The Gum Bichromate Process

OVERVIEW AND EXPECTATIONS At first glance, the gum bichromate process looks amazingly uncomplicated. However, to nearly every one of my students who has been seduced by the process, and for those artists who are dedicated to it, gum is one of the most complex in the alternative genre. Gum bichromate printing is certainly seductive due to its limited chemistry, simple water development, and unlimited color potential with watercolors of the artist’s choice. Gum printing is quite flexible and easily combined with other processes and graphic disciplines. Because of its pigment, paper, and brush roots, gum bichromate is one of the few photographic processes capable of achieving that wonderful element of gesture—gesture being that painterly expression of the “artist’s hand” in the creation of a mark. In this chapter I, as always, give you a little history and describe how the process works. I then discuss the negative and a technique, euphemistically referred to as registration, that will allow you to place multiple applications of color on the same piece of paper without losing the original sharpness of the image. You will also learn how to make a gum print from a single contact negative. You’ll learn about mixing the chemicals for the sensitizer and the relationship among the three primary ingredients in the technique: gum arabic, a dichromate sensitizer, and watercolor pigment. This is followed by instructions for applying the coating, processing, and the reapplication of the sensitized coatings. A discusion about development and clearing gum prints is included, and the chapter concludes with a comprehensive trouble-shooting section.

220 Figure 13–1 Christopher James, Grace in Gum, 1977 This is from a series of gum bichromate portraits that I made from damaged internegatives that had been thrown in the trash in the Harvard photography labs. The final negative was enlarged on SO- 339 direct duplicating film (now SO-132) and then abused for several days with gum bichromate applications, paint, ink, dyes, bleaches, and etch- ing tool abrasion in wet emulsion. (Courtesy of the author)

221 - eat time gr a e av process artistsprocess when uctions in this chap e eading that last sentence e’s talking about me!” e’s You’ll find that you’ll be able to make excellent gum be able to make excellent find that you’ll You’ll individually modifying the myriad elements of the tech- style, imagery, personal working own nique to suit your and intentions. sionate and stubborn of all alternativ it comes to their particular I can way of doing the process. just imagine many of my friends r and saying, “H doing, and real- are keep notes of what you relax, Just ter. at it work if you you will reward that the gum process ize without a need for instant gratification. H prints using, and adapting, the instr - e my n I . ery few v e ar e , ariables within gum printing ar Vol. 6, No. 1, Vol. gum printing ther face simplicity of the process, you’ll face simplicity of the process, Cigarette Girl n tions of the information in this chap ways to do anything, and much of what to por y Camera Notes, you investigate the process beyond this book beyond the process investigate you correct f ou to see that the v of choice for the individual teacher or author e Considering the sur (Courtesy of the George Eastman House, Rochester NY) Robert Demachy (1859–1937), (Gum bichromate print reproduced as a photogravure in Figure 13–2 July 1902) Robert Demachy was an artistic force in the 1880s and began to interpret his work in gum in 1894, because it allowed him to use consider- able handwork and was similar to the feelings he had when looking at Impressionist paintings. Demachy founded the Photo-Club de Paris and was a stalwart member of the Linked Ring as well as an honorary member of the Royal success, In spite of his Photographic Society. Demachy completely divorced himself from photography in 1914. experience, gum bichromate printers are the most pas- printers are experience, gum bichromate has been previously published has simply been the proce- published has been previously dur notice that there is a lot of information to absorb, and I to absorb, is a lot of information notice that there want y absolutely infinite. I you will find published evidence that will occasionally will find published you seem contrar ter. Some of that information will work quite well for you, quite well of that information will work Some ter. morsels of other instruction for you will not work whereas with equal success. I

THE BOOK OF ALTERNATIVE PHOTOGRAPHIC PROCESSES 222 The perfection oftheprocessbyJosephAlbertin1868. print. In1844,Talbot publishedthe type paper plate withthe pher’ make aprint,theplateisrolledwithgreasylithogra- portion tothedegreeofbichromate’s exposure.To hygroscopic glycerin coatingallowstheremainingbichromatetobe atin washesout,andthencoatedwithglycerin.The is thenwashed,sothattheunexposed/unhardenedgel- to theexposure,asinagumbichromateprint.Theplate light, andthebichromatedgelatinhardensinproportion baked glassisnextexposedtoanegativeunderUV a mated gelatin.Thecoatedglassisnextbakedtocreate which apaneofgroundglassiscoatedwithbichro- process inventedbyAlphonseLouisPoitevin(1855)in The Collotype: Calotype ically illustratedbook, following someimprovements,wasrenamedthe piece ofpapertoproduceadirectpositive.Thisprocess, the papernegative)incontactwithanewlysensitized times waxed,oroiled,toenhancethetransparencyof ride, andafterithasdried,usedasanegative(some fixed inasolutionofpotassiumbromideorsodiumchlo- causes thelatentimagetoemerge.Theprintisthen gallo nitrateofsilver(gallicacidandnitrate)that exposed imageisthenresensitizedwithasolutionof light-sensitivity), dried,andexposedtoUVlight.The and gallicacidisappliedtothepaper(increasing exposure, asecondsolutionofsilvernitrate,aceticacid, ver iodide:potassiumiodideandsilvernitrate.Priorto quality writingpaperissensitizedwithasolutionofsil- direct positive.IntheCalotypeprocessapieceofhigh- produce anegativethatwouldfacilitatethemakingof 1835, isthenameforfirstphotographicprocessto his Calotypesthroughoutthe manuscript. fine reticulated(grainy-mezzotint-like)surface.The Calotype, and is,incurrentdefinition,muchlikeasaltedpaper Collotype s . ink; theinkadherestoexposedareasof Commercial usagewascommonfollowingthe (able toabsorbmoisturefromtheair)inpro- least invented byWilliamHenryFoxTalbot in is aphotomechanical/lithographic-like water content,andthenprintedon The PencilofNature, second photograph- hand tipping Talbo- - Prince entitled, An inter A for thefirstphotographicimagesev authors, ifcorrect, wouldgive Leonardo da Vinci credit why, it’s da Vinci’s ofcourse. self-portrait, The book’s mal urine.G by usingamixture ofdichromated eggwithhumanorani- 1519) mayhave beenthecreator oftheShroud of Turin P else da Vinci accomplished,itmight betrue. century.fourteenth Who knows? Consideringeverything books dealingwithconspiracytheoriesdatingbacktothe ous factoidincontext,thepublisher’s catalogueisrifewith before themedium’s “official” beginning. To putthiscuri- Behind theCenturies-Long Conspiracy ofSilence (Courtesy oftheRoyalPhotographicSociety) Cover ofIssue#3, Figure 13–3 ress, 1994)suggeststhatLeonardo da Vinci (1452– LITTLE HISTORY esting hypothesisfr uess whoseimageisonthe The PencilofNature, Turin Shroud—In Whose Image? The Truth om abookb 1844 eral hundr T urin shr y Picknett and ed y oud? — (Acacia ears 223

