A P P E N D I X

B A Brief Historyof Photography

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Throughout the centuries, people have tried to find a quicker and better way to cap-ture the world around them. Drawing and painting were the most visible forms ofthis type of endeavor. Since not everyone is a skilled craftsman or artist when itcomes to faithful renditions, instruments have been invented to make the rendering processeasier. One of the earliest of these instruments is the camera obscura, which literally meansdark room. This tool started as a full-sized darkened room with a small opening on the end;it was used to observe solar eclipses and to aid artists in understanding perspective. Eventu-ally, images projected through a small opening were miniaturized and improved through theuse of lenses. These lenses made the image sharper and were able to resolve more details.Later, mirrors was added to a portable camera obscura, which facilitated the tracing of nat-ural subjects. This invention became known as the camera lucida.

EARLY ATTEMPTS AT PHOTOGRAPHYIt was Thomas Wedgwood who first tried to capture images using silver compounds (silvernitrate). First, he tried to use the camera obscura, but it was not very successful, because thechemistry he used was not very sensitive to light. He was able to make vivid impressions ofobjects such as leaves, and today, this process is known as the photogram, which is done byplacing an object on top of photosensitive paper. The object is then exposed under the en-larger for a few seconds to create tonality.

Wedgwood was not able to make his images permanent, because they fade when exposedto light. He needed a way to make the images stay on the photosensitive media, which wasaccomplished by Joseph Nicephore Niepces heliographs.

HELIOGRAPHSThe first documented success of capturing and fixing an image was done without the use ofsilver compounds. Joseph Nicephore Niepce used Syrian asphalt, called Bitumen of Judea,which is a varnish. He coated pewter plates with it and dried them. The exposed areas hard-ened when struck with light. The unaffected areas were then washed away using oil of laven-der and petroleum, so the bare metal was exposed, perceived as black. Niepce called his workheliographs, meaning sun drawings. Heliography is actually lithography as we know it today,but it was the first successful way to fix an image into a substrate.

DAGUERREOTYPESWhen Joseph Niepce announced his photographic invention, it attracted the attention of aset designer, architect, and painter named Louis Daguerre, which led to them working to-gether in 1826. Daguerre had regularly used the camera obscura to do paintings in perspec-tive, for he was a set designer and architect. His photographic partnership with Niepce wascut short by Niepces death in 1833.

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APPENDIX B A BIREF HISTORY OF PHOTOGRAPHY

Daguerres continued experimentation led to his use of copper plates coated with silver io-dide compounds that could be exposed in minutes rather than hours. This method forms apositive image on the metal plate by fusing it with iodide crystals and then exposing the plateto bright light for 1520 minutes. The metal plate is then developed using heated mercury.The mercury blends with the exposed silver to form a hard amalgam. The areas that are notexposed are washed away using hypo (sodium thiosulphate). Dagurreotypes, as these imagesbecame known, are renowned for their exquisite detail and fidelity. They were the first typesof photograph to be widely disseminated and commercialized. With all their success, how-ever, daguerreotypes have one major drawback: their inability to be reproduced. Thisuniqueness, as well as their mercury toxicity, sealed their fate.

CALOTYPESA few weeks after the daguerreotype was announced to the world, another photographicprocess was revealed. This new photographic process can be replicated from a single master.It is in this process that we first encounter the ideas of a positive and a negative image. AnEnglishman named Henry Fox Talbot invented the form, and he called it calotype, based onthe Greek kalos, for beautiful and typos-for impression. He went back to Wedgwoods silvercompounds coated and dried on paper. Then the paper was exposed to light until the imageemerged from it. The paper was then fixed in potassium iodide. Talbot later found a way tomake a latent imagethat is, an image captured without waiting for it to emerge. This papernegative then could be used to make numerous positive prints.

Talbots photosensitive paper had the emulsion blended in with the paper. The fibers of thepaper interlocked with the emulsion. This made the images fuzzy and grainy. Another type ofpaper has been used, a salt paper print, which is paper immersed in sodium chloride, dried,and then coated with silver nitrate and dried again before use. The use of salts in paper sensi-tization resulted in the invention of cyanotypes by Sir John Herschel. These are iron-based salts,basically ferric ammonium citrate/dichromate and potassium ferricyanide, coated and driedin the dark. The paper was then contact printed with a negative and exposed to the sun. Thepaper was then washed in water. The iron oxide formation gave it its name, blue-colored paperprocess. Photosensitive paper that does not require development is called a print-out process. Itis the oxidation and exposure to the sun that causes the image to come out.

Although calotypes and salted print papers were particularly attractive when directlycompared to a daguerreotype, they did tend to fade over time and required longer exposuresdue to less sensitivity. Calotypes image quality also varied depending on the paper used, sowhat was needed was a process that combined the strengths of both the daguerreotype andthe calotypethe collodion wet process.

THE COLLODION WET PROCESSCollodion (dissolved nitrocellulose) is a flammable white to yellowish transparent substanceused for holding surgical dressing and for sealing small wounds. Frederick Scott Archer

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found that collodion is better than albumen (egg whites, which have been used for centuriesas an emulsifier for pigments) for making glass-based photographic plates. However, thenewly coated glass plate needed to be exposed right away while it was still wet or its light sen-sitivity would be diminished. The collodion was evenly distributed on the glass surface, andany excess was drained off. Dipping it in silver nitrate sensitized the plate. It was then fixedwith pyrogallic acid or iron sulfate and dried. The drawback was that the exposed wet plateneeded to be done right away, which meant having access to a darkroom in the field.

