Additive color mixing: definition and function
In lighting technology, additive color mixing refers to the mixing of colored light by adding spectral ranges. The primary colors of additive color mixing are the complementary colors red, green and blue. The uniform mixing of the three primary colors generates white light.
How do light colors mix with additive color mixing?
If the three primary colors red, green and blue are projected isolated as light spots (e.g. from an LED spotlight) onto a white surface and uniformly superimposed, new secondary colors are created due to additive color mixing in the overlapping areas. These are brighter than the original, adjacent primary colors. In addition to light color, intensity is a property of the light source.
Thus, the additive color mixing of red, green and blue results in the following secondary colors:
- red and green = yellow
- green and blue = cyan
- blue and red = magenta
Good to know:
In additive color mixing, the three primary colors when evenly combined produce the tertiary color white, which appears the brightest.
Additive and subtractive color mixing differ in that in the variant described above, color is added or colors are combined, whereas with subtractive color mixing they are subtracted, meaning removed and/or absorbed, e.g. with use of filters.
How does additive color mixing work in LED lighting?
The process of additive color mixing in LED lighting is used when (colored) light is to directly reach the eye without reflection, i.e. by projection. This can be observed well on television screens or computer monitors, because the LEDs of the monitors are constructed with the phosphors red, green and blue (RGB). Due to a physiological addition that takes place in the brain, the impression of a white surface is achieved despite adjacently positioned color areas.
In lighting design, what added value does additive color mixing offer?
Electronic control units allow individual light colors or the color temperature (tunable white) to be modified. In this way, discreet but also very effective color creations and changes can be achieved, and the perception of color in works of art can be influenced. This is particularly advantageous in rooms where the uses frequently change: museums and galleries for example can flexibly adapt their lighting to the respective exhibition via additive color mixing, thus gaining further display options.
In Human Centric Lighting (HCL) applications, a color temperature adapted to the time of day is also relevant for the well-being of people. Ideally, the lighting concept should take into account the circadian rhythm, i.e. the ‘inner clock’ of human beings, and create a dynamic adaptation of the course of daylight.
