Glass Plate Negatives: A Brief History

This glass plate negative, along with 200+ others, was discovered in Everett Block’s attic in 1946.

Glass plate negative on light box fabricated by Block to more easily view the negatives. The light box has 12 individually wired light bulbs, so that Block could precisely control the backlight.

Glass plate negatives are heavy, therefore, they are often found stored in wooden cases. The Block negatives arrived in hand-crafted wooden crates. They are the boxes labeled 1 and 2. Pictured with the collection is the former Champaign County Historical Archives Director, Anke Voss.

Glass plates were in use from the 1850s through the 1920s and were popular with both amateur and professional photographers. There are two formats of glass plate negatives: collodion wet plate negatives (1855-late 1880s) and gelatin dry plate negatives (late 1880s-1920s). Both types have a light-sensitive emulsion with a binder thinly layered on one side of a glass plate.

Collodion wet plate negatives, first produced in 1851 by British inventor and photographer, Frederick Scott Archer, need to remain wet and have to be processed very quickly after exposure. Therefore, this process of making photographs is complicated, inconvenient, and not very portable. In 1871, British physician and photographer, Richard Leach Maddox, produced the first practical dry plate negative. This improvement was so well-received that it completely replaced the wet negative process and within ten years the plates were mass-produced and widely available to amateur photographers. Gelatin dry plate negatives were widely used into the 1920s when they were replaced by gelatin silver paper negatives and celluloid roll film. However, using glass negatives and wet plate processes to take photographs has experienced a resurgence in popularity among today's photographers (see "Today's Photography"). 

Being able to determine if your glass plates are wet collodion negatives or dry plate negatives is useful for dating the images. To identify wet plate negatives, place the negative against a dark background and the image will appear as a positive. Wet plate negatives were entirely handmade -- unlike the mass-produced dry gelatin plates that followed -- so look for manufacturing irregularities such as rough cut edges, uneven glass, thickness of the glass (as machine-made glass is usually thinner), and an uncoated corner (where the plate was held during the coating process). The plates in the Everett C. Block Collection are dry plate negatives taken in the early 20th century between 1900 and 1905.