘370 PHOTOGRAPHIC FACTS AND FORMULAS

Name Symbol a on i sul ide 5 2 C rb , b ph C Celloidin C12 H 00 ( N03) ; eric sul a e Ce 4Hz O C , ph t " Chloral hydrate C C : CH ( OH ) : l Chloro form CH C : H NH Chrysoidine C. 5 N , C. H; ( 2) 2

o al c lori e C0 C12 6HSO . 5 C b t, h d o er romi e C pp , b d

Chloride Cu C12 Z Hz O 0 0 0 0 0 0 0 0 0 0 0 0 0 0 nitrate C11 ( N03) : 6H20 sulphate Cu 8 0; SH20 H Cyanine C29 as N; I

Dextrine ( Co H10 05 ) X Diamidophenol O H; OH

Eosine N a or K Salt of CO H4 ( CO ) 20( CO H OH * Erythrosine CoH4 ( CO z O ( CeHO HXa ) 2 Ether C4 Hm O

Ferrous and ferri c salts ( see Iron ) ormalin 40 sol f H F e % . o C aO l 2 G ycerine Ca H5 ( OH ) : 9 l i 167 G yc n? Co H4 OH NHCH: G OOH ol c lo i e ellow A u C14H 0 412 G d, h r d y H 4 2 brown H A u C14 340 potassium K A u C14 2H20 414 sodium Na A u C14 2HeO 398

ro en erox i e H o 34 Hyd g , p d z z i Hydroqu none Co H. ( OH ) : 110

Iodine I 127 ri i l ri I d ous ch o de Ir Cl: tetrachloride I r Cl. 335 i potass um tetrachloride K. Ir Clo 484 iu r 2 sod m tet achloride Na: Ir Clo 45 RO N I . i Ferr c chloride ( dry ) Fez Cl. 325 chloride ( lump) F6 2 C10 l Z Hz O 541 ammonia ci a e rown 4 Fe C H 0 3 NH tr t , b o 5 7 ( 4 ) 3 Co HsO e 3Fe ( OH ) ; 2030 green 5F6 C8 H5 072( N H4 ) c HsotN H4C0H107 2HsO 1956 l oxa ate Fee ( C: 04 ) 376 The X i n t ese ormu ae ma b e r omi n e i odi n e or c or i n e whi c h f l y b , , hl , h el emen ts i n ot er r o or ti on s con s i tu te th r i ous omm r i d e p p t e va c e c al y s. . h G l cI n 18 ox hen l - ci n or ox hen l - mi o-a e i c ci d t y y y p y gly T y p y a d c t a . CHEMICAL TABLES

Name Symbol RO N I . H Fe C 04 a 3H20 428 Ferr1c Ammoni um ox alate ( N 4 ) 3 ( 2 ) ) 3H 0 491 potassium ox alate K3 Fe ( C2 2 F 0 l l O 976 sodium oxalate N3 8 e ( C2 4 ) o e ous c lo i e Fe C13 127 F rr , h r d ( dry) cr s Fe C14H20 199 ( y t. ) 2 180 oxalate Fe C2 04 2H20 H 328 potassium oxalate K2 Fe ( C2 O 4 ) 2 2O 278 sulphate Fe 5 04 7H20 6 H 0 392 ammonia sulphate Fe ( NH4 ) 2 ( S O d z 2

ea aceta e Pb C2 H3 O s 2 3H20 379 L d , t ( ) 331 ni trate Pb ( N03) 2 i ia caustic L i 24 L th , OH it ium romi e L i 87 L h , b d Br 74 carbonate L i z C03 s has 2H O chloride L i Cl ( cry t. e ) i odide L i I 134

Ma nesium c lo i e C12 95 g , h r d Mg 246 sulphate Mg 5 04 7Hz o an anese e ox i e M11 0 87 M g , p r d 2 225 sulphate M11 5 04 4H2O ercur 200 M y, Hg 271 bichloride Hg Cl: iodide Hg 12 454 2KI 786 o ass io i e s lu le H I . p t . d d ( o b ) g z 1* 344 Meto C8 H4O HNHCHSP) s S 04

Palladious chloride Pd C12 177 26 potassi um chloride Kg Pd C14 3 P r - mi o 10 a a a d phenol Ca H4 NH; OH 9 P enol see ci ca oli c h ( A d, rb ) P l i at num per ( or bi ) chloride H2 Pt Cle 6H20 Po assium ammonium c oma e K N H Cl' 0 173 t , hr t 4 4 10 bicarbonate K H CO ; 0 bichromate K2 Ch 07 294 - boro tartrate C2 H2 ( OH ) : ( C01) : BOK 214 bromide K B r 119 carbonate ( dry ) K2 C03 138 chlorate K Cl 08 chloride K CI - chloro platinite Kt C14

’ chromate K2 Cl 04 194

citrate K3 Co H5 07 HeO 342 cyanide K C N 65 ferri cyani de K3 Fe ( CN ) e 329 err f ocyanide K4 F e ( CN ) 6 3H20 422 hydrate K H0 56

oto i s the su ate of mon o-met - ar a-ami do- n M l lph hyl p p h e ol . 372 PHOTOGRAPHIC FACTS AND FORMULAS

