Chroma colorant properties

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. 

Color Strength, Hue, Chroma [20, p. 99-105], The coloring properties of a dye are assessed by preparing a dyed test sample whose color is evaluated. This must, in principle, always be done by the human eye because color perception, being a subjective sense impression, is not accessible to direct measurement. However, with the aid of colorimetry this visual perception can be represented more or less closely by measurable quantities. Since colorimetry is an objective method and is therefore more accurate and reproducible than subjective visual assessment, it is veiy widely used today. Color is a three-dimensional quantity and must therefore be expressed by a set of three numbers (color coordinates). In practice, these are typically the values of color strength, hue, and chroma. 

Antistatic additives are designed to be present on the surface of the molded part to achieve the full antistatic benefit. The types of additives used to enhance antistatic properties include quaternary ammonium salts, alkyl sulfonates or phosphate plus alkali metals, ethoxylated amines, or gylcerol esters. Antistatics are typically used at higher levels than other additives such as antioxidants. Therefore, antistatics are likely to increase light scattering, making it more difficult to achieve the higher chroma colors. 

Of these barriers, the one that is most overlooked is the first. Many of the new thermoplastic materials coming into the market place are blends and alloys that are specifically engineered to provide a combination of the properties of the individual polymers. Often these materials combine crystalline and amorphous polymers with an impact modifier. The products of these marriages often contain a maze of phase boimdaries that result in light scattering (miUdness) equivalent to as much as 0.5% titanium dioxide. Obtaining high chroma colors (e.g., some electrical code colors or even a jet black) in the presence ofthis inherent miUdness becomes an expensive proposition. Often so much color has to be added to the material formulation that critical material properties are affected - a double whammy, cost and performance. 

Color and Coloring Materials. The third key property of all types of ink is color which may very weU be the most important one to the consumer because it has such a great psychological impact. Color (qv) has three different attributes described as hue or shade, saturation or chroma, and lightness or value. 

Name from chroma (Greek = color) forms many colored salts Properties... 

The colorant requirements for the different ink-jet applications differ widely. For example, high chroma is the key requirement for photorealistic printing, whereas high lightfastness is the key parameter for the wide format and outdoor markets. These widely differing properties provide opportunities for a variety of dye classes, as well as for pigments. 

The name and symbol come from the Greek chroma, meaning color. In 1797, Nicolas-Louis Vauquelin (1763-1829) was examining the properties of the mineral crocoite. He found that it turned vibrant colors when mixed with various chemicals. In 1798, he produced chromium metal. Chromium ores are found in a number of places, but it rarely appears in elemental form. The greatest use of chromium is for plating because it produces a hard, reflective surface that resists corrosion. It is also used as an alloy in steel, as a catalyst, and to produce emerald-green glass. 

HISTORY. Chromium was discovered by the French chemist Vauquel in 1797, while he was studying the properties of crocoite, an ore which is rich in lead chromate, its common name of chrome was derived from the Creek word chroma, which means color, because the element is present in many different colored compounds. These compounds have long been used as pigments in dyeing, and in the tanning of leather. In the early 1900s, chromium became... 

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