The primary colors are red, blue, and yellow. The secondary colors are purple, green, and orange. What happens if you mix the secondary colors purple and orange, orange and green, purple and green?
So, if you combine orange with green, both secondary colors, you are mixing all four of the above colors. The same goes if you mix purple and orange. So, a tertiary color contains some of all three primary colors, hence the word tertiary coming into play.
When you mix a primary and a secondary color together, it’s called a tertiary color. Depending on the mixture, tertiary colors can be either robust and brilliant or dark and muddy.
