Chemicals : 2, 4-dinitrochlorobenzene, 2, 4-dinitroaniline, 6-bromo-2, 4-dinitroaniline, 2-amino-4-nitrophenol, 6-chloro-2, 4-dinitroaniline, Sodium 2-amino-4-nitrophe-nolate, sulfur Black, Water sulfur Black, sulphur Balck, 2, 4-dinitrochlorobenzene.