- 24 • photography or photostat of each map finally completed for publicationo These re­ produotions are made on the same scale 1:24,000 to simplify the matohing of Unfin­ ished adjoining sheets. These reproduotions in negative form make it practioa1 to supply the demands for oopies of the map pending the final pUblioation of the map.

-000- THE REPRODUCTION OF MAPS DRAWN ON ACETATE SHEETS by C. H. Birdseye Chief, Division of EngraVing &Printing. U.S.~.S.

Other papers on this Program have described the compilation of maps on acetate sheets and the writer will outline Just enough of this compilation to indioate the type of drawings ti~t are presented for reproduotion, so that this paper will be oom­ plete in itself. The proJeot is oonduoted in oooperation between the Tennessee Valley Authority and the U. S. Geological Survey. It consists of a oomplete series of planimetric maps of the entire area of the Tennessee River Basin in about 750 seven and one half minnte quadrangles on the scale of 2000 feet 'to the inoh (lI24,OOO).~ Each of these maps is given a serial number of the fifteen minute area t.ogether w1t.h 'the proper­ quarter and also a name selected from an appropriate town or featu%'e on the map, suoh as Johnson City, 19B-SE Tenn.-N.Car. rhese sheets are oompiled in Ohattanooga on sheets of cellulose aoetate. At the beginning of the proJeot, three sheets of oopy were presented, as follows; (1) culture and lettering in blaok, for reproduc­ tion in b1aok. (2) Drainage in black for reproduction in blue. (3) Woodland areas in yellow or green for reproduction in green. Before the sheets are sent to Washing­ ton for reproduotion, ozalid prints are made in Chattanooga for the preliminary use of the Tennessee Valley Authority. This procedure requires that all of the copy, in­ cluding the lettering, be drawn on transparent media. All of the names ar~ set in type and printed in black on Japan tissue by what is known as the !'loat Lettering Prooess invented and patented by Colin Landin. These sheets of tissue are coated on the baok With a solution of adhesive made from glyoerine, gelatin, sugar and water, a.nd the separate names are cut from the tissue sheets a.nd "floated" in place by rubbing each name With a fine brush dipped in water. At first, the lettering was placed on the oulture sheet but some difficulty was experienced in making the names stick to the cellulose sheets and some of them be- came detached by handling during the reproduotion processes. Ea.rly in the program, -'---J therefore, the lettering was placed on a specially prepared ozalid print of non­ photographic blue. This procedure had two objections, first that the ozalid prints presented to the Tennessee Valley Authority had to be lettered by hand and seoond, that we had to use a different camera in Washington because of the opaque background. The first of these difficulties has been eliminated by II floating" the names on a sheet of transparent traoing paper mounted on oe1lu10se aoetate to register the base projection. At first, the ~ulture and drainage were inked on separate sheets of cellulose. Some diffioulty in register was experienced and soon after the project was started. the oulture and drainage data were combined on one sheet of cellulose~ Later, the woodland copy was submitted i~ black whioh has a more even body and better photo­ graphio properties trAn either yellow or green. At the present time, three sheets of copy are presented for each quadrangle, as fo110ws: (1) 'Julture and drainage drawn on cellulose acetate in black for reproduction in black and blue respectively; (2) woodland sprayed on cellulose aoetate in black for reproduction in green; and (~1 lettering stuck on a sheet of thin tracing paper mounted on cellulose acetate. At the beginning of the proJeot a ·stiok-up projection" W8,B drawn on a metal mounted sheet of drawing paper for a eheet in each row of quadrangles (25) to cover the basin. This Was done for two purposes, first beoause there Was some doubt. that the different oolor plates would register well enough for combined color printing and second, beoause the ·stiok-up· saved the photographers time in bringing the - 25 - different drawings to a perfeot 80ale without setting beam oompasses to measurements taken from proJeotion tables. No effort was made to draw these proJeotions on ground ground glass which would have saved the photograph.ers a little more time but would not have been available for the transferrer. Because of a series of circumstances, it was deoided to print these maps on a direot, rather than on offset press. This deoision was influenced largely by the faot that the edition is relatively small, that a few oopies are printed on traoing oloth and traoing paper, and that we oould use either a straight or a prism camera. in the photography. Photography. All of the photography is accomplished by the wet plate prooess. these plates are made by using seleoted plate glass of size 24 x ~O inohes. The first operation is to flow evenly over the plate a solution of albumen used to hold the other solutions on the plate; when dried, the plate is coated With collodion, an organio base composed of