PRESSED POWDER TECHNOLOGY 601 amount of binder and type vary with the particular formulation. Since binding is so important in producing a quality finished pressed product, much care must be used in selecting the proper binding agent and the correct amount to be used. Problems such as glazing (too hard a cake), crumbling or laminating (too soft a cake), cake tone, and the amount of color development on the skin may be attributed to improper binder or binder amounts. Perfumes When required, a perfume should be neutral in fragrance, compatible with other materials in the formulation, and nonirritating. Most pressed eye products do not contain perfume. Different shades of pressed powders are generally obtained from two types of colors: (a) certified organic lakes and toners which cannot be used in the area of the eyes, and (b) noncertified inorganic pigments. Certified organic lakes and toners are available in many bright shades and are used in face powder for their brilliance of color. Lakes have had the serious drawback that they are more easily oxidized, are not completely light-fast, and occasionally are subject to bleeding. Some of the most important organic lakes used in pressed powder are D&G Red No. 7 Calcium Lake, Dg:C Red No. 9 Barium Lake, Dg:C Red No. 10 Sodium Lake, DEC Red No. 37 Stearate& and DEC Yellow No. 5 Aluminum Lake. A natural organic product that may be used around the eye area is a bright blue-red powder called carmine. There are many colors available among the inorganic pigments which are stable, light-fast, and nonbleeders. Aluminum powder, titanium dioxide and zinc oxide, carbon black and iron oxide black, yellow, red and brown iron oxides, ultramarine blue and violet, iron blue, manganese vio- let, anhydrous (Cr2Oa) and hydrated [Cr(OHa)] chrome green oxide are among the most popular shades used in this class. Finally, one cannot discuss pigments without discussing the pearles- cent varieties needed to produce frosted shades of pressed powder. Mica, titanium-coated mica, bismuth oxychloride, bismuth oxychloride-coated talc, bismuth oxychloride laminated on mica, and pearl flakes (CaCOa) are the most popular frosting materials used today. Natural pearl or guanine flakes are too costly and rarely used. Aluminum powder may also be used as a pearlescent material, but tends to produce dull, gray shades if not used properly. The coated and laminated mica materials

602 JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS are generally used for cake tone and sparkle and not for feel. They are relatively coarse when compared to the various grades of bismuth oxy- chloride which have more slip and luster when applied to skin. The bismuth oxychloride material is more compressible than the mica coun- terparts which are difficult to press in concentration above 15%, without special binders. Water, alcohol, and emulsions have been used as successful binding agents when high amounts of titanium-coated mica are used in pressed powder lornrelations. If a special binder is not employed a spongy, crumbling cake is pro- duced, due to the laminar quality of mica. M',:tr•y formulations con- tain blends of bismuth oxychloride and titanium-coated mica products in order to achieve combined top tone and skin effects. Bismuth prod- ucts are not light-fast and may darken on extended exposnre to daylight. QUALrr¾ CONTROL METHODS There are several basic steps in the quality control of pressed powder. First, and perhaps foremost, is the checking of colors to be used in the cake. Usually colors are checked for shades by making a 1% dilution in any standard talc, and the solution is then micropulverized through a 0.027-in. screen. Certain tolerances must be allowed for, as there are some slight variations from color batch to color batch. Color differences should be critically evaluated if the pigment is on the dirty or gray side, as it is possible to alter a final shade towards the gray side but almost impossible to brighten one on the gray or dirty side. Talcs, kaolin, and other fillers do not require too elaborate checking except for an occasional spot check of their specifications. Note should be taken o1: the color of the talc itself, as talc is the major ingredient in most powders, and differences in color may affect the finished cake tone. Raw materials, especially talcs and pigments, should be continuously checked for bacteriological contamination. A discussion dealing with make-up would not be complete without considering the technical aspects of formulation, evaluation, and press- ing of these products. FORMULATION ASPECTS Pressed powder technology can be divided into two basic areas of formulation. The first group comprises those cake powders that are ap- plied to the face or cheek area. Those cakes that are applied all over the [ace area called "pressed powder" cakes. Their intended use is either as a complete make-up finish to the face when applied alone, or as a