The frame along with its mounts protects and often complements the artwork. Art work framed well will stay in good condition for a longer period of time. Joan Miró once did a work specifically to frame with a flea market frame, and many painters and photographers who work with canvas "gallery-wrap" their artwork, a practice wherein the image extends around the edges of the stretched canvas and therefore precludes use of a decorative picture frame. As picture frames can be expensive when purchased new, some people remove pictures from a frame and use the frame for other pictures.
Picture frames have traditionally been made of wood, which is still the most common material, although other materials are used including silver, bronze, aluminum, and plastics such as polystyrene. A picture frame may be of any color or texture, but gilding is common, especially on older wooden frames. Some picture frames have elaborate mouldings which may relate to the subject matter. Complicated older frames are often made of moulded and gilded plaster over a plain wood base. Picture frames come in a variety of profiles, but generally the lengths of moulding feature a "lip" and rabbet, the function of which is to allow a space to hold in the materials in the frame. The lip extends usually about a quarter of an inch past the edge of the rabbet.
The picture frame may contain a pane of picture framing glass or an acrylic glass substitute such as acrylite or plexiglas to protect the picture. In some instances where the art in the frame is dispensable or durable, no protection may be necessary. Glass is common over watercolors and other artwork on paper, but rare over oil paintings, except very valuable ones in some museums. Picture framing glass may be treated with anti-reflective coatings to make the glass virtually invisible under certain lighting conditions. When a picture frame is expected to be exposed to direct sunlight, or harsh lighting conditions such as fluorescent lights, UV filtering may be added to slow down the photocatalytic degradation of organic materials behind picture framing glass.
The elaborate decoration on this frame may well be applied plaster pieces stuck to the wood beneath
For pieces to be framed under glass, except for the most disposable and inexpensive posters or temporary displays, the glass must be raised off the surface of the paper. This is done by means of matting, a lining of plastic "spacers", shadowboxing, stacking two mouldings with the glass in between, and similar methods. If the paper (or other media) were to touch the glass directly, any condensation inside the glass would absorb directly into the art, having no room to evaporate. This is harmful to almost any medium. It causes art sticking to the glass, mildew or mold spore growth, and other ill effects. Raising the glass is also necessary when a piece is done in a loose media such as charcoal or pastel, to prevent smudging. Care should be taken with these works however, if acrylic glass is used, as a static charge can build up which will attract the pigment particles off the paper. Using real glass helps to prevent this.
A passe-partout (or mat) can be put between the frame and picture. The passe-partout serves two purposes: first, to prevent the image from touching the glass, and second, to frame the image and enhance its visual appeal.
Certain kinds of pieces do not usually need glass when framed, including paintings done in acrylic or oil paint (the former is usually waterproof; the latter needs to breathe due to the decades-long drying process), stained glass or tiles, and laminated posters. These kinds of pieces are still sometimes put under glass though, if for example they are framed using mats, or (in the case of oil paintings) they are kept in a carefully climate-controlled environment.
There are some examples in which the protective function of the frame is dispensed with, such as in Daniel C. Boyer's gouache The Three Sphinxes of the Metis in the Meadow of Louis Riel's Shameful Career, in which slits are cut all the way through the frame from the outside of the picture to its inside, and Boyer's The Distant Landscape allows for a figure inside the frame to raise and lower her arm by means of a brad attached through the backing, letting the sword she is holding move up and down in such a slit. In the case of Boyer's scented marker drawing Waiting for a Biscuit, a hole has been drilled in the frame to allow for the work to be smelled more easily.
The treatment of the back of the framed artwork varies widely, from usually nothing in the case of oils, to the frequent use of foam-core boards and other backing boards to provide support, or backing paper[3] or "dust covers" to keep dust and insects out. While these are almost invariably simply functional, there are some examples of works in which they have been decorated (such as Daniel C. Boyer's After the Age of 50, The Angry God and His Rabbit Harem), with this being considered part of the artwork. The use of backing boards is common with watermedia and other art on paper. Usually paper dust covers will be inexpensive craft paper, but sometimes this can tear, so at least one website sells Black Tyvek as an alternative.[4] Another common backing paper in use for archival-quality framing is the acid-free Lineco backing paper, with some citing the risk of tearing of craft paper.[5]
Plique-à-jour picture frames, made of enamel by Bulushoff, are among the most expensive frames in the world.
Source: http://en.wikipedia.org
Reference:
1,"Weird Bird in Love >> Blog Archive >> Upcycling Picture Frames". Retrieved 2010-06-27.
2, Daniel C. Boyer's acrylic on canvas The Prime Ministers of the Acerbic at the Samurais´ Picnic is wood-framed and decorated in pencil and "Dad Bay, or, The George
Strait" has a frame similarly decorated with coloured pencil.
3 "Patent application for trimmer to remove excess backing paper". Retrieved 2009-12-07.
4 "Black Tyvek sold as backing paper". Retrieved 2009-12-07.
5 "Daniel Smith: Lineco Frame Backing Paper". Retrieved 2010-06-15.
6 "Soccer Ball (Football) Shaped Frame for sale on Amazon.com". Retrieved 2010-06-25.
7 "Weird cool images". Retrieved 2010-06-27.
8 Mummy Portrait found within a wooden frame, Egyptology Online
9 Picture Framing Magazine, "A Survey of Frame History, part 1" by Diane Day, August 1998, p.82
10 Picture Framing Magazine, "A Survey of Frame History, part 1" by Diane Day, August 1998, p.82, 84
11 Picture Framing Magazine "Frames of Reference" by Tracy Gill, May 2000, p.85
12 Francis I of France Francis I]
13 Louis VIII style
14 "Picture Frame" (SHTML). Crafty Ideas. KinderArt. Retrieved 2009-03-21.
15 "Block Mounting". Retrieved November 30, 2011.