FROM ALBUMEN TO DRY PLATE


The primary problem in applying silver chloride solutions to glass is that it will not adhere. It simply isn't sticky enough. Niepce de St. Victor, the cousin of Nicephore Niepce, considered this problem. What was needed, he reasoned, was some sort of organic binder. His solution came from the core of French cuisine. It was the egg.

In 1848 Niepce mixed several egg whites with a few drops of potassium iodide, potassium bromide, and a little salt. He spread this solution on a glass plate, let it dry, and dipped it in silver nitrate. The plate, still wet, was exposed in a camera and then hastily developed. Known as albumen photography, it was widely adapted. The process was also used to make the first commercially manufactured printing papers. They remained popular long after albumen negatives were replaced.

In 1851 British sculptor Frederick Scott Archer brought wet-plate photography to the forefront. Archer replaced albumen with collodion, a much more sensitive, albeit temperamental, emulsion. Dissolving gun cotton in a solution of ether and alcohol, he added silver iodide and iron iodide. In another refinement of the albumen process, the dried plate was immersed in silver nitrate and distilled water.

Exposed while still wet, collodion negatives were the fastest yet, taking only two or three seconds. They were very fragile and rapidly evaporated if not immediately developed. This meant that photographers needed to travel with cumbersome portable darkrooms. Depending on the nature of the project, this sometimes meant carting hundreds of pounds of equipment to remote or hostile environments. Still, the collodion process was eagerly embraced. Never before had such fast exposures been possible.

The collodion process spread to nearly every corner of the globe during the next 30 years. Using it, photographers captured subjects never before recorded, from the harsh alpine regions of the Swiss Alps to the battlefields of the American Civil War.



Color photography presented another enigmatic challenge. Like black-and-white photography, color emerged from a web of older ideas and discoveries.

In 1861, James Clerk Maxwell, a Scottish inventor, showed that all color hues derive from three primary colors. Working with photographer T. Sutton, he projected three monochromatic slides of the Scottish flag from three different projectors. The combined images produced an exact color representation of the flag. Although it was a promising demonstration, practical color photography was still decades away.

Until the advent of Kodachrome, Agfacolor, and other commercial films in the 1930s, making a color print was an arduous process. Three negatives were required of the same subject. These negatives were converted into three layers of colored gelatin, and then carefully combined. The process was painstaking, time consuming, and demanded an arsenal of chemistry. For many years even the most dedicated photographers avoided color printing.

As universal as wet-plate photography had become, it was a far from perfect medium. Slow and delicate emulsions and cumbersome darkroom equipment impeded the art's practical expansion. Dr. Richard Leach, an English physician, was particularly frustrated by the limitations wet-plate photography imposed on his medical research. In 1871 he developed the gelatin-bromide dry plate.

Although the plates were a milestone, they were not immediately adopted. Slower than wet-plate emulsions, dry plates seemed to have little application. Still, Leach published his findings and amateurs began to experiment. By 1878, faster dry plates were being commercially produced. Easy to store, the plates could be developed long after exposure. Photographers shed hundreds of pounds of darkroom equipment overnight. Exposure time dropped to fractions of seconds, allowing handheld cameras to be used for the first time. Within two years dry plates were universally adopted.