Name Symb ol

Potassium i o i e , d d metabisulphite K: S z 05 nitrate K NO nitrite K NO ox alate K2 C2 0. H 0 percarbonate K2 C2 00 perchlorate K Cl 04 permanganate K2 MHz 0 persulphate K2 S z 08 sulphate K2S O 4 Sulphocyanide K C N S Pyrocatechin C ; H; ( OH ) ,

Rochelle salt K Na C4 H4 00 41120

’ S chlippe s salt ( sodium sulphanti moniate) Nae Sb S 4 9H20 479 ilver aceta e C2 H3 02 167 S , t Ag + 2 ammonium nitrate Ag N03 2NH3 04 bromide Ag B r 188 A carbonate ga C03 276 chlori de Ag Cl citrate A ge Ce H5 01 513 ﬂuor ide Ag F 4H20 199 iodide Ag I 235 nitrate Ag N O S 170 Ag N O 2 154 ox alate A 8 2 C2 04 304 ox ide A 8 2 0 224 phosphate A ge P 04 419 A sulphate ge SO. 312 sulphide A 8 2 S 248 tartrate A gz C4 H4 08 o ium aceta e N a C H 0 3H 0 136 S d , t 2 3 2 2 ( fused) N a C2 H3 02 182 bicarbonate Na H CO 84 ' bichromate N 3 2 CI 2 O 2Hz O 298 Na H SO 104 N 3 2 B . 07 l O Hz O 382

Na B r 2H20 139 * carbonate ( dry ) N3 2 C03 106 car onate r N I H 2 b ( c yst. ) 3 2 C03 O z o 86 chloride N a CI l r - ch o o platinite N 3 2 Pt C16 6H20 citrate N 3 3 Ce H5 07 5V3 H20 357 ﬂuoride N a F 42 n f r m 1 I o ul ae 0 p ar ts an hydr ou s ( z . dr y ) soda car b on ate can b e u sed i n

ace of 27 ar ts cr st. so a car on ate . 10 ar t f cr u 3 ar t p l p y d b p s o yst. eq al 34 p s of the dr y .

374 PHOTOGRAPHIC FACTS AND -FORMULAS

Name Cadmium Caesium Calcium Carbon Cerium Chlorine Chromium Cobalt Copper

Erbium Fluorine Gadolinium Gallium Germanium Gold

O O O O O O O O O O O O O O O

O O O O O O O O O O O O O O O O

O O O O O O O O O O O O O O O O O O

Niobium Nb Cb Nitrogen

O smium Oxygen ( Standard)

Palladium Phosphorus Platinum P otassium P raseodymium CHEMICAL TABLES

Name Radium Rhodium Rubidium Ruthenium

S amarium S candl um S elemum

Strontium Sulphur

Tantalum Tellurium Terbium Thallium Thorium Thulium Tin Titanium Tungsten

Uranium

Vanadium

Ytterbium Yttrium

Zinc Zi rconi um A pp endix

— u 30 1924 u EASTMAN PLATES . After J ne , , the distrib tion f u o Seed , Standard and Stanley Plates will be discontin ed by the Eastman Kodak Company . The new Eastman Plates listed in the left hand column can be used for the same u purposes as those formerly s pplied , which plates are listed u r opposite in the centre col mn . The approximate elative speeds are given at the r ight . Eastman 40 Seed 30 Eastman 36 Seed 26 X Eastman Speedway Seed G raﬂex Eastman Process Seed Process Eastman 33 Seed 23 Standard Extra Imperial Eastman Universal Stanley Regular Eastman Polychrome Standard Polychrome Eastman Commercial Stanley Commercial Seed Nou- Halation L Ortho Eastman D C Ortho Standard O rthonon Eastman S C Ortho Seed L Ortho Eastman Post Card Standard Post Card Eastman Lantern Standard Lantern Slide

e ula low Slide ( R g r, S )

e ula low ( R g r, S ) _ Seed Lantern Slide Eastman X-Ray Seed X-Ray

W . W . Panchromatic Seed Panchromatic

378 PHOTOGRAPHIC FACTS AND FORMULAS

omi Pa 1 l 13 n e e 99. Co d ath e ia Pla i ot e Br d p r, S p t yp , B ron e Pa e evelo men 279 p r D p t, l gg ol P o ess 2 a c 77. C d B th r , 2 l ni s 1 1 B ror e Pa e e elo e s 00 o a es 50 54. p r D v p r , C d V r h , , gég Coll <1io lo i e Emul si on Ch r d , mi 1 q ( o e P a e Ex o su e 99. 6 ) Br d p r p r , o mi e Pa e ac o ial D e llo i o- lo i e P i nts la Br d p r F t r Co d Ch r d r , F t vel o m n 2 2 ni n 16 e t 0 . te 9. p , g, m 2 o i e Pa e ee s 67. ollo i on ac i n 3 . Br d p r Sp d , C d B k g, omi e P i n for romoil 311 oll ion n fe 252 o a s . Br d r t B , . C d Tr r, mi n o e v . Pla i ot e 294 o lloi al ul u o ni n 235 . Br d t yp , . C d S ph r T g, m il l e c o o 03. ollo t e 3 4 a 3 5 . Br B h , C yp , o m il r mi e P i n 11 l P o o o 3 . o ou ot a 344. Br B d r t, C r h gr phy, m il P 1 i o o esses 3 0. Coluni bian e anol or i Br r , . M th Sp r t, omoil P oc 02 ess 3 . z l Br r , omoil u i n 307 om i ne evelo i n F x Br , R bb g, . C b d D p g i romoil ansf s 06 12 n e 3 3 . i 8 5 . B Tr r , , g, u ou s ell come Plate Com i ed oni n 8: ix in B rr gh W T g F g,

