Light and Colour Theories, and their relation to light and colour standardization

by Joseph W. Lovibond

A measured simple colour, finds its position directly on its corresponding colour scale at the point of its measured value.

A measured complex colour, finds its position within the angle, at that point where perpendiculars drawn through the two colour values meet.

The above statements are complete only for colours of standard brightness, should the colour be brighter or duller than standards, a light factor is necessary, the value of which is furnished by the measurement itself, and must be written in numerals near the colour point.

By this method the chart position of even the most complicated colour is indicated by a single point which is determined by the analytical value of the composing factors.

Examples.

Simple Colour of Standard Brightness.	Complex Colour of Standard Brightness.	Simple Colour Brighter than Standards.	Complex Colour Duller than Standards.
3· Red.	6· Blue, 10· Violet.	7· Yellow, Light 2·	Red 6, Orange 5, Black 2.

The number of complex colour charts is limited to the six represented in [Fig. 1] as lying in their order on a continuous spectrum. The red and violet mixtures having no visible spectrum position are represented in the ultra violet. The ordinates of the charts are made by erecting the overlying red, yellow and blue scales as perpendiculars.