Abstract: Liquid to pasty dyestuff preparations are described consisting of at least 35 % of an optionally hydrous solvent from the class of alcohols, esters, ethers or ketones having a boiling point of above 90.degree.C, at least 10 % and at most 40 % of a dyestuff or optical brightener and at least 5 % and at most 25 % of a partially or fully synthetic thermostable synthetic resin present in the dissolved form. These preparations are useful for the coating of compounds of thermoplastic high polymers in the form of granulates or in the form of flakes or powders, particularly those made from polyester, polyamide and polypropylene.