value
How light or dark a colour or tone is.
value scale
A strip of evenly stepped values from white to black.
form
A three-dimensional object with height, width and depth (a sphere, a cube), or the illusion of one on a flat surface.
chiaroscuro
Italian for "light-dark": using strong contrasts of light and shadow to model forms and create drama.
highlight
The brightest area on a form, where the light hits most directly.
core shadow
The darkest band on the form itself, where the surface turns away from the light.
reflected light
Light that bounces off a nearby surface back onto the shadow side of a form.
cast shadow
The shadow a form throws onto another surface, on the side away from the light.
stippling
Building value with many small dots; closer dots look darker.
scumbling
Building value with small overlapping circles or scribbles.