Hi Jim,
long time ago shading was a wash, higlighting was drybrushing, but painting techniques had evolved to enplacing hl and sh individualy, layer by layer to places where you decide to put them, not where the paint flows by itself, or the releief on the figure pulls out the paint from the brush, this way you have a better control over your work, eg paint hl or sh where there is no sculpted detail - kind of 'painting details in', tricking the eye, or, creating effect of texture, shine (eg lether, silk), setting a zenital light source, etc, etc. This is similar to creating light/shadow effect in 2D (like paintings), the figure is 3D, but you create extra detail on a flat, or badly detailed part or exaggerate it.
The little preactical advise I can give you is that wash in the classical meaning to brush on dilluted paint, running all over your figure, creating pools, is really the past (especially as the fine pigment in acrylics will gather around the edges of the pools).
-you can use it in a moderate way though, when your base colours are painted, applying a thin wash can guide you to see recessed areas, details, where you later apply your shadows.
-Clavin Tan describes using it for pre-shading his figures, applying before the base coat, as acrylics are transparent, dark washes help you again with the shadows.
-another use I found of it is to modify colours, once I painted a jacket grey greenish colour, higlighted with pale blue and it just looked too blue, applied a few, light, green washes and it changed the colour as I wanted and gave an interesting depth, modified shadows, base and higlights at once. But when I do this a get most of the excess out of the brush, so it's not running, or is it a glaze then?!
Hope this helps somewhat
Denes
