Subtractive Color Cube

Subtractive color is a method of producing color by removing (absorbing) certain wavelengths of light from white light using pigments, dyes, inks, or colored filters. The remaining wavelengths that are reflected or transmitteddetermine the color that the human eye perceives. The primary colors in the subtractive system are cyan, magenta, and yellow (CMY). A CMY Cube is a wonderful little physical demonstration of subtractive color mixing—the system used by printing, painting, photography filters, and most physical pigments. It’s essentially the opposite of how light mixes on a screen.

Expanded Explanation

Subtractive color begins with white light, which contains the full spectrum of visible wavelengths. When light strikes a colored surface or passes through a colored material, some wavelengths are absorbed and others are reflected or transmitted. The absorbed wavelengths are effectively subtracted from the light.

For example:

• Cyan absorbs red light and reflects blue and green.
• Magenta absorbs green light and reflects red and blue.
• Yellow absorbs blue light and reflects red and green.

Because each subtractive primary removes one component of white light, combining them removes progressively more of the spectrum.

Mixing two subtractive primaries produces the secondary colors:

• Cyan + Yellow → Green
• Cyan + Magenta → Blue
• Magenta + Yellow → Red

When all three are combined, ideally all major wavelengths are absorbed, producing black. In practical printing, however, the mixture usually creates a dark brownish tone, which is why printing systems add a separate black ink, forming the CMYK color model.

Subtractive color is the basis for painting, printing, photographic film, colored inks, dyes, and transparent filters. It contrasts with additive color, which creates colors by adding light (as in digital displays using red, green, and blue light).

A CMY cube is a physical visualization of this system, showing how cyan, magenta, and yellow filters overlap in three dimensions to progressively subtract light and create the full range of subtractive color mixtures.