ether, aicohol, guncotton and iodide; the plate is then lowered on a rack into a stone or enamel bath containing a silver solution. The plate is fully sensitized after it has remained in the silver bath about 5 minutes, and it is plaoed, in the negative holder of the camera which extends into the dark room. Using the 50 x 50 inoh direot oamera with a lens of 45 inch fooal length, the oellulose acetate sheet of the oulture and· drainage base is placed on the copy board under plate glass, the transparent sheet being reversed over a sheet or white paper so that the negative is made by exposing the drawing through the cellulose sheet. The ·oamera is focused for sharp defin1tion at the proper scale, using the ground glass focusing plate in the fooal plane of the oamera, and a pair of beam compasses set to proper lengths from the ·stick-Up· proJeotion. The sensitized plate is then substituted for the focusing plate and the oopy is illuminated by two arc lights placed in front, but slightly to each side, of the copy board. The proper exposure 1s tlmed accurately, usually from two to four minutes. After exposure, the photo­ grapher, still working under a safe light in the dark room, develops the plate by using a solution ot sulphate of iron and acetic acid, and washes the plate with olear water. The photographer repeats the process With the same setting of the copy board and oamera 80 that he makes two duplicate plates ot the culture and drainage, for use by the negative cutter. The photographer then photographs the woodland copy in the same manner, revers­ ing the draw1ng and expos1ng it through the oellulose sheet. All three of these negatives thus beoome direot plates suitable for processing to a reversed print1ng plate and printing in a direct press, Just as though the negatives were made by a prism oamera. Inasmuoh as most of the lettering sheets used thus far have an opaque baokground, and the new lettering sheets on thin traoing paper mounted on cellulose acetate are not transparent enough to photograph sharply through both cellulose and tracing paper, we use a prism oamera with a 42 inoh focal length lens and do not reverse the lettering draWing. In all other respects the operations are the same as With the direot camera. After the plates are developed 1nthe dark room, they are taken into the outer laboratory and subjected to several operations. They are first cleared up by an ap-. pl1cation of oyanide of potass1um flowed over the plate, whloh removes all silver not affected by light. The plates are Washed thoroughly and placed in a rocker bath oontaining a oopper sulphate solution. After washing again the plates are placed in another rocker bath containing a nitrate of sllver solution, whic.h tends to bring out the desired blaok and White baokground. These two rocker bath operations are usual­ ly repeated With thorough washing of the plate between each operation, so as to give the proper density to the plate. The plates are then ooated With a gum-arabiC solu­ tion to proteot the surtace. Allor the above operations after the plate is brought from the dark room result in a properly fixed and intensified negative. . Negative Cutting. On one of the duplicate plates showing both oulture and drainage, the neaat1ve outter paints out, by means of a brush and asphaltum, every­ th1ng except the oulture and the projection lines whioh are to be printed in black, - 26 - restores with a fine engraving tool or ne~dle any lines whioh have been damaged by painting out the drainage, and retouohes the negative to remove any spots or other blem1shes. On the other duplioate plate he paints out everything esoept the drainage and retouohes the negative in the .ame manner. Usually, all that the negative outter has to do with the woodland and lettering plates is to restore any lines that are not sharp enough to print and to retouoh the negatives to remove any blemishes that would print.' Sometimes, however, either the woodland or lettering plate requires oonsider­ able Iglass engravingl (outting through the film but not into the glass) by means of a fine engraving tool or needle. An expert glass engraver oan out new lines, letters or figures nearly as fine as a oopper plate engraver. fhQ.to-prooessi!16. The negatives are then sent to the photo-prooess seotion where the metal printing plates are made by prooessing eaoh negative direot to a sensitized aluminum plate 24 x 30 inches in size, by placing the negative over the sensitized metal plate in a vaouum printing frame and exposing it to light from one or more strong arc lights. If any negative is slightly distorted in soale, the prooess man makes a ~ino plate and sends it to the Transfer Section where the final printing plate is made, as is explained later. The metal plate, either aluminum or zino, is sensitized in somewhat the same way as the photographer used With the glass plate, but by different operations and by the use of different ohemioals. A freshly grained plate is oleaned by using a solution of hydrofluric, nitrio and aoetio acids, after whioh it is washed and ohemioally treated With a solution of phosphoric aoid and gum. The plate is then rinsed and while wet is plaoed in a whirler