Aqueous solid particle dispersions in chemical sensitization

The invention is generally accomplished by providing a method of chemical sensitization comprising providing a silver halide emulsion, and adding to the silver halide emulsion aqueous solid particle dispersion of a chemical sensitizing agent having a water and organic solvent insolubility (i.e., 50 mg/100 ml or less), and heating said emulsion wherein said chemical sensitizing agent comprises at least one member selected from the group consisting of (A) gold compounds represented by Formula I: {AuS 2 X} n I wherein X is PR 2 (dithiophosphinates), P(OR) 2 (dithiophosphates), COR (xanthates), CNR 2 (dithiocarbamates), CR (dithiocarboxylates) R is alkyl or aryl n = 1-6, (B) tellurium compounds represented by Formula II: TeL n X 2 wherein L is thiourea or substituted thiourea, n is 2 or 4, X is Cl, Br, I, OCN, SCN, SeCN, TeCN, or N 3 and wherein X is COR, CSR, CNR 2 , CR, CAr, PR 2 , P(OR) 2 , (PR 2 ) 2 N R is alkyl or aryl, and (C) palladium compounds represented by Formula III: PdX 2 (TeR 2 ) 2 wherein X is Cl, Br, I, NCO, NCS, NCSe, NCTe, or N 3 R is alkyl or aryl.