CHAPTER 13 THE GUM BICHROMATE PROCESS w oitevin was not t I In Ponton’s In vided a ne . e, that is, the o Pontontype. Pontontype. ement and pr (a wood and metal device used ” ocesses: the Carbon Print and the ocesses: the Carbon Print ed out that Daguerreotypes could ed out that Daguerreotypes chase ocess that was permanent. P ectly proportional to the degree of UV ectly proportional to the degree for two pr e who first figur eproduce photographic images in quantity. The images in quantity. photographic eproduce , 1854, William Henry Fox Talbot began working Talbot Henry Fox William 1854, n I The Collotype, like others within the genr typographers for blocking, setting, and locking type for oodburytype, which utilized the unique hardening qual- oodburytype, hardening the unique which utilized sizing technique for liquid emulsions on paper, both of both liquid emulsions on paper, sizing technique for negative image. The exposed print was then washed, to was thenprint washed, The exposed image. negative uynes, an exceedingly wealthy arts up a prize put wealthy patron, uynes, an exceedingly y on the concept by observingon the concept by the ability of potassium effect on a colloidal gel- a hardening to have dichromate atin that was dir process, paper was coated with a potassium dichromate with a potassium paper was coated process, to create using objects exposed to sunlight solution and a a and dried, leaving any unexposed dichromate, remove image that consisted of chromium positive sepia brown rather handsome at first but tended The print was dioxide. months. after several green to fade to a gossamer-like to related is directly single solution Pontontype Ponton’s (1858) and process Dusting-On the idea behind Poitevin’s a in 1840, later, A year later in this text. covered which are (1820–1891) added to this rapidly Becquerel Edmund images using producing by expanding base of knowledge by was Becquerel, in combination with iodine. It starch the way the continuation of the be supplementally intensified by filter. glass a red through exposure Daguerreotype’s when he discovered that paper impregnated with potas- paper impregnated that he discovered when modestly to light. Ponton was sensitive sium bichromate the his discovery christened of 10,000 francs to anyone who could describe a photo- of 10,000 francs to anyone graphic printing pr won the priz light that the gelatin received. Fox Talbot’s modest success Talbot’s Fox light that the gelatin received. Louis of Alphonse the work by was followed in this area (1819–1882), who continued the investigation Poitevin gelatin insoluble able to render were bichromates of how de Duc d’Albert, Honoré 1856, to light. In on exposure L Collotype. only serious drawback to these techniques was that hand- set typography in a “ way to r b W to ultraviolet and colloids on exposure ity of bichromates light, was a significant achiev inking and subsequent printing) and the photographic image could not be printed simultaneously 1844 , oman W estingly, he was one of the first academics estingly, nter ongo Ponton (1801–1880), the Scottish inventor (1801–1880), ongo Ponton The earliest attributable thinking about the effect of M consider instructing means of actual, his students by (Courtesy of the National Museum of Photography, Film and (Courtesy of the National Museum of Photography, Television/SSPL) (Salted paper print from a Calotype negative) but bemoaned the fact Claudet learned the Calotype process from Talbot that he had that it was too slow and less perfect than the Daguerreotype photographer and was learned from Daguerre. Claudet was a very active and the concept of a responsible for the first red safelight in the darkroom sequence of images to express movement. Figure 13–4 Antoine Francois Jean Claudet (1797–1867), light on bichromates seems to be the property of the light on bichromates (1763–1829), at Vauquelin chemist Louis-Nicolas French over published Vauquelin the end of the 1700s. Although the bulk of his 378 separate dissertations on chemistry, analytical observations than provide writing did little more and data. I (with the all-time best name in the history of photogra- analytical wisdom in 1839 Vauquelin’s phy), expanded on to hands-on practice in the laboratory.

THE BOOK OF ALTERNATIVE PHOTOGRAPHIC PROCESSES 224 Woodburytype (a.k.a. Photoglyptie – Stannotype – Photomezzotint) Walter Bentley Woodbury (1834–1885) created the Woodburytype in 1864—a process that was widely prac- ticed for nearly 25 years and known for its amazing ren- dition of values and tonal range without grain. To produce a Woodburytype, the artist would make a thick gelatin relief on a piece of carbon paper by exposing it to a continuous-tone negative. The relief image was dried and then squashed into a lead intaglio plate under enormous pressure from a hydraulic press. The lead, having taken the detail of the hardened gelatin impression, would now become the printing plate for the next step. The lead intaglio plate was encased in a mold and pressed against a fine-quality paper. Pigmented gelatin ink was then poured into the mold, where it deposited the gelatinized ink in proportion to the depth of the plate. The Woodburytype is generally a dark reddish brown even though any color could have been used. Interest- ingly, it was seldom printed in black. Figure 13–5 Nadar (a.k.a. Gaspard Félix Tournachon), 1820–1920, Portrait of George Sand, 1877 (from Galerie Contemporaine, littéraire, artistique) Nadar had a brief, but stunning, career as a photographer in the mid-1800s primarily due to his extraordinary social connections within the French until the 1880s, with the advent of the halftone (the dot artistic and literary circles. His list of occupations and interests included patterns in magnified press reproduction) plate, that this poacher, freedom fighter, smuggler, cartoonist, and proponent of heavier- limitation could be addressed. than-air flying machines. His photographic studio became the main office From the same time period, the French painter Jean- for the Society of the Encouragement of Ariel Locomotion By Means of Baptiste-Camille Corot (1796–1875) tried his hand at Heavier Than Air Machines. Nadar was the president, and Jules Verne was the secretary. This is a Nadar Woodburytype of his friend and novelist, processes utilizing bichromates and colloids and made George Sand, who is remembered for her notorious affair with Chopin, her cliché-verre prints on glass using pure albumen as his siz- wardrobe of men’s clothing, her feminist politics, and for writing eighty S

novels about love, nature, and morality. S ing agent (see Figure 2–16). He also made colloidal etch- E (Courtesy of the George Eastman House, Rochester, NY) C ings by coating glass plates with wet sensitized collodion O R P emulsion. The plate was exposed to light, which darkened E T the entire plate. Corot then etched into the darkened In 1895, John Pouncy (1820–1894), a gentleman pri- A M O emulsion and, when finished, contact printed the plate to marily remembered for his photographic illustrations deal- R H

ing with Thomas Hardy’s (Return of the Native) home turf C a piece of sensitized paper for a paper print. Corot and I of Wessex, gathered everyone’s information and claimed B others also utilized a technique in which they would burn M U a tallow candle close to a glass plate, leaving a soot-black- to have produced the first consistent and satisfactory gum G E ened sheet of glass. The soot was then drawn into with a bichromate printing process. Pouncy published Dorset- H T

shire Photographically Illustrated in 1857. This book, 3

variety of art-making tools to create a negative plate of 1

despite criticism that it lacked halftone characteristics, was R lines and textures. The etched soot on the glass was then E T

the first British book illustrated by means of photo- P used as a contact negative in conjunction with a sensitized A H sheet of paper. lithography. C

225 - time , esting time and and indi y e oid inv e, paper ou av with the chemistr obably spent mor k alues open in relation to the above alues open in relation water type, temperatur esting as long as y , these wor eigel has pr th and abilities as an artist on guaranteed suc- w udy S etc.) on any given day, may change the final results day, etc.) on any given , ocess so inter said, harden in direct proportion to the degree of UV proportion to the degree in direct said, harden ear By itself, the dichromated salt and the gum arabic (sap the dichromated itself, By will, as arabic mixture The dichromate/pigment/gum dening. The exposed print is then “developed” in water, The exposed print is then “developed” dening. Few Words Before We Begin Before We Words Few e contact printing frame and exposed to a UV light source to a UV light frame and exposed contact printing v our self-wor tive liquid mixture is then applied to a substrate such as substrate to a then applied is liquid mixture tive as the same size the negative, and dried. A contact paper, coating in dried sensitized is placed on the finished print, a The portions paper of the sensitized such as sunlight. will become the negative UV light through affected by proportion amount of light to the insoluble in direct received. image. a tan-colored produce will tree) an Acacia from as a pre- This particular employed solution is sometimes liminary for hand-applied liquid emulsions sizing layer a coloring agent, to in Chapter 12. If and was referred occasionally a gauche pigment, but most often watercolor mixture, is added to the sensitized or a metallic powder, emulsion. in the UV light-hardened the color will remain I’ exposure received. In a first exposure, the thinnest parts a first exposure, In received. exposure and the most exposure will allow (shadows) of the negative vidual technique. cause the image on the coated paper to become the most cause the image on the coated paper The densest parts of the negative in those areas. hardened will permit less exposure, more (highlights), which require har on the gum/pigment remains the hardened whereupon sen- the dichromate paper in proportion to the exposure, the ratio, and the amount of pigment in sitizer-to-pigment will clear in the development The less-exposed areas mix. leaving the highlights in proportion to their exposure, clear and the middle v and paint water, and other factors, which include paper, type and ho of y what makes This is exactly print. will get in a gum you the pr y try My to conquer the process. don’t patient and cess. Be friend J A Any change in the principal components of the gum ratios of type and strength, (gum type, sensitizer process both to one another coalition of photog- a Their inspiration came Works They worked extensively with the gum extensively They worked . Photo-Secessionists, Photo-Secessionists, teichen, Käsebier, and White, and in due time, White, and in due and teichen, Käsebier, ession in the medium. Pictorialists the late nineteenth and early twentieth centuries, the late nineteenth and early twentieth Gum Bichromate n I w The Fish-Glue Process The Fish-Glue “Fish known as the there was a technique As an aside, but same principles that used these Glue Process” metal plate substrate. for use on a applied them is credited with the invention of Alphonse Louis Poitevin Fish Glue Process, ammonium this process. In the fish glue were mixed and bichromate and water-soluble Following exposure, the unhard- coated on a metal plate. the gum arabic) washed off the ened glue (acting like heat hardened. The heat hardening plate and was then surface that was subsequently produced an enamel-like in a press to make a bas-relief acid etched and used being manufactured and can be image. Fish glue is still try this seldom- purchased, should you get an urge to book for a sup- used technique. See Appendix E of this plier of fish glue. Steiglitz) who were dedicated to pictorialist, and individ- dedicated to pictorialist, who were Steiglitz) ual, expr raphers (S organizations the aesthetic integrity of European from and the Broth- Kamera Club (Berlin) Wiener such as the erhood of the Linked Ring (London), who battled to have context rather within its own photographic art appreciated of informational reality. reflection than as an imitative photographic image makers saw themselves as dedicated photographic image makers saw themselves to them- artiststhan scientists, and some referred rather as selves process due to its innate ability to express the artist’s inten- artist’s the innate ability to express due to its process this indi- critics of the movement tions and feelings. For cated that the imagery and fuzzy. was warm, romantic, printing was a technique that was championed in Gum the America by Ho to a conclusion, the underlying princi- had come Pouncy or ammonium, of a potassium, ple being: a mixture describe the and bichromate salt (dichromate bichromate with a colloid such as same thing) in solution is mixed light-sensi-This UV gum arabic, gelatin, glue, or starch.