ee s 55 . ﬁg Sp d ,

ombimn enses 43. C g L ,

om ari son of Pla e ee s 69. C p t Sp d , ame as lac en n 6 C r , B k i g, . on u ate o ci 49; C j g F , m l i n 2 a a e ac 3 . r B g, 1 C k onti nen al Plate ee s 6 . C t Sp d , n 2 a o i ssue a i n 50. C rb T , M k g, Contr st evel o e ame D p r, Cr r, a on P o cess 249 C rb r , . l gl P o c ss 2 a o e 99. C rbr r , Conversi on o f Weights M eas mi n 2 a e o ni n 44. r T g, C u es 360. r , asei n Pa e 195 337 C p r, , . Copp er Bro mo-I o di d e I ntensi ll l 1 e u oi a ni s 55 . d r h , 1 C V ﬁ er 39. , m n e e ts 8 . C , Copp er Ferrocyani d e I ntensi e i c ul a e e uce 143 C r S ph t R d r, . 1 her, 37.

Certi nal , 109. - o e H alf o ne E namel 353. C pp r T , mi c l l ‘ e a a es 368 . h T b , C o e cum emove 354. C pp r, S R r, hlorate agnesi um Flash - 1 C M o e ilve I ntensi fier 35 . C pp r S r , li ts 340 gh , . - o e Ti n I ntensifier 136 . pp r , h ’ C C reveto t s ac in 33. B g, k o e o nin 216 . C pp r T g, m l m ix i n a 12 ’ o e u t 4. hr F g B h , c n 2 C A o nu s a i 3 . C r B k g, omi m n i 1 u I tens fier 34. hr , i n for ectacl e enses C Correct o Sp L , i l 1 C to 09. , 47 l ni n ea lass 8 . g , C G stal a ni s 156 . Cry V r h , Cl ea P o o a u Pl e g h g e a , 17 t r v r t a o n ix ative 5 . gég Cr y F , i c lo i e e uce 144. Cupr Ch r d R d r, l eani n i nc o 1 e 35 . C g Z C pp r, anot e P ocess 258 C y yp r , l eari n a s g B th , ans a enc1es 26 1. C C yanotyp e Tr p r , oati n a on i ssue 250 C g C rb T , . 22 o alt oni n 8 . C b T g, - - o alt o n P ocess 2 m oof lue 9. 68 . a C b Ir r , D p pr G , ’ 1 i n m h m s e uce 14 . o effi c e t e e a u e 78 . D eben a C , T p r t r , R d r, l 21 oi ns P oto ra i n 3. enatu e l co o . C , h g ph g, D r d A h ,

ol at Plati no 2 1 of ocus 42. t e 8 . C d B h yp , D epth F , INDEX

122 1 e elo er Toz ol . e of ocus cal e 4 . D pth F S , D v p , , 1 esensi ti si n Plates 28 . evelo e s 9 . D g , D p r , 1 D evarni shi n e a i es 154. e elo e s an 9 . g N g t v , D v p r , T k, D v l o ed e ia P a i no e e el o i A utochromes 345 e p S p l t typ , D v p ng , , z8 s 347 1 Dev lo i n 8: ix i n om i ne evelo e e ol 9 . D p r, A r , p g F g C b d , c i l 109 gs e elo e A t vo . D v p r, , 2 evel o e l ali ne mi ol 93. e el o i n i ne P i nts 64. D p r, A k A d , D v p g L r ,

13. 1 l o i n P . . P . 8 evel o e mi ol 9 . eve D p r, A d , D p g O , - - 204. evelo e mi ol P o 9 . evelo i n out Pa e s D p r, A d yr , 3 D p g p r ,

1 evel o ment 76 . evelo e A z ol 09. D p r, , D p , ’ 13 vel o ment ac o s 76 . evel o e eac s . D p r, B h , 1 D e p F t r ,

