A one-part colour developer concentrate which contains at least one colour developer substance, at least one antioxidant, at least one water softener, a buffer system, alkali, which concentrate contains at most 0.1 mol of sulfate ions/L, is usable for a wide range of regeneration rates and exhibits no precipitation at down to -7°C if it is prepared as a multi-phase concentrate using organic, water-soluble solvents.