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(4.0) GLOSSARY OF TERMS

PAPER Abrasion​: surface loss caused by friction. Accretion​: deposit of extraneous material on the surface of the object. Base​: non-image side of a photographic print, which serves as the support for the

emulsion. Bloom​: superficial surface cloudiness, white or blue-white in color, caused by moisture

penetrating a surface coating, such as a varnish, emulsion, or gum Arabic. Blister​: separation between layers appearing as an enclosed raised area. Brittleness​ (also called embrittlement): loss of flexibility causing paper to break of

disintegrate when bent. Chalking​: loss of a paint or emulsion layer by powdering off. Cockling​: buckling or waving of the paper caused by expansion and contraction under

changing atmospheric conditions, including temperature and humidity. Crack​: visible break in the surface, occurring when paper is creased or embossed,

sometimes called “crazing” in photographs. Crease​ (also called fold): line or mark made by, or as if by, folding. Dent, Dig, Gouge​: defect in the surface, caused by a blow; a dent is a simple concavity; a dig

applies that some material has been displaced; and a gouge applies that some material has been scooped out and removed.

Deterioration​: breakdown of the paper caused by ingredients added during the manufacturing process or by natural aging; can yield volatile acid products.

Discoloration​: changes in color, such as darkening or fading. Dog-ear​: term commonly used to describe a diagonal crease across the corner of a page. Emulsion​: light-sensitive chemical layer which contains the image of the photograph. Fading​: discoloration seen as a loss of color and sometimes with a change of hue. Ferrotyping​: glossy patches found on the surface of photographs, which have had lengthy

contact with a smooth-surfaced storage enclosure such as polyester or glass. Flaking​ (also called flaked loss): lifting and sometimes loss of flat areas of the surface layer. Foxing​: brown or reddish-brown spots probably caused by mold or the oxidation of iron

particles in the paper support, mount, or backing. Frilling​: separation and lifting photographic emulsion from the edges of the support. Insect damage​: damage caused by insect invasion, such as holes, surface loss, or organic

residue. Loss​: missing area or hole.

Mild, mildew​: group of small fungi which grow under warm, moist conditions on organic substances causing the breakdown of those substances; sometimes apparent as foxing; detectable only by a characteristic musty odor in early stages; appear as web-like outgrowths on the surface in the most advanced stages.

Mount​: paper or other heavy board attached to certain works on paper for the purpose of extra support.

Reticulation​: overall random pattern of cracks which may occur in the emulsion layer of a photograph.

Silvering​ (also called bronzing or mirroring): shiny or mirror-like discoloration in the shadow areas of a photographic images caused by the aging of excessive residual silver compounds.

Soil​: dirty material either loosely distributed on the surface of an object (dust) or firmly ingrained in the surface (grime).

Support​: the paper itself on which a design is executed of which bears the photographic emulsion.

Tear​: linear break in the paper resulting from tension or torsion.

SCULPTURE Acid stain​: removal of color from wood. Accretion​: accidental deposit on the surface of an object, may also be called incrustation,

e.g. salt deposits. Alligatored finish​: network of fine cracks due to improper drying of layers produced by

shrinkage; also called checked finish. Bleaching​: lightening of color through exposure to light and/or chemical agents. Bloom​: hazy, bluish-white color cloudiness, which appears on parts of all of the surface

finish, resulting from exposure to moisture. Bronze disease​: appearance of powdery, light green spots, resulting from exposure to

moisture, attacks copper, bronze, and brass. Buckling​: loosened layers lifted from their normal position; also called flaking. Burn​: darkish discoloration penetrating the veneer, due to excessive heat. Cast​: to form a shape by pouting a liquid metal into a mold. Check​: rupture in wood running along the grain from the edge of a board or panel for a

part of its length, caused by accelerated drying. Corrosion​: chemical alteration on the surface or metals caused by agents in the

environment; tiny nodules or crust may form on the surface; color may change. Crazing​: surface fractures of glass caused by a reaction of moisture, against an unstable

chemical composition; shows up in various degrees ranging from simple cloudy or

dulled appearance to severe “crizzling” (surface fractures) and occasionally, even the repeated formation of moist, slippery, surface films.

Dent​: physical depression on the surface of the object. Dry rot​: decay of seasoned timber caused by fungi that consume the cellulose of the wood,

leaving a soft skeleton that is readily reduced to powder. Dust​: loose soil or other solid matter distributed on the surface. Efflorescence​: powdery surface crust formed when substances in plaster or varnish

migrate to the surface and crystallize upon contact with air/ Erosion​: surface destruction of metal caused by excessive wear. Finish​: final treatment or coasting of a surface. Fluorescence​: remnants of restoration exposed as greenish tint under ultraviolet light. Grime​: soil tenaciously held on the surface of an object. Incrustation​: a crust or hard coating of a surface. Insect manifestation​: light colored powder (frass) left by wood boring insects. Mildew​: whitish coating of fungi. Mold​: growth of minute fungi under the conditions of high humidity and lack of ventilation;

visible as fine fluff or furry coating. Oxidation​: surface “crust” or tarnish on metal resulting from a chemical reaction with

oxygen in the presence of moisture; can be dull, reddish-brown, or black film, depending on the type of metal.