1 evelo ment ac o al 76 . evel o e Certi nal 09. D p r, , D p , F t ri ,

1 e elo men Pa e s 204. evel o e Ci tol 09. D p r, , D v p t p r , 11 v l ment Pa e s rtu a evel o e ont as 0 . D e D p r, C r t, p r , A r , n ez gg evelo e i o e 94. D p r, D g , evelo e Eastman ilm 100 evel o men Pa e s ena D p r, F , , D p t p r , Ath 2 6 11 O ld aster 0 . 103 9. , M , 211 men P e s A z o . evelo e Edinol 94. evel o a D p r, , D p t p r , , 2 k 09. evelo e Ei ono en 95 . e elo men Pa e s C o D p r, k g , D v p t p r , y , m n P e s e elo evelo e Elo n 95 101. evel o e t a D p r, , , D p p r , D v p x l 204 evel o e e ous a ate 95 . ers . D p r, F rr O , , n men Pa e s evelo eve o e l ci 98 . evel o D l p r, G y , D p t p r , D p - n 20 evelo e o c i non 99. ers N on asi o 5 . D p r, Hydr h , , Abr , n men Pa e s e en e evelo e ac i 109. evelo f D p r, K h , D p t p r , D d r, 109 212 213 evel o e Kal o en . . D p r, g , , n 1 1 el o men P a e s Enla i n evel o e Kodelo 0 . ev D p r, , D p t p r , rg g 1 10 evelo e an ern Pla e 33 . C k o 2 . D p r, L t t , y , evelo e etol - oc non e elo ment P a e s E c i n D p r, M Hydr hi , D v p p r , t h g

10 own 206 . 3. Br , 1 l m n P s t P 00. e e o e t a e evae evelo e . . D p r, M , D v p p r , G r , l l 11 21 eve o e oto 0 . 3. D p r, M , 1 l m n P evel o e eol 07. eve o e t a e s evae D p r, N , D p p r , G rt 1 - 21 l 07. s 4 evelo e o ova G a . D p r, Ort , N , mi do henol 1 1 m evel o er Para 08 . D ev 1 ent Pa e s aloi D p , p , p p r , H d , r m l 109 3 e elo e Pa a o . 68 D v p r, , P n l 109 lo men Pa e Ko elo n evelo e ara o . eve s d D p r, , D p t p r , h n l n m n l 2 e el o e Para e e dia i eve o e 07. D v p r, p y , D p r, 1 el o men Pa e s imo sa 09. ev D p t p r , M 1 210 evelo e P o ca ec i n 09. V erot e . D p r, yr “t h y p , 112 e el o men Pa e s o o 210 evel o e P o . . . v . D p r, yr , B J , D p t p r , N k , 111 l o men Pa e s P o D evelo e P o allol . eve e D p r, yr g , D p t p r , yr l - c 112 elo er 2 i 05 . eve o e P o aus . v D p r, yr C t , p , - 11 vel o men Pa er s R o lon evel o er P o cetone 3. e D p , yr A , D p t p , y - 2 evel o e P o Metol 119 evel o e 07. D p r, yr , . D p r, elo o i n l 10 e elo men Pa e s o e e a 8 . t D v p r, R d , D v p p r , Sh rt 21 5 . evel o e tan a H . D . to at D p r, S d rd , S p B h , 112 evel o ment P a e s Toz ol . D p p r , 20 evelo e an 113 a 7. D p r, T k, . B th , 380 PHOTOGRAPHIC FA CTS AND FORMULAS

’ D l o m n P lox End m nn P oc 2 eve e t a e s e e a s ess 3 0. p p r , V , r , - z 08 . E nla i n E x o su n es i 335 . rg g, p r , evelo ment Pa e s elve E nla i n Ex osu es a iati on D p p r , V t rg g p r V r , 21 2 een 0. 7 Gr , D eve1> ment Pa e s i ta a E nla n e uci n a l e p p r , V v , g g R d g T b , 265 gcj D l m n P i x E c i n at - i n ev o e t a e s V tte t c 353. p p r , , h g B h , Z , g1 E c i n M i n 3. t ac e 354. h g, h , l m n n 0 E c i n P o o avu Pl eve o e t ta 8 . e a e D p , S d , t h g h t gr r t , D l m n - l i nin 3 eve o e t u e o 57. p S ph d T g, x 1 6 é 4s E o su e 5 0. p r ; , evelo men e mo E x c1 ure Effec of l i u 77. e D p t, Th r , p , t A t t d , ex tri ne oun ant 325 73 D M t , . x i n - m n n 2 E x osu i n E nl i n e t e G u ou a t 3 5 . e a 335 . D r M t , p r rg g, l f Pl 4 E x o sure eter 7 ia ona s o ates 6 s 5 . D g , . p M , i m n n li E x o su e ete P a e a a a te es 330. 75 . D gr L r S d , p r M r p r, i mon m n Ex o su es for n i a e e t 9 e o s 73. D d C , . p r I t r r , i m Ex o su es Pi n ol es 4 a ra e u es 44 8 . D p h g Ap rt r , . p r , h , i n m s em Ex osu es i e uci n 33 . a ra s 74. 5 D ph g Sy t , p r R d g, i a o e P ocess 320 Ex osu e a l es me i can D z typ r , . p r T b , A r c 2 P o a 1 i oi c or een Fo 19 ot 5 . D hr Gr g, . h gr phy,

i o en 94. D g , i c 1 e e a i es 5 . D r t N g t v , 1 F al ues a i a i on of 7 . V , V r t , i rec P i nts on i nc 358 . D t r Z , a i cs i e oo ﬁn 5 . i c l 2 F br , F r pr g, e t u i e o nin 34. D r S ph d T g, 1 a i cs ensi ti si n 95 . F br , S g, D i strib uti on of p ectrum Col S m n a tori al evelo e t 6 . F c D p , 7 o urs, 23. 2 Factori al D evel opment of B ro D r ounti n 3 7. y M g, 2 mi e P a e s 20 . D uo d cimal et i c s ems d p r , r t , M Sy m n t 6 acto s evelo e 7 . F r , D p , 3g4. ’ 1 a mer s e uce 45 . u ati o n of las 343 F r R d r, D r F h , . 2 F eert e P rocess 3 0. usti n -O u P e e 316 y p , D g , pp r, . erri c x alate Ma i n 274. D e I n en i ﬁ c i F O k g, y t s at on, 140.

