490 JOURNAL OF COSMETIC SCIENCE CHEMISTRY OF COLORANTS: THEIR PROPERTIES AND USES IN COSMETIC APPLICATIONS Sanjoy Ganguly, Ph.D. Sun Chemical Corporation The introduction to this presentation will focus on the various types of color additives like dyes and pigments, and the different classes like organic, inorganic, absorption and interference types of pigments. This will be followed by the definitions of the subclasses and commonly used terms such as: 1 diluents substrates and 3 precipitants The common allowable substrates and precipitants that are used with the pure colors in cosmetic lakes will be discussed along with the certifiable and exempt colors. This overview of colorants will be followed by the chemistry, stability and other properties of the cosmetic absorption pigments. This section will comprise of the individual families of organic and inorganic pigments which contribute towards the gamut of colors as seen in the color charts for use in cosmetic formulations. The organic

2004 ANNUAL SCIENTIFIC SEMINAR 491 pigments will be our main focus while the more durable inorganic pigments will be briefly touched upon. The need to identify pigments as chemical species in a cosmetic formulation becomes evident as emphasis will be given to the structural aspects of these pigments. The relationship between the pigment structures, their stabilities and other properties will be highlighted. The other pigment properties that affect the cosmetic formulations will also be discussed along with their restrictions in use. The latter part of this discussion will point out certain common color improving techniques available today. Today's cosmetic formulators can take advantage of these varied and improved color systems to enhance productivity and process efficiency. The various color enhancing techniques in general improves tinctorial strength, consistency, dispersibility, gloss, and the likes. This presentation is an attempt to capture some of the salient features of cosmetic colorants which would aid beginner formulating chemists to use such colorants or color systems in an efficient way in cosmetic and toiletry formulations.