Red, green, blue are called primary colors. These three colors are mixed in different proportions to produce a variety of colors. There are two basic methods of color mixing: additive color mixing and subtractive color mixing.
Additive color mixing is when different colors of light mixed, they put their share in the spectrum together, resulting in a new method of mixing colors. When Red, green and blue light the three primary colors mixed:
Red + green = yellow green + blue = cyan light
Green + red = magenta red + green + blue = white light
If not equal to the three primary colors when mixed, you can get a variety of intermediate colors, for example:
More Red light + Less green = orange light
More Red light + Less blue = pink light
Subtractive color mixing is a method of producing a composite color effect by selectively absorbing the respective portions of the incident light from their respective portions in the spectrum when mixed in different colors. After adding any two kinds of color light, such as white light, these two kinds of color light complement each other (complementary color). Such as yellow and blue complement each other color, cyan and red complement each other color, magenta and green complement each other. Therefore, yellow, cyan and magenta are respectively referred to as ” subtractive blue”, “subtractive red” and “subtractive cyan”. In other words, the three complementary colors are made of white minus a corresponding color. Therefore, yellow, cyan, magenta can be called subtractive color three primary colors.
When yellow, magenta, cyan subtractive primary colors overlap together will produce black. In subtractive process, the density of the three subtractive primary colors control the absorption ratio of red, green and blue, respectively, resulting in a variety of mixed colors to achieve the same effect as additive color mixing.
The purity is also affected by the size of the area occupied by the color in the picture.
Large area appears to be more than a small area of color and more attractive to people’s attention.