The question of what colors combine to create black depends entirely on the medium being discussed. Black is understood differently when dealing with light, which uses an additive process, versus physical materials like paint or ink, which use a subtractive process. Examining these two fundamental models of color theory is necessary to understand the makeup of black.
Black in the Additive Color Model
In the additive color model, which governs all sources of emitted light such as computer screens, televisions, and stage lighting, black is the complete absence of color. This system uses Red, Green, and Blue (RGB) as its primary colors of light. When these three colors are combined at maximum intensity, the result is white light.
If all three light sources—red, green, and blue—are turned off or set to zero intensity, no light is emitted. This state of zero light energy is what our eyes interpret as black. Digital displays produce black by instructing the light-emitting elements, or sub-pixels, to have zero luminance, represented by the values R:0, G:0, B:0.
Black in the Subtractive Color Model
The subtractive color model applies to physical pigments found in paints, dyes, and inks, where black is created by mixing colors. Pigments work by absorbing, or “subtracting,” certain wavelengths of light and reflecting the rest back to the eye. When multiple pigments are mixed, each one absorbs more light, making the resulting color progressively darker.
The two main subtractive systems are the traditional Red, Yellow, and Blue (RYB) model, and the modern Cyan, Magenta, Yellow, and Key/Black (CMYK) model used in printing. In the RYB system, mixing the three primaries creates a dark, murky color that approximates black. This is because the combination of these pigments absorbs almost all visible light.
The CMYK model, used in professional printing, uses Cyan, Magenta, and Yellow as its primaries. Theoretically, mixing equal and full amounts of C, M, and Y should absorb all light and produce black. However, due to impurities in the inks, this mixture typically results in a muddy, dark brown shade rather than a true, deep black.
For this reason, a dedicated black ink, known as “Key” or ‘K,’ is added to the system, forming CMYK. The separate black ink is necessary to achieve a pure, dense black, add detail to text, and reduce excessive ink saturation. Printers often use a “rich black,” which combines the black ink with percentages of the other three colors to create a deeper, more saturated black than the ‘K’ ink alone.
The Physics of Total Light Absorption
Beyond color mixing, the physical appearance of black is defined by the total absorption of visible light. An object appears black because its surface absorbs nearly all wavelengths of light across the visible spectrum. The absorbed light energy is converted into thermal energy, which is why black objects heat up more quickly when exposed to sunlight.
A truly perfect black object, which does not exist outside of theoretical physics, would absorb 100% of the light that strikes it. The closest real-world examples are materials like Vantablack, which is composed of vertically aligned carbon nanotubes.
This specialized material can absorb over 99.965% of visible light, making it appear nearly two-dimensional because the eye cannot perceive any surface contours. When light is absorbed rather than reflected, the eye perceives a lack of incoming photons from that direction, which the brain interprets as the color black. Even objects we perceive as black still reflect a small percentage of light, which allows us to see their shape and texture.