In this paper, we describe a study on the relationship between photographic emulsion manufacture and hardening test of films. The hardeners were prepared by condensation of equimolar amounts of trichlorotriazine with benzene- or naphthalene-based amino or oxy acids at 0 to 5$^{circ}C$ and at pH 7, and used as hardening agents for gelatin. The hardening test of photographic emulsion was studied at pH 5.5. For example I(R=ONa) had strong hardening properties, I substituted with an aminobenzosulfonate moiety (R=$NHC_6H_4-p-SO_3Me$ where Me = K, Na) was a much weaker gelatin hardener, and when substituted with amino- or oxynaphthalene derivative (II, III) did not harden gelatin at all. Compound with 2 dichlorotriazine groups as IV exhibited strong hardening properties. The hardener can be used in photographic emulsion of film and showed very good hardening effect.