There are two
basic types of glass plate negatives -
Collodion Wet Plate and Gelatine Dry Plate.
- Collodion Wet Plate Negatives were in use
from 1851 until the 1880s. They were invented by Frederick Scoff
Archer, an English sculptor, who using a viscous solution of collodion,
coated glass with light-sensitive silver salts. Because it was glass and
not paper, wet glass plates created a sharper, more stable and detailed
negative. Furthermore, a photographer could
produce several prints from one negative. A
Collodion wet plate negative can usually be identified by an unevenly
coated emulsion, thick glass, rough edges, and sometimes a photographer's
thumb print on the edge.
- Silver Gelatine Dry Plate Negatives were
invented by Dr. Richard L. Maddox and
first became available in 1873. They were the first economically
successful durable photographic medium. Unlike the wet plate variety gelatine dry plates were
more easily transported, usable when
dry, and needed less exposure to light than the wet plates. Other
distinguishing features between the wet and dry variety were the thinner glass and a
more evenly coated
emulsion in the dry plate negative form. Dry plate glass negatives
were in common use between the 1880s and the late 1920s.
Two examples of vintage glass plate negatives from our collection.
Film Dictionary History