The secondary color purple or violet is made by mixing the primary colors red and blue. However, to get a purple that is not muddy in appearance, it is important to mix the right types of blue and red, especially when mixing paint colors to use in a painting.
In theory, a pure blue color mixed with a pure red should give a proper hue of purple. However, many paint colors contain different mixtures of pigments. To avoid a muddy purple, it is wise to find a blue color that does not contain any of the added pigments red, yellow or green. Similarly, the red paint color should not have yellow pigment.
Besides red and blue, the other primary color is yellow. These are colors that cannot be made by mixing other colors together. Secondary colors are colors made by mixing two primary colors.