THE BOOK OF ALTERNATIVE PHOTOGRAPHIC PROCESSES 226 adventure, anddiscovery. and flexibleshouldbeapproached withaspiritofplay, attention. The gumbichromate process isamazinglyfluid justbythat onecancometoaworking paying truce time. Judy provides somedecentadvicewhenshesuggests be a“fool’s toconquerthisprocess errand” inashort totry face withunexpectedinformationandimager one Iknow, andsheisstilloccasionallycomingface-to- energy exploringthevariables ofthistechniquethanany- y. It would that willbethesamesiz tohave anenlargednegative(s) towork with is necessary Because gumbichromate isacontactprintingprocess it The GumNegativ ar a majority ofgumprintingexperiences requires more than of single exposure; multipleapplicationsofsensitized color e registered the norm.F negatives thatwillallow you toprintgood or thisr e e eason, itiscommontohave aset a digital print,printeditout,andthenmade alternative process.Karenfirstmadea students theretocombinedigitaland and, accordingtoSarah,oneofthefirst (Courtesy oftheartistandSVK) V Karen wasaformerstudentofSarah Karen Fiorito, Figure 13–6 to generatethegumprint. camera. Thelithnegativewasthenused as y an Keuren’ lith negativeoftheprintusingacopy our finalprintedimage. s at theUniversityofArts Study forMyV oice, 1997 The 227

CHAPTER 13 THE GUM BICHROMATE PROCESS re looking for. re ’ ou There are a host of film varieties and developers avail- and developers a host of film varieties are There have been separating transparencies in separate CMYK transparencies been separating have that are too high in contrast—unless, of course, that is that are what y able for nearly any type of negative interpretation you are you interpretation able for nearly any type of negative timing is tight, where in workshops Recently, wishing for. I K= black) files in Pho- Y= yellow, (C= cyan, M= magenta, toshop and printing them out on acetates on a quality ink- options decent negative CMYK separations are jet printer. or the time and and eliminate the need for darkrooms of for dealing with a service Most bureau. money required perfectly satisfactory are the time, digital negatives for gums reproduction. and speed in negative flexibility and offer you made from may also wish to consider using negatives You with a cliché-verre own laser copy machines or making your single color gum, with many applications a e Jesus Singers Seigel, It is advisable to have negatives that would be appro- that negatives is advisable to have It (Courtesy of the artist) (Single coat gum bichromate with acrylic border) Judy Seigel has been a champion influence in the renewed interest in alternative photographic processes. Her specialty is gum bichromate, and her passion for the alternative image is unflagging. Figure 13–7 Judy of the same color, one negative may be all that you will may be all that you one negative of the same color, all one has to do is adjust a single negative, With require. the components, such as the concentration of pigment, a to make in order and amount of sensitizer exposure, image. resolved This gelatin paper. priate for a normal grade of silver den- negative an average will have means that the negative This is a general suggestion unless you sity of 1.0 to 2.0. intend to make gums for interdisciplinary intentions, secondary are you the tonal values to the concept. If where than looking for a full tonal range, and gum is more are negatives it is best to avoid capable of giving this to you, highlights, midtones, and shadow details. If your inten- your details. If highlights, midtones, and shadow tion is to hav

THE BOOK OF ALTERNATIVE PHOTOGRAPHIC PROCESSES 228 S it intentionally. This accidentmayw you willquiteoftengetcuriousandunexpectedresults. essar transpar a intend tomakemultiplepassesorify R Registration ter 3,“ Negative,”technique. (Refer toChapter2,“The andChap- ome ofthemethodsinclude paperpunches,pushpin egistration isdoneaftersizingandhar more complex gum, such as trying toduplicateacolor more complexgum,suchastrying There are manywaystoregister negatives andpaper. y to register your negatives.If you don’t register them, The D ency fr igital O om fourCMYKseparations,itwillbenec ell bea“ ptions,” formor good ” technique ify e ou are working on information.) dening. I ou use f y ou - to thesensitiz paper onalighttable,quicklyregistering your negatives board. You canalsoregister simplyby layingyour coated during negativ holes, stick-ontransparent registration targetsapplied light, y table. Even thoughyour driedemulsionissensitive to parent tape.Don’t stress aboutthelightfrom thelight the baseimageafterrecoating. is assignedtoeachnegativ piece ofpaper. whenadifferentThis isespeciallytrue color aligning your negative, oradifferent one,onthe same y out foggingtheimage. The pointofregistration istogive speed andwillhave timetosecure theregistration with- ourself ar ou stillhav epeatable andmechanicalwayofaccurately ed paper e pr oduction, oranolddy e plenty offorgiv (Courtesy oftheartist) process classmakingacyanotypemural. Maine PhotographicWorkshops alternative 35 mmtransparency(Figure3–14)ofmy1999 Figure 3–18,whichcomeoriginallyfroma the CMYKseparationsinFigure3–15through This gumbichromateprintwasgeneratedfrom 1999 print madefromdigitallyseparatednegatives, John Quackenbos,Fourcolorgumbichromate Figure 13–8 , and lockingitinpiecesoftrans e and wher eness intheemulsion e it isdifficulttosee e transfer punch - - 229

