Simple but not easy. This is what I would say about painting volumes.
The principle I use in such ornamental paintings is simple :
_ a mid-tone ( the soft grey I basecoated my canvas with)
_ one value ( darker than the mid-tone) for the shadows
_ another one ( even darker) for the drop shadows, sometimes a third value for the accents ( the darkest darks)
_one value for the lights ( lighter than the mid-tone)
_ another one ( even lighter) for the highlights.
|I did the drawing in charcoal, "inked" it in with some watered down soft grey ( black, yellow ochre and white) and painted the shadows and drop shadows.
|Then I painted the lights and higlights.
|Finally I painted some lighter greys between the leaves and into the moldings.
I guess it sounds and looks easy but I do not think it really is.
If you work, like in this example in flat tones with no gradations ( no blending, it is not possible anyway if, like me, you paint with casein paints on a very absorbent surface) you have to put your strokes in the right place ( this means that you must have a good knowledge of how lights and shadows behave on complex volumes) and these strokes must have the right shape ( which implies that your hand can draw with your brush).
If this was easy we would all be great painters and beautiful paintings would not fascinate us like they do .
If you use the same technique but allow yourself to do a little bit of softening on the edges of you tones, this is what you will get...