Imparting color to products and creations has been the manifestation of aesthetic and intellectual acumen of commercial and artistic endeavors.
The term dyes entered into our vocabulary well before the term pigments.1 Lexical sources define dye as a soluble or insoluble coloring matter, and pigment as a substance that imparts black, white or a color to other materials. Pigments are specifically described as insoluble powdered substances that are mixed with a liquid in coating materials such as paint and ink. A fair amount of confusion existed in the early days by using the terms dyes and pigments interchangeably. According to the American Dry Color Manufacturers’ Association,2 “…[pigments are] any coloured, black, white or fluorescent particulate solid, which is insoluble in, and essentially unaffected by, the vehicle or substrate in which it is incorporated. It will alter the appearance of an object by the selective absorption and/or scattering of light. A pigment will retain a crystal or particulate structure throughout the colouring process.”
Ink makes use of pigments and dyes, even though the use of dyes is limited to some kinds of writing, security, and ink jet ink. Most printing inks use pigments for their color efficacy. Pigments can be natural (plant or animal origin) or synthetic, and belong to both organic and inorganic classes. Synthetic analogues of natural pigments are also known.