I thought I’d use my painting of the black cloth to demonstrate glazing and scumbling as a way to build up value and texture. After my monochromatic underpainting was dry, I loosely painted over it using grays. I wasn’t trying to get the values correct at this point. I’ll work towards that as I progress, using glazes and scumbles. I’ll let this layer of paint dry for a few days.
Below, at my next session, I painted over all of the cloth with a dark glaze mixed with ultramarine blue, raw sienna, and glaze medium. The shadow areas are now approaching their final dark value, but the lights are now all too dark. Instead of wiping the glaze away in these light areas to lighten them, I leave it. After the glaze is dry, I’ll lighten these areas with a scumble.
Below, I started my scumbles. A scumble is a partially-covering layer of a light-valued dryish paint that is scrubbed onto a darker area with a hogs hair brush held on its side. The paint gets caught on the top layers of the canvas’s weave, creating a sparkling effect through which the darker area underneath can still be partially seen. Scumbling always produces a cool look, so I added quite a bit of raw sienna to the gray mix so that my lights would look warm. Since I’m using a spotlight, the light is warm. If the light was coming from a window, it would be cool, and I wouldn’t need to add the warmer tones.
I’ll continue to refine my lights and darks with more glazes and scumbles. You can achieve quite subtle effects this way. The thin dark glaze looks convincingly shadowy and mysterious, and the thicker, more textured paint in the light areas really convey the look of light falling on cloth.