A long day glazing a commissioned work today. I've had the same daily painting routine for some years now: 09:00 - 10:30 painting session 1, 10:30 - 11:00 break, 11:00 to 12:30 painting session 2, 12:30 to 13:30 meal break. 13:30 to 15:00 painting session 3, 15:00 to 16:10 long break, 16:10 to 18:00 painting session 4, 18:00 to 19:00 meal break, 19:00 to 20:00 painting session 5 - but rarely and only if needed due to some wet paint that must be tackled in one day.
I thought I'd write something about glazing and mixing colours in this wonderful, transparent dimension. In glazes, colours mix like transparent light filters. The primary colours of red, green and blue transmit only those hues, so a glaze of pure red over a pure blue background would result in black, not violet as in normal paint mixing. It's all about what blocks what. In light the secondary colours are yellow (a mix of red and green), cyan (blue and green) and magenta (red and blue).
This rule means that generally it's better to use secondary colours when painting in layers, unless you want to tend towards black or a primary colour. This is also why a grey underpainting is the easiest colour to use, anything over the top will colourise exactly as you expect, rather than obscure or malform, but the result is less chromanant (that is less 'saturated' in Photoshop-speak). Over many glazes, and the long term, colours will evolve towards the luminary primaries of red, green, blue; or towards black.
I favour one glaze layer, partly because it gives the most flexibility of hue with the greatest efficiency. The most beautiful colours are the most transparent, and perhaps more importantly, the ultra-thin glaze layer makes it easier to add extreme detail to a degree that is not possible in a single layer due to the viscosity of the paint. The more liquid the medium, the more transparent and weaker the paint layer. A good painting needs a solid, perfectly homogenous foundation to be glazed over.
As a rule, glazing a secondary colour over a primary or vice versa will enhance the colour of the primary. Glazing yellow over a green, say a blue-green like Chromium Oxide, will leave the green, contribute the yellow and cut out all of the blue. The same goes with reds glazed with yellows or purples etc. It is with this spell that your Venetian Reds and violet-tinged earth reds can be wonderfully orangified by using yellow glazes.
