Just three colours?

Playing around with colours again, I remembered something I'd heard about a watercolour artist who only uses 3 pigments in her work. Quinacridone magenta, Quinacridone gold and Ultramarine all by Winsor and Newton. The W&N Quinacridone Gold is a three pigment mixture and not as pretty as a colour as the Daniel Smith PO49 version, but nor is it as warm - a bit more of a neutral orange/yellow. The W&N Quin Magenta is the wonderful PR122, a great primary red option. I experimented with Daniel Smith, with single pigment colours, and you can see the results below.

This combination makes beautiful purples, as you can see, but with these colours the oranges are dull and the greens useful but neutralised. DS Quin Magenta PR202 is not as clean for mixing as the W & N PR122 colour, though it has a better lightfast rating. So what is the perfect trio of watercolours?

Quinacridone Magenta, Ultramarine and Quinacridone Gold

Living in Australia, Ultramarine Blue is the perfect blue. Our sky is often almost purple in hue. Sunsets have a tinge of pink, and often a golden glow. Australian trees are largely a dull green so the warm Quinacridone gold is a great choice. But for the red I think a more crimson colour is needed. I tried Permanent Red Deep (Daniel Smith watercolour), as this makes brighter reds and oranges, great purples as well as neutralising greens to make greys. The colour is less pink than it looks on my screen though - more of a bright crimson red. Other options are Quinacridone Red PV19 and Carmine by Daniel Smith. (2014 update - Permanent Red Deep is a lovely colour but the lightfast ratings are not as great as they should be. Carmine or Quinacridone Rose is a better option)

Quinacridone gold, Ultramarine and Permanent Red Deep

In Europe, the Phthalo Blue (red shade) might be a better blue. And perhaps a mid yellow to create the lush greens of Europe. I've tried it here with Hansa yellow medium and Phthalo blue red shade.

Permanent Red Deep, Hansa Yellow Medium and Phthalo Blue (R.S.)

But is three colours enough? I think I would be spending all my time washing my brush. I wonder what three colours others would choose? 

To speed up the mixing process, I would add at least a burnt sienna and a yellow earth - yellow ochre or raw sienna, along with a mixed grey. You can mix a burnt sienna hue and a raw sienna hue with just about any RYB triad, so they would speed up mixing, without losing colour harmony.