The purpose of moldings is to define key architectural elements (for example windows or doors) while introducing proper scale and proportion to the room. How is this done? Moldings are any strip of material whose surfaces have been modified with various cross sections to create attractive bands of light and shadow. Moldings apply light and dark shaded stripes to a structure or object without having to change the material or apply pigment.
These contrasts of dark and light areas provide the required definition to the object. If you imagine the vertical surface of a wall lit by sunlight at an angle of about 45 degrees above the wall: a concave (see fig. A) molding against the wall will produce a horizontal shadow that is darker at the top and lighter at the bottom, while a convex (see fig. B) molding will cause the shadow to be lighter at the top and darker at the bottom.
These basic shapes, their variants, sharp edges, and flats form a decorative vocabulary which can be assembled and rearranged in endless combinations. It is this vocabulary that forms the basis for classical architecture, and ultimately the moldings that we use today. For example:
Placing a convex shaped molding directly above a concave creates a smooth ‘S’ shaped curve with vertical ends. This is called an ogee (or cyma reversal) (see fig. C) molding with the resulting band of light at the top and bottom, but dark in the interior.
A concave shape above a convex shape forms an ‘S’ with horizontal ends and is called a reverse ogee (or cyma recta) (see fig. D) molding, appearing as two dark bands with a light interior.
WHERE MOLDINGS GO
The moldings that are used on the interior of today’s homes are usually found in three basic areas, where walls meet floors, around doors and windows and, where walls meet the ceilings. Moldings are also used on walls in paneling, wainscoting, picture molding, or on ceilings. There are also a myriad of other miscellaneous moldings, such as hand rails, sills, drip caps etc., that provide more of a utilitarian purpose.