As Promised here is the spectrum of colours mixed using a split primary palette of Watercolour.
Just to recap,Watercolour paint is colour bound in gum arabic. It can be used wet from tubes or dry in bricks .It is water soluable when wet and dry unlike Oil or Acrylic.
Below from the top left I have placed the primary colours of Alazarin Crimson and Cadium red, then Raw Sienna[darker yellow] and Windsor yellow [Lemon yellow], lastly Manganese blue[Phthalo blue] and French ultra-marine.In between these I have mixed the secondary colours of orange, green and violet.
Below I have mixed in between each of the primary and secondary colours to give a good transition f one colour into the next.