Moulding
Introduction
The term "moulding" simply denotes contours that embellish a surface. Such contours produce variation in the value (lightness/darkness) of a surface given the shadows they cast. Moulding can be reduced to seven basic types.
| static | transitional | ||
| flat | projecting |  fillet |
 bevel |
| receding |  channel |
||
| curved | projecting |  bead |
 quarter-round |
| receding |  flute |
 cove |
|
Static mouldings, which begin and end on the same plane, can serve either to divide a surface (when used individually) or to provide a texture (when used repetitively). Transitional mouldings, on the other hand, terminate on a higher or lower plane than they begin. A series of transitional mouldings can be stacked to form a projecting or receding profile, as in base moulding (which widens downward) or crown moulding (which widens upward).
The overall aesthetic effect of moulding depends on the distribution of convex and concave elements. Convexity is strong and supportive, while concavity is delicate and refined.
Flat Mouldings
Fillets and channels are often found in isolation. Small fillets are sometimes used to accentuate larger mouldings.
Curved Mouldings
A bead is often applied on its own, with a similar effect to that of a lone fillet. (A thick bead that encircles the base of a column is called a torus.) A flute may also be used singularly like a channel, or applied repetitively as fluting.
The quarter-round and cove are the building blocks of crown and base moulding, though they may also be used alone for simple transitions, as may the bevel.