A picture frame is a protective and decorative edging for a picture, such as a painting or photograph. It makes displaying the work safer and easier and both sets the picture apart from its surroundings and aesthetically integrates it with them.
Traditionally picture frames have been made of wood, and it remains very popular because wood frames can provide strength, be shaped in a broad range of profiles, and allow a variety of surface treatments. Other materials include metals, e.g. silver, bronze, aluminum, and stiff plastics such as polystyrene. A frame surface may be of any color or texture. Both genuine gilding and imitation gold remain popular, although many other surfaces are to be found in most framing establishments. Some picture frames have elaborate molding, which may refer to the subject matter. Intricate decorations are often made of molded, then gilded plaster over a wood base. Picture frame mouldings come in a wide variety of profiles, generally in some sort of L shape with an upward "lip" and a horizontal rabbet.
