Color additive mixing

Spectrophotometric methods based on an enhancement of the blue color produced on reduction of 12-molybdophosphate (arsenate) in the presence of antimony(III) are widely used for the determination of phosphoms(V) or arsenic(V). However, nature of heteropoly blue, their spectra, mechanism of the reaction are obscure. In addition, mixed POMs were shown as very efficient analytical forms for the determination of P(V) and As(V). 

Sodium copper chlorophyllin, approved by the FDA as a color additive in citrus-based dry beverage mixes, should have a ratio of absorbance (SoretQ band) not less than 3.4 and not more than 3.9. In Europe, purity criteria of the food additives E141[i] and E141[ii], which are copper complexes of chlorophyll and chlorophyllin, respectively, are set out in the EC color specifications that include identification and spectrophotometric assay tests. ... 

Additive flame retardants, brominated and chlorinated, 11 461—470 Additive mixing, in color photography, 79 240-241... 

Color measuring instruments, 7 323-326 Color-order systems, 7 308-311, 325-326 Color perception, 7 303-304 Color photographic products, 19 197 Color photography, 19 231-272. See also Chromogenic materials additive, 19 284 additive mixing in, 19 240-241 dye stability in, 19 263... 

Colorimetry [1.17] - [1.19]. The principles of colorimetry are based on the fact that all color stimuli can be simulated by additively mixing only three selected color stimuli (trichromatic principle). A color stimulus can, however, also be produced by mixing the spectral colors. Thus, it has a spectral distribution, which in the case of nonluminous, perceived colors is called the spectral reflectance q (2). After defining three reference stimuli, the trichromatic principle allows a three-dimensional color space to be built up in which the color coordinates (tristimulus values) can be interpreted as components of a vector (CIE system for standards, see Table 1, Colorimetry CIE = Commission Internationale de l Eclairage). For uncolored illumination the three CIE tristimulus values depend on the spectral reflectance as follows ... 

In color picture tubes, the final color is formed by additive mixing of red, green, and blue light. Each of the three phosphors (Table 58) is excited by its own modulated electron beam and emits light of intensity corresponding to the particular degree of excitation. The phosphors for color picture tubes have an average particle size of 8-10 pm. 

The principles of colorimetry are based on the fact that aU color stimuli can be simulated by additively mixing only three selected color stimuU (trichromatic principle). A color stimulus can, however, also be produced by mixing the spectral colors. Thus, it has a spectral distribution, which in the case of nonluminous, perceived colors is... 

As we have seen in Sect. 6.2, additive mixing of primary colors in the form of blue, green and red phosphor emissions allows the production of all colors within the triangle enclosed in the chromaticity diagram (Fig. 7.2). For black-and-white television a bluish-white emission color is preferred. This can be obtained by several... 

Color cannot be measured because it is perceived in the brain. However, it can be specified instrumen-tally using additive or subtractive mixing to produce a color that matches the object color. In the former, a match to most colors can be made by the additive mixing of light of the three primary colors. A measure of the intensity of the three primaries provides a specification of the color. Primary colors are defined such that none can be matched by mixtures of the other two. The principle of additive mixing is the basis of the common tristimulus and spectrophoto-metric methods of measurement. 

To assist dispersion of colorant in the polymer melt the use of screw back pressure is recommended. The barrel temperatures at the hopper zone should be set lower than that at the nozzle to allow for additional mixing to take place within the feed section of the screw. PS is also sold as color compounded material and a color matching service is available but many processors purchase natural (clear) polymer and color in-house. 

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