Getting to know your paints is an important step towards good results in your painting. Colour wheels are a good tool to locate pigments around their hue / saturation space. Then you can decide more easily about which colours you might use in terms of harmonies and combinations.
To decide which pigments you prefer to use for mixing colours there are other factors to take into account: transparency, flow and staining nature. And the issue of neutralizing pigments is another complex question, without a consistent pattern around the wheel. However, it is still good to have a basic wheel around to remind you of the alternatives you have when starting a new painting.
Here, on a 65 x 50 cm sheet, I have created swatches of all the single-pigment watercolour paints in my paintbox, using several references. Each tube or pan from the professional brands now indicate which pigment(s) have been used in the manufacture of the paint and this makes the job easier.
In this wheel there is a big gap in the green pigments area. The reason is I only have three single-pigment greens. The rest of my green colours (Sap green, Hooker green and others) are commercial mixtures prepared with different pigments. For the rest of the palette I have very few multi-pigment paints (I think the only one is Sepia.)
Other interesting exercises with your paints:
- test as many different mixes as possible, thoroughly, using different proportions and dilutions.
- test combinations of transparent or semitransparent pigments with other transparent pigments, or combinations transparent + opaque. Two opaque colours usually produce undesirable muddy mixes.
- test glazing effects using transparent or diluted colours over dry washes of a different colour
- try granulating washes
- experimental mixes and wet-on-wet interactions.
Bruce McEvoy, in his very informative site, Handprint, already commented here, offers a wealth of details about colour wheels. Check out the sitemap of his website to explore it in detail.
Some good books and tools for colour mixing: