This is an extra post on colour theory as I have spent quite a lot of time trying to understand modern takes on the traditional colour wheel.
There is a brilliantly informative website by Bruce MacEvoy www.handprint.com (accessed 11/4/17) from which I gained the following information (in summary).
- Spectral hues (‘ the rainbow’) are united around a visual colour wheel through the extra-spectral hues of the red-violets. This is an artificial continuum as the wavelengths of individual colour light at the ‘join’ do not correspond. However it is helpful to think of this wheel as it is a link between light, visual colour and material, pigment colours.
- Whilst artists need to understand mixing colour pigments from mixing colours from traditional primaries of red blue and yellow, to understand how we perceive that colour we also need to understand the sensitivity of our eye’s cone receptor cells to various wavelengths of visual light. Our cones are sensitive to red blue and green light, the visual primary colours. If both red and green cones are stimulated we ‘perceive’ yellow.
- The sensitivity range of our cones allows us to visualise many more colours than are actually able to be produced by mixing the three light primaries (RGB)
- A primary colour pigment in theory is produced by pure reflected light of either red, yellow or blue wavelength. In reality you can not have a complex compound that is paint that does not contain particles that scatter other wavelength.
- Because of this artists have traditionally used what is known as the split primary palette, or a warm and cool tone of each ‘primary’ colour, so that compensation may be made for the lack of purity in the paint hue.
- In the same way we are capable of seeing colours not able to be mixed by primary light, the colours able to be mixed by a split primary palette fall short of the colours available in the spectral wheel.
- By using a palette of ‘secondary’ colours you increase this range considerable, especially in the blue, green to yellow range.
My notes are accompanied by some coloured annotation that I have made in my sketchbook:
MacEvoy has also produced this amazing colour wheel based on the secondary palette (ie equally spacing the secondaries around the wheel) for many of the colours of proprietary watercolours paints. As he is concerned with looking at pure pigments (although he does include some pigment mixes in his colour wheel) I surmise that most of the colour relationships observed here will also stand for oil and acrylic colours. Certainly the binders/ mediums will have a bit of a difference but as a working modern colour wheel it will do for me!
MacEvoy, B. (2005). http://www.handprint.com. (Accessed 11.4.17)