The salts such as Silver Chloride (AgCl) and Silver Bromide (AgBr) are used in black and white photography. Both of the salts undergo photo decomposition i.e they decompose in the presence of sunlight. AgCl when kept in sunlight decomposes into Ag and Cl and AgBr decomposes into Ag and Br. AgCl gives white colour and AgBr gives black colour.