erri c e uce s 145 . ei n i - l P i n F R d r , s ue ts 353. Dy g F h G r , 2 F erro alli c P o cess 63. g r ,

r ssi ate P o cess 258 . Ferrop u r , E s m n ilm l a a e e o e s 100 er ou s x ala e 95 . t F D v p r , , F r O t , 103 11 10 9. ilm ev elo e s 0 . , F D p r , E astm n Pl 1 a ates 376 . ilms t i i n 57. , F , S r pp g, ’ E e s e 1 . 4 uce 44 il ters i tive 3 4. d r R d r, F , Add , Edi n 2 ol 94 mati c 9. . il ers r t o c ro , F t , O h h , f - E f ec o f to e tu e 71 il ers ree olour 344. t S p Ap r r , . F t , Th C ,

Ei ono en 95 . i nal u o t 253. k g , F S pp r , E l co n l 1 c a 09. i e roo ﬁn a ri s 5 . , F r p g F b , E limi nator - n s 12 P r nts ei 353. o 6 . i s lue i , Hyp , F h G , Dy g, - Elo n 95 . i s lue ensi ti ser 35 1. , F h G S , m l i n - E u s o . . Pri n i n out ix ative for P i n s 157. , C C t g , F r t , 160 . ix i n 123 F g, m l - 12 E u sio n Pri nti n out 1 x n Pla1n at 3. 73. i i , g , F g, B h , mel or 12 Ena f nc 352. ix i n l aline at 3. Zi , F g, A k B h ,

382 PHOTOGRAPHIC FACTS AND FO R MUL A S

I ntensifier o Ferroc an ea onin 22 e 5 . , C pp r y L d T g, 1 r i de 37. eat e ensiti si n 195 , L h , S g, . n n - 1 ens I e i r il 5 . o t s fie o e ve 3 cus 35 . , C pp r S r, L F , - I ntensifi er o e Ti n 136 . L en e arati on e eosco i c , C pp r , p , St r p , I ntensifi er D 1 zz e 40. g , y , ’ I n n i 12 enses f te s fier E e s 3 . a e o 50 , d r , L , C r , I n en ifi m lin 132 enses om i ni n t s er o a . 43 , F r , L , C b g, . I ntensifi er e 1 i a l e for 2 a 38 . s a itu es 5 . , L d , L ght T b L t d , I nteri si fi er e cu i c o i e i ne rawi n s f om P i nts 14 , M r r I d d , L D g r r , . l 3s i ne P i n s evelo i n 3 2 L r t , D p g, 5 . I ntensifi er e cu i c ul o i ne P i nts n i n -U 352 , M r r S ph L r , I k g p, . 1 i ne en si i c ani e 33. t se 35 1 y d , L S r, . I n nsi r c 10 i ui l te fie e u 3 . ue 9 , M r ry, L q d G , . ’ n n Monckho en 11 i ui a eli s I te sifi er v s 3 . f t 16 , , L q d S gh , . n 13 ive of l r n I ntensifi er ui one 8 . u u o i n 236 , Q , L r S ph T g, . ’ n i r hli 132 o cal evel o m n I nte s fie S c e s al . e Platino , pp S t, L D p t, I ntensi fier il e - ani e 131 t e 286 , S v r Cy d , . yp , . ’ I nteri ifier nno s a a e L umi ére s e u 1 1 a u ce 43 47. , St T rtr t , R d r, , l gz n i n m 13 I nte s fier a iu 7. , r , U i n E in ac e tc 354. n ensif i n A u o chromes 4 M h h g, t t 3 8 . I y g , ac i ne P oto a in 3 h ry, h gr ph g, . I ntensifyi ng Carb on Transpar M a nesium lo a e las n i M g Ch r t F h e c es, 253. li ts 340 ntensif i n Pla i not es 287 gh , . I y g t yp , . Ma nesium- i t a e ixtu es g N r t M r , nte io Ex o su es 73. I r r p r , 33g o i e- o e uce 143 I d d Hyp R d r, . a n ium 2 es n e o un 34 . - ni c 13 M g , U d rgr d , o o a e e u e 4 . I d Cy d R d r, a i n a on i ssue 249 on or ano e Toii i n 220 M k g C rb T , . Ir Cy typ g, . a i n er i c x 2 alate 74. on P ocesses 258 M k g F r O , Ir r , . ’ a ine lue 9 I tterheim s P o cess 316 M r G , . r , . a t L ac Plai n Pa e s 10 9 . 2 M t p r , o i nal u o 53. Iv ry F S pp rt, a ni 1 a s es 50. M tt V r h ,

