A colorant/color additive is a substance that is added or applied in order to change the color of a material or surface. Colorants can be used for many purposes including printing, painting, and for coloring many types of materials such as foods and plastics. Colorants work by absorbing varying amounts of light at different wavelengths of its spectrum, transmitting or reflecting the remaining light in straight lines or scattered.

Both dyes and pigments are used in the coloration of textiles. The former substances are present in solution at some point during their application, whereas the latter colorants remain insoluble within any vehicle in which they are applied as well as within the textile material itself. Pigments must therefore either be incorporated into textile fibers during their construction.