To mix or not to mix?

Another nice benefit of getting involved in the WetCanvas forums, as I mentioned yesterday, is it gives me ideas for new blog posts!

I spotted a post earlier today discussing whether it was ok to use greens and purples/violets straight from the tube, or better to mix them from primary colours.

To explain why this is even a question worth asking, we need to consider at the colour wheel.

The three primary colours are Red, Blue and Yellow.

The secondary colours are Orange, Violet and Green.

In theory, it should be possible to mix any secondary colour from a combination of the three primary colours:

  • Red + Yellow = Orange
  • Yellow + Blue = Green
  • Blue + Red = Violet

However, in practice, there are certain colours, such as bright greens and violets that can’t be mixed from the three primaries, so if you’re painting, say, a bright purple flower, then you may need to use a purple tube colour to make sure you can get a bright enough colour. If you try to get the purple by mixing blue and red, it’s likely to end up too dark, and then if you try to lighten it with white, you’ll reduce the saturation, leaving your purple looking chalky and washed out.

So this is one argument for using secondary tube colours, although it’s rare that you’d need them when painting a landscape. Even if there are bright green trees or purple flowers in your scene, they will very rarely be as bright as the colour that comes out of the paint tube.

The other reason it can be useful to have these tube colours is for mixing with other colours. A cobalt violet can do a nice job of greying down a cadmium yellow, for example, or you can add viridian (green) to cadmium red to reduce the saturation.

So while it may be rare for you to need these colours as they appear out of the tube, they can be used to great effect when combined with other pigments.

As for me, I do have tubes of Viridian, Sap Green, Pthalo Green, and Cobalt Violet. Up to now I’ve never had a use for the violet, but I occasionally use the greens if I find them useful. Pthalo is great for a tropical green sea (knocked back with a bit of red of course!) and Sap Green can be handy for grass/trees at times. But in general, if I can mix a colour easily from the primaries, I find that it usually results in a more harmonised colour scheme.





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