Picture Framing Terms
This glossary contains many common terms relating to framing techniques, tools, equipment and supplies.
Many of these techniques, tools, and supplies will be used in the designing of your framing job.
These definitions of picture framing terms are to help you understand some basic concepts with regard to framing.
If you should have any questions please do not hesitate to contact us for more information.
Acid Free
Material with a pH of 7 or greater
Archival Paper
Paper that is free of acid and lignin. The paper may have neutral pH (6.5 to 7.5) or be buffered.
Adhesive
A material that causes two surfaces to adhere to each other. Adhesives used in picture frames include pressure sensitive tapes, cooked starch paste and polyvinyl acetate.
Alpha Cellulose
The most pure of the three forms of cellulose, the chief constituent of all plants. Alpha cellulose is characterized by the longest polysaccharide chain. The strongest, most stable papers are made from alpha cellulose fibers.
Anti-Reflective Glass
Glass that is treated, usually with a thin film coating, to significantly reduce reflections without significantly affecting the sharpness of a framed image or object behind the glass.
Barrier Material
A layer of material that is used in the framing package to impede the migration of acid, especially between moulding and fillet and art. Aluminum foil with an acrylic adhesive on one side and buffered, acid-free, lignin-free paper on the other is most commonly used.
Buffering Agent
A chemical used to regulate pH. Buffered mat and mounting boards typically have calcium carbonate added to the paper to achieve a pH of about 8.5. This is sufficient to counteract migrating acid from decomposing lignin in the wood frame if the mat has at least a two inch border.
Conservation
Framing art and objects with materials and methods that provide a stable environment and minimize the deterioration of the framed item. Synonymous with preservation.
Conservator
A person specially trained to restore an item to as close to its original condition as possible. The amount of restoration possible depends upon the item’s current condition. A conservator usually specializes in a narrow field, such as art on paper, oils, needleart, etc.
Cotton Linters
Cotton fibers adhering to cotton seeds after the ginning operation. The fibers must be removed from the cotton seeds before they are pressed for cotton seed oil. Cotton linters are used to make rag paper. Rag matboard is made entirely from cotton linters and buffering agents.
Deckle Edge
The irregular edge of handmade papers. Machine made papers can have imitation deckle edges produced mechanically after the paper is dried. Art on deckle edge paper is often float mounted so that the irregular edges can be viewed.
Dustcover
Paper applied to the back of the picture frame. As the name implies, its purpose is to keep dust from entering through the back. It also inhibits the entry of insects.
Face Paper
The outer layers of paper on mat, mounting and filler boards. The front face paper on mat boards are available in many colors, patterns and textures that enhance framed art.
Fillet
A narrow strip of wood placed in the rabbet of a moulding or inside a mat opening to provide an accent color or texture.
Float Glass
Glass produced by floating molten glass on a bed of molten tin, resulting in an optically flat surface. Float glass is the picture framing standard glass. After cooling the glass may be treated to control light reflections and increase ultraviolet light filtering properties.
Float Mount
Mounting artwork on a decorative mat so that all edges are visible after the art is framed. Most commonly done with art on deckle edge paper or very old documents where the edge has deteriorated through repeated handling or the chewing actions of small animals.
Fugitive Colors
Pigments and dyes that fade or change color upon exposure to light (particularly ultraviolet) and/or heat. Artists and printers of reproduced art are not always sensitive as to whether or not the inks or pigments they use are fugitive. Ultraviolet blocking glass is an economical way to preserve color fidelity.
Glazing
A transparent material used to cover some artwork. The most common materials are float glass and acrylic. Acrylic is lightweight and colorless, but not optically flat. Low iron content float glass has recently become more available so that it is now possible to use optically flat, almost colorless glazing in picture framing. Artwork on paper should always be covered with glazing to protect the paper. A spacer should always be included between the art and glass to prevent the art from adhering to the glass. The spacer can be a window mat or a small strip of acrylic.
