The colors that are positioned opposite one another are complementary colors.
The 3 pairs are:
Blue – Orange
Red – Green
Yellow – Violet
How can we keep them easier in our mind?
Imagine the following triangle:
– put the primary colors (Red, Yellow and Blue) in the tips of the triangle
– put the secondary colors on the sides
Red + Yellow= Orange
Yellow + Blue= Green
Blue + Red= Violet
Mixing complementary colors:
As stated by Johannes Itten, complementary colors do annihilate each other when mixed to create dark neutrals. Complementary colors bring out the best in each other. If you want to have a nice green dress with a red pair of shoes, this does not go well. But if you will search for a brown pair of shoes (brown is the mix between red and green) this will be the talk of the town, I am sure. This means: complementary colors do not go well together in pairs. But if you want to obtain a harmonious pair of colors, you should leave one of the complementary pure and mix the other with its complementary.
red <->green (red does not go well with green)
red – red+ green = brown (red goes well with the mix between its complementary color + a bit of red itself)
So, if you want to have harmony between complementary colors, all you have to do is keep one color pure and the other mixed with a bit of the pure color. If you want to wear purple and yellow, you either keep yellow and mix the purple with a touch of yellow or you keep purple as pure color and you mix in yellow a bit of purple. The result will be the association of a pure color near an impure color.
When fully saturated complements are brought together, interesting effects are noticeable. This may be a desirable illusion, or a problem if creating visuals that are to be read. See the illusion of highlighted edges and raised text?