History
What made an Autochrome a color photograph on glass?
Autochrome plates used colored starch grains as a filter mosaic over a photographic emulsion, producing a unique transparency.
The Library of Congress says Autochrome photography flourished from 1907 into the 1930s. Microscopic starch grains dyed red, green and blue formed a screen over silver-gelatin emulsion on glass; the developed plate was a positive transparency.
Autochrome’s mosaic on glass
This physical mosaic gives an Autochrome a different structure from a modern color print or digital file. The plate is unique, and both its glass base and image materials can deteriorate.
Evidence: Collection research
Autochrome color and the capture chain
A booth’s color output is created through a different capture and printing chain. Comparing the two helps separate the appearance of color from the materials that make it.
Evidence: Collection research · Encyclopedia; discovery and cross-check only
Digitized image versus the transparency
A digitized Autochrome can communicate the picture but is not the transparency itself; keep the original object’s record and condition information attached. The image is viewed by transmitted light, so a backlit transparency and a paper reproduction can look strikingly different. The plate’s glass support also makes it vulnerable to breakage. When encountering an Autochrome online, distinguish the digitized color from the physical transparency and rely on collection records for process identification.
Sources & further reading
Sources for the specific facts and product descriptions above. Our worked examples, interpretations and practical suggestions are original editorial guidance.
- Library of Congress — AutochromesCollection research
- Wikipedia — Autochrome LumièreEncyclopedia; discovery and cross-check only