Mixtures of azo dyes for navy blue to black hue

Dye mixtures comprising a) one or more azo dyes of the formula I where Y is hydrogen, C1-C6-alkyl, C1-C4-alkoxy, substituted or unsubstituted C1-C8-alkanoylamino or C3-C4-alkenoylamino, and Y and Y are each hydrogen or substituted or unsubstituted C1-C6-alkyl, b) the azo dye of the formula II where L is allyl or else, optionally, hydrogen, and c) optionally an azo dye of the formula III and/or IV where R is nitro or substituted or unsubstituted C1-C4-alkylsulfonyl, R and R are each hydrogen, chlorine or bromine, R and R are each hydrogen or chlorine, R and R are each hydrogen, phenyl or substituted or unsubstituted C1-C4-alkyl, X is hydrogen, hydroxyl, methoxy, acetylamino or nitro, X , X , X and X are each hydrogen, methyl or methoxy, and X is hydroxyl, 2-hydroxyethoxy, formyl or methoxycarbonylamino, dye preparations comprising the novel dye mixtures, and the use of the novel dye mixtures for dyeing or printing polyester-containing substrates in textile form.