a ti n lass 7. 1 M t g G , ac i n 09. K h , c i al c i n e an c e u t o 148 . M h R d , lli P oc 2 0 a t e ess 7 . K yp r , i m lo c i n - e u out 157. M d , B k g , K l o n 10 a e 9. g , i m n 16 1 e u e ouc i 5 57. M d , R t h g, , Ko d lon 11 e 0 . , Mon o ri al on es asses St Br , g ’ L ai ner s c 1 I n nsi 10 e u e 43 e cu te ﬁers 3 . R d r, . M r ry , n n Pl - 1 a te a e ee s 68 . e cu ani e e uce 44. L r t Sp d , M r ry Cy d R d r, n n c n l l n n 2 2 a te ee exi l e 6 . e cu u i e o i 4 . L r S r , F b , M r ry S ph d T g, 1 ante n li es 330. e cu i c o i e I ntensiﬁ er 33. L r S d , M r r I d d ,

ante n li es i n i n 330. e cu i c ul o c ani e I nten L r S d , B d g, M r r S ph y d n 1 i ﬁ 1 a te n li e evelo e s 33 . s er 33 L r S d D p r , , . n rn li i r m 0 Mercuro-Uranot e 293 a te e a a s 33 . L S d D g , . yp , nte n li i 0 e ec a e es 33 et 75 . L r S d S z , . M r, B k, n n m e ial 5 a e n li e o ti 330 e er 7 . L t r S d Sp t g, . M t , I p r , i i l 2 e t i n s 5 at u e a es 5 . et a 7 . L t d L ght T b , M r, W k , 1 nn ea I ntensiﬁ er 38 . ete e 75 . L d , M r Wy , - 22 x ea on oni n 5 e e s E osu e 75 . L d Ir T g, . M t r , p r , INDEX

ol 101 o c oma i c P oto e . a M t , Orth hr t h gr phy, 12 22 e ol P oi sonin 0 . . M t g, - 1 h chr m etol H o evel o e 03. O rt o o ati sin Pl es 2 a 4. M ydr D p r, g t , 21 ol 10 e anol Ea l e . 7. M th , g , Ort , 21 o ome P o c ss 29 et l l co ol . e 7. M hy A h , Oz br r , et i c uo ecimal E uiva o e P o cess 295 M r D d q Oz typ r , .

l ents, 364. M m P P 187 i o s A ro e . . . a u ty p . O , Pa e olou Pla e 348 1 g t C r t , . ol enum o ni n 23 . M ybd T g, ’ P alladi o t e 282 293 131 y p , , . Monckho en s I ntensiﬁer . v , Palla ium oni n 182 l 100 d T g, . P eve o e s . M . . D p r , Panc omati c 8: R ed S ensi ti s otol 101 hr M , . 2 ers 5 . 2 , o un ants 3 5 . M t , Pan chroma i i n Pl 2 t s ates 7. 2 g , ountants ex i ne 3 5 . M , D tr , P a e for Ex o su e ete s 75 . Mo un nts ex i ne G um p r p r M r , , D tr , Pa e N on-actini c 20 3gg p r, , . P a e s e elo i n -out 204 l ti ne 26 p r , D v p g , . ountants e a 3 . M , G , Paramido henol 10 8 . 2 p , ountan s i ui ela i ne 3 6 . M t , L q d G t , Paramol 109 - 2 , . oun tants ta c ela i ne 3 6 . M , S r h G t , Paranol 109 2 , . ountants ta c Paste 3 7. M , S r h , Para hen l endi amine 109 o un i n D r 327 p y , . M t g, y , . ’ P ell et s Pro cess 26 1 oun i n P o o a u e R e , . M t g, h t gr v r P e e us in -on P ocess 316 6 pp r D t g r , . si s 35 . t, P e cen a e olu i o ns 362 i 2 r t g S t , . oun n te eo P i nts 3 8 . M t g S r r , P e man anate e uce 142 o i n ects ut e r g R d r, . M v g Obj , Sh t r P os a e f il 1 t o ve Pa e 69. 2 h ph S r p r, ee s 7 . Sp d , P oto a at i t 73. h gr phy N gh , P o 6 o avu e 35 . ’ h t gr r , Namias e uce 142 R d r, . Pho t ravure l eanin Pla e g C g t , e atives D hi n 1 o evarni s 54. N g , g, 3s6 e a ives i 1 ec 5 . N g t , D r t, Photo gravure Etch i ng S olu e ro ra hi c Pro c 16 ess 3 . N g g p f , ti ons, 357. eol 10 7. N , Pho r r i mn t< g avu e G ra g Pla e, i t P o o a 73. N ght h t gr phy, 3g6 i trate- a nesium las li s N M g F h ght , Phot ravure e in ai n g , g , 339 S tt Gr . 3os6 N o n-acti ni c Pa e 20 p r, . Phot ravure ounti n esi st g M g R , N o n-A chromati c Lens Corree 3os6 . i on 47 t , . P o o a u e arni s i n 357. h t gr v r V h g, P o oli o t t a 357. h h gr phy, ects n e l 1 ass P oto P otomec ani cal P o cesses 35 . Obj U d r G , h h h r , - a i n 4. Piments for um i c o mate gr ph g, G B hr , x ll a ac i n 34. O g B k g, 255 . O ilo ra h P ocess 306 Pi n l Ex o e o su es 48 . g p r , . h p r , O il P i n i n ~ 30 5 . Plai n ix i n a 123 r t g, F g B th , . O il 8: B omoil Pro cess 302 1 . Plai n Pa e s 89 r , p r , . al lass i nal u 2 n 1 o t 53 Plai n Pa ers asei 95 . O p G F S pp r , . p C , t oc omati c il 2 n 12 e s 9. Plai n Pa e s P ri n i 9 . Or h hr F t r , p r , t g, O rtl c ehro mati c l 1 as li s Plai n Pa e s esi n si e 93. F h ght , p r , R z d , gz i n i n 11 Plai n Pa e s e si ti s 9 . p r , S g, 384 PHOTOGRAPHIC FACTS AND FORMULAS

