Tones and Values

Tonal Values:

Highlight - Lightest value on the form (shiny surfaces) typically the white of the paper

Halftone - Entire area of the form facing the source (mid tone)

Reflected light - Light that bounces onto the shadow from surrounding objects. Gives a 3D quality to the image. Slightly darker than a mid tone

Core of the Shadow - Darkest part of the form, provides the contours of the form 

Cast Shadow - The shadow that the form casts. The darkest region is often where the cast shadow originates from the object. Diffused light yields soft shadows, concentrated light yields dark, hard shadows. 

Types of Shading: 

Hatching: Parallel lines (diagonal, horizontal, ocassionally vertical)

Cross Hatching : Crossing (often diagonal across each other)

Stippling : like dots, but small dashes

Scumbling: compact, small circular motions

Durer  - Veronica

Ingres

Self portrait of Steichen