An aqueous, pigment-containing coating composition comprising a) at least one polymer P1 in the form of an aqueous polymer dispersion and b) at least one water-soluble polymer P2 which is composed of ethylenically unsaturated monomers M and which comprises in copolymerized form at least 30 wt%, based on the total amount of the monomers M, of N-vinylpyrrolidone, the water-soluble polymer P2 being selected from copolymers which comprise in copolymerized form A) 30 to 90 wt% of N-vinylpyrrolidone as monomer A, B) 10 to 70 wt% of at least one neutral, monoethylenically unsaturated monomer as monomer B, and optionally C) 0 to 20 wt% of a cationic monomer as monomer C, the figures in wt% being based on the total mass of the monomers M, and the monomers A and B making up at least 80 wt%, based on the total mass of the monomers M, the monomers B being selected from b1) vinyl esters of saturated C 2 -C 12 monocarboxylic acids, b2) primary amides of monoethylenically unsaturated C 3 -C 6 monocarboxylic acids, b3) N-vinyl lactams having 7 to 10 C atoms, b4) vinyl-substituted nitrogen heteroaromatics, b5) N-C 1 -C 4 alkyl amides and N,N-di-C 1 -C 4 alkyl amides of monoethylenically unsaturated C 3 -C 6 monocarboxylic acids, b6) N-vinyl amides of saturated C 1 -C 6 monocarboxylic acids, and mixtures thereof, the water-soluble polymer P2 being coating comprised in an amount of 0.5 to 10 wt%, based on the polymer P1. a) at least one polymer P1 in the form of an aqueous polymer dispersion and b) at least one water-soluble polymer P2 which is composed of ethylenically unsaturated monomers M and which comprises in copolymerized form at least 30 wt%, based on the total amount of the monomers M, of N-vinylpyrrolidone, the water-soluble polymer P2 being selected from copolymers which comprise in copolymerized form A) 30 to 90 wt% of N-vinylpyrrolidone as monomer A, B) 10 to 70 wt% of at least one neutral, monoethylenically unsaturated monomer as monomer B, and optionally C) 0 to 20 wt% of a cationic monomer as monomer C, the figures in wt% being based on the total mass of the monomers M, and the monomers A and B making up at least 80 wt%, based on the total mass of the monomers M, the monomers B being selected from b1) vinyl esters of saturated C 2 -C 12 monocarboxylic acids, b2) primary amides of monoethylenically unsaturated C 3 -C 6 monocarboxylic acids, b3) N-vinyl lactams having 7 to 10 C atoms, b4) vinyl-substituted nitrogen heteroaromatics, b5) N-C 1 -C 4 alkyl amides and N,N-di-C 1 -C 4 alkyl amides of monoethylenically unsaturated C 3 -C 6 monocarboxylic acids, b6) N-vinyl amides of saturated C 1 -C 6 monocarboxylic acids, and mixtures thereof, the water-soluble polymer P2 being coating comprised in an amount of 0.5 to 10 wt%, based on the polymer P1. A) 30 to 90 wt% of N-vinylpyrrolidone as monomer A, B) 10 to 70 wt% of at least one neutral, monoethylenically unsaturated monomer as monomer B, and optionally C) 0 to 20 wt% of a cationic monomer as monomer C, b1) vinyl esters of saturated C 2 -C 12 monocarboxylic acids, b2) primary amides of monoethylenically unsaturated C 3 -C 6 monocarboxylic acids, b3) N-vinyl lactams having 7 to 10 C atoms, b4) vinyl-substituted nitrogen heteroaromatics, b5) N-C 1 -C 4 alkyl amides and N,N-di-C 1 -C 4 alkyl amides of monoethylenically unsaturated C 3 -C 6 monocarboxylic acids, b6) N-vinyl amides of saturated C 1 -C 6 monocarboxylic acids,