Color description systems

Under the guidance of the hitemational Commission on Illumination (Commission Internationale de TEclairage or CIE), several color description systems and notions have been developed and have established the present procedures ... 

An example of the application of the CIE system for color description is shown in Figure 6-7. The curved, dotted line originating from C represents the locus of the chromaticity coordinates of caramel and glycerol solutions. The chromaticity coordinates of maple syrup and honey follow the same locus. Three triangles on this curve represent the chromaticity coordinates of U.S. Department of Agriculture (USDA) glass color standards for... 

The American Academy of Ophthalmology (AAO) recommended to the agency that a uniform color coding system be established for the caps and labels of all topical ocular medications. An applicant should either follow this system or provide an adequate justification for any deviations from the system. Although ophthalmic drug products can be considered topical products, they have been grouped with injectables because they are required to be sterile [21 CFR 200.50(a)(2)], and the descriptive, suitability, and quality control information is typically the same as that for an injectable drug product. 

Whatever the system of color measurement or color description ordering in 3D space is essential. In terms of the measurements described above relative values of L, a, b are indicted in Figure 4 together with directions of increasing hue and chroma. Flowever,... 

The overall objective of research under way as of ca 1997 is to develop a system of sale by description for fine and medium wools whereby the buyer is presented only with measured data on the principal characteristics of the raw wool, as well as an assessment of the less important characteristics by an independent skilled appraiser (8). A scheme for assessing the risk of the presence of colored fiber content in greasy wool has been proposed which depends on production parameters and on the age and sex of the sheep (5). Instmmentation and computer algorithms for the measurement of style and handle... 

We conclude this chapter with a few illustrative color plates. Simple B W graphics are sufficient for viewing CA only in the special case when sites take on one of two values. In all other cases, color is indispensable for visualizing the behavior of the system. The plates were produced using the freely available CA software packages MCell, Cellab and WinCA. See Appendix A CA Research Tools for a description of these programs and links to web sites from which they can be HnwnlnnHpH... 

Objective Evaluation of Color. In recent years a method has been devised and internationally adopted (International Commission on Illumination, I.C.I.) that makes possible objective specification of color in terms of equivalent stimuli. It provides a common language for description of the color of an object illuminated by a standard illuminant and viewed by a standard observer (H). Reflectance spectro-photometric curves, such as those described above, provide the necessary data. The results are expressed in one of two systems the tristimulus system in which the equivalent stimulus is a mixture of three standard primaries, or the heterogeneous-homogeneous system in which the equivalent stimulus is a mixture of light from a standard heterogeneous illuminant and a pure spectrum color (dominant wave-length-purity system). These systems provide a means of expressing the objective time-constant spectrophotometric results in numerical form, more suitable for tabulation and correlation studies. In the application to food work, the necessary experimental data have been obtained with spectrophotometers or certain photoelectric colorimeters. 

The red tetrasulfide radical anion 84 has been proposed as a constituent of sulfur-doped alkali hahdes, of alkah polysulfide solutions in DMF [84, 86], HMPA [89] and acetone [136] and as a product of the electrochemical reduction of 8s in DM80 or DMF [12]. However, in all these cases no convincing proof for the molecular composition of the species observed by either E8R, Raman, infrared or UV-Vis spectroscopy has been provided. The problem is that the red species is formed only in sulfur-rich solutions where long-chain polysulfide dianions are present also and these are of orange to red color, too (for a description of this dilemma, see [89]). Furthermore, the presence of the orange radical anion 8e (see below) cannot be excluded in such systems. 

The Boltzmann equation, S = kXxiW, establishes the zero point for entropies. Because ln(l) = 0, this equation predicts that the entropy will be zero for a system with only one possible description. Figure 14-1 la shows a system with W =, nine identical marbles placed in nine separate compartments. The figure also shows two types of conditions where > 0. Figure 14-llZ) shows a condition when the marbles are not identical. If one marble is a different color than the other eight, there are nine different places to place the different marble. Figure I4-IIc shows a condition where there are more compartments than marbles. If there are more places to put the marbles than there are marbles, there are multiple ways to place the marbles in the compartments. 

Figure 4. A random instance of the TS trajectory (black) and a reactive trajectory (red) under the influence of the same noise in a system with N — 2 degrees of freedom, projected onto the reactive degree of freedom. See text for a detailed description. (From Ref. 38.) (See color insert.)...

A large number of different color spaces exist. Most of the color spaces are just a linear transformation of the coordinate system. Each color space was created for a certain task. For instance, some color spaces were devised for paint programs, while other color spaces were devised for color perception. Poynton (1997) gives a good overview of many of the different color spaces. See also Wyszecki and Stiles (2000) for a description of the CIE color spaces. 

Figure 14.2 Likely description of the color constancy algorithm used by the human visual system to compute color constant descriptors. The parameter p is simply a small percentage as described in Section 10.2.

There has been significant effort expended in trying to relate the genetic code to the simpler conditions of color blindness. However, the papers reviewed below have consistently taken a very elementary view of the operation of the visual system. They have assumed that all failures related to abnormal color vision are based on the chemistry of the chromophores. Section 18.1 provides a more comprehensive description of the types and potential sources of such failures. Section 18.1.5.6.4 documents the very important work of Lakowski. Lakowski documents the variety of failures that can occur within the neurological portion of the visual system. 

In compiling the information in this chapter, I have relied heavily on several very comprehensive reviews that have appeared over the past few years [1-7]. In particular, the 1978 review by T irro et al. [1] is extremely thorough in describing the intra- and intermolecular photophysics and chemistry of upper singlet and triplet states. In fact, rather than reproduce the same details here, I direct the reader to this review for a summary of upper state behavior reported prior to 1978. (A description of azulene and thione anomalous fluorescence is included since these systems are the best-known systems that display upper state behavior.) I also direct readers to the reviews by Johnston and Scaiano [2] and Wilson and Schnapp [3] which focus on the chemistry of both upper triplet states and excited reaction intermediates as studied by laser flash photolysis (one- and two-color methods) and laser jet techniques. Also, Johnston s thorough treatment of excited radicals and biradicals [4] and the review of thioketone photophysics and chemistry by Maciejewski and Steer [5] are excellent sources of detailed information. 

Note "Tanning Chemicals, Dye, Paint, Putty Inks" refers to "tanning or dyeing extracts tannins and their derivatives dyes, pigments and other coloring matter paints and varnishes putty and other mastics inks," HS (Harmonized Commodity Description and Coding System) Code 32. 

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