In early photography, plates were sheets of glass coated with a light-sensitive emulsion used to capture images. These glass plates served as the negative, replacing paper and providing a stable, flat surface for sharp, high-resolution photographs.
Plates were commonly used in studio and field photography during the 19th and early 20th centuries. They required careful handling and precise exposure but offered exceptional detail and tonal range. As flexible film became more practical, glass plates were gradually phased out, though they remain important in the history of photography and are still used in some traditional or experimental photographic techniques today.