OPTICS ANIMATION / SIMULATION: Colour mixing

ADDITIVE COLOUR MIXING

​Red, Green, and Blue lights illuminate a screen. Each source emits pure red, green, or blue light (the additive primary colours). As the light beams converge and the colours overlap, so they illustrate additive colour mixing, yielding the additive secondary colours (yellow, magenta, and cyan). At the area where all of the primaries overlap, white light appears:

    red + green light gives yellow light
    red + blue light gives magenta light
    green + blue light gives cyan light
    red + green + blue light gives white light

SUBTRACTIVE COLOUR MIXING

​Subtractive colour mixing works by subtracting (filtering) certain colours while reflecting others. The animation shows three printing inks (cyan, magenta, and yellow) pouring from cans onto a sheet of white paper. The filtering effect of each one of these inks creates all the colours necessary for colour printing. In real four colour printing, the inks are applied as screens (tiny dots that vary in size to carry the image information), and black ink is added to enhance contrast and outline the colours (CMYK). CMYK stands for Cyan Magenta Yellow and Key (black). See the Wikipedia article on CMYK printing.

    CYAN subtracts RED passes BLUE & GREEN
    MAGENTA subtracts GREEN passes RED & BLUE
    YELLOW subtracts BLUE passes RED & GREEN