PURPOSE: To prevent generation of precipitate and to decrease generation of gaseous acetic acid as well by using a liquid fixer which contains thiosulfate, is specified in the content of acetic acid ions and is specified in the content of a compd. selected from citric acid, tartaric acid, malic acid, succinic acid and the salt of the compds. thereof.

CONSTITUTION: This liquid fixer contains the thiosulfate and the content of acetic acid ions is <0.33mol./l. At least one kind selected from the citric acid, tartaric acid, malic acid, succinic acid and the salts of the compds. thereof are incorporated at ≥0.04mol./l into the fixer. For example, the fixer finished into 1l by 167g ammonium thiosulfate (in terms of 100%), 17g potassium sulfite, 90.7g sodium citrate dihydrate salt, 34.1g aq. ammonium sulfate soln. {Al(SO4)}, 20.5g sulfuric acid and water (25°C, liquid pH=4.21). The acetic acid ion concn. of this liquid fixer is 0mol./l and the citrate concn. is 0.308mol./l. The wetting threshold of the photosensitive material is satisfactorily attained according to this fixer.