Abstract: In the Thermosol and like processes in which a dye-impregnated textile material is dried prior to fixation, uncontrolled migration of the dye to the surface of the material during the drying operation is obviated by the incorporation of an antimigration additive in the aqueous dye bath liquid, said additive being an amine salt of poly(vinyl methyl ether/maleic acid). The parent poly(vinyl methyl ether/maleic anhydride) from which the said poly(vinyl methyl ether/maleic acid) is prepared by hydrolysis has a specific viscosity of about 0.75 to about 4.5, preferably about 1.0 to 3.5, more preferably from about 2.0 to about 3.5, measured at a concentration of 1 gram of said parent polymer per 100 ml. of methylethyl ketone at 25.degree.C. The additive, employed within the general range of from about 0.05% to about 0.50% by weight based on the total weight of the dye bath, serves to enhance the uniformity of the dyeing operation and the color properties of the dyed textile material.