Mixing colors is something we often do, whether mixing paints for an art project or wondering what colors make up the white light we see. A common question is whether mixing two colors together can result in the color white. The short answer is yes, you can combine colors to create white through a process called additive mixing of light. However, the specific colors that need to be mixed depend on whether we are talking about mixing pigments (like paints) or mixing light (like on a computer screen).
Additive vs. Subtractive Color Mixing
There are two main ways that we mix colors: additive mixing and subtractive mixing.
Additive mixing involves combining wavelengths of light. In this method, mixing different colors of light together produces a cumulative effect, with more white light created as more colors are added. Computer and TV screens use the additive mixing of red, green, and blue light to create the colors we see.
Subtractive mixing involves combining pigments. With paints, dyes, inks and other pigments, each material absorbs some wavelengths of light and reflects others. The more pigments that are combined, the more wavelengths are absorbed, resulting in darker colors.
So while combining paint pigments typically results in darker browns and greys, combining wavelengths of colored light results in brighter, lighter colors. This difference is key to understanding how two colors can make white.
Additive Mixing of Light
When it comes to mixing light, the primary additive colors are red, green, and blue (RGB). This is because these are the primary colors detected by the cones in our eyes. Mixing red, green, and blue light together in equal amounts produces white light.
This is the principle used by TVs, computer monitors, and other digital displays. By varying the intensity of the RGB light emitted by individual pixels, these devices can create the illusion of any color. Mixing red, green, and blue at full intensity results in white.
So in additive mixing, combining the primary colors of red, green, and blue makes white. However, other combinations of colors can also produce white when mixed:
| Color 1 | Color 2 |
|---|---|
| Cyan | Red |
| Magenta | Green |
| Yellow | Blue |
This table shows secondary color combinations that can additively mix to create white light. The key is that the two colors must be complementary colors from opposite sides of the color wheel.
For example, red light and cyan light (a mix of green and blue) will combine to form white light. When added together, the wavelengths from the two complementaries create the full spectrum of visible light our eyes perceive as white.
Subtractive Mixing of Pigments
Mixing pigmented colors like paints, inks, and dyes relies on subtractive color mixing. Since each pigment absorbs and reflects different wavelengths, combining them results in a darker, murkier color. The more pigments added, the less light is reflected off the surface.
So with subtractive mixing, combining two arbitrary colors will not make white. The exceptions are mixing complementary colors, which can theoretically produce grey or black by absorbing most visible wavelengths of light. However, in practice impure pigments make truly neutral greys difficult to achieve.
While paint mixing cannot make white by combining two color pigments, white paint does exist. This white pigment reflects nearly all visible light equally, creating the appearance of white to our eyes. Common white pigments include:
– Titanium dioxide – Most common white paint pigment, highly opaque
– Zinc oxide – Natural mineral white, less opaque than titanium dioxide
– Lead white – Historically used but toxic, being replaced by safer options
So while white paint is available, it requires a specially formulated pigment designed to reflect all wavelengths of light, rather than mixing two colored pigments.
Mixing Paints to Create White
Given that paint mixing is subtractive, is there a way to mix colors to simulate white paint? Here are some options artists use to approximate white with blended paints:
– Mix a near-white color like light yellow with white paint or gesso to lighten it. The more white used, the closer to white the mix will be.
– Mix complementary paint colors like orange and blue. Complementaries neutralize each other, desaturating the mixture.
– Mix adjacent paint colors like red, yellow, and blue. This approximates an even spread of wavelengths in the mix.
– Add a matte medium or glaze to any light color to dilute the pigmentation, reflecting more light.
– Use lighter, opaque paints like titanium white or zinc white to maximize light reflection.
– Mix soft pastel versions of pure RYB primary colors. The purity reflects more light than deep pigments.
While these mixtures can produce near-whites, they lack the complete light reflection and opacity of true white paint pigments. But they allow artists to simulate white using colored paints.
Light vs. Pigment Mixing
The key takeaway is that additive mixing of light can easily create white by combining all wavelengths, but subtractive mixing of pigments cannot reproduce the full spectrum reflection of white paint.
This is because pigments selectively absorb certain wavelengths of light. Mixing colored pigments cannot perfectly reflect the full span of visible light. Only specially engineered white pigments can evenly reflect all visible wavelengths.
So while computer screens and other light sources can mix colors to form white, paints and other physical pigments cannot mix arbitrary colors to make a true white. The physics of light and pigments lead to different results when combining colors.
Conclusion
In summary, the answer to whether mixing two colors makes white depends on whether we are working with light or pigmented color mixing:
– Additive mixing of colored light can produce white by combining complementary colors or the primary RGB colors. The full spectrum of visible light appears white to our eyes.
– Subtractive mixing of paints and other pigments cannot make true white by mixing two arbitrary colors. Engineered white pigments are needed to reflect all visible wavelengths.
So white light can be produced through additive color mixing, but white paint requires specially formulated pigments designed for maximum reflectivity across the full spectrum. While artists can approximate white with blended paints, the physics of light and pigments prevent two colored paints from making a perfect white.
