The primary colors are the three basic colors that can be mixed together to create all other colors. There has been some debate over what the true primary colors are, but most artists and scientists agree that the 3 true primary colors are red, yellow, and blue.
The Primary Color Theory
The primary color theory dates back to the early 19th century when French chemist Michel Eugène Chevreul concluded that all colors could be mixed from three primary colors. Chevreul based his theory on his observations of how dyes and pigments mixed together. His theory became widely accepted and by the late 19th century red, yellow, and blue were established as the three primary colors in art and physics.
The reason these three colors were chosen as primaries is that they cannot be created by mixing any other colors together. All other colors are derived from different combinations of red, yellow and blue. For example:
| Red + Yellow | = | Orange |
| Yellow + Blue | = | Green |
| Blue + Red | = | Purple |
The more primary colors that are mixed together, the darker the resulting color becomes. When red, yellow and blue are mixed in equal proportions, they create neutral grays, blacks and whites.
The Additive and Subtractive Color Models
There are two main color models that are used to understand how primary colors work – additive and subtractive. The additive color model deals with light and is used for computer screens and other digital displays. The subtractive color model deals with pigments and dyes and is used in painting and printing.
In the additive color model, the primary colors are red, green and blue (RGB). When red, green and blue light are combined together in equal amounts, they produce white light. The absence of all three makes black. Computer screens and other digital displays create color using varying combinations of red, green and blue light.
In the subtractive color model, the primary colors are cyan, magenta and yellow (CMY). These are the complementary colors to RGB. When CMY pigments are combined, they absorb all light wavelengths and produce black. The absence of all three makes white. Printers use cyan, magenta and yellow ink to absorb subsets of RGB light and create color.
| Additive (RGB) | Subtractive (CMY) |
|---|---|
| Red | Cyan |
| Green | Magenta |
| Blue | Yellow |
While RGB and CMY are primary colors in additive and subtractive color models, they are not considered the true primary colors in art and physics. Red, yellow and blue maintain their status as the three true primaries that all other colors are derived from.
Why Red, Yellow and Blue are the True Primaries
Red, yellow and blue are accepted as the three true primary colors for the following reasons:
- They cannot be created by mixing any other colors.
- All other colors are derived from combinations of these three.
- They represent the primary colors in human vision and physiology.
- They align with the historical artistic primaries dating back centuries.
The red, green and blue used in digital displays are not true primaries because red and green can be created by mixing yellow and magenta. Cyan can be created by mixing blue and green. This makes RGB more of a functional model for emitting light rather than definitive primaries.
While red, yellow and blue can’t exactly match the whole gamut of colors the human eye can see, no other set of three colors can produce such a large range. This visible spectrum coverage is why they are considered the closest representation to true primary colors.
The Physiology of Red, Yellow and Blue
The special status of red, yellow and blue as primary colors is rooted in the physiology of human color vision. The cells in the retina that detect color are called cones. There are three types of cones that are each sensitive to different wavelengths of light:
- S cones – sensitive to short blue wavelengths
- M cones – sensitive to medium green/yellow wavelengths
- L cones – sensitive to long red wavelengths
These three cone types allow the eye to perceive the full range of colors through combinations of stimulation. The wavelengths for blue, yellow and red roughly align with the peak sensitivities of the S, M and L cones.
Due to this biological basis, red, yellow and blue are considered the optimal primary colors for visually matching the largest gamut detectable by human vision. Other primary sets like RGB can produce more colors, but RGB still has to be converted by the cones into the same blue, yellow and red signals.
Cultural and Historical Significance
The choice of red, yellow and blue as primary colors has both cultural and historical significance. Primary colors are deeply rooted in human culture and language. These colors align with the historical artistic primaries used for centuries of painting and dyeing:
- Red – Associated with blood, fire, passion. Used as a primary color in ancient Greek paintings.
- Yellow – Associated with sunlight, joy, happiness. One of the first synthetic yellow pigments was yellow ochre used since prehistoric times.
- Blue – Associated with skies, seas, sadness. The ancient Egyptians and Mayans used blue pigments like azurite and lapis lazuli.
While many alternate color wheels and primary systems have been proposed, red, yellow and blue remain the accepted convention across biology, physics, art, design and culture.
Using the Primary Colors in Art
Understanding the fundamentals of the primary colors allows artists to mix a vast range of secondary and tertiary colors. The primary colors provide the foundation for color theory and practical applications in painting, drawing, and digital design.
Some key concepts when working with the primaries include:
- Mixing equal parts red, yellow and blue makes shades of gray, black and white.
- Mixing two primaries makes a secondary color – orange, green or purple.
- Mixing a primary and secondary makes a tertiary color like red-orange or blue-green.
- Complementary colors are across from each other on the color wheel.
- Analogous colors are adjacent colors on the color wheel.
- Warm colors are reds, oranges, yellows. Cool colors are blues, greens, purples.
Mastering the primary colors provides endless options for bringing color art and design to life. Even with all the digital tools and effects available today, the fundamentals of red, yellow and blue remain every artist’s essential palette.
Conclusion
While many different primary color systems exist, red, yellow and blue stand out as the definitive primaries. This is due to:
- Their ability to mix all other colors through different combinations.
- Aligning with the peak sensitivities of the eye’s cone cells.
- Matching the historical artistic primaries used for centuries.
- Forming the basic palette for applying color theory in art and design.
Red, yellow and blue may not match every nuance of color visible to the human eye. But no set of three other colors can come as close to creating the full spectrum of visible hues. This makes red, yellow and blue the ideal choice for the 3 true primary colors.