and flowed With a sensitive solution oomposed of al­ bumen and dioromate of ammonia. . The whirling motion distributes the solution evenly and the eleotrio heater inside the whirler dries the plate. After the plate is evenly sensitized and dried, it is plaoed faoe up in a vaouum printing frame, the negative is plaoed on the plate in its proper position w1th the film side down, and the air is exhausted so that the negative and plate are brought into olose oonta~t. The assembly is illuminated by strong arc lights, the proper time of exposure being recorded by an alann olook set to oonform to the strength of the lighting and the olearness of the negat~ve. Both the oulture,and lettering plates'oould be processed to the same printing pla.te, by removing the first plate from the printing frame and substitut1ng the second in proper registration, but thedift10ult1es in securing perfeot registration in printing a small edition oonsumes more time~and cost more than mak1ng a separate printing pl~te for the lettering. The prooess man developes and Washes the plate in muoh the same way as the glass plate was developed arid washed exoept that he first ooats the plate With a solution of asphaltum, or ink developer, washes the plate thoroughly and 1t the ink has a tendenoy to st1ok, he flows the plate With a solution of bioarbonate of soda and washes it again With olear water. The p~ate is then rolled up With greasy litho­ graphio 1nk, pOWdered With Idragons blood-·, etohed With phosphorio gum and Washed again thoroughly. The plate is now ready to print unless the lithographio art1st has to make oorreotions or additions or to repair minor defects. Some oorrections are required on most sheets and these are made by the ~1thographio art1st rather than by the negative outter whioh would reqUire reprooessing the plate. Lithographio Drafting. The lithographio artist oan draw or letter on a metal plate, by means of a fine brush or pen, Just as well as a draftsman Oan draw on paper or an engraver can cut in oopper or on glass. When oertain features, suoh as double line streams, lakes and ponds are to be shown by blue tints, the transferrer pre­ pares an impression from the base plate, dusts it With chalk and the chalk impression is 'offsettedl to another plate whioh enables the lithographic artist to Igum outW the areas not to be covered by tlntand to draw the tint. and 11nes by fine brush or pen. The plate is then returned to the transferrer who cleans and 'rollsup· the plate w1th lithographio ink ready for printing. Transferrl!16. A few of the oellulose -drawings have been so unequally distorted in 80ale that they oould not be brought to perfect soale in both dimensions by photO­ graphy, and it beoame necessary to transfer the data to a ·stiok-up proJeotion- • 87. drawn by a draftlman on metal mounted paper. ~s is done by the transferrer who follows a prooess .1milar to what 1s known as the deoaloomania process. In other words, he ooats a .heet of .ott fibre paper with a stioky 8tarch and glyoerine solu­ tion, rubs up the zino plate with 11thographlo transfer ink, plaoes the transfer :paper w1th sticky' side down on the ~lno plate and runs the combination through a transfer press operated under pressure by hand or eleotrio power. The transfer paper 11 pulled from the z1no plate oarrying With it all of the 11nes inked on the plate. The transferrer fits the paper in proper places on the projection, tapping the paper With a sharp pointed stylus 80 that it will rema1n 1n proper position. He shrinks or stretches the transfer paper by heating it in an oven or moistening it with a sponge and fits it to the Istick-up proJectionl , tapping the paper with a sharp pointed stylus so that it will remain in proper position. The ·stick-up· transfer plate is then plaoed face down in oontact with a metal printing plate and run through the transfer press again so as to transfer all of the lines to the final printing med1um, Just as one used to transfer p1ctures from paper to h1s hand by the old decalcomania prooess. The plate is then rolled up With 11thographic 1nk and 1s ready for pr1nt1ng, unless the l1thographic art1st has some add1tions to make. Lithograph10 pr1nting. The Geolog1oal Survey uses d1fferent types of 11tho '. graphio print1ng presses. It has one large multioolor rotary press tak1ng print1ng plates 44 x 64 inohes in size and prlnting from four plates In four oolors at the same time. This press Is semi-automatl0 feed and is the largest map printlng press in Washington. The Survey has one offset rotary press taking prlnting p1.ates 41 x 54 1nohes 1n size, and one taking printing plates 22 x ~4 inohes in s1ze. ~oth o~ these are au­ tomat10 feed. The Survey has two Hoe flatbed presses tak1ng metal plates or stones 36 x 52 inohes in size. One of these is automatl0 feed and the other Is hand feed~ The Survey also has three Hoe flatbed presses, two of Which are oonverted by the Hall attachment into offset presses so as to print e1ther direct or of~set from f~at sur­ faces. The plate size ot one is 30 x 42 inches and ot the other two Is 26x 36 inches. All print from either stone or metal ana are hand teed$ The oapacity ot all of the presses