Based on the color wheel, the combination of red and blue creates the color purple. On the color wheel, however, purple is referred to as "violet."
This combination works in theory, but not as often in practical usage. For red and blue to make a pure purple color, the blue must contain no traces of red, yellow or green in its tint. Additionally, the red color must tint closer to a pink and have no yellow tint. Therefore a color combination of standard red and standard blue often results in a more Burgundy shade or darker purple than true violet.