Abstract: In the present paper, a series of experiments of hypersensitization by hydrogen soaking was made for various types of emulsions ripened with different single and combined chemical sensitizers, such as gold(Au), sulphur (S), reduction (R), Au+S, S+ R, Au+R, Au+S+R, and primitive.Comparison has been made of the sensitometric properties, such as surface sensitivity, internal sensitivity, total internal sensitivity, r.m.s. granularity, modulation transfer function (MTF), before and after hypersensitization by hydrogen soaking for all above-mentioned emulsions. It can be seen from our results that the sensitivity of the combined, especially that of Au+R and Au+S+R sensitized emulsions, can be increased 2-3-fold, and the level of low intensity reciprocity failue greatly reduced after hydrogen soaking treatment. Internal sensitivity can be increased too, but in less extent. However the r.m.s. granularity was only changed slightly (10%) and the modulation transfer function remained basically unchanged after hydrogen treatment. All these results further reveal the advantages of hydrogen hypersensitization.