.jpg)
Fig. 23.The modifiers used in the color designations of the ISCC-NBS system [75].
brown, olive) preceded by modifiers (light, dark, grayish, strong) indicating the lightness and saturation of the perceived color. Figure 23 shows the complete list of modifiers used in the ISCC-NBS system; note that vivid is a substitute for very strong; pale, a substitute for light grayish; deep, for dark and strong, and so on.
The boundaries between the groups of colors known by these designations have been adjusted to accord as closely as possible with common usage and have been expressed in terms of Munsell Book notation. Figure 23 also shows these boundaries for colors of purple hue.
The ISCC-NBS designations are not to be considered a substitute for numerical designation of color resulting from application of a suitable colorimetric method, but they do supply a certain precision to verbal color designations that has previously been lacking. Table 11 gives the ISCC-NBS designations of the four printing-ink specimens shown on figure 4 and the ISCC-NBS hue designations have been used throughout the text of this chapter. These color designations are used in the current edition (N.F. VII) of the National Formulary, and they are being inserted into the 'United States Pharmacopoeia and into a textbook of qualitative analysis [130]. They have been used for describing the colors of building stone [83] and soils [138], and for a considerable variety of research purposes such as the description of mica colors after heat treatment [53]. Kelly [80] has found the Munsell notation for the centroid color of each compartment assigned an ISCC-NBS color designation and has recommended a system of abbreviations; see table 11.
| Name | Abbreviation |
|---|---|
| Red | R |
| Reddish orange | rO |
| Orange | O |
| Orange yellow | OY |
| Yellow | Y |
| Greenish yellow | gY |
| Yellow green | YG |
| Yellowish green | yG |
| Green | G |
| Bluish green | bG |
| Greenish blue | gB |
| Blue | B |
| Purplish blue | PB |
| Violet | V |
| Purple | P |
| Reddish purple | rP |
| Purplish red | pR |
| Purplish pink | pPk |
| Pink | Pk |
| Yellowish pink | yPk |
| Brownish pink | brPk |
| Brownish orange | brO |
| Reddish brown | rBr |
| Brown | Br |
| Yellowish brown | yBr |
| Olive brown | OlBr |
| Olive | Ol |
| Olive green | OlG |
The ISCC-NBS designations are generally unsuited for use in sales promotion. The method has been approved for color description of drugs and chemicals by the delegates of nine national societies, and it has been recommended for general use by the United States of America Standards Institute [161a].
In 1958 the method was recommended by the Subcommittee on the Expression of Historical Color Usage [60], Inter-Society Color Council, for the statistical expression of color trends. The adaptation of the method for this purpose involved the tabulation of six distinct, but correlated, degrees or levels of accuracy in color description [82]. In the first level the color solid is divided into just 13 parts, ten described by a generic hue name and three neutrals, white, gray and black. In the second level, the color solid is divided into 29 parts, ten of the original 13 parts being further divided and assigned intermediate hue names. In the third level each part of the color solid described by a generic or intermediate hue name and the appropriate modifier descriptive of its lightness and saturation; that is, in the third level of accuracy, the 267 color designations of the ISCC-NBS method are used without abridgement. Level four is illustrated by the Munsell Book of Color [100] with its more than 1,000 uniformly spaced color samples. Level five is illustrated by the interpolated Munsell book notation by which about 100,000 different colors can be reliably specified. Level six, the level in which the greatest accuracy of color identification is possible, is illustrated by two basic methods: the CIE method, and the interpolated Munsell renotations. This degree of accuracy is realizable only through the measurement of the color with a spectrophotometer, and is equivalent to the division of the color solid into about 5,000,000 parts. Figure 24 gives further information about the six levels: (A) level of fineness of color identification, (B) number of divisions of color solid, (C) type of color designation, (D) example of color designation, and (E) alternate color-order systems usable in that level.
Through the cooperation of the Inter-Society
33
