Frames come in assorted colors, materials and sizes. Most picture frames are made of wood, but they may also be metal, plastic or fiber board. They are usually molded to create depth and may contain a section with an alternate textured material such as canvas, or a gold-leaf stripe. They can be rustic or formal, painted or varnished, and provide for eyes or hooks so they can hang, or fold-out "legs" so they can stand.
Matting for artwork should be archival -- acid-free and made from all-rag fiber. Matting can be purchased from art supply stores and comes in a variety of colors, textures and thicknesses. The mat is used to enhance the art piece, and it is a spacer to keep the piece from directly resting against the glass. Mats are usually cut to the shape of the frame, and may be 3 to 4 inches in width, with the bottom portion being a little wider than the top and sides. The color should be selected to enhance the picture itself and not the room in which the art is to be displayed.
Glass is the traditional protective sheet placed in front of pictures. It is easy to clean and resists scratches. Acrylic substitutes such as Plexiglas are becoming more popular because they are lighter, do not shatter when dropped, and can come with an ultraviolet screen to protect the artwork from light. Pastels and charcoal paintings should not be framed with acrylics because the material's static electricity can cause particles of the medium to separate from the painting.
The mount board or backing mat provides support for the painting and prevents it from buckling. This mat also should be archival, and should fit into the frame exactly. The painting is attached to the mat or the mount board with hinges made from hinging tissue or Japanese rice paper only at the top of the painting to allow for expansion and contraction. The mat is attached to the mount board with linen hanging tape at the top.
The mats and glass are secured in the frame using "points" and a point driver or brads and a brad gun. Points are similar to flat nails and brads are very thin rounded nails. They are driven perpendicularly into the inside wall of the wooden frame. Masking tape or regular transparent tape should not be applied to the painting because they can cause acid damage. However, they can be used over the back of the mount board to close the gaps between the board and the frame and prevent dust and moisture from entering the frame.