CHAPTER 13 THE GUM BICHROMATE PROCESS - - er ), or ® our con our sensitiz e. It is a typical e. It ou can begin to see w-light conditions omate is y hung the motel’s yellow hung the motel’s e w e king lot on a rainy day and had er can be adapted to suit y wher y omate but generally clears out in the color paint to make the complete solu eady to make an exposur an in a par r e ou ar king with it under normal lo sheets over sun-filled windows and there was no problem and there sun-filled windows sheets over with fogging. I performed in another gum demonstration the back of a v because it doesn’t become truly until it is light-sensitive because it doesn’t demonstration in gum print- a workshop I once gave dry. ing in a motel lobb The Ammonium/Potassium The Ammonium/Potassium Dichromate Sensitizer Ammonium or potassium dichr and is added to your mix of liquid gum arabic (with a spe- and is added to your pigment and watercolor cific gravity of 12˚ to 17˚ Baumé) when y suitable only for contact printing emulsion, alternative to worry have very much about don’t You under UV light. wor ammonium dichr Whichever highlights a little better than does ammonium. of gum elect to use is added to a mixture you sensitizer arabic and water water can also be added and tion for coating. Additional The proportions emulsion smoother. will help make your of gum arabic to sensitiz albumen, for the gum arabic. I hope y albumen, for the gum arabic. I hope and fast rules apply. hard is not one where that the process trast and exposure time requirements as well. Some gum Some as well. time requirements trast and exposure glue (like Gloy practitioners also substitute a liquid - - - es egis oss the ou will be printing and ent lengths of all but one neg ® un a strip of tape acr 1996 paper that y ed ent height but will still be in r siz differ our Mixed Fruit #6, a ith a mat knife or sliding blade paper cut ith a mat knife or sliding blade paper e W face that will accept a pushpin and poke a pin- face that will accept a pushpin and poke ea of y light table, register all of the negatives to be used in to be used all of the negatives light table, register a trim the margins at differ When this is done, place the packet of taped negativ When this is done, place the packet of , n lot more sophisticated than what I’ve described above. I’ve sophisticated than what lot more clean sur our print. translated in true-to-life color. It was the color. translated in true-to-life use the first time I had seen a student for a unique computer solely as a tool her success alternative process, and importance of demonstrated to me the incorporating digital technology as an alternative process component. (Courtesy of the artist) Mary Pat did a series of four color gum Mary Pat did a series of senior thesis at bichromate pieces for her The negatives the Art Institute of Boston. Photoshop were CMYK separated in Figure 13–9 Mary Pat McNally, on. Move the sized paper and the taped negative pack to paper and the taped negative the sized on. Move a set and margins of the negative two or three hole through reference These holes will serve registration as your paper. a lot more wish to have course, if you guides later on. Of to be techniques will have registration then your control, a com- more urge to make this process a strong have you If so. to do plicated, please feel free The Components in a Gum Emulsion in printing is prepared The emulsion for gum bichromate dichro- mixing your by simple and separate steps. Begin gummists use either potassium or mate solution. Most but it is also acceptable to use ammonium dichromate, who anyone know although I don’t sodium dichromate, than tends to be a bit slower dichromate does. Potassium O One Example of a Simple Registration Technique ative so that when they are in registration each piece of in registration so that when they are ative film will hav y tration with the others. R packet of trimmed edges so they can be picked up as a set. packet of trimmed edges so they can ter on the ar

THE BOOK OF ALTERNATIVE PHOTOGRAPHIC PROCESSES 230 sensitiz own systemtoaccuratelypredict outcome. tor willimpactanotherandy the printwithpotassiumasy the same,butyou mayexperienceaneasiertimeclearing dichr be thatexposure withtheammonium timewillbeshorter the solution),butonlydifferences thatyou noticewill potassium dichromate (duetomore dichromate ionsin to 13%.Ammoniumdichromate ismore sensitive than around 25%to30%andpotassiumdichromate at10% mentioned earlier, ammoniumdichromate issaturatedat can bedissolved inwaterwithoutleavingasediment. As solution isdefinedasonewhere nomore ofthechemical Dichromates are usedinasaturatedsolution.A Ammonium orPotassiumDichromate Making aWorking SaturatedSolutionof as you wouldwithotheralternative processes. n potassium orammonium,willlastforav case, thissaturateddichromate solution,whetheritis decide whatstrength isbestforyour own work. In any making aslightlyfastersensitizer. You canexperimentand would beusing13gtothe100mlofwaterand opted tomakeasaturatedsolutionof13%theny dichr solution in100mlofwater. This makesa10%working w solution at10%,takeadigitalortriplebeamgramscale, Kno of simpleexplanationwe’ll usea10%solutionasourgoal. o eigh out10gofpotassiumdichr sensitivity toUVlight. the pH(lessthan7)and greater thedichromate’ (above 7)andthelessdichromate’ tion. Themorealkalinethewater, thehigheritspH to thepHofwaterusedincreatingcoatingsolu- The speedoftheemulsionwillbeslowerinproportion Regarding Dichromates An InterestingFact light. Conversely problems there either. Avoid excessive fluorescent light I f wing thatpotassiumdichromate isinasaturated omate. The contrast,allthingsbeingequal,willbe omate solution. y ou decidedtousepotassiumdichromate asyour er , make asaturatedsolutionofit.F , the moreacidicwater Ther e our sensitiz is arangehere, andifyou ou ’ ll needtowor omate, andstiritinto s er. Again, onefac- sensitivity toUV or thepurpose er , y the lower k long time out y s our ou O color blind,orimpair stock aslongthequalityisgood. Those readers who are quality The water Watercolors X also wishtohav than theotheryellows, asis Transparent Yellow. You may mium). N blue (thaloorcobalt),andyellow gambogeorcad- (new on hand. colorsincludered (alizarincrimson), The primary dichromate solutionslookalotlikesugared drinks! the Appendix before usingdichromates. hands onthem.Please reference thechemicalsectionin chemicals unlabeledorwhere children cangettheir carefuling itin.Be very withstorageandnever leave the through contactandcandamageyour lungsby breath- This chemicalcancauselesionsonyour tenderflesh potassium dichromate: It isdangerous andpoisonous. in asafeplacewhere children cannotreach it; centage, andthedateitwasmixed, andbesure tostore it bottle withinformationregarding itscontents,per- w beginning wor paint, butI’m notsure whichpaintstheymight be.For There are exceptions tothiswarningaboutacademygrade and toomuchsensitiz can beoneofthereasons, besidespoorpaperpreparation, often doesnotclearwell inthehighlightsandshadows and so don those thatar identical colorfrom another. You willhavediscover to one manufactur stage. I manence andabilitytoclearinthewashdev Be awaresons. regard that somecolorsarein suspect toper- (water y brand Ihave alwaysused. Again,keepcareful notesand in. Ir are somanydifferent brandsofwatercolor and ou hen stored inadark air-tightbottle.Be sure tolabelthe f course, useanycoloryou wishfrom themanufacturer’s ’ ll wor Be cautiousinhow you handleammoniumor color withwhitepigmentadded),andafr , ecommend Winsor–Newton, becausethatisthe t ’ t not would benumbingtopr avoid thegumbichromate process forthoserea- k colors you useshouldbeof“professional” artist aples y student or“ it alloutev e best fory k e er willbehave quitedifferently thanthe it isagoodideatohav a ellow isalsoanicecolorandcreamier black and/oragraysuchasDavy’s Gray. er intheformula,forpaperstaining. academy ou withintheparametersy entually. ed, mightbeconsider ” ovide thislistbecausethere grade paint.I e “primary colors” when mixed, nferior paint ed cr elopment ou wor gouache eativ om e, k 231

CHAPTER 13 THE GUM BICHROMATE PROCESS - Spirits of Spirits eed book et for using This formula is ebb-R omate sensitizer W ext, place a small The not attempted y e mess,” mix the ingredients y ubber r grade watercolor pigment s it thoroughly, put the coated paper and neg- it thoroughly, y solution artist’ in a ceramic cup. Then add 5 ml liquid glue to Then add 5 ml liquid in a ceramic cup. adding the 9 ml of gum arabic to a small plas , y irst, make up a 5% potassium dichr is a nice idea that I hav ml gum arabic ml saturated ammonium dichromate sensitizer this paste, add 3 ml of a saturated ammonium F e 9 3 to 1˝ e ˝ Traditional Gum Bichromate Sensitizing Traditional few gum bichromate artists claim that different types of artistsfew gum bichromate that different claim 2 ⁄ “rubbery mess.” Add 5 ml of the 5% potassium dichro- mess.” Add “rubbery egin b alts. 1 (5 g to 100 ml of distilled water). N (5 g to 100 ml of distilled water). of a #2 pen- pigment, about the size amount of watercolor S liquid glue as a substitute for gum arabic. liquid glue as a substitute for gum arabic. book, Reed and Martin Webb the Randall from in tiny little bottles, and sells for a premium. I like the look I like the premium. sells for a and little bottles, in tiny very but it is not of their product, A print- cost effective. arabic that is syrupy will sell a gum supply and maker’s Don’t not nearly as precious. at a price that is quite dark because it color of the gum, with the concern yourself of the print. in the quality difference seems to make little A prob- They are speeds. printing different gum arabic have sleep over should lose you not sure but I’m ably correct, arabic is also handy for masking. Gum this possibility. and acacia tree, an the sap from buying are you Essentially, Most not always determine the quality. the color of it does art the quart supply outlets sell it by or gallon to meet the of printmakers and lithographers. requirements Using Glue as a Substitute for Gum Arabic Ther cil eraser the cup and stir it into the paint. mate mix to the “ indicates that you shouldn’t be concerned if the mixture is be concerned if the mixture shouldn’t indicates that you a B paint add the watercolor Next or glass container. tic, paper, sen- To smooth. and stir the paint into the gum until it’s sitiz be and stir it into solution. Please solution dichromate that of those old “horses” that this formula is one aware A (Ammonium Dichromate) Formula together, quickly coat your paper with a thin coating of the paper with a thin coating quickly coat your together, solution, dr in a printing frame, and expose in UV light. Presto! ative ell made and able to 1998 , eight of 140 lb. might be adequate. For gum might be adequate. For eight of 140 lb. Gum Flower , tant to use a paper that is w Arabic is impor t (Courtesy of the artist) Figure 13–10 Kathy Pillsbury of Boston who Kathy Pillsbury was another student at the Art Institute for her gum bichromate adopted the process of making digital negatives work. Gum arabic can come in a variety of purities. Winsor– of purities. arabic can come in a variety Gum comes one that is very makes an expensive clear, Newton Gum stand up to all sorts of abuse: specifically, repeated wash- repeated stand up to all sorts of abuse: specifically, minimal passes, a ing times of extended duration. For paper with a w projects with several applications, exposures, and devel- applications, exposures, with several projects I have well. paper will work opment experiences, a 300 lb. intended to make gums I have when Arches used 1,160 lb. tools and sanders as part of the I could use power where water- with high-quality all cases, even In process. working and harden color papers, it is a good practice to gelatin size pass is planned for. than a single the sizing if more I Paper

