Aqueous dye solutions

A concentrated aqueous dye solution consisting essentially of

• a) at least 5% by weight, based on the weight of the solution, of a red dye of the formula
• in free acid form, in which
• R and R1 independently of one another are each hydrogen, chloro, methyl or methoxy,
• R2 and R3 independently of one another are each hydrogen, methyl or methoxy,
• R4 and R5 independently of one another are each hydrogen or C1-C4alkyl,
• A is an unbranched or branched C2-C6alkylene radical, which can be interrupted by O, and
• R6 and R7 independently of one another are each hydrogen or C1-C6alkyl, or in which
• R6 and R7, together with the N atom bonded to them, form a substituted or unsubstituted 5-, 6- or 7-membered ring, which can contain further O or N heteroatoms,
• b) formic acid or a C1-C4alkylcarboxylic acid,
• c) 3 to 20% by weight of urea, based on the weight of the solution, and
• d) water,
• with the proviso that the solution does not contain either a quaternary ammonium halide or a glycol- or diglycol ether.