Photographic salted collodion, 2%

Description

The base of the wet collodion process: nitrocellulose in alcohol and ether with iodides and bromides dissolved in it. Not light-sensitive itself — it becomes so in the silver bath.

How it is used

Hold the plate level, pour a pool of collodion in the middle and tilt it out to the edges, draining the excess back. The layer sets in a few seconds and the plate goes straight into the silver bath. An even pour is the central skill of the process, and it costs a dozen ruined plates to learn.

Storage

Ether is volatile and flammable: keep the bottle tightly closed, cool and away from flame. Collodion ripens and darkens with age — that is normal and even desirable, as older collodion pours more evenly.

Questions and answers

Why «salted»?

For the dissolved salts — iodides and bromides. In the silver bath they become light-sensitive silver halides within the layer itself.