After the sheets are secured to the wall studs or ceiling joists,
the seams between drywall sheets are concealed using joint tape
and several layers of joint compound (sometimes called "mud").
This compound is also applied to any screw holes or defects. The
compound is allowed to air dry then typically sanded smooth before
painting. Alternatively, for a better finish, the entire wall may
be given a skim coat, a thin layer (about 1 mm or
1/16 inch) of finishing compound, to minimize the visual
differences between the paper and mudded areas after painting.
Another similar skim coating is always done in a process called veneer plastering, although it is done slightly thicker (about 2 mm or 1/8 inch). Veneering uses a slightly different specialized setting compound ("finish plaster")
