How much red blue do you mix for purple?

start with the drop of RED to make the amount of Purple you want. Then slowly add 2 drops of BLUE. Mix it up. If that shade of PURPLE isn't what you want, SLOWLY add 1 more drop of BLUE, mix again. See if you want that color of PURPLE. Add 1 drop at a time SLOWLY till you want the right shade of PURPLE. If you mixed in too much BLUE, add more RED. that should even things out. Good Luck!!