- 1 P rim li n Plain Pa e s e ia i on 94. u e P o cess 320 p r , S p r , r , . ’ 1 P i n n Plai n Pa ers i i n 8 9. te s I k P o cess 265 p , S z g, r r r , . Pl i n P o ni n 192 Pri n ni 1 a a e s a s 54. p r , T g, . t V r h , Plate ac i n 31 P ri nt-O ut Pla inum Pa 28 4 e . B k g, t p r, m 2 P ri n i n - Plates D esensiti s 8 . O ut omi e Pa e , g, g , Br d p r, Pla e i a o nal s 46 t7l t D g , 26 Pri i - Plates e sensi i si n . nt n O ut Pa e s 173 , Hyp r t g , g p r , . 2 P i n - Plates O rthochromati si n 4. ti n O ut Pa e s e elo , g, r g p r , D v p P n m i n 2 n lates, Pa chro at si g, 7. i g, 18 3. - Plate s ee s 55 . P i n i n O ut Pa e s i sco p d , r g p r , D , Plate ee s me i can P oto t8 6 Sp d , A r h - a 55 . P i nti n O ut Pa e s Eas man gr phy, r g p r , t Pl ee s ou s- ell 8 0110 1 ate u 8 6 . Sp d , B rr gh W , m Pri n i1 - u co e 55 . O t Pa e s P i nti n , g p r , r g, Pla e ee s om a i son 69 t7z t Sp d , C p r , - Pla e ee s onti nental 6 1. P ri n i n O ut Pa e s oni n t Sp d , C , g p r , T g , Pl t76 ate ee s a ve 55 . Sp d , H r y, P i Pla e ee s at i ns 55 . r nts i ne wi n s f om 1 a 4. t Sp d , W k , , L Dr g r ,

Pla e ee s nne 55 . P ri nts on i ne i c 5 e t 3 8 . t Sp d , Wy , l , D r , l ti n ol a 28 1 P o cess P 111 P a ot e d t . o e el o e yp , C B h , r yr D v p r, . P 2 P 111 lati no e evelo e s 78 . o typ , D p r , yr , . 2 P - 11 Pl i not e Ho t a 8 0. ro ceton 3 a e . t yp , B th , y A , Pl i n c el P - mi l a o e o al e o o o 93. t typ , L D v p yr A d , men 2 P ro- i c 112 86 . aust . t, y C , Plati n t e P in -O ut e ia P o- l ce i ne 111 y p , r t S p , yr G y r , . 29% P ro- etol 121 y M , . Pl i n P 2 P o-P o s 74. as 1 at o e oce s t 13. typ r , yr h , Plati not e omi e 294 P ro - o da 112 yp v. Br d , . y S , . Pla i not es nten sif in 2 P ro - o a 112 87. . . t yp , I y g , y S d , B J , . Pl ti no o 291 P o n 11 a t es es i n . a evelo e s 3 yp , R t r g , yr T k D p r , . Pl i not e ni n 2 r c e i n 1 at s o 88 . P o at c 09 yp , T g, y h , . Pl i n s n i n 2 2 P llol 11 at o e s 9 . o a 1 a i . typ , V r h g, yr g , Pl i n - r n 2 at o U a oty pe, 93. Pl ti n m ci 2 i c - i n 2 1 a u a 78 . u ensi i ser 5 A d B th , Q k Dry g S t , . Pl i num Pa i i n 274 ui no ne I ntensi ﬁer a e 138 . t p r, S z g, . Q , l - - P ati t m i n e el o e P ocess Q ui none onin 240. aé D v p r r , T g, Pl n m P i n - P 2 ati o r a i u O ut a e 84. e u e 44. t r t p r, R Ap t r , n m P R ed o n 12 Plati ocess ol a al es 8 244. r , C d B th , Ch k T , , z ﬁ R ed o nes 178 T , . Pla i n m e i ue 12 2 2 e uce s 141 u s s 6 9 . . t R d , , R d r , Plati num oni n 229 e uce mmonium P ersul T g, . R d r, A 16 P n m oni n P P 1 ate 4 . lati u 80. T g . O . . , ph , ’ n m ol ni n P e uce B eli tz ski s 141 Plati u 8: o . . . G d T g O R d r, , 1 1 e uce i om 12 P . 8 c ate 4 . , . R d r, B hr , Pla ert P o c 2 educe eri c ul a e 143 e ess 67 . y y p r , . R r, C S ph t , P oi n n 1 e u e u i c lo i e 14 so i etol 02 c 4 . g, M , . R d r, C pr Ch r d , ’ P ow e P c 1 e e D benh m 141 o ess 3 4. uc e a s . d r r , R d r, , ’ P m l 1 ce E e 1 esses for o oi 3 0 e u s 44. r Br , . R d r, d r ,

