TETRAD COLOR PALETTE----------------------This is a scheme that includes one primary and two complementary colors, plus an additional color that highlights the accents. An example: blue-green, blue-violet, orange-red, orange-yellow.
A Triad is a combination of 3 colors that are equidistant from each other on the color circle. It produces a high contrast effect while preserving ’harmony.’ Such a composition looks vibrant even when you use pale and unsaturated colours.
Color Wheel (Moses Harris, Moses Harris's chart was the first full-color circle. The 18 colors of his wheel were derived from what he then called the three 'primitive' colors: red, yellow and blue. At the center of the wheel, Harris showed that black
Analogous colours are groups of three colours that are next to each other on the color wheel. They share a common colour, with one being the dominant colour, which tends to be a primary or secondary colour, and a tertiary.