Subtractive color mixing refers to the process of mixing colored pigments, dyes, inks, or paints to create a new color. This is different from additive color mixing, which refers to mixing colored lights to create new colors. Subtractive color mixing involves subtracting certain wavelengths of light by absorbing them, while additive mixing involves adding wavelengths of light together.
Some common examples of subtractive color mixing include mixing paint colors, combining printing inks, or dyeing fabrics. When two or more pigments are combined, they absorb or subtract certain wavelengths of light. The color we perceive is the wavelength of light that is reflected rather than absorbed.
Primary Colors in Subtractive Mixing
The primary colors used in subtractive color mixing are cyan, magenta, and yellow. These are known as process colors or CMY colors. When combined in different proportions, these three colors can create a wide range of hues.
| Color | Absorbs/Subtracts |
|---|---|
| Cyan | Red |
| Magenta | Green |
| Yellow | Blue |
As shown in the table above, cyan pigment absorbs wavelengths of red light, magenta absorbs green, and yellow absorbs blue. When two primary colors are mixed, the resulting secondary color reflects the two wavelengths of light not absorbed.
For example:
- Cyan + Magenta = Blue (absorbs red and green, reflects blue)
- Cyan + Yellow = Green (absorbs red and blue, reflects green)
- Magenta + Yellow = Red (absorbs green and blue, reflects red)
Tertiary Colors
Mixing the three primary subtractive colors together creates new tertiary colors:
| Color Mix | Absorbs | Reflects |
|---|---|---|
| Cyan + Magenta | Red + Green | Blue |
| Cyan + Yellow | Red + Blue | Green |
| Magenta + Yellow | Green + Blue | Red |
| Cyan + Magenta + Yellow | Red + Green + Blue | Black |
Mixing all three primary colors together absorbs all visible wavelengths of light, resulting in black. By varying the proportions of the primaries, a wide range of dark and neutral colors can be created.
Lightening and Darkening Colors
In subtractive mixing, a color can be lightened by adding white, which reflects all wavelengths of light equally. This reduces the saturation of the color. For example, adding white to red makes pink.
A color can be darkened by adding black pigment, which absorbs all wavelengths of light. Adding black to a color creates a shade of that color. For example, adding black to orange makes a darker orange color.
The tint, tone, and shade of a color can be modified by changing the ratios of the color, white, and black pigments. This allows artists to create subtle variations using subtractive mixing.
Examples of Subtractive Color Mixing
Mixing Paints
One of the most common applications of subtractive mixing is mixing paint colors. Using just the primary colors cyan, magenta and yellow, along with black and white, painters can create any imaginable color. By mixing paint on a palette, new colors are generated by layering and blending the pigments together before they are applied to the canvas.
For example, a green paint can be mixed by blending a yellow paint with a cyan paint in a roughly 4:1 ratio. Different shades of green can be made by adjusting the proportions of yellow and cyan.
Four-Color Printing
Commercial printing uses four process colors to reproduce full-color images: cyan, magenta, yellow and black (CMYK). Tiny dots of each ink are printed in patterns to create the illusion of other colors through subtractive mixing.
When overlaid on paper in combinations, the CMYK inks create a wide spectrum of colors. For example, overlaying cyan and yellow dots absorbs red and blue light, creating the perception of green. Black ink is added for improved contrast and sharpness.
Dyeing Fabric
The dyeing industry also relies on subtractive color mixing. Different classes of dyes are used to impart color to fabrics like cotton, nylon, or polyester. These dyes work by being absorbed into fibers where they subtract certain wavelengths of light.
Multiple dyes can be applied sequentially or simultaneously to generate new colors through subtractive mixing. A red dye and a yellow dye applied to fabric will result in an orange color. The intensity of the color depends on the dye concentrations.
Color Perception
Our perception of color from subtractive mixing depends on several factors:
- The wavelength composition of the illuminating light
- The reflectance spectra of the pigments/dyes
- Interactions between the pigments
- The color vision and perception mechanisms in the human eye and brain
Subtractive color mixing relies on reflected light. The illumination conditions can therefore change the apparent colors significantly. A yellow paint under blue daylight will appear greenish because the blue light is subtracted by the yellow pigment.
Additionally, the human vision system is incredibly complex in how it interprets color information. Optical illusions can trick our eyes into perceiving colors differently than may be expected from simple subtractive mixing. So while the physics of subtractive mixing is straightforward, predicting color perception is highly complex.
Conclusion
Subtractive color mixing is essential for art, design, photography, and printing – any field that involves generating color from pigments, dyes, or inks. By manipulating cyan, magenta, yellow, black, and white in different combinations and ratios, a vast array of hues can be created through the selective absorption of certain wavelengths of light. This allows the color possibilities from a few primary colors to be greatly expanded. Understanding subtractive mixing principles helps artists masterfully control color for their creative works.
