There are two types of color models – additive and subtractive. Today we will explain additive mixing, also known as an additive color model or additive color system.
The human eye mixes the three RGB additive primary colors – red, green, and blue – in various combinations and intensities to simulate the full range of colors in nature. Reflected light that contains a mix of pure red, green, and blue is perceived as white. When no light is present, we perceive black. This is the basis of how the RGB color model can create colors.
Additive Color Models – Input and Output
RGB is an additive color mixing process where various wavelengths of light combine to form white light.
Additive Color Models – Input and Output Devices
Input and output devices that leverage RGB start with darkness and add red light, green light, and blue light beams over a black surface or screen to create color. RGB input devices include digital cameras and scanners. RGB output devices include TVs and computer monitors. Of course, some devices like smart phones and tablets can be both RGB input and output devices.
Additive Mixing
RGB devices start with darkness and add red, green, and blue light beams over a black surface or screen to create color. Each of these beams has a level of intensity, from fully on to fully off. These red, green, and blue beams superimpose in various intensities to create a spectrum of color.
The color we perceive is determined by the intensity of each beam. For example, if each beam has zero intensity, meaning no light, the screen or surface will appear black. If each beam has full intensity, the screen or surface will appear white. If all three beams have the same intensity, the color will appear gray.
We see color based on the intensity of each beam. If the red beam is strongest, we will see red. If the red and blue beams are equal intensity and the green beam is low, we will see magenta. This secondary color is achieved by mixing the two primary colors, red and blue.
Red Light, Green Light, Blue Light
The color rendering methods used by these devices are based directly on our response to stimuli of red, green, and blue light. Like the human eye, these devices must also process a large amount of color information at once—on screen. In logical fashion, these devices imitate the eye’s response to the additive primaries to create a colorful illusion.
For example, a computer monitor blends varying intensities of colored light—red light, green light, and blue light—at each of its tiny pixels. These pixels are so small and tightly packed that the eye’s RGB response is “fooled” into the perception of many different colors when really there are only three.
Learn More About Additive Color Mixing
This is just a basic introduction to color models and additive color mixing. If you’d like to learn more about color theory, check out our library of online training courses.
Learn More About Subtractive Color Mixing
If you're interested in subtractive color or subtractive color mixing, check out this blog.
First published: September 28th, 2020
