Mixing paints together can result in a variety of new colors, but whether this is considered additive or subtractive color mixing depends on the type of paints used. Both additive and subtractive color mixing rely on the primary colors of red, yellow, and blue, but they differ in how the colors interact to produce new shades.
Additive vs. Subtractive Color Mixing
Additive and subtractive color mixing refer to two different ways that colors can be combined:
Additive color mixing involves combining light of different colors. The primary additive colors are red, green, and blue. When combined, these can create the appearance of other colors. Computer and TV screens use additive color mixing by emitting different amounts of red, blue, and green light to display many colors. Combining all three additive primaries together results in white light.
Subtractive color mixing refers to what happens when pigments, dyes, inks, or paints are mixed. The primary subtractive colors are cyan, magenta, and yellow, which are the complements of red, green, and blue. When subtractive primaries are combined, they block certain wavelengths of light and subtract colors from white light. Combining all three subtractive primaries results in black.
Paints Use Subtractive Color Mixing
When paints are mixed together, this causes subtractive color mixing. Paints contain colored pigments that absorb and subtract some wavelengths of light while reflecting others. For example:
- Red paint pigments absorb blue and green light while reflecting red.
- Yellow paint pigments absorb blue light while reflecting red and green.
- Blue paint pigments absorb red and green light while reflecting blue.
When two paint pigments are mixed, the resulting color is whatever is reflected from the combination. For example:
- Mixing red and yellow paint makes orange paint because it absorbs blue light but reflects red and green light.
- Mixing blue and yellow paint makes green paint because it absorbs red light but reflects blue and green light.
This chart shows how combining the subtractive primaries of paint pigments results in secondary colors:
| Color 1 | Color 2 | Resulting Color |
|---|---|---|
| Yellow | Blue | Green |
| Yellow | Red | Orange |
| Blue | Red | Purple |
The more paint pigments that are mixed together, the darker the resulting color becomes, eventually reaching black if all pigments are combined. This is the subtractive color mixing process in action.
Primary Paint Pigments
The primary colors used in paint pigments are cyan, magenta, and yellow rather than red, yellow, and blue. This is because it is difficult to find pigments that fully reflect light at the red and blue wavelength ranges.
- Cyan is a blue-green that absorbs red light.
- Magenta is a reddish purple that absorbs green light.
- Yellow absorbs blue light.
Mixing together cyan, magenta, and yellow pigments produces black by subtracting all colors of light.
Tinting Strength of Paint Pigments
Different paint pigments have different tinting strengths, meaning some colors have stronger coloring power than others. Generally:
- Yellow has the highest tinting strength and overpowers other paint pigment colors.
- Red and blue have medium tinting strength.
- White and black pigments have very low tinting strength.
Stronger tinting strength colors have a greater impact when mixing paints. Even a small amount of strong yellow pigment will dominate over weaker tinting red and blue pigments.
Properties of Mixed Paint
When mixing colored paint pigments, the resulting paint takes on combined properties of the ingredients:
- Opacity – Adding opaque paint will make the mixture more opaque. Translucent paints become more opaque when mixed with opaque colors.
- Glossiness – Satin, semi-gloss, or gloss paint added will make the mixture more glossy. Mixing with flat/matte paint makes it less glossy.
- Texture – Coarse or textured paint will give the mixture some texture. Smooth paint helps keep the texture minimal.
- Density – Thick paint has higher density than thinner paint. Mixing the two results in an intermediate density.
Considering these factors allows painters to predict how the mixed paint will look and apply once dried.
Mixing Paint of Different Bases
Paint has either an oil-based or water-based formulation. The base impacts properties like drying time and cleanup requirements. Mixing paints of different bases is not recommended because it can interfere with proper curing and bonding of the paint.
However, when needed, careful mixing of oil- and water-based paints is possible. Some guidelines include:
- Mix in small quantities – the mixture will have a short pot life.
- Only mix colors that are similar in shade.
- Stir thoroughly to integrate the two paint bases.
- Test how long the mixture takes to dry and if the bonds are strong.
- Apply thin coats of the mixture.
Oil and water do not naturally mix, so expect the paint to separate over time. Remixed occasionally during application.
Other Color Mixing Methods
While mixing paint pigments is subtractive color mixing, there are other ways to mix colors additively with light:
RGB or CMY Color Mixing
Using red, green, and blue light or cyan, magenta, and yellow pigments allows full color mixing by addition instead of subtraction. This is how color is mixed for digital displays, photography, and printing.
Colored Light Filters
Overlapping filters of different colored light, such as red, blue, and green gels, transmits only the colors that pass through all the filters. This filters out other wavelengths to give an additive mix.
RGB LED Lights
Combinations of red, green, and blue LED (light emitting diode) lights can produce many colors through additive mixing. Many light fixtures and displays use RGB LEDs.
Conclusion
Mixing paint pigments results in subtractive color mixing, as certain wavelengths of light are absorbed while others are reflected. This differs from additive mixing of light sources like RGB pixels on a screen. The primary colors and color theory still apply, but work in opposite ways – combining paint pigments together eventually produces black, while mixing colored light can eventually produce white. Understanding these principles helps artists predict the colors that will result when mixing paints.
