Mixing Cadmium Red Middle and Phthalocyanine Blue cannot give you a acceptable violet: you only get vaguely tinted grays. With Ultramarine, it’s a little less bad. It becomes a little better with Ultramarine and Quinacridone Magenta and still better with Ultramarine and Quinacridone Rose. But for a true bright Violet, the best solution is to choose a naturally violet pigment like Mineral Violet or Cobalt Violet.

Even if you mix together natural violets, e.g. Quinacridone Magenta or Quinacridone Rose with Mineral Violet, you won’t get such bright colors.