mOVing at full speed is 12,000 impressions per hour. Dur1ng the fiscal year of 19~5, the Survey prlnted about 4,600,000 ooples ot ~,OOO ditferent maps and dlagrams. The Tennessee River Basin maps are printed on the two 26 x 36 inoh presses. The basio prinoiple of lithographio print1ng is the use of lithographic stone or metal plates so prepared that the lines on the plates to be reproduoed attract ink and repel water and the rest of the surface on the plates attracts water and repels ink, these two 'substances being non-affinitlve. Therefore, in any lithographl0 pr1nting press, the plate first passes under a water roller, then under ink rollers ooated with the proper oolor of ink, and then under the map paper; except In an off­ set press a rubber blanket fastened to a cylinder takes the impressions from the plate and transfers them to the paper. Lithographio plates are usually aluminum or zino sheets and oan be used In either flatbed or rotary presses. New sheets are smooth and shiny and would not hold ink.. New as well as old plates are grained so as to give them a frosted sur­ taoe, something like frosted glass, by plaoing them in a graining machine oomprlsed of a large tray in whioh the plate Is placed face up covered With water, quartz land and marbles made ot wood, marble or steel depending on the texture of grain de­ dred. An electrio motor vibrates thls tray in a rotary fashion and' the sand aots as an abras1ve and gives the plat~ a ·sanded· surfaoe. The otily runotion of the marbles Is to keep the abrasive movlng uniformly over the plate. Several edit10ns ot the Tennessee River Basin maps are printed of eaoh quadran­ gle and delivered to the Tennessee Valley Authority at Knoxvi1le, a8 tollOWS: \ll 300 oopies on map paper of oulture and lettering 1n black, water features 1n blue and woodland in green•. (2) 75 oopies on map paper of culture and lettering In blaok and water teatures in_blue. (3f76 oopies on map paper of oulture, letterlng and drainage (Without water tint) oomb1ned in blaok. (4) 2 copies on traoing cloth -28- of oulture, lettering and drainage (without water tint) oombined in blac~ (~) For speoial areas, such as reservoir sites, a copies on tracing cloth and 12 oopiee on tracing paper of culture. lettering and drainage (without water tint) oombined in black. These tracing media 'sheets are used by the Tennessee Valley Authority to add additional data for reproduction by various blue printing methods. Reports. At the end of each month, the Geological Survey submits to the Tenne.­ see Valley Authority a report on the progress of reproduotion work during the month, entering eaoh sheet in the order reoeived in Washington until the sheet is printed and delivered to the Authority at KnOXVille. The data included in this report are as follows: 1. Designation of sheet. 2. Date reoeived in Washington. ~. 'Date inspected. 4. Date approved by DiVision Chief. 5. Date transmitted to Reproduotion Division. 6. Number of days consumed in inspeotion and approval. 7. Date reoeived 1nReproduct10n D1v1s1on. 8. Date photographed. 9. Date of negative outting (for each plate). 10. Date of processing plates (for eaoh plate). 11. Date proofs submitted. 12. Date proofs returned. l~. Date pr1nted. 14. Date sent to· Knoxville. 15. Number of days consumed in reproduotion. 16. Number of days in Washington. The time consumed between the arrival of sheets 1n Washington and shipment to Knoxville has Varied from 30 to 200 calendar days, the differenoe in actual work being due to slower progress at the start and preferenoe g1ven to priority of areas, and the differenoe in total time in Washington being due to hold1ng certain sheets for corrections.

-000-

'fBi USE or AERIAL PHOTOGRAPHS nt CADAS'l'BAL SURVEYS by George D. Whitmore Chief', Surveys Section, Engineering Servioe Division Tennessee Valley Authority Property surveys of traots needed for reservoir lands by the Tennessee Valley Authority were started at Norris Reservoir, in northeast Tennessee, late in 1933. The existing land records for this area, and indeed for all of the area Within the Tennessee River watershed, were so inadequate that a new survey of eaoh property traot was necessary before title examination and land buying could be started. These first surveys were made by oonventional transit-tape or transit-stadia trav­ erses around the boundaries of eaoh traot. The results were unsatisfaotory, the prooesses slow, and the costs high. It was soon reoognized that different methods would have to be used. A new method was found, based on aerial photographs. ThE results have been entirely satisfaotory, the prooess rapid, and the oost. reasonable. General Program !he land acquisition program of the Tennessee Valley Authority is oomprised ot three principal features. '!'hese arel (1) casiastral surveys and maps of the areas within whioh land purchases w111 be made; (2) determining the amount of land to ao­ quire, called approval for purchase; and (~) the actual purohase, or acqUis1tion. inoluding suoh items a8 title examination, appraisal, condemnation sUits, and re­ lated actiVities. '!'he first two of these items. the oadastral. surveys and the approval. for