THE BOOK OF ALTERNATIVE PHOTOGRAPHIC PROCESSES 232 Figure 13–11 Sarah Van Keuren, Phoebe Among the Leaves, 1998 Sarah Van Keuren teaches alternative processes at the University of the Arts, and a number of her former students are represented in this book. This is a nice example of Sarah’s combination gum and cyanotype prints from an .pinhole camera negative ”10ן”8 (Courtesy of the artist)

has made its way from one source to another since the An Alternative Sensitizing Formula: beginning of time (more or less). It works perfectly well, “The 5-10-10” but it isn’t, by any means, the last word in gum formulas. Each individual will adopt his or her own personal work- This formula makes a coating that is texturally smooth ing styles, techniques, and mixes to suit his or her inten- and a bit pale. I like it as a formula for high detail nega- tions and imagery. In addition, each person’s coating tives. It’s a good choice for print details that are delicate technique, washing style, or purist to nonpurist approach and built up patiently over subsequent exposures. This is will be different according to who they are and what it is a great formula for darker colors used to increase shadow they need from the ratios and combinations of gum, depth in gum and combination processes such as gum and paint, and dichromate. As they say in the gum labs, “It’s cyanotype. not how impeccable your formula is, it’s how you use it.” 10 ml gum arabic (poured into a small plastic or glass container) 10 ml distilled water (add to the gum and stir) S S

1˝ or more quality watercolor paint (add to the E C

Another Sensitizer Formula gum and water and mix well) O R P

(Potassium Dichromate) 5 ml ammonium dichromate (stir into the solution to E T sensitize) A This formula is generally very successful, and the pro- M O R

portions of potassium dichromate to gum are similar to H C I

the mix used by many of the most technically successful Sensitizing the Paper B M

gum artists. Use the following ingredients and mix them When your paper has been correctly sized and hardened, U G

according to the directions for ammonium dichromate. and you have registered your negatives with the paper so E H Pigments have different densities, and therefore the that multiple applications of exposure are possible, it is T 3 formula such as this one will 1 ˝10ן˝amounts used in an 8

time to coat the paper. If this is your first experience with R E fluctuate, depending on the color. T

gum, or if you have not had any success with the process P 6 ml gum arabic A before, select one of the dichromate formulas above and H 1 C ⁄4˝ to 1˝ watercolor pigment prepare for success. 6 ml saturated potassium dichromate solution 233 - lastic siz esults, in ost-Factory P This r ush to pull away fact, I had always 10˝ print) will result n et br ן than 1˝, but not so much staining. Judy Seigel con- Seigel staining. Judy e less omate and stain. color papers prior to making water- ssue #2 of her excellent ssue #2 of her excellent doing this I was able to paint and then y nal. our made sense, thinking about this fact, that extra made sense, thinking about this fact, t aphy J I . For many years, I have been laying multiple gum ara- been laying I have many years, For Few Words Regarding Words Few more “true to the tube” pigment interpretation. It does, It pigment interpretation. to the tube” “true more hotogr alues and less stain potential. Be aware that a greater con- that a greater aware alues and less stain potential. Be eturn to specific sections with a w what the color will look like when it’s not wet. Keep in Keep wet. not it’s like when will look the color what to the water- the dichromate add when you mind that due to the color will change arabic solution the color/gum worry Don’t sensitizer. of the dichromate orange color wash out orange color will change, because the about this during processing. pigment and expose highlights. This was possible because pigment and expose highlights. rather than the the paint was sitting on the gum arabic paper in staining when paint would not be a significant factor sitting in a gum arabic solution. I thought of extra pigment (mor in cleaner resulting as a quasi filter, that flaking occurred) v in a shorter tonal scale, centration of paint may also result higher print contrast, and possible flaking. in staining in your print’s highlights. I have generally I have highlights. print’s in staining in your concentration of paint in the emul- found that a greater in sion will actually result firms this point in I bic washes on water color paintings. B r The Relationship of Sizing and Color and Staining Type formula you the sizing between is a relationship There select and the final colors and highlight tonalities in the for the suc- gelatin sizing, which allows print. A hardened cessful clearing of highlights, will occasionally hold fast to the ammonium dichr A and Staining Wisdom Gum Conventional concentra- stipulates that a greater rules” of the “old One than 1˝ of (meaning more “normal” tion of paint than for an 8˝ mix paint in a standard P some cases, in a yellow tinting of color within the print. some cases, in a yellow in a sodium tints can generally be cleared These yellowish metabisulfite or potassium metabisulfite bath. P ing, like the gesso/matte medium formula, often provides a - ou wish to mix for the first coat 1998 , Brynmore e. Measure a small amount of watercolor pigment of watercolor a small amount e. Measure elect the color(s) y S It is quite permissible to work under normal room is quite permissible to work It It is not uncommon to make a first exposure using is not uncommon to make a first exposure It (Courtesy of the artist) Figure 13–12 Cheryl Harmeling, of Boston, created a Cheryl Harmeling, while a student at the Art Institute a single negative and powerful portfolio of gum bichromate portraits using dichromate, and gum ammonium multiple “passes” with black watercolor, arabic. light conditions, but I generally prefer to mix my colors light conditions, but I generally prefer is them. It under a brighter light so I can better evaluate also a good idea to paint a piece of the scrap paper with and blow-dry intended emulsion your it to quickly see only the gum arabic and the sensitizer. This exposure, pro- This exposure, only the gum arabic and the sensitizer. a light tan-colored you viding it is not too long, will give may also elect to begin your You negative. image of your process another non-silver on top of first gum exposure will initial base color this case, your such as cyanotype. In toning. changed it through have be blue unless you into the gum and stir it well until it is thoroughly in solu- until it is thoroughly into the gum and stir it well tung- under low sensitizer dichromate add the tion. Now are until all of the ingredients sten light and stir slowly together as one. ing. Generally, a lighter value is used first so that you can is used first so that you a lighter value ing. Generally, This will be going with the print. you get a sense of where the highlights in the lighter color is often used to print for negativ

