Red and blue mixed together make purple. Red and blue are usually mixed in equal parts, but more red or blue are added for preference. Adding white to this mixture creates a lighter tint of purple, while adding black creates a darker shade of purple.
Red, blue and yellow are primary colors that occur naturally; they cannot be mixed from other existing colors. The secondary colors are purple, green and orange; they are formed from mixing two primary colors together. A mixture of blue and yellow makes green, while a mixture of red and yellow makes orange. Tertiary colors are formed by mixing primary colors with secondary colors; red-violet and blue-green are examples of tertiary colors.