666 JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS X .... in the starch sample as compared to about 4% fading in the lactose sample (25). These studies and others previously conducted on drug-adjuvant interactions (28) point out the need for dye incompatibility tests in con- junction with other considerations in the formulation of pharmaceuti- cals. CONCLUSION The fundamental measurement prindples indicate that the use of instruments for the control of color will continue to be of great benefit in the cosmetic and pharmaceutical industry. Although future problems will not be totally solved with the aid of instrumentation, the amount of information gained from these techniques more than justifies the use of these methods for the control of color. (Received December 18, 1967) 1) 2) 3) 4) 5) (6) (7) (8) (9) (10) (11) (12) (13) (14) (15) REFERENCES Lach, J. L., and Bornstein, M., Diffuse reflectance studies of solid-solid interactions I, J. Pharm. Sci., 54, 1730 (1965). Swartz, C. J., and Cooper, J., Colorants for pharmaceuticals, Ibid., 51, 89 (1962). Lachman, L., Swartz, C. J., Urbanyi, T., and Cooper, J., Color stability of tablet formu- lations II, Ibid., 49, 165 (1960). Lachman, L., Weinstein, S., Swartz, C. J., Urbanyi, T., and Cooper, J., Color stability of tablet formulations III, Ibid., 50, 141 (1961). Lachman, L., Urbanyi, T., Weinstein, S., Cooper, J., and Swartz, C. J., Color stability of tablet formulations V, Ibid., 51,321 (1962). Goodhart, F. W., Kelly, M. A., and Lieberman, H. A., Characterization of tablet colors obtainable from some certified dyes, Ibid., 54, 1799 (1965). Everhard, M. E., Dickcius, D. A., and Goodhart, F. W., Spectrophotometric reflectance method for matching the color of solid dosage forms, Ibid., 53, 173 (1964). Raft, A.M., Measurement of a color gamut obtained from FD & C colorants, Ibid., 5/i, 380 (1964). Raft, A. M., Tristimulus color measurements in fading studies and other color changes of pharmaceutical dosage forms, J. Soc. Cosmetic Chemists, 18,367 (1967). Harris, C., Jr., Color Instrumentation Seminar, Instrument Development Laboratories, Attleboro, Mass., 1966. Ives, H. E., The transformation of color mixture equations from one system to another iI, J. Franklin Inst., 195, 23 (1923). Guild, J., The colorimetric properties of the spectrum, Phil. Trans. Royal Soc., London, A230, 149 (1931). Nickcrson, D., History of the Munscll color system and its scientific application, J. Opt. Soc. Am., 30, 575 (1940). Wright, W. D., The Measurement of Colour, 3rd Ed., D. Van Nostrand Co., Inc., Prince- ton, N.J., 1964. Committee on Colorimctry, The Science of Color, Optical Society of America, Washing- ton, D. C., 1963.

COLOR AND ITS MEASUREMENT 667 (16) (17) (18) (19) (20) (21) (22) (23) (24) (25) (26) (27) (28) Judd, D. B., A maxwell triangle yielding uniform ehromatieity scales, J. Opt. Soc. Am., 25, 24 (1935). Adams, E. Q., X-Z planes on the 1931 I.C.I. system of colorimetry, Ibid., 32,168 (1942). MacAdam, D. L., Visual sensitivities to color differences in daylight, Ibid., 32, 247 (1942). Hunter, R. S., Photoelectric color difference meter, Ibid., 48, 985 (1958). Judd, D. B., and Wyszeeki, G., Color in Business Science and Industry, 2nd Ed., John Wiley and Sons, Inc., New York, N.Y., 1963. Stanziola, R., Practical colour instrumentation for the dyer, Can. Textile J., 1-5 (Sep- tember 17, 1965). Kubdka, P., New contributions to the optics of intensely light scattering materials, J. Opt. Soc. Am., 38, 448, 1067 (1948). Hardy, A. C., Handbook of Colorimetry, The M.I.T. Press, Cambridge, Mass., 1936. Lieu, V. T., and Frodyma, M. M., Selection of the optimum concentration range for reflectance spectrophotometric analysis, Talanta, 13, 1319 (1966). Bornstein, M., Walsh, J. P. Munden, B. J. and Laeh, J. L., Diffuse reflectance studies of dye-adjuvant ehemisorption, J. Pharm. Sci., 56, 1410 (1967). Laehman, L., Kuramoto, R., and Cooper, J., A study of the interaction between qua- ternary ammonium compounds and several certified dyes, Ibid., 47, 871 (1958). Scott, M. W., Goudie, A. J., and Huetteman, A. J., Accelerated color loss of certified dyes in the presence of nonionic surfaetants, Ibid., 49, 467 (1960). Bornstein, M., and Lach, J. L., Diffuse reflectance studies of solid-solid interactions II, Ibid., 55, 1033 (1966).