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Transparency by Winsor Newton | 
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Transparency by Winsor Newton |
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Every colour is relatively transparent or opaque and this also affects colour mixing. Colours can be optically mixed by layers of transparent colours on the surface rather than directly on the palette. Depth is built up in paintings by this method, it is called �glazing�. Flat areas of colour are achieved by using opaque colours such as cadmiums. The relative transparency or opacity of Winsor & Newton colours is noted on the colour charts.
Utilising glazing Utilising opaque colours
Stephen Godson Emma Pearce
| The thickness of the paint film will of course affect the relative transparency. Thin films of colour will tend to be transparent either because they are physically thin or because the colour has been substantially diluted with medium before application. Thick films will always tend to be opaque because of the density of pigment on the surface. |
Thin
film Thick film
French Ultramarine |
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Thick films of transparent colours will actually appear almost black in masstone. Transparent colours can only be seen when light is reflected back through the paint film from the support. In thick films, the light is absorbed and the colour appears dark. |
  Permanent Permanent Alizarin Alzarinn Crimson on crimson on black white |
When used thinly on black or dark backgrounds, transparent colours will not show as the light is absorbed by the dark surface - typically, a water colour on black paper. Transparent colours therefore appear brightest on white. |
  Cadmium cadmium Red Deep on deep red on white black |
In comparison, opaque colours reflect the light from the colour itself and appear bright on any surface. Opaque colours will also appear very bright when surrounded by black because the light is being reflected by the colour and absorbed by the black. |