Halftoning, The electromagnetic spectrum, Visible light – Oki C 9400 User Manual
Page 340: Neutral colors, Primary & secondary colors, Problems using color

perception of everything around us.
White Light
White light contains light from all visible wavelengths in balanced quantities.
Black Light
Black light is the absence of all wavelengths.
Perceived Light
Different individual wavelengths in the spectrum give rise to what we perceive as color. For 
example, a wavelength around 700 nm (0.0007 mm wavelength) in interpreted by our eyes as 
red, while the other end of the scale, 400 nm, is interpreted by our eyes as violet. 
Neutral Colors
Although the term color is used, neutral colors do not have properties of hue or saturation. They 
are described in terms of lightness only. 
The neutral colors are black and white and all shades of gray in between. A balanced mix of the 
subtractive primariescyan, magenta and yellowyields the neutral color or black (in theory). The 
same effect can be achieved with the additive primaries by having an equal mix of red, green 
and blue light. 
Primary & Secondary Colors
In theory, all colors can be made up from a very small group of color elements.
Primary Colors
There are three primary colors: blue, red and yellow. All other colors can be obtained by mixing 
the primary colors in varying proportions. 
Secondary Colors
Mixing two primary colors in equal proportions produces what is known as a secondary color. 
For example, mixing blue and yellow produces the secondary color green. 
Problems Using Color
Computer monitors and printers use different methods to generate colors. Computer monitors
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