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Paintings and Frames Terminology [1]
Canvas - Cloth used as the paint support. Material is commonly cotton, hemp, flax, or sometimes silk.
Enamel -Hard-gloss paint varying somewhat in composition; generally the medium consists of heat-treated oil combined with either natural or synthetic resins.
Encaustic - Method of painting with wax that was common in ancient times; the process consists of melting or burning the color, mixed with wax, into the surface.
Fresco - A painting on damp plaster that uses lime water as a medium; often finished with egg tempera. Sometimes called buon fresco; secco fresco is on dry plaster.
Gesso - Pale, creamy, white priming that provides a ground layer for oil and tempera paintings. The term originally meant a substance composed of burnt gypsum (plaster of Paris) mixed with glue, but it has come to have a wider meaning and now includes grounds made from chalk: (whiting) or other inert white pigments bound with glue size (usually parchment size, calfskin glue, rabbit skin glue, or isinglass).
Gouache - Synonymous with poster paint and opaque watercolor; also known as distemper.
Liner -Traditionally, a fme linen canvas that was made to adhere to the reverse side of a canvas painting to counteract structural weakness in the original canvas or to secure cleavage between the paint/ground and canvas layers.
Lining - A new canvas added to the back of to an old, deteriorating canvas for additional support.
Medium - Material that holds together pigment particles in a paint.
Moisture Barrier - Layer with high water vapor impermeability, such as beeswax, which is often applied as the last stage of conservation treatment to the back of a painting on canvas. Wax-resin lining acts as its own moisture barrier. A moisture barrier may also be applied to the reverse and edges of panel paintings to protect them from changes in atmospheric humidity.
Oil -Oil paints consist of pigments pulverized in a drying oil, usually linseed. Oil paintings are usually varnished after a period of drying to increase the amount of light reflected by the pigments and to impart to the painting a somewhat glossy finish.
Panel - Stiff primary or secondary support of wood, metal, or composition board.
Pastel - Chalk or crayon made from pigments and fillers held together in stick form by a weak gum medium.
Relining - Act of removing and replacing an old canvas' lining.
Size - In its broadest sense, any material that is used to seal a porous surface; the term is frequently applied to a glutinous mixture of gelatin, skin glue, starch, resin, or gum in water. Raw canvas is normally "sized" before the application of the ground or priming.
Stretcher - Wood frame to which the canvas is attached.
Surface Coating - Transparent layer or series of layers applied over the surface of a painting for protection and for a uniform reflection and surface texture; usually consists of natural. or artificial resins, waxes, or oils.
Polymer -Type of thermoplastic material (i.e., may be softened with heat) that is dissolved in a solvent when used as a medium for mixing with pigments to create synthetic polymer paint Common synthetic polymers are polyvinyl acetate, polyesters, epoxies, and acrylic resins.
Tempera - Until the 15th century it may have meant all painting media, but the term "tempera" generally refers to a medium prepared from egg.
Varnish - Transparent surface coating used to protect and enhance the design layer. Varnish contains resinous matter either dissolved hot in drying oil (oil-resin varnish) or cold in a solvent (solvent-type or spirit varnish)..
Frames Terminology
Backing Board -Sheet attached to the back of a frame to protect it from dust, pollutants, and mechanical shock.
Batten, Cleat - Strip of wood nailed or glued across parallel boards or across the grain of a panel for reinforcement, flattening, or to prevent warping. Several battens constitute a cradle.
Compo - Any of various combined substances, such as mortar or plaster, formed by mixing ingredients. Short for composition.
Cradle - Wood structure slotted and joined with glue to the back of a panel painting. Designed to prevent warping, the cradle often forces the panel to crack WIth changes in humidity.
Glazing - Glass or acrylic sheeting that sometimes covers the surface of a painting.
Gilding - Gold leaf or paint containing or simulating gold, usually applied in very thin layers.
Keys, Stretcher Keys - Thin triangular pieces of wood that, when tapped into the corner of a stretcher, cause the stretcher members to be forced apart, thus tightening the canvas.
Mending Plate - Device used to secure the painting in the frame by pressure.
Miter, Miter Joint -The corner where two perpendicular sides of a frame meet. A joint usually made by beveling each of the two frame surfaces to be joined at a 4SO angle, to form a 90° corner.
Rabbet - Groove cut in the edge of the frame to hold the painting.
Stretcher - Wood frame, often with jointed corners, over which canvas paintings are stretched; may be expanded and the canvas tightened by driving in keys or various kinds of springs.
[1] Based largely on Basic Condition Reporting, A Handbook, Marie Demeroukas, editor. SERA, 1998.