Ammonium Thiosulfate 60% Solution Photography Grade

Ammonium thiosulfate 60% solution, (NH₄)₂S₂O₃, is a clear to pale yellow photography-grade liquid supplied by the quart. It is the active ingredient in rapid fixers, clearing undeveloped silver halides considerably faster than sodium thiosulfate does.

Darkroom workers use it for film and paper fixing, wet plate collodion, and archival printing, where its neutral to mildly alkaline pH is gentler on emulsions and pyro-stained negatives than acid fixers. It is fully water miscible, low in odor, and stable in the concentrate when kept sealed.