PURPOSE: To obtain a concentrate which can be used as a level replenisher, regenerating agent, or an initial bleaching bath or a replenisher by preparing a liquid having each specified concn. of ammonium iron (III) complex salt, ammonium bromide and ammonium nitrate and controlling the liquid to pH<3.

CONSTITUTION: A water-based concentrated liquid for a bleaching bath having pH<3 is prepared in such a manner that liquid may contain at least 0.4mol/l of ammonium iron (II) complex salt, 1.5 to 3mol/l ammonium bromide and 0.25 to 1mol/l ammonium nitrate, and up to 1mol/l of acetic acid, if necessary. Thereby, a single concentrate for a partial bleaching bath can be obtd., and it can be used for preparation of a bleaching soln., a replenisher for a bleaching bath, a level replenisher and a regenerating agent.