A colour matched by
Standard Glasses. Colour Developed.
Blue. Red. Blue. Violet.
6·0 + 1·8 = 4·2 + 1·8
The colour developed is a blue violet in these proportions.
The standard glass colours are necessarily of a given brightness, and colours for measurement may be either brighter, or sadder than the standards.
A given complex colour of less than glass standard brightness, is matchable by unequal numbers from the three standard scales; the smallest unit value always represents the “black,” or neutral unit factor. The equation is as follows:—
A colour matched by
Standard Glasses. Colour Developed.
Red. Yellow. Blue. Neutral Tint. Green. Blue.
1·0 + 3·0 + 9·0 = 1·0 + 2·0 + 6·0
The colour is a blue green, in the proportion of six to two, saddened by one of neutral tint.
A given complex colour of greater brightness than the glass standards, is first dulled by the interception of neutral tint units, until measurable in the manner described above; the intercepting glasses represent the unit value of excess of brightness, and is shown in the equation as light units, for instance—
Standard Glasses. Colour Developed.
Neutral Tint. Yellow. Blue. Light. Green. Yellow.
1·5 + 7·5 + 0·5 = 1·5 + 0·5 + 7·0