Fiber-reactive dyes form strong covalent bonds with cellulosic fibers, which result in good wash fastness. Reactive dyes are subject to hydrolysis, which is the chemical reaction of the dye with the water. Hydrolysis must be controlled for dye optimization. A wide range of reactive dye chemistries is available, resulting in a range of performance attributes. Dyeing Basics Dye Color Perception Basic Dyeing Principles Fiber Reactive Dyes Direct Dyes Vat Dyes Sulfur Dyes Pigments