| 摘要 |
At least one cpd. of formula and at least one cpd. of formula: (R1 and R3-R5 are opt. substd. alkyl, opt. substd. hydroxyalkyl, carboxyalkyl, or a deriv. thereof or sulphonylalkyl or a deriv. thereof R2 is lower alkyl; Z1 and Z2 are S or Se, Y1 and Y2 are H, halogen or lower alkyl; Y3 is H, lower alkyl or lower alkoxy; X is an anion and n and m are 1 or 2) are incorporated into the emulsion. At least one of the substituents at the N atoms of the heterocycles contains a sulphonylalkyl or carboxyalkyl gp. Cpds. are preferably added immediately after second ripening. Emulsions may be sensitised by gold-sulphur- or polyalkylene- oxide sensitising agent. |