THE BOOK OF ALTERNATIVE PHOTOGRAPHIC PROCESSES 234 exposur coating formula,paintamounts, andtype,date,timeof mor will beprinted,andtogracefulwiththecoating. Again, becareful topaintlightly, cover theentire area that for additionaluse,andsimplyfeelsbetterinmyhand. br working withthehakebrush. This isbecause thehake tainly viableasacoatinginstr W thing you won’t know aboutuntilyou develop theimage. on acoolsettingbecauseheatmayfogyour print—some- itwithahairdryersemidark set environment orforce-dry the coatedsur heart’s content. When you are satisfied withthelookof just gowithyour instinctsandcoat“gesturally” toyour hav appreciate theresults. Of course,ifyour intentionisto ing. Barely touchthepaper whendoingthisandyou will your applicationstreaks have blendedintoasmoothcoat- untilallof gentlywhiskitbackandforth andvery brush siv with ifyour coatingarea islarge.Althoughitlessexpen- ing. O of y the emulsionjustbeginstobecometacky horizontal strokes. Work fast,smoothly, andlightlyuntil inevenmarks andthen vertical andquicklybrush-coat Markbrush. theprintingarea withlightpencilregistration sized, andhardened watercolor paperusingahakeorfoam well. One ofthem,thestandard way, istowork ondry, ficult butrequires practice. There are several waystocoat Coating agumbichromate emulsiononpaperisnot dif- thatyouof theproportions are testing. medium willflakeoffindevelopment, sokeeparecord contrast. There are alsoinstanceswhenthegesso/matte h also onthebackofpaper forr owever, occasionallyyieldanimagethatresults inmore ush absorbslessoftheemulsion,canbeeasilywashed rite do e When theemulsionbeginsto“set up” (looksandfeels e our hakebr e to useahar a gummy than liquid), take a clean and dry 4˝hake gummy thanliquid),takeacleananddry b coating thatisnotsmoothbutmore “painterly,” viously e, andstageoftheprint. wn allofthetechnicalinformation, suchasthe face, allowina thesensitized papertodry , ush b a dwar Coating 1˝ y br e the siz ush isamor store andcer- typeoffoambrush, e of thearea thatyou are coat- ument, Ipersonallypr W efer e difficult tooltowor rite thisinformation ence. . Select thewidth efer k a the previously definedalternative processes, you will need “crisper” imageandafasterexposure time.Aswithallof the sun.In myexperience,sunlightappearstoprovide a more inthelightof organicandcasualritualofprinting times inadeductive manner. likethe Other gumartists with lessguesswork, andtheycanbetterevaluate exposure with aUVexposure unitare abletocalibratetheirwork sistent year round, 24hoursaday. Gum working artists unit. The advantage ofaUVprintingunitisthatitcon- with aUVlightsource suchasthesunorUVprinting building your imageover timewithmultipleapplications. finebecauseyou willbe lighter image,whichisperfectly image. The wet coatingmethodwillgive you asomewhat fresh emulsionhasdried,becausethiswillyieldthebest good ideatocontactprintimmediatelyafterthepaper’s theprintwithahairdryer setonacoolsetting.Itdry isa thecoatedpaperinasemidarkDry environment orforce- forevening theemulsioncoating. use the4˝hakebrush to smoother coatingandwillprobably finditunnecessary paper.in thesamemanneraswithdry You maynoticea careful nottoabusethepaper’s fiberswhenblotting.Coat damp withnovisiblewaterreflection Be onthesurface. paper from thewaterbath,gentlyblotituntilisslightly pared paperinroom temperature water. Afterremoving the An alternative methodofcoatingistofirstsoakthe pre- An AlternativeWet CoatingTechnique that willchangewhenanotherv oftheprocessments ofthisprocess, isavariable eachpart is nosuchthingasa“correct” exposure. Aswithmostele- of paper, oftheprocess. oranythingelsethatisapart There tive density, strength ofsensitizer, typeofgumarabic, density andtypeofpigment,humidity, timeofday, nega- numerous todefinesuchastandard. These variables include exposure orcontrastcontrol, becausethevariables are too It ispointlesstoattemptauniformgum“standard” for hinged-back contactprinting frameforsunprinting. The exposure ismade,asinotheralternative processes, Exposing theNegativ ariable enterstheequation. e 235

CHAPTER 13 THE GUM BICHROMATE PROCESS - eason for this The r ou see the need. One er mix, playing with the ratio theo omate in order to lay down a “tan”- to lay down omate in order our elements as y uring the water development, the highlight areas uring the water development, ed base for the highlight detail. This would, or could, ed base for the highlight detail. You can also play with the proportions can also play with of gum to You D In a single negative/single color gum it is advisable to a single negative/single In d, adjusting y ou may also refer to an earlier mention of printing with ou may also refer Printing a Single Color Gum Gum Single Color a Printing Single Negative with a that environment workshop especially in a often, Quite within a short processes many alternative compresses of the techniques common to demonstrate time, it is This is a cost- and time-effi- negative. gum with a single works gum bichromate how cient method of describing density vari- multiple time to produce without taking the This separations, of a single negative. ations, like CMYK has occasionally been a source method of demonstrating the discussion of strategy regarding of confusion due to details within the and shadow printing for highlights solution is not The negative. source parameters of a single of the emulsion. complicated; the key is the variability as concentrated as 1:1 with ratios sensitizer dichromate is the contrast is The reason or 2:1 (gum to dichromate). sensitivity of the emulsion and the reduced bumped up by will clear due to the that the highlight areas the degree the same At concentration of gum arabic in the formula. will not completely “close areas time, the open shadow on you. (overexpose) up” areas shadow clear quickly (contrast), while the exposed thing to keep in mind when making a gum print from a thing to keep in mind when making a gum print from necessarily want to print don’t you is that single negative for the finished image on a single pass. bet- It’s blocking up. shadows your may find is that you take the place of a color if you don’t clear the paper with don’t take the place of a color if you sodium metabisulfite or sodium bisulfite. rather than make the coatings thinner and less sensitive use a normal sensitiz can you subsequent exposures On ries mentioned above. back to the stan- the ratio of gum to dichromate, increase dar color will not have had enough exposure to close up on the to close had enough exposure will not have the highlight to penetrate order details within them. In a first exposure make your negative, densities of your details will show. fairly lengthy one so that the highlight Y only gum and dichr and test strip , step-wedge.” If step-wedge.” es using a “ 1998 , acancy 20 to 40 seconds during the exposure. When 20 to 40 seconds during the exposure. Occupancy V y er ou should use—that day. Remember that the gum Remember ou should use—that day. doing, including formula, time of day It might be a good idea when beginning a new might be a good idea when beginning print It e strip ev our printing strategies and be patient. (Courtesy of the artist) Melissa Good, created this gum bichro- Keuren’s, Melissa, a former student of Sarah Van in gum bichromate. mate print as part of a melancholy series of portraits Figure 13–13 to make a test strip of exposur the contact one, lay opaque strips over have don’t you Remove paper. and sensitized frame holding the negative a the test develop times. After making the test exposures, good idea what exposure a pretty have will print and you times y using dark colors it is not a bad idea to increase the num- is not a bad idea to increase colors it using dark forget to keep notes of what you ber of test strips. Don’t ar process is an evolving one and is more like printmaking one and is more is an evolving process for a plan gelatin printing. Make than traditional silver y

