Normalized color

Fig. 3. CPK (Corey-Pauhng-Koulton) rendering displaying shaded soHd surface for ranitidine, normally color-coded according to atom types (black representing carbon green, hydrogen yellow, sulfur blue, nitrogen and red, oxygen colors not shown here).

Fig. 5. A representation of ranitidine displaying four layers of the Connolly solvent-accessible dot surface normally color-coded in this process to correspond with the energies of electrostatic potential (color not shown here). Thus, the highest charge density would be indicated by red dots representing points where the attraction to an atom is strongest, and conversely, purple points would signify regions of maximal positive charge.

When a metal ion is chelated by a ligand such as citric acid, it is no longer free to undergo many of its chemical reactions. A metal ion that is normally colored may, in the presence of citrate, have Httie or no color. Under pH conditions that may precipitate a metal hydroxide, the citrate complex may be soluble. Organic molecules that are catalyticaHy decomposed in the presence of metal ions can be made stable by chelating the metal ions with citric acid. 

Meat Products. Laboratory investigations as well as practical experience have shown that aluminum containers do not cause the objectionable darkening of meat that occurs with other metals. Wunsche (13) found that luncheon meat stored in lacquered aluminum cans retained its normal color after more than one year, while a slight surface discoloration was observed on the same product packed in lacquered tinplate cans. 

The CIELAB system (1976) strictly standardizes the light source and the observer. CIE recommends three standard sources, A is an incandescent lamp, and B and C are lamps provided with different two-cell Davis-Gibson liquid hlters that simulate noon daylight and average daylight, respectively. Since the main object of the system is to obtain colorimetric results for normal tri-chromats (people with normal color vision), the standard observer must represent the human population with normal... 

These materials are normally colored by low concentrations of 3d transition-metal ions or more rarely by lanthanide ions. The pale green color of ordinary window glass is due to the presence of Fe2+ impurities and small amounts of doping of Cr3+ into AI2O3 (corundum) creates ruby. 

Figure 11.19— Visual colorimetry. To the left, a rotating filter comparison system. By using two cells, one of which contains the sample and the other the blank, it is possible to take into account the normal coloration of the two lubes. Observation is made by comparing the transparency for a specific filter against white light. To the right, a portable reflectomeler that allows comparisons to be made without the human eye. (Reproduced by permission of Merck.)...

Fig. 4. Film sensitivities ami final image color of normal color iml color infrared films. "Blue light absorbed by yellow filter. (JUS. Geological Survey)...

The CIE transformed the original experimental curves from Wright and Guild into more useful functions that would facilitate the identification of color stimuli by numbers. The three functions resulting from the transformation represent the color-matching response functions of the average observer with normal color vision. The observer functions were stand-... 

There has been a growing interest in the food industry for a color space based on a polar model. In 1976 when CIELAB was adopted, the CIE recommended an alternative color scale known as CIELCH or L C H. Of the three dimensions of color, the hue is the most critical in terms of perceptibility and acceptability for normal color observers. The L C H color space identifies the hue as one of the three dimensions. A color is located using cylindrical coordinates with L being the same as in CIELAB and C and H computed from a and b. The coordinates of CIELCH (also see Fig. F5.1.11) are ... 

If the energy of each primary color is increased by the same percentage, then the relative responses of the receptors will not be any different. Therefore, colors are usually specified using normalized colors, or chromaticities. The chromaticities of the CIE color space are given by... 

Figure 11.10 Computation of color constant descriptors using normalized color shifts. The first layer is the input layer. The second layer computes local space average color. The output is computed in the third layer. The measured red, green, and blue components are stored in cells c, with i e r, g, b. The average of these three components is stored in cell c. Space average color is stored in cells a,, the average of these three components in stored in a. Output cells are denoted by n, (from Ebner 2003c).

Color Shifts and Normalized Color Shifts in Combination with an Increase of Saturation (Nos 4-7)... 

Comprehensive color normalization, colors with original lightness. 

Local space average color, normalized color shifts. 

Figure 14. Normalized color change of UV irradiated Parylene-C film.

As organic molecules considered dyes become more complex, they become more susceptible to photon excitation (absorption) without the necessary spontaneous de-excitation. They are described as bleaching under illumination. The resonant conjugate dyes (chromophores) of vision bleach completely and become transparent in the absence of assisted de-excitation. Many related chromogens bleach and then return to their normal color over a short time interval (normally less than minutes). 

Neitz, J. Neitz, M. Jacobs, G. (1993) More than three different cone pigments among people with normal color vision Vision Res. vol. 33, no. 1, pp 117-122... 

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