Follow my guide to mixing vibrant purple without it turning into a muddy mess. I show you how I balance red and blue pigments, adjust for light or dark shades, and get a professional violet result every time.
Mix in a small amount of blue until you reach your desired color
Blue Paint (or food coloring)
Notes
If you want to keep your purple looking vibrant even when it is dark, I suggest using a tiny bit of dark, cool blue instead of black. Black can sometimes make the color look a bit flat or dull.