THE BOOK OF ALTERNATIVE PHOTOGRAPHIC PROCESSES 236 it alone. away theprint. simply haven’t hadenoughexposure yet. Don’t throw having acorrect exposure areas time,but thoseparticular your print’s surface. This indicatesthatyou are close to shadow detailsonlytohave themfloatawayordripoff detail. the well-exposed shadow values have tonaldelineationand means thatthehighlightsare paper basecleanandwhen place theprintfacedo minute andthenv will takeforever. Gently agitatethepaperforabouta erase subtledetails.If thewateristoocold,clearing perature water. If thewateristoohotyou willunwittingly larger thanyour paper, whichisfilled withambienttem- ple andeasytoemploy duringthedevelopment stage. sentences. the printthatImentioninafew These are sim- many hours. There are waystoenhanceandclearareas of soaking andtimethatmayrangefromminutesto afew There isnodevelopment chemistry, justagoodwater Development simple. oftheexposedgumprintisvery Clearing Development: thing you do. complete thefinisheddensity. Again,keepnotesonevery- to each takingapercentage ofthetotaltimenecessary t aggr drop gentlytothebottomoftray. If you agitate the bottomofy posed por are stillonthepaperandswollenwithwater. The unex- exists becausetheexposed(har y the paper’s afteryour highlightshave surface cleared and y low orDavy’s Gray maytakeonlyminutestoclear. Single thincolors suchasNaples exposures withvery Yel- take longertoclearthanwillprintswithlightercolors. haven’t radically overexposed theimage.Black printswill developed printwithin10to15minutes,providing you er toparcel outexposure timeover several exposures— ou willseeadistinctbas-r ou willwr Often you willinitiallyseeniceseparationwithinyour Following exposure, immerseyour paperinatray, In myexperience,lightcolorswillyieldaperfectly essiv The unexposedar ely orr tions oftheimagewillbelyingpeacefullyon eak hav our washtray. W un wateronthesur ash itw oc onaw ery carefully changeyour water.ery Then wn in thefr eas oftheimagewillsoftenand ell, dry it,andrecoat withthe ell, dry elief oftheimage. et, fragileimage.Lookacr dened) ar esh waterbathand face oftheemulsion eas oftheimage This relief Clear leav oss e the emulsionisv the softandswollenpigment.Remember, inthewet state glovedusing abrush, finger, oretchingtooltomark in print. achieved waterdirectly by running onspecificareas ofthe where you wishtoeliminateortransformdetail,canbe dried. the imageby reexposing thepapertoUVlightafterithas progress becauseyou likethewayitlooks,you canharden If stopadevelopment yourun. in decidetoabruptly on ablottingsur about halfwaythrough andlayingthepaperflat,faceup, highlights), canbeachieved by stoppingthedevelopment leav of thehighlights.I where you lefttheclearing print togently soakforatotal produce animage thatissignificantlydifferent from one your cyanotypeswithamistof Tilex ticular remedy oftenbecomesatechnique,likespraying detail inahurry, especiallyifthesolutionishot. This par- efficientatremovingful becausethisbathisvery alotof ammonia orhouseholdbleachtoaliterofwater. Be care- flaws canoftenberepaired by makingabathof15ml trast, flathighlights,orblockingintheshadows. These for aslightlylongertime. s adjust waterstr handheld garden sprayer, thetypethatallows you to not alwayssomethingtoavoid. Ihave usedacommercial the softemulsion.Use your imaginationandhave agood the printtocompletionor personal tasteandworkflow. to achiev exposure onthissecond“pass” willlikelyrequire lesstime it, register, andreprint thesamecolorandnegative. Your if you underexpose it,recoat theprintyou onlyhave todry exposed printsissimplytoletthemsoakforaday. Again, for anunusualreticulated effect. exposur that alr exposure becauseyou willbebuildingonalayer ofdetail ame oradifferent color, andexposethenegative again O Prints thathave beenoverexposed mayshow lesscon- There willbetimeswhenyou may notwanttodevelop Another methodforclearingheavilystainedorover- e a n Y good dealoforiginalcolorbehind(especiallyinthe eady exists.Personally, Iprefer aseriesofsmall the otherhand,for ou mayalsochangethewayaprintwilllookby es toonebigexposur e the effecty eam pr face. If you hangittodry, thecolorswill er y ncomplete dev sensitive toabrasion,andabrasionis essure and flow size, to“draw” into ou w , ced dev conv er e, butthisisjustamatterof e going forintheoriginal ersely elopment oftheprint, elopment, wher ® , toilet bowl cleaner when you wishto e you 237

CHAPTER 13 THE GUM BICHROMATE PROCESS , mass our first color impres- rouble-Shooting T that is important. Spraying warm that is important. Spraying detail, on. You may also consider making a gum “pass” on may also consider making a gum “pass” You on. k engthy water washes will damage the paper and dete- the paper damage washes will water engthy rather than the water can also open up blocked shadows. You can try using a 2% solution of Ilford’s Acid Hard- Acid can try using a 2% solution of Ilford’s You ener as a clearing bath. can be upbeat about the entire Last, but not least, you might also consider You again. experience and start over or a can- process using the print as a base for another to paint, paste, and play on. for you vas If nothing is working, and you’re feeling particularly you’re and is working, nothing If of hot a solution of 1 liter soak the print in stubborn, This solution ammonia. 10 ml to 30 ml of water and on the print, and it will a lasting impression will leave Just original intentions. your from look quite different and rapidly, image and watch your immerse the print about the careful be Please change personality. forever, brings forth.fumes that this technique also try can for less time, printing imme- exposing You because different diately on drying, or changing paper, clear differently. types of paper will proportion of gum arabic a greater incorporating Try much sensitizer Too formula. in your to the dichromate may be the problem. of clear- after a significant degree may wish to try, You ing frustration, blasting warm or hot water onto the print and detail. can get any separation of values to see if you to all delicate will be saying good-bye you Chances are it is the highlight details, but for many gum printers l sizing. riorate the Consider making a cyanotype as y blue (or some and finely detailed a strong provides sion. It a fine visual map to tone it) and gives other color if you wor want to raise top of a platinum/palladium print if you was quite pop- this combination Actually, some eyebrows. N N Other Miscellaneous Notes and Suggestions if Any of these notes and suggestions may be disregarded style. working fit your they don’t First Impressions N N N N al ectify chiv ’s formula ’s er committing e This can often r aggressive than you had than you aggressive e ne manufactur to do a test piece befor e sur e failed you can tryfailed you a few things in the next print- ush. If you notice that your emulsion has become notice that your you ush. If e all will work exactly like another with your choice like another with your exactly all will work changing the brand of paint. the same line of thought, try changing the type of away. y r n Clear the print in the sodium metabisulfite bath for 1 Clear the print in the sodium metabisulfite staining in the highlights. O for cadmium red is seldom identical to another’s. is seldom identical for cadmium red Soak the print face down in a water bath—for a very the print face down Soak its disadvantages; This solution does have long time. I and many varieties are There using. are gum arabic you not of paint. First, review your sizing and hardening technique. sizing and hardening your review First, T small br ime with the options. If the end result is a mess, then is a mess, result the end If options. with the ime fragile in the sodium or potassium metabisulfite clearing fragile in the sodium or potassium metabisulfite may want to consider dryingbaths, you the print and going gum all attempts to clear your to the final wash later on. If print hav the same problem. ing session to avoid your print to a bath and adjust the percentage strength as strength print to a bath and adjust the percentage your with may also spot-clear with this solution You necessary. a N N N N anticipated. B intentions you have for your image. This step will be your image. for your have intentions you been made. have color impressions last one after all of your Be in clean water. to 2 minutes and wash it for 10 minutes concentrations of the metabisul- cautious of the percentage fites because they may be mor Clearing Stains with Clearing Stains Metabisulfite Sodium or Potassium high- stains in your dichromate have that you the event In clear them out may color), you (the tan lights or borders 5% solution of sodium metabisulfite with a simple 1% to or can be immersed or potassium metabisulphite. Prints may elect to spray the solution on the surfaceyou of a painting consider selectively might even You damp print. also try can potas- You areas. the metabisulfite on problem help the ar sium alum, but this chemical may not chalk it up to experience and see if you can use the knowl- can use see if you to experience and chalk it up of this fundamental wisdom The way. positive edge in a and development of exposure relationship is that the and the the gum between on a good marriage depends and only suitor” The paint is the “unrequited dichromate. to and refuses if the gum hardens stays in the relationship wash t

