THE ROLE OF COLOR IN COSMETICS 551 alcohol. Crocin is the digentiobiose ester ofcrocetin (C=0H=404). Crocetin is a dicarboxylic acid with seven double bonds in the chain between the two terminal carboxyl groups. Saffron is used in cooking for its coloring and flavoring properties. Henna-Lawsone the yellow pigment lawsone is extracted from the tropical shrub henna (Lawsonia inernine) which is grown chiefly in Egypt. Lawsone has been identified as 2-hydroxy-l,4-naphthoquinone. Henna has long been used and still has a limited market for the coloring of hair in a red shade. The isomeric 8-hydroxy compound is juglone which occurs in unripe walnuts and is occasionally used for staining or darkening the skin. I•oRoAme CoLoRs Except fbr the white pigments--titanium dioxide, zinc oxide, blanc fixe and talc--the inorganic colors have an extremely limited use in cosmetics. They usually have excellent light fastness and complete insolubility in solvents and aqueous solutions. The most important pigments are the iron oxides, chrome oxide greens, ultramarine blues and pinks and the carbon blacks. Iron oxides offer the yellow hydrated iron oxide or ochre brown iron oxide, red iron oxide and black iron oxide. The yellow oxide is made by an alkaline precipitation from the ferrous salt followed by an oxidation. The product is approximately 85 per cent Fe=O3 and is supplied in shades from light lemon yellow to a deep orange. The brown iron oxides are made by treating a mixture of red, yellow, black iron salt with alkali and partially oxidizing the precipitate. The brown oxide is a mixture of Fe=Oa and FeaO4. The red oxides are usually made by calcining the precipitated yellow iron oxides. A light to dark red can be obtained depending on calcining conditions and the product is 96-98 per cent Fe=Oa. The black iron oxide results from the precipitation of FeaO4 under careful conditions and is probably FeO-Fe=Oa. Chromium oxide greens are quite different from the chrome greens. The chromium oxide green is pure Cr2Oa containing no lead chromate or iron blue. For cosmetic use it must have less than 20 p.p.m. of lead or 2 p.p.m. of arsenic. The anhydrous pigment has a dull green shade and the hydrate shows a bluish tint. This type of pigment has found its way into eye shadows and eye make-up. Carbon blacks may be obtained from vegetable or natural gas origin. The vegetable or bone blacks vary from 50 to 90 per cent fixed carbon. The gas blacks are produced by impinging the natural gas flame on a coal surface and collecting the carbon deposits. These blacks find wide cos- roetic application, particularly in eye shadow and eye make-up. The ultramarine blues and pinks are made from sulfur, soda ash, china

552 JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS clay and charcoal pitch or rosin. The mix is heated in a muffle furnace for a day at 850øC. The finely pulverized pigment gives shades of ultramarine blue from the pink to the green side depending on its silica content. The ultramarine finds its way into mascara, soaps and also into eyebrow crayons. CONCLUSIONS In formulating colors in cosmetics the Food, Drug and Cosmet{c Act of 1938 plays a major role. The certificat{on of nearly one hundred and twenty coal tar dyes is controlled by this Act and their exclusive use in all cosmetics other than hair dyes is clearly outlined. The natural colors and pigments have found only a very limited area of usefulness. It is hoped that future years will see many new colors certified for drug and cosmetic use making possible brighter, more attractive and glamorous products. REFERENCES (1) American Association of Textile Chemists and Colorists, Year Book 1954, New York, Howes Publishing Company. (2) A. O. A. C., Methods of Analysis, 6th edition, Washington, D.C. (1945). (3) Bainbridge, W. C., Ind. Eng. Chem., 18, 1329 (1926). (4) Calvery, H. O., ,qm. )e. Pharm., 114, 324 (1942). (5) "Coal-Tar Color Regulations," U.S. Dept. Agr., Food Drug Admin. Service and Regula- tory Announcements, Food, Drug and Cosmetic No. 3 (Sept. 1940) Suppls., Nos. 1, 2 (1939). (6) Colour Index, 1924 Suppl., 1928. (7) Coutinho, H., Proc. Sci. Sect., Toilet Goods ?lssoc., No. 2, I (1944). (8) deNavarre, M. G., "The Chemistry and Manufacture of Cosmetics," New York, D. Van Nostrand Co., Inc. (1941). (9) Edman, W. W., Proc. Sci. Sect., Toilet Goods ?lssoc., No. 8, 29 (1947). (10) Evenson, O. L., •. ?lssoc. O•c. ?lgr. Chemists, 22, 773 (1939). (11) Evenson, O. L., and Forrest, S.S., ?lm. Dyestuff' Reptr., 26, 117 (1937). (12) Fiene, F., and Blumenthan, S., "Handbook of Food Manufacture," New York, Chemical Publishing Company (1938). (13) Freeman, K. A., Proc. Sci. Sect., Toilet Goods ?lssoc., No. 11, 20 (1949). (14) Goodman, H., "Cosmetic Dermatology," New York, McGraw-Hill Book Company, Inc. (1936). (15) Harry, R. G., "Modern Cosmetology," London, Leonard Hill, Ltd. (1955). (! 6) Jablonski, C. F., "Coloring Matters in Foods," in Jacobs, "Chemistry and Technology of Food and Food Products," Vol. 1, New York, Interscience Publishing Company (1944), pp. 300-26. (17) Judd, D. B., and Kelly, L. K., )•. ?lm. Pharm. ?lssoc., 27, 208 (1938). (18) Koch, L., •. ?lssoc. O•c. ?lgr. Chemists, 26, 245 (1943). (19) Liebet, H., "Use of Coal-Tar Colors in Foods," New York, Liebet (1904). (20) Mattiello, J. J., "Protective and Decorative Coatings," Vol. II, New York, John Wiley and Sons, Inc. (1942). (21) Mayer, F., "The Chemistry of Natural Coloring Matters" (A.C.S. Monograph No. 89), trans. and rev. Cook, A. H., New York, Reinhold Publishing Corp. (1943). (22) Morrish, E. P., Proc. Sci. Sect., Toilet Goods ,qssoc., No. 2, 17 (1944). (23) Merck Index, 5tb edition (1940). (24) Peacock, W. H., "The Application Properties of the Certified 'Coal-Tar' Colors" (Calco Tech. Bull. No. 715), American Cyanamid Company (1945). (25) Public, No. 717, 75th Congress, 3rd session, S.5 (1938) Sec. 402. (26) Thomasset, P. H., Proc. Sci. Sect., Toilet Goods ?lssoc., No. 3 (1945). (27) U.S. Dept. Agr., Bur. Chemistry Bull., No. 147 (February 1912). (28) Woodman, A. G., "Food Analysis," New York, McGraw-Hill Book Co., Inc. (1942). (29) Zuckerman, S., "Colors for Food, Drugs and Cosmetics," "Encyclopedia of Chemical Technology," New York, Interscience Encyclopedia, Inc., pp. 287-313. (30) Zuckerman, S., and Koch, L., •. ?lssoc. OJ•c./lgr. Chemists, 29, 307 (1946).