The collodion wet-plate process yielded both a negative and a positive. When the driedcollodion plate was contact printed, it gave a positive image. However, when the negative wasbacked with a black or dark material, the negative became a positive image. Collodion plateswith backing were called ambrotypes, which were really underexposed collodion negatives.Metal-based collodions were called tintypes, which used cheap tin plates instead of enamelediron. The advent of the Civil War saw tintypes widespread use and popularity by war pho-tographers including Mathew Brady.

The collodion negative plates required a good paper to print on, and these led to the pop-ularization of the albumen process and eventual phasing out of the collodion as suspensionbased for photochemistry. Although effective, collodions were very flammable and danger-ous, albumen was sticky, coated evenly, and suspended solutions very well. The early albu-men negative plates were very slow to develop compared with collodion, but the albumenprocess was retained for making photosensitive paper. In this process, albumen and salts weremixed, coated, and dried onto paper. They were then dipped in silver nitrate, dried, andprinted. Printing onto paper meant that the paper was exposed to light, along with the neg-ative, to bring out the image.

The albumen process led to the development of alternative emulsifiers that wouldmake the negative and printing aspect of photography easier. Albumen prints were sosuccessful that they were not phased out until the development of modern gelatin-basedphotography.

There are other alternative printing processes, such as platinotypes or platinum printingmethods, developed by William Willis in 1876. The paper was coated with a layer of potas-sium chloroplatinate and potassium oxalate and exposed to the sun until a faint image de-veloped. It was then developed with potassium oxalate, which removed the iron salts andretained the platinum metal on the paper. The paper was then washed thoroughly in hy-drochloric acid to further remove the iron salts; finally, it was washed with water.

Another type of printing used no metal; rather, it used carbon. Called the carbon process,of course, it involved coating the paper with potassium bichromate, gelatin, carbon, and pig-ments. This paper was then contact printed with a negative. The areas that were exposed tolight hardened and the unexposed areas had a soluble gelatin. The exposed carbon paper wasthen transferred to another paper to show the image. Soaking it in warm water dissolved theunexposed gelatin; by peeling the original paper, the image was revealed. Since the imageshown was reversed, it could then be transferred to another substrate such as glass or ceram-ics. Carbon prints could be in color because pigments could be mixed in the solution.

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APPENDIX B A BIREF HISTORY OF PHOTOGRAPHY

THE DRY PLATE PROCESSThe necessity of having a portable darkroom and exposing the collodion wet plate beforedrying pressured photographers to find a dry photographic process. In 1871, Richard LeachMaddox published the thesis that gelatin could be substituted for collodion. Charles Ben-nett, in 1878, invented the dry-plate process, which made the portable darkroom necessity ob-solete and placed the burden of making quality plates on commercial manufacturers insteadof the photographer. The dry-plate process was also more sensitive to light, so it was able tocapture more spontaneous events.

Gelatin is hygroscopic, meaning that it is moisture/water loving. It is easily dissolved inwarm or hot water and readily solidifies when cooled, if dissolved enough. These propertiesof gelatin make it an ideal emulsifier of photochemistry. The flexibility of gelatin led to thepossibility of mass producing dry plates because machines could now coat the emulsionevenly. This machine coating made the quality better and the emulsion somewhat reliable.Gelatin pushed the photographic process to be more scientific and industriala radicalchange from the craftsmanship roots of early photography, with the quality of results varyingfrom one photographer to another.

THE GELATIN EMULSION/ROLL FILM BASEThe daguerreotype made photography widespread, the calotype made it reproducible, thecollodion wet plate made it fast and detailed and reproducible but fragile, and dry platesmade it reliable and portable. Photography was practiced by professionals and serious ama-teurs, not by lay persons due to the photochemical processing involved. What was neededwas a photographic process that combines all of these methods.

A young man in 1877, bored with his bank clerk job, wanted to document his vacation,but the only available process he had was the collodion wet-plate process. Bringing a pack-horse load of photographic equipment did not seem like a vacation, so he ventured to dis-cover an easier way to take photographs. This mans name was George Eastman. Heresearched and experimented until he was able to improve his dry-plate process enough tomake it the basis of a business. He also invented a machine that commercially coated emul-sion on paper. The existence of roll film made hand-held, portable photography possible. Al-though the paper roll film made photography easier, it needed a black, opaque paper backingthat needed to be peeled, which sometimes resulted in stretched negatives. Letting Eastmanscompany handle the processing eventually solved this problem.

Although Eastman made an impact with photographers and craftsmen, amateur pho-tography was still not possible, even with his paper-based roll film. Eastman introduced thefirst portable box camera, Kodak No.1, in 1888 with the slogan Press the button and we dothe rest. The Kodak No.1 camera still used paper-based roll film that had some of the soft-ness associated with Talbots calotype process. The widespread success of photography de-

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pended on making a film that had the collodion process detail but the speed, convenience,and longevity of the dry plate. The breakthrough needed was the development of celluloid, ahighly flammable cellulose nitrate with camphor and alcohol. It was the first synthetic plas-tic. In 1890, Darragh de Lancey developed a way to coat celluloid with a continuous emul-sion. Hannibal Goodwin invented the modern roll film that does not need a paper backingfor support, which made handling the film easier. In 1885, Eastman Dry Plate and FilmCompany introduced the Eastman American Film. It had a transparent substrate coatedwith emulsion. This is the form of film we recognize today.

This development led to the eventual introduction of the camera that made photogra-phy possible all over the world: the one-dollar Kodak Brownie of 1900, which featured six-exposure film selling for 15 cents. This camera ensured the success of Eastman Kodak as wellas photography itself. Before George Eastman, photography was a kind of craftsmanshipcrossed with alchemy. His ingenuity made cameras easier to use, portable, and accessible toeveryone. Celluloid-based photography also led to the development of the Kinestoscope byThomas Alva Edison in 1891, which in turn led to the birth of cinema.

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