Patina​: color or finish of bronze, copper, or wood surfaces. Pitted​: series of small physical surface depressions due to the spattering of some eroding

or corrosive agent. Split​: rapture in wood running along the grain from end to end of a panel or board, causing

complete separation. Tarnish​: see oxidation. Warpage​: distortion in wood cause by expansion and contraction across the grain. Wear​: surface erosion, usually at edges resulting from repeated handling.

CERAMIC Biscuit​: pottery after the first firing and before glazing. Bone china​: combination of china clay, china stone, and bone ash; intermediate between

hard porcelain and soft porcelain. China​: generic term for all types of ceramic; originally denoted important Chinese

porcelain in England. Crazing​: of fine cracks in the surface of the glaze; less prevalent after 1885.

Dry edge​: unglazed portion of the edge of the base. Earthenware​: coarse, opaque, unglazed, porous, ware, which has been fired once. Enamel​: glassy substance, colored by metallic oxides, applied by fusion as ornamentation. Glaze​: vitreous or glossy coating or surface on ceramics. Greenware​: unfired clay ware; does not denote color. Marbling​: coating earthenware in imitation of variegated marble. Molding​: method of pressing soft clay into a mold used for forming hollowware. Porcelain​: vitreous, translucent china. Pottery​: soft, fired opaque earthenware. Sponging​: stipple-like decoration of color applied by dabbing with a sponge. Springing​: molded ornamentation applied to body before firing. Spur mark​: rough spot left on bottom of china by spurs or stilts during firing. Throwing​: shaping clay on a potter’s wheel to form a vessel. Transfer print​: applied, engraved, color decorative elements to ceramics. Turning​: shaving greenware in a lathe to make it lighter and more symmetrical. Underglaze painting​: color glaze applied to biscuit ware and fired before coating with

clear glaze.

GLASS Abraded decoration​: shallow grinding process to apply design to surface. Agate glass​: decorative opaque glass resembling semi-precious stones such as agate, onyx,

and malachite. Alabaster glass​: white, translucent, ornamental glass. Applied relief​: relief decoration attached to a surface after it has been formed. Bevelled glass​: flag glass with edges cut at an angle, forming chamfered corners. Blown-molded glass​: glassware formed by blowing molten glass into a mold. Crizzling​: network of fine, internal cracks and drops of moisture forming on surface

because of defect in glass; also called “diseased.” Cut glass​: decoration of grooves and facets formed by cutting into the surface with a

rotating wheel. Diseased​ glass: see “Crizzling.” Enamel​: glassy substance, colored by metallic oxides, applied by fusion as ornamentation. Engraving​: process of cutting a design into glassware with a sharp instrument or rotation

wheel. Etching​: design produced by coating surface with acid-resistant material then scratching

the design into the surface and exposing it to acid.

Free-blown glass​: glassware formed by blowing molten glass into a blowpipe and shaping tools; also called ​“hand-blown glass.”

Gilding​: process of decorating glassware using gold leaf, gold paint, or gold dust. Hand-blown glass​: see “Free-blown glass.” Iridecscent glass​; glassware, which has a lustrous, rainbow-like surface appearance

resulting from burial in soil; not to be confused with diseased glass. Pontil mark​: rough mark int he center of the bottom of a glass vessel, formed when the

pontil, or blowpipe, was broken off. Pressed glass​: made by placing a blob of molten glass in a mold and pressing with a

planner to form the inside shape.

TEXTILE DEFECTS Abrasion​: wearing of surface, such as loss from scraping, rubbing, grinding, or friction of

some kind. Accretion​: accumulation of extraneous material on the surface, such as flyspecks. Corrosion of metal threads​: chemical alteration of metal threads causing hard nodules or

crusts on the surface. Crease​: tightly pressed fold, causing threads to weaken and break. Crocking​: rubbing off on color, resulting in loss of dyestuff but not loss of fiber. Cut​: clean break in the fabric. Discoloration​: general area of change in the color from the prevailing tone. Embrittlement​: perceptible decline in firmness, pliability, and suppleness to the degree

that damage may be imminent. Fading​: discoloration seen as a loss of color. Fold​: pleat resulting from one part double or laid over another part. Fraying​: raveled or worn spot indicated by the separation of threads, especially on the

edge of a fabric. Hole​: area of missing fibers, from both the warp and the weft. Insect damage​: evidence of insect invasion, such as holes, or deposits such as larvae, silky

deposits, or grass (accumulations of granular excreta resembling sand). Loss​: general term for an area of missing fibers. Missing element​: loss of an integral component of, or an addition to, the fabric, such as a

basket handle, curtain pull, or tassel. Mold​: large group of small fungi which may cause staining. In advanced stages, colored,

furry, or web-like outgrowths may appear on the surface. Previous repair​: evidence of previous conservation work on an old defect. Stain​: soiled or discolored spot.

