When added together, red, green and blue lights produce what we perceive as white light. As mentioned before, television screens and computer monitors are examples of systems that use additive color. Thousands of red, green and blue phosphor dots make up the images on video monitors. The phosphor dots emit light when activated electronically, and it is the combination of different intensities of red, green and blue phosphor dots that produces all the colors on a video monitor. Because the dots are so small and close together, we do not see them individually, but see the colors formed by the mixture of light.
Colors often vary from one monitor to another.
This is not new information to anyone who has visited an electronics store with various brands of televisions on display. Also, colors on monitors change over time. Currently, there are no color standards for the phosphors used in manufacturing monitors for the graphics arts industry. All image capture devices utilize the additive color system to gather the information needed to reproduce a color image. These devices include digital cameras, flatbed scanners, drum scanners, and video cameras.