Colorants: General survey

AbstractThis survey shows how colorants are not only ubiquitous in modern life, but also pervade many fields of science and technology. It reveals their diversity with respect to properties, origin of color, applications, composition and usage. After opening with a technical definition of “colorant”, this survey exemplifies the huge assortment of uses to which colorants are put. It highlights the breadth of characteristics, other than color, that are of importance to the roles of “functional colorants”. Following a description of the technical distinction between the terms “dye” and “pigment”, the survey discusses the differences between these two colorant types from the perspective of how their color arises and the ways in which they are exploited, then goes on to demonstrate that particular colorants may be applied in certain instances as a dye and in others as a pigment. It outlines the wide ranges of composition, properties and economics of commercial colorants. This survey closes with a look at the nomenclature of colorants and the means by which they are classified into practically useful categories. It is intended to prepare the reader for the enormous technical and commercial variety that one encounters when dealing generally with colorants.