The Interdimensional Traveler: A Full Body Character Design - ZBrush Creature Design: Creating Dynamic Concept Imagery for Film and Games - page 167

Zoom into the face and use the Sandard brush with Alpha 01. Dial down your draw size to about 25 and
loosely sketch raised wrinkles all around the mouth and eye areas. Try to keep these lines gestural and loose.
The idea is to create the impression of raised tissue wrinkles in the skin, like wet tissue paper over bone
( Figure 3-73 ) . You may continue these wrinkles down the neck.
A quick way to add raised wrinkles like this to select Alpha 58. Figure 3-74 shows Alpha 58 applied to
the model surface with ZAdd on. This helps create a fine crosshatching wrinkle pattern of raised rather than
recessed lines.
Figure 3-73: Using the Standard brush and Alpha 1 to freehand sculpt a wrinkle pattern on the face