Glue
Adhesives made from animal bone and skin. Often it must be heated before it is capable of being applied to the surfaces which are to be joined.
Hinge Mount
A low intrusion method that attaches art on paper to the mounting board using Japanese paper and cooked starch paste. A strip of long fiber, acid-free paper is torn so that the fibers stick out well past the edge of the paper. A small amount of cooked starch paste is used to moisten the fibers at one end. The strip is placed on the art so that the fibers touch the paper of the art just past its edge. Another strip of torn paper is attached to the first strip and the mounting board with starch paste well away from the art.
Japanese Paper
Thin, strong papers made in Japan from native plants among which are kozo (paper mulberry). The papers are handmade from long fibers. When torn, rather than straight edges, the edges are very feathery with long fibers, which do not tear. This paper is used for hinge mounting and mending art on paper.
Lignin
Lignin occurs in most plant cell walls and gives structural strength to the plant. Lignin is unstable and becomes acidic as it breaks down. The acid that forms can migrate to framed art unless the mat is buffered, turning the paper brown and causing it to dry.
Molecular Trap
Natural or synthetic aluminosilicates (zeolites) having uniform, small pores. They are important in picture framing, since when they are added to mat board and backing board, art harming airborne pollutants that enter the pores can be immobilized.
Mylar®
A registered trademark of Dupont for polyester films. Mylar-D is the most stable polyester film and is used by picture framers to encapsulate art on paper, paper documents or other planar objects where it is important to be able to view the entire object.
Non-Glare Glass
Glass where one or both surfaces have been treated chemically or mechanically to slightly roughen the surface, causing reflected incident light to be dispersed in all directions. Because the glass surface is not smooth, art images behind the glass tend to be softened. The softness depends on how far the art is from the glass. No more than two or three mats are recommended to be used with non-glare glass. Objects in deep frames (shadow boxes) should never be displayed with non-glare glass.
Optically Flat
Produces distortionless reflections.
Polyvinyl Adhesive
A water based adhesive made from polyvinyl acetate. It is used to bond porous and semi-porous materials such as wood, paper, cardboard, cloth and leather. When dry the adhesive is an almost colorless, translucent, flexible, acid-free solid. Polyvinyl adhesive remains flexible for long periods of times, perhaps 300 years according to some experts researching adhesives for conservation book binding. This adhesive is almost universally used to join picture frame corners.
Premium Clear Glass
Float glass without special treatment. It reflects about 8% of incident light and blocks about 42% of incident ultraviolet light.
Preservation
Framing art and objects with materials and methods that provide a stable environment and minimize the deterioration of the framed item.
Reversible
Any method used to mount art or objects that can be undone in such a way that essentially no harm is done to the art or object. Methods include hinge mounting works of art on paper, stitching textiles to mounting boards with cotton thread and pinning needleart with stainless steel or nickel plated brass ball point pins. Adhesive tape and glue are not reversible.
Starch Paste
Paste made by cooking refined rice starch or wheat starch granules with a small amount of water until they burst and a gelatinous paste is formed. The paste is used as a hinging adhesive in preservation framing.
Ultraviolet Blocking
Glass that is treated, usually with an applied coating, but may have a plastic filter sandwiched between two pieces of glass, that prevents 97% of ultraviolet radiation from being transmitted through the glass. UV blocking glass is the glazing of choice for art that will be displayed in daylight, fluorescent or halogen lighting.
Ultraviolet Radiation
Very energetic electromagnetic radiation just beyond the blue end of the visible spectrum, it is very damaging to fugitive pigments and dyes.
Window Mat
Mat board with a hole (window) cut in it through which the framed art is visible. The color of the mat is chosen to direct the eye of the viewer into the art. The width of the mat should be at least 2 inches, but in harmony with the dimensions of the art and the width of the frame moulding. The mat also provides space between the art and glazing. For preservation framing, the mat board should be made from purified alpha cellulose or cotton linters.
