DIN 55977 is a standard for the determination of dyestuffs that do not dissolve easily in solvents. The standard specifies a method for the detection of trace elements of insoluble or insoluble substances in solvents, water and water-solvent mixtures. It is suitable for dyestuff testing in materials such as Printing ink, paints, Spinning & weaving fibers. Through precise experimental procedures, including dissolving, filtrating and drying, the standard can help evaluate the dissolving performance of dyestuffs in specific solvents, providing an important reference for the production, application and quality control of dyestuffs.