Color strength

Transparent white pigments (extenders) commonly used in inks, in order of decreasing transparency, ate alumina hydrate, magnesium carbonate, calcium carbonate, blanc fixe (precipitated barium sulfate), talc, and clay. Extenders ate sometimes used to reduce the color strength and change the theology of inks. 

Quality Control and Testing. Control of inks is done by examining their color strength, hue, tack, rheology, drying rate, stabiHty, and product resistance. Elaborate control equipment and laboratory testing procedures are employed to test the finished inks. Weather-Ometers,... 

In Rhodamine 6G, also sold as Rhodamine F5G [989-38-8] (15), the caiboxy estei gioup prevents fiee rotation of the lower phenyl group. Its position is roughly perpendicular to the plane of the other three rings. Retention of color strength is good because there is less electronic interaction between the lower ring and the rest of the molecule. 

ASTM E20-843 for color strength in ink, and ISO 8781 (parts 1—3) for evaluating tinting strength, fineness of grind, and gloss. 

Inks. Refined kaolin is a common ingredient in a large variety of printing inks (qv). In addition to extending the more expensive polymers present, ka olin also contributes to improved color strength, limits the penetration of the ink into the paper, controls rheology, and improves adhesion. Kaolin for this appHcation must usually be as white as possible and free from oversize particles. Surface treated clays are used to improve compatibiHty with oil-based ink. Clays can also be an ingredient in the newer water-based or uv-cured inks. 

Fig. 12. A, the schematic variation of scattering, and B, color strength for pigment particles of various sizes (5).

Dispersibility. Pigments modified with a dispersion additive take less time and energy to disperse in a coating (12,44). The equipment for blunging is simpler and less expensive than bah. mihs. Color correction is simplified and settling is minimized. Color strength in letdowns is often improved... 

Typically, grape skin extract has a specific gravity of 1.13 g/mL at 20°C, a solids content of 28—32° Brix (=t3°), a pH of 3.0, and a color strength as anthocyanin of about 1.25% (as measured at 520 nm ia pH 3.0 citrate buffet). Grape skin extract is also available as spray-dried powders with color values three to four times those of the liquid. The properties and uses of grape skin extract ate similar to those of grape color extract. 

As an initial step, the product designer must anticipate the conditions of use and the performance requirements of the product, considering such factors as life expectancy, size, condition of use, shape, color, strength, and stiffness. These end use requirements can be ascertained through market analysis, surveys, examinations of similar products, testing, and general experience. A clear definition of product requirements will often lead directly to choice of the material of construction. At times incomplete or improper product requirement analysis is the cause for a product to fail. 

Mapari, S. A.S. et al., Exploring fungal biodiversity for the production of water-soluble pigments as potential natural food colorants, Curr. Opin. BiotechnoL, 16, 231, 2005. Dufosse, L., Mabon, R, and Binet, A., Assessment of the coloring strength of Brevi-bacterium linens strains spectrocolorimetry versus total carotenoid extraction/quan-tification, J. Dairy ScL, 84, 354, 2001. 

The same features were found for pilot-size micro-reactor operation (Figure 4.59). Brightness and transparency were the same and color strength could be increased to 149% [55]. The mean particle size was even set to a lower value compared with the laboratory-scale processing (micro reactor, D5Q = 90nm, s= 1.5 ... 

It should be noted that the terms do not necessarily correspond to their normal connotation, e.g., quality refers primarily to the presence of a desirable aroma fraction. Some terms that characterize black tea, as compared to green tea, include quality , color , strength , and briskness . 

Coloring strength Not proportional to dye content Directly proportional to pure dye content... 

The effect of particle size, and hence dispersion, on the coloring properties of aluminum lake dyes has been studied through quantitative measurement of color in compressed formulations [47], It was found that reduction in the particle size for the input lake material resulted in an increase in color strength, and that particles of submicron size contributed greatly to the observed effects. Analysis of the formulations using the parameters of the 1931 CIE system could only lead to a qualitative estimation of the effects, but use of the 1976 CIEL m v system provided a superior evaluation of the trends. With the latter system, the effects of dispersion on hue, chroma, lightness, and total color differences were quantitatively related to human visual perception. 

The primary chemical aspect of a mesomeric pigment system concerns the correlation between tinctorial strength and extent of electron delocalization. A higher degree of conjugation in a molecule is associated with a bathochromic shift color strength improves with the intensity of absorption. A resonating system proliferates by ... 

Molecular dimerization, as in the transition from Hansa Yellow to disazo yellow pigments, increases the color strength considerably. A comparison of a Naph-thol AS/disazo condensation pigment pair gives similar results ... 

TT-electron interactions between the aromatic ring and adjacent conjugated free electron pairs, either nonbonding electron pairs or double bonds of substituents, improve electron delocalization, which in turn increases absorption intensity, that is, color strength. 

Considerable shearing forces will break down the particles in the variety with a coarser particle size. It is interesting to note that the tendency of a pigmented system to become hazy decreases as the dispersion time increases, accompanied by improved gloss, color shift towards more yellowish shades, enhanced color strength in white reductions, and increased viscosity [22],... 

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