Mix in a small amount of blue until you reach your desired color
Notes
As long as you have mixed blue and red, you have made a purple. The issue is there are different kinds of purples, created by what are called "undertones."These undertones are called warm and cool. Warm tones are reds, yellows, and oranges, whereas cool tones are blues, purples, and greens. Funnily enough, this means you can actually have a "cool" red, meaning a red that has blue undertones.A "classic" purple is made with a red with warm undertones and a blue with cool undertones. This way the warm and cool undertones are balances, making a balanced purple.