386 PHOTOGRAPHIC FACTS AND FORMULAS

lo e o ni n n er o un a nesium or S ulphi de D eve p r T g, U d gr d M g W k, 2 241 34 . . - n oni n 22 I C ani de oni n ranium ro , 7. S ulphi d e F err y T g, U I T g 21 ranium oni n 9. 236 . U T g, ’ - 12 l Ton rani um o ni n P . . P. 8 . Sulphi d e S chlippe s Sa t U T g O , 1 ranium I ntensi ﬁ er 37. i n 244. U , g,

si n las li ts 339. ul i d e o n i n 234. F , S ph T g , U g h gh o nin at Sulpho cyani d e T g B h , m ni n 222 ana i u o . 1 V d T g, 77.

an e P o cess 358 . V dyk r , ul u oni n 247. S ph r T g, 1 a i ati on o f F alues 7 . u ort l ex i l e em o a V r V , S pp , F b T p r ry, 1 Vari ati on O f Enl arging Ex p o 25 . 2 sures 7 . m ol s ol ecula ei s , Sy b , M r W ght , 1 arni s es 50. V h , 368 . 1 arni s B lac 54. V h , k , 1 arni s ellul oi d 55 . h , , Tabl e E nlar 1n 8: e uci n V C , g g R d g, 16 a ni s r stal 5 . V r h , C y , 334 10 1 arn i s ol 5 54. V h , C d , , an evelo e s 88 . k D p , T r ni H "10 ar s o t 5 . mul s 4 V h , , el e oto o r a 7. T ph F , M 1 arn i s att 53. - V h , , em eratur e Co E fﬁci ent 78 . p , T i n 1 arni s Pr t 54. 2 1 V h , , em orar u o t 5 . T p y S pp r , 16 arni s etouc i n 5 . m l o men t 7 V h , R h g , er o eve 7 . Th D p , 1 arni s a on 55 . The r i o evel o men ee s V h , Z p , D p t p d , S hrom s 48 a n i s i n A to c e 3 . gg V r h g u , a ni s i n P oto ravu e Pl ate mo m r c l es 366 V r h g h g r , er ete a . Th S , 7 35 . i c mi - ul i To n Th o arb a d e S ph de 2 2 arni s i n Plati no t es 9 . i n 2 V h g yp , g, 38 . i ew n l es 45 . Thi omol bd te o ni n 240 V A g , a . y T g , 2 0 i o stanna e o ni n 4 . at i n s Plate ee s 55 . Th t T g, W k Sp d , - ol o ilter s 344 - m s 49 ee u . at i n s P owe s u e . Thr C r F , W k r N b r , 1 imi n utte ee s 5 . ave en t s aun o fe T g Sh r Sp d , W L g h Fr h r i n 2 lue P ri ts 60. o n n i n es 22. T g B , L , oni n ro mi e 8: asli ax i n olution 252 T g B d G ght W g S , . P n 21 1 i s 6 Me re 360. t . ei ts 8: asu s r , W gh , , m n 232 o ni n e evelo e . i e s onve T R , e ts 8: a u es g by d p t 5 W gh M r C r ni n Pl ti no s 288 o a t e . sio n 360. T g yp , , ni n P P 16 o 7 . l e . . . Wei s easu es a s T g O , M r T b , ni n l li n 1 f o at a e 76 . gg T g B h , A k , ’ To ni n l o c ni e illi s Pro c s 1 at u a W s es 3 8 . g B h , S ph y d , , l 77 P N um e s 49. W . . b r , oni n 8: ix i n at Com oo lac en in 4 T g F g B h , W d , B k g, . bi n 1 2 ed 78 . o o i nal u or t 53. , W d F S pp , ‘ Toz ol 122 i i n 1 . oo en sit s 96 . , W d S g, n n 2 1 nchr l s ra sfer Pa e i l e 5 . Wra en Pa o e e o e T p r, S g , D v p r , ransfe s romo il 0 3 6 . ﬁé T r , B , ransfer wit ollo i on 2 2 nn Pl t ee s 5 5 . e a e 5 . T h C d , Wy Sp d , ran s arenci es lue 26 1 T p , B , . 2 n 1 r ns r nci e r n i 55 . a a e s a o 53. a on a s T p , C b , Z p V r h ,

rans ar en ci es an ot e 26 1 i nc 8: o er l eani n 35 1. T p , Cy yp , . Z C pp , C g, - - l P 26 n c c i n t s 53 ue to ca e ro cess 5 . i Et a 3 . Tr S , Z , h g B h , n sco Photo r odu cts I n c. A p ,

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