Potassium Bromide: Iron Bromide and Potash

Potassium bromide is the bromide of photography. Thorpe (1913): iron bromide solution run into hot potash solution until it is just neutral throws down the iron as oxide and leaves potassium bromide in solution, which is filtered, evaporated and crystallised. 100 parts of iron bromide take 56 to 60 parts of potash. The picture: potassium bromide crystals (Wikimedia Commons).