The invention relates to a photographic emulsion comprising silver iodochloride grains, said grains further comprising iridium, said grains chemically sensitized with gold in an amount of between 120 and 200 mg gold per silver mole and sulfur in an amount between 0.1 and 20 mg sulfur per silver mole, 1-(3-acetamidophenyl)-5-mercaptotetrazole, 1-phenyl-5-mercaptotetrazole, and a disulfide compound represented by the following formula: ##STR1## wherein X is independently --O--, --NH-- or --NR--, where R is a substituent;m and r are independently 0, 1 or 2;X is --H or a cationic species;Ar is an aromatic group; andL is a linking group, where p is 0 or 1.