Editing Ambrotype (section)

== Process ==

One side of a clean glass plate was coated with a thin layer of [[Iodine|iodized]] [[collodion]], then dipped in a [[silver nitrate]] solution. The plate was [[exposure (photography)|exposed]] in the camera while still wet. Exposure times varied from five to sixty seconds or more depending on the brightness of the lighting and the [[lens speed|speed]] of the camera lens. The plate was then [[photographic processing|developed and fixed]]. The resulting [[negative (photography)|negative]], when viewed by reflected light against a black background, appears to be a positive image: the clear areas look black, and the exposed, opaque areas appear relatively light. This effect was integrated by backing the plate with black velvet; by taking the picture on a plate made of dark reddish-colored glass (the result was called a '''ruby ambrotype'''); or by coating one side of the plate with black [[varnish]]. Either the emulsion side or the bare side could be coated: if the bare side was blackened, the thickness of the glass added a sense of depth to the image. In either case, another plate of glass was put over the fragile emulsion side to protect it, and the whole was mounted in a metal frame and kept in a protective case. In some instances the protective glass was cemented directly to the emulsion, generally with a [[Canada balsam|balsam resin]]. This protected the image well but tended to darken it. Ambrotypes were sometimes hand-tinted; untinted ambrotypes are [[black-and-white|monochrome]], gray or tan in their lightest areas.