Roger wrote about our very successful Photowalk in Harpers Ferry last weekend. Since there was a huge Civil War reenactment ongoing, lots of our group have been processing our photos to look older. I started thinking that we all know what images from then look like, but wanted to know why?
Photography was still a relatively new art and science at the beginning of the war. People had to sit really still for a very long time under very bright light for any kind of image to take hold. The first “easily” replicated process was done by Daguerre in France. A glass plate was coated with chemicals and exposed to light. Mercury vapor then fixed the image. It created a bright image, but only one. There was no way to reproduce them. Starting in the 1850’s they created the Ambrotype.
It was easier to produce, but also used dangerous chemicals. It too only could produce one image. Finally a relatively inexpensive process which printed the image directly on to a metal plate-a tintype was introduced and soon everyone had pictures in their pockets. These tended to be fairly dark, but were relatively stable
Now the great Civil-War photographers like Gardner and Brady used a different wet-plate process, which did produce negatives and could make prints. Gradually during the war, this process largely replaced the others for fine photography. Unfortunately the prints made from these negatives had problems all their own. The silver nitrates tended to crack and turn all black when exposed to sun. Photographers discovered that they could use different chemicals which would replace the silver salts, and which would add new tones to the image, but preserve the relationships between the lights and the darks in a picture.
Cuttlefish ink, or sepia added to the image imparts a nice warm brown tone, while selenium adds a cooler bluish tint. Because these colors are stable they became the standards for what we think of in old photos.
It's fun to play with these and see the history come to life.