Laser printer technology depends entirely on the CMYK color model to produce laser images on paper. The human perception of color is dependent upon the light reflected back to the human eye in order to distinguish one color from the other. Colors of images are therefore seen as subtractive or additive depending upon the light rays reflected back to the human eye.
CMY Color Combinations
By combining the colors yellow, magenta and cyan, it is possible for the human eye to perceive a wide range of colors. However CMY is not sufficient. Black is added to improve the reproduction of some dark colors. Meanwhile, white light is the combination of different colors. In the CMY color space, pertinent light colors are absorbed and transmitted as follows:
Toner / Ink Color
|Color Absorbed||Colors Transmitted|
|Cyan||Red||Blue & Green|
|Magenta||Green||Red & Blue|
|Yellow||Blue||Red & Green|
The white substrate is important in color perception since it reflects the transmitted light back to the human eye (the viewer). In actual application, the CMY toner also reflects a substantial amount of color; thus deep and neutral black is difficult to achieve and black toner is added to compensate for the deficiencies.
When printing with the CMYK color model, half toning is necessary to reduce the saturation or purity of primary colors and define various shades of a particular color. The halftone technique uses tiny dots of the primary colors, projected and printed in a pattern so small that the human eye only sees it as solid color.
For instance, cyan ink/toner printed in varying percentages in halftone will simulate the color light cyan, turquoise and aquamarine. The tiny cyan dots in contrast with the white paper in between (dots) communicates to the human eye a subdued hue that is less defined than that of pure cyan ink/toner. Without half toning, the CMY process colors can only be printed and seen as solid colors.
It is only through half toning that a continuous range of colors can be produced. Layering the primary process colors under the CMYK color model would only produce 7 colors.
|Cyan + Yellow||Green|
|Cyan + Magenta||Purplish Blue|
|Yellow + Magenta||Red|
|Cyan + Magenta + Yellow||Black or Muddy Brown|
However in color laser printing, the black tone yielded from layering the primaries is unsatisfactory. Thus, a black toner cartridge is added to add zing to color reproduction.
Again, color reproduction is not a perfect technology since color perception is dependent on viewer perception and this varies from one individual to the next.
Photo by Salvatore Vuono