THE BOOK OF ALTERNATIVE PHOTOGRAPHIC PROCESSES 238 problem. detailed notessothaty more delineatedtonalscale. Work carefully andkeep times. tiz remixing afresh dichromate, usinglessofitinthesensi- mists” whoweigh theirpaintonadigitalgram scale. arabic. Iactuallyknow successful“gum- of several very of image andmayresult inflakingoftheemulsion.Keep track other variables. Extra pigmentwilllikelyaddcontrast to the wor Adding more pigmenttoyour formulamayornot a more dichromate tothesensitizer mixyou willexperience color, ora paint, alighterversion ofthenegative, acomplementary for asecondorthird exposure. You adarker mayalsotry Try repeating thesamecoatingandnegative, inregistration, To DarkenanImage using adiffer add more ofittotheformula. You mightalsoconsider have nottrieditasofthiswriting. suggested thataRowney Thalo Green clearswell, butI and ayellow ratherthanoptforthetubegreen. It hasbeen greens. When Iwantagreen Iwillgenerallymixablue clear, andpersonallyI’ve alwayshadawfulproblems with out insplotches.Some colorsare toughto particularly of andwilloftenendupstainingyour printorwashing Student-grade watercolors oftenhave littlequalitytospeak Always usethehighestqualitywatercolors you canbuy. duplicating your techniquewithadifferent brandofpaint. staining toconsider. If you are experiencingstaining,try in thesectionyou’ve justread. There is,however, alsopaint Many ofthesolutionsfordichromate stainingare covered Staining did. begin withabriefgreen orbluegumexposure asSteiglitz this, additional depthtotheimage.If you intendtotry and definecomplexshadow detailsandoftenprovides tury. The additionalgumbichromate stephelpsbringout u lar withmanyPictorialists ofthecen- intheearlypart reduction ofcontrastandincrease inyour exposure time. er mix,orexposingy the paintamountsthatyou are intothegum squeezing You usingadifferent typeofgumarabicor mighttry k, andthesuccessofthischoicewilldependonafew Y ou mayalsoneedtomakeane little ent paper more dichromate intheformula.If you add , our colorsformultipleandshor tr ou cangobackwar ying adiffer ent sizing-har w negativ ds tofindthe e with a dener ter , (Courtesy oftheartist) subject. tern herewithgumbichromate—whouseshimselfalmostexclusivelyasa Scott isanotherformerstudentofSarahV Scott McMahon, Figure 13–14 metabisulfite, potassium orammonia. washing theexposedimage, orusingasolutionofsodium result in lesscontrast. You hotwater, very mayalsotry over- image by usinglesspigment intheformula,andthiswill only shadows willprintout. You maylightentheentire slower (reduced sensitivity)andmore contrastybecause dichromate intheformulawillresult inasolutionthatis exposure andwillwashoutduringdevelopment. Using less trast becausemor a Try usingalightercolor, amore dilutecolor, orexposefor To LightenanImage shorter time.Short exposuresshorter willoftenyieldmore con- Surveyor 1, e of thepigmentwillunharden during 1997 an Keuren’ s—seems tobeapat - 239

CHAPTER 13 THE GUM BICHROMATE PROCESS Figure 13–15 Stefanie London, Tulips, 1989 Stefanie, who teaches at the Art Institute of Boston, works with many materials in the trans- lation of her intentions. This piece, made while a student of mine at Harvard, combines gum T

H bichromate, cyanotype, acrylic, and watercolor. E (Courtesy of the artist) B O O K O F A L

T To Increase Shadow Density To Enhance Highlights E R

N Without Changing Highlights Without Blocking the Shadows A T

I Try decreasing the exposure times of subsequent coatings. Decrease the amount of watercolor pigment you add to your V E

P You may also try using less dichromate in the formula. sensitizer and modestly increase the exposure time. Both of H

O Also try adding proportionately less pigment, by half, to these options will result in less contrast in the print. You can T O

G each subsequent formula and exposure. This allows shad- also achieve a full tonal range by altering the amount of pig- R

A ows to build slowly and may help minimize staining in the ment added to each additional coating, but the success of P H

I highlights. Many alternative gum artists will add more this tactic will be dependent on several other factors. C P

R pigment to subsequent coatings to increase contrast. If you O To Reduce Contrast C have the time, try both methods and determine which E S

S works best for you. Use lighter colors, use a higher concentration of dichro- E S mate sensitizer and decrease the amount of pigment,

240 Figure 13–16 Dana Leight, 1992 Dana made this compelling work as a student in Sarah Van Keuren’s MFA Bookarts/Printmaking seminar at the University of the Arts in Philadelphia in 1992. (Courtesy of the artist) S S E C expose longer, and/or develop for less time. To tone down A Single Negative Strategy O R P colors, try using their complements instead of immedi- If you are brand new to this technique and have one large E T ately reaching for a tube of black watercolor paint. A

contact negative to play with, here is a possible strategy M O

for you. Try printing a single negative with a long expo- R If the Highlights Will Not Print at All H C sure and a small amount of paint. Then, for a second pass, I Try “flashing” your entire image area without a negative B after washing and drying the first pass, use a lot of pig- M U in the contact printing frame with only a sensitizer coat- ment and a short exposure. For a third pass with the same, G E

ing of gum arabic and dichromate and the color you H

or third color, try using the right amount of paint, with T

would like as a “whisper” in the highlights. You can also 3

the right amount of exposure. You should end up with 1 simply omit the color part of this equation and make your R your first good-looking gum print. E T highlights a tan color. P A H C

241 Figure 13–17 Lois Johnson, Audience Freeze Installation, 1982 The 100 figures in Lois Johnson’s installation “Audience Freeze” at the 1980 Winter Olympics in Lake Placid, NY, were made by screen printing canvas with images of gloves, scarves, and cow- boy boots. The faces were blue gum bichromates from ortho-film negatives on Rives BFK paper. (Courtesy of the artist)

Color Inventory To avoid a hard edge on the selective color, wet a fan- Some gum artists like to make up their color and gum shaped watercolor brush in clean water and lightly drag emulsions in small batches and store them in Tupperware® it along the edge of the applied color before it dries. This or urine sample containers from the local health care “feathering” creates a softer edge line. provider. This allows you to establish a color inventory and Create Area “Masks” Using Gum save time. Urine sample containers are great because most have an embossed graduate scale on the side and a very Painting an extra coating of gum arabic in the areas you do not want completely colored after exposure works

T secure screw-cap. Next time you go in for a physical check- H quite well. You can also use other masking devices in con- E up, pick up a few for free. Do not add the dichromate yet. B O Be mindful that these solutions will not last a long time junction with the negative, such as rubylith film or O ® K once the dichromate has been added to the gum and Mylar . The image in the emulsion achieves its tonalities O

F based on the degree of its hardening. The harder it is after

A paint mixture. L

T exposure, the less of it washes off. The less it is hardened, E R Make Color Charts the more of it washes off. Pay attention to your exposure N A

T times.

I Each new paper, paint type, sensitizer, sizing, hardener, V E

P and emulsion will show you a different look. Write this

H Exposure

O information on swatches, cut them into slide size shapes, T O and keep them in a slide sheet to use as a reference chart. Exposure is controlled by several factors that must be G

R kept in mind when creating print strategy: source of light, A P

H Painting on Gum Emulsions the color of the pigment in the emulsion, the time of expo- I C sure, the proportion of dichromate to gum, the thickness P Try painting on gum emulsions in selected areas of the R

O of the application, and the humidity. Some practitioners

C print, that is, eyes, clothing, and so on, instead of total cov- E

S find that the higher the humidity, the shorter the expo-

S erage in the traditional manner. This allows you to add E S specific areas of color without affecting the entire print. sure. Others report the opposite is true in their work. Long

242 Figure 13–18 Stephen Livick, Mural #528 (meters gum bichromate mural 2.4ן5) This image is another example of Stephen Livick’s artistic and technical dexterity. This Canadian artist is one of the most fearless gum bichromate artists I know of. Each of his mural size works takes a minimum of three months to execute. (Courtesy of the artist)

exposures will result in less contrast because more of the Random Last Thoughts sensitizer becomes insoluble and refuses to clear in the Take your time learning gum printing and enjoy the sim- water development. Shorter exposures work in the oppo- plicity of the process as well as its often maddening com- site manner. plexity. Unless you wish to show evidence of working stress on the surface of your print, sometimes you just have Photoshop and Illustrator put the print face down in the water and do something If you are proficient using Adobe Photoshop or Illustra- else for a while (this will make sense later on). Gum S tor, try making your CMYK gum separation negatives in S

bichromate is different from others in the alternative E the computer and having them reproduced as film nega- C process genre, and it is unhealthy for your creative self to O R tives at a local service bureau or doing it yourself on your P

think there is a perfect way to do it. I write this even E T desktop printer. Be sure to separate in CMYK (see Chap- though I know of at least six gum printers who claim that A M ter 3, “Digital Options”). In a CMYK separation set, C= O

their technique is sublime perfection and the “only way” R thalo blue, M= magenta, Y= cadmium yellow/hansa yel- H C

the process can ever be performed. The variables in gum I low, K = lamp black. B

printing are infinite, and each individual’s intentions will M U

never be exactly like another’s. Play and practice are the G

If Your Print’s Surface Texture … E

secrets to becoming a good gummist. Play with the myr- H If your surface looks uneven, you can take a piece of fine T iad elements of gum and practice to make your personal 3 1

sandpaper or steel wool and gently give it a nice matte- R

technique compatible with your intentions—so that it E T

luster finish by softly sanding the surface in small, circu- P

works for you. A lar swirls. H C

243