The evolution of the concepts of photographic sensitivity

摘要

The first useful gelatin silver bromide emulsions were made by Maddox in 1871. He stirred a solution of silver nitrate into a solution of cadmium bromide and gelatin and coated the mixture without washing. The use of potassium bromide and washing by dialysis were introduced by King in 1873. In the smae year, Johnston used an excess of bromide and washed the shredded gel. Bennett found in 1878 that the sensitivity was increased by ripening the emulsion for several days at 32 deg C . Monckhoven showed in 1879 that ripenting increased the grain size and that the process was accelerated by ammonia.