Mt. Shasta, California, cyanotype, mammoth plate negative

Mammoth plate photographs are photographic prints made through contact printing a photographic print from a large glass plate negative, usually 18 by 21 inches, but may vary in size from 15 by 18 inches to 22 by 25 inches, which were used in the late 19th and early 20th centuries to create very large photographic prints. The plates were typically made of glass and coated with a light-sensitive emulsion and were commonly used for landscape and architectural photography, as well as for portraiture. Mammoth plates were particularly popular in the United States in the 1880s