Learning OpenCV 4 Computer Vision with Python 3 - Third Edition

Light is not paint

For newcomers to the BGR color space, it might seem that things do not add up properly: for example, the (0, 255, 255) triplet (no blue, full green, and full red) produces the color yellow. If you have an artistic background, you won't even need to pick up paints and brushes to know that green and red paint mix together into a muddy shade of brown. However, the color models that are used in computing are called additive models and they deal with lights. Lights behave differently from paints (which follow a subtractive color model), and since software runs on a computer whose medium is a monitor that emits light, the color model of reference is the additive one.