What things influence the appearance of color?
Chapter 2

 

Environmental changes in which color is observed influences perception of color.
To be more specific the following conditions influence our perception of color:
The color quality of light under which colors are observed.
The proximity of other colors to the color or colors we are observing. Or changes in the value (lightness/ darkness) of the background against which colors are observed.
The surface texture underlying the color we are observing.
Let's look at each of these three conditions in order:

THE INFLUENCE OF THE COLOR QUALITY OF LIGHT UNDER WHICH OTHER OBJECTS ARE OBSERVED.

 

We see colors under varying light conditions. The color "makeup" of daylight differs, for example, from the color quality of an incandescent light bulb. This simply means that though both are seemingly white, there are certain wave lengths in each source that are stronger than others. North light at noon, for example, is energy rich in the blue end of the spectrum, while incandescent lighting is characteristically rich in the yellow-red end of the spectrum. Fluorescent lights may simulate most any energy distribution. Candlelight is distinctly yellow.

A white object viewed under each of these sources exhibits the characteristic (though slight) color of the source. An observer may or may not be conscious of this-depending on the light source. (A white object, remember, reflects the same quality of light that strikes it.)

The color perception of all materials that selectively absorb some wave lengths from light and reflect or transmit others is influenced by the composition of the light that strikes them. For example, flesh tones which reflect red light must have sufficient red wave lengths in the light source to appear natural. This photograph was taken under illumination made up of equal amounts of red, green and blue wave lengths. (Figure hA)

This photograph was taken under illumination with a deficiency
of red (or a predominance of blue) which resulted in a dead and grayish flesh tone because the needed red wave lengths were not available. (Figure 11B)

Because light sources vary, color matching and comparing is difficult unless observations are made under the same light source. This is a metameric color match. Under one light source the colors will appear to match; under another they will obviously differ.

Under fluorescent lights of a bluish white; under fluorescent lights of a pinkish white; under incandescent light, which is used in most home lighting; and under daylight, these colors will change in their relative appearance. Colors which are not made from a single pigment or dye, but are based on mixtures of colors, can be mixed to match under one set of conditions and may not match under other conditions. Take this sample to the window and see. Inks are normally matched under daylight conditions. (Figure 12) It is possible to demonstrate dramatically the influence that a light source has on color observation. If a blue object were viewed under pure red light, the object would appear black. The subtractive color phenomenon, of course, explains this. (Figure 13) In addition to the spectral quality (color makeup) of the light source, the strength or brightness of the light source influences color perception. We may observe the effect of varying brightness when daylight turns to darkness and the greens and reds of nature become darker and duller until eventually their hues are no longer identifiable. (Figure 14)