Video display terminal filter

DETAILED DESCRIPTION OF THE INVENTION An understanding of certain important aspects of the present invention may be facilitated by the following brief review of some basic concepts of color science.
Every color in the visible spectrum may be produced by a combination of colored lights of the appropriate intensity and of a particular basic hue.
A color television picture tube, for example, produces all of the colors in the visible spectrum by causing a group of three phosphor dots or stripes one for each pixel, to glow at a particular intensity level.
Only three different phosphors, each producing a different color, are used.
The colors used are red, green and blue, and are referred to as additive primary colors.
The name derives from the fact that any color can be produced by combining additive primary colors.
Combining the light produced by the red, green and blue phosphors produces white light.
Other colors may be produced by the primary color-emitting phosphors according to the following table:
TABLE 1
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red light + green light =
yellow light
red + blue = magenta
green + blue = cyan
red + green + blue = white.

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An additive complementary color is defined as a color of a which when added to another colored light, "neutralizes" the second colored light, producing white light.
Thus, from the table above, a table of additive complementary colors may be formed as follows:
TABLE 2
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Additive Complementary
Primary Color Color
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Red + cyan (green & blue) =
white light
Green + magenta (red & blue) =
white light
Blue + yellow (red & green) =
white light.

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As stated above, every visible color in a black universe may be produced by combining additive primary colored lights, (red, green and blue), of the appropriate intensity