Deterioration and Preservation of Negatives, Autochromes, and Lantern Slides
Negatives
General Information Genthe photographed his subjects in both black-and-white and color, using a variety of formats. Photographic negatives are made of an image-forming substance or emulsion, which is coated onto a base or support. The bases found in the Genthe collection are either glass, nitrate film (nitrocellulose), or safety film (cellulose acetate). Each type of negative base has a different aging process with a...
Autochromes
Autochrome photography flourished from 1907 to the 1930's. Each autochrome is a unique transparency image; there is no negative. Autochrome plates were created by coating a sheet of glass with microscopic starch grains dyed red, green, and blue. These formed a screen of color particles. Carbon black was applied over the plate, filling in the spaces around the starch grains. Then a silver gelatin...
Lantern Slides
This image of Margaret Severn is from a fractured glass lantern slide. Lantern slides are positive glass transparencies made for projection. Genthe used these "magic lantern slides" for lectures.
Negatives General Information Genthe photographed his subjects in both black-and-white and color, using a variety of formats. Photographic negatives are made of an image-forming substance or emulsion, which is coated onto a base or support. The bases found in the Genthe collection are either glass, nitrate film (nitrocellulose), or safety film (cellulose acetate). Each type of negative base has a different aging process with a...
Autochromes Autochrome photography flourished from 1907 to the 1930's. Each autochrome is a unique transparency image; there is no negative. Autochrome plates were created by coating a sheet of glass with microscopic starch grains dyed red, green, and blue. These formed a screen of color particles. Carbon black was applied over the plate, filling in the spaces around the starch grains. Then a silver gelatin...
Lantern Slides This image of Margaret Severn is from a fractured glass lantern slide. Lantern slides are positive glass transparencies made for projection. Genthe used these "magic lantern slides" for lectures.