Complex sentence: In chromogenic films, the remaining metallic silver must be removed by solution in a chemical called a bleach fix or "blix", which contains a mixture of ammonium thiosulfate and ferrous EDTA, a powerful chelating agent.
Split into simpler sentences: In chromogenic films, the remaining silver must be removed by a chemical called a bleach fix, sometimes shortened to "blix". This contains a mixture of ammonium thiosulfate and ferrous EDTA, a powerful chelating agent.