Pigmentation index

The results are showu as index numbers, pigmentation index also denominated melanin index, which can vary from 0 to 1000 (Edwards, 1995). The system can also be used to calculate haemoglobin index from the same experimental determinations this index is of interest to quantily the cutaneous degree of erythema (Fullerton et al, 2003) and consequently skin improvanent after using after-sun cosmetics. 

The final product of all the above processes is iron(III) oxide, a-Fe202, but its properties are deterrnined by the method of preparation. Thermal dehydration of goethite yields a pigment of lowest (4.5 g/cm ) density. The highest (5.2 g/cm ) density pigment is one prepared by two-stage calcination. The particle si2e varies from 0.3 to 4 p.m the refractive index varies from 2.94 to 3.22. 

Color Index (Cl) name CAS Registry Number Cl constitution number Pigment class (common name) Method of preparation... 

Table 7. Refractive Indexes and Reflectivities of White Pigments...

Diphenylmethane Dyes. The diphenyhnethane dyes aie usually classed with the tiiaiyhnethane dyes. The dyes of this subclass are ketoimine derivatives, and only three such dyes are registered in the Colour Index. They ate Auramine O [2465-27-2J Cl Basic Yellow 2 (Cl 41000) (21, R = CHg), Auramine G [2151 -60-2] Cl Basic Yellow 3 (Cl 41005) (22), and Cl Basic Yellow 37 [6358-36-7] (Cl 41001) (21, R = C2H5). These dyes are still used extensively for the coloration of paper and in the preparation of pigment lakes. 

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