Subtractive Color System [CMYK]

T he Subtractive color system involves colorants and reflected light. Subtractive color stars with an object (often a substrate such as paper of canvas) that reflects light and uses colorants (such as pigments or dyes) to subtract portions of the white light illuminating an object to produce other colors.

If an object reflects all the white light back to the viewer, it appears white. If an object absorbs (subtracts) all the light illuminating it, no light is reflected back to the viewer and it appears black. It is the subtractive process that allows everyday objects around us to show color. Remember the example of the red apple? The apple really has not color. It has no light energy of its own. Colorants in the apple's skin absorb the green and blue wavelengths of white light and reflect the red wavelengths back to the viewer, which evokes the sensation of red.

The Limitations of Color Reproduction

The colors we see in nature represent an extremely wide range of colors. When it comes to reproducing color, however, we run into limitations. No color reproduction system (color film, color monitors, printing presses, etc.) can reproduce the entire range of colors we see in nature.

Color Gamuts

Color gamma is another term for "range of colors." Each color reproduction system has its own color gamut. For example, the gamut of colors that can be reproduced on photographic film is greater than the gamut of colors that can be produced with process color inks on paper using the offset printing process. Computer screens display more – and different – colors than can be produced on color film or most color printing devices.
How many colors are there?
If you are a human eye - billions

If you are a computer screen - 16 million

If you are a photographic film - 10 to 15 thousand

If you are a printing press - 5 to 6 thousand