Leather dyes are chemical products with an affinity for leather, used to color leather goods; they primarily include acid, basic, direct, mordant, reactive, and metal-complex dyes. Categorized by application, they fall into the D series (for immersion dyeing) and the SP series (for spray coloring); among these, metal-complex dyes are classified as premium dyes for leather due to their vibrant colors and excellent fastness properties. These dyes are characterized by slight solubility in water and high solubility in organic solvents such as ethylene glycol, diethyl ether, and ethanol, making them suitable for the spray coloring of pigskin, cowhide, and sheepskin.