Chemical sensitization of photographic emulsions prepared with the use of ammonia

It was found that the dependence of the light sensitivity of photographic emulsions whose solid phase was synthesized with the use of ammonia on the duration of sulfur or sulfur + gold sensitization could exhibit two maximums. The maximum observed at shorter hold times is due to light sensitivity centers that are silver in nature, which are formed by the thermal decomposition of Ag2O, and the other maximum is determined by silver sulfide or mixed silver gold sulfide centers. The effect of tetravalent iridium ions introduced during the production of AgBr grains on the chemical sensitization of photographic emulsions was revealed.