Stiffness​: loss of flexibility and suppleness of fibers, offering resistance to bending. Surface grime​: general term for any type of material, which dirties the surface. Tear​: irregular break in the fabric. Weak seam​: looseness in the attachment of two adjoining pieces of fabric.

PAINTINGS Abrasion​: damaged area of paint, resulting from scraping, rubbing, or grinding away of the

upper paint layers. Accretion​: accidental deposit on the surface of an object or picture; in paintings, often

flyspecks. Batten​ (sometimes called 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.

Blister​: convexity or bulge in the paint surface indicating cleavage of paint and/or ground layers, either from each other or from the support.

Bloom​: hazy, bluish-white color cloudiness, which appears on parts of all the surface of some varnish films, resulting from the breakdown of the consistency of the coating by moisture or other pollutants.

Buckling​: appearance of waves or bulges in a canvas that has slackened on its stretcher. Canvas​: cloth used as a paint support. Common materials used are cotton, hemp, flax, or

sometimes silk. Chalking​: loss of pigment in a paint layer by powdering off. Results from either an

insufficient quantity of binding medium in the paint when originally applied for a loss of the binding medium as a result of damage or deteriorating conditions.

Check​: rupture in wood running along the grain from edge of a board or panel for a part of its length.

Cleavage​: separation between paint layers, paint and ground layers, or ground and support, occurs where adhesion between layers has deteriorated.

Crackle​ (or craquelure): a network of fine cracks which develops in grounds, paint layers, and surface coatings of paintings in the aging or drying of the materials. Age cracks usually penetrate both the paint layer and ground; they are caused by strain from movement of the support. Drying cracks (or youth cracks) are caused by the failure of the film to withstand its own contraction during drying and they usually do not penetrate the whole structure from support to surface. Mechanical cracks, although similar in appearance and character to age cracks, are often caused by external local pressure.

Cradle​: wood structure fixed to the back of a panel painting. Consists of wood strips slotted and joined with glue to the back of the panel parallel to its grain. Designed to prevent warping, the cradle often forces the panel to crack with changes in the humidity.

Craze​: fine system of crackle, usually found in aged film, which has lost plasticity and becomes dry and brittle.

Cupping​: islands of paints with upward curving edges bounded by cracks. A weak canvas support is often drawn upward with the curving edges.

Dent​: depression on the surface of the painting. Draw​: system of wrinkles radiating from a corner of a stretched fabric or parallel wrinkles

running into a stretched fabric from an edge. Flaking​: breaking away of detachment of one or all paint and ground layers from the

support in either small particles or larges areas. See also blister, buckling, cleavage, and crackle, of which flaking is an extreme stage.

Gesso​: pale creamy white priming, which provides a ground layer for oil and tempera paintings. The team originally meant a substance composer of burnt gypsum (plaster of Paris) mixed with glue, but has come to have a wider meaning and now includes grounds made from chalk (whiting) or other inert whit pigments bound with glue size, usually parchment size, calfskin glue, rabbit skin glue, and isinglass.

Granular surface​: paint structure, which consists almost entirely of pigment particles with little or no vehicle; used generally in describing the condition of materials, which have lost their cohesiveness.

Ground​: opaque coating applied to the support of a painting after sizing to give it the correct properties for receiving paint or gold leaf. The common ingredients are glue or oil as a medium, inert fillers, earth colors, white or red lead, and driers. The ground used on commercially prepared canvas is often called priming (see priming).

Impasto​: thick, often opaque, are of paint, which protrudes above the surface to which it has been applied.

Inpainting​: introduction of new paint material into the areas of loss in an original construction.

Interstices​: crevices between the threads of a canvas support. Keys​: thin triangular pieces of wood which are tapped into the corners of a stretcher

causing the stretcher members to be forced apart, thus tightening the canvas. Lining​: fabric (traditionally a fine linen canvas) adhered to the reverse side of a canvas

picture to counteract structural weakness in the original canvas and/or to secure cleavage between the paint/ground and canvas layers.

Loss of surface​: gap or cavity caused by the loss of a flake of paint or ground from the surface of a painting.

Medium​: material that holds together pigment particles in paint.

Moisture barrier:​ layer with high water vapor impermeability; such as beeswax, which is often applied as the last stage of treatment to the back of a glue past relining. 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.

Overpainting​: additions, which partially or wholly cover original paint. Paint​: finely ground pigment, suspended as discrete particles in a film-forming material or

medium, having the proper of drying to a continuous adherent film when applied to a surface or ground. Generally, the pigments used to make various types of paint, e.g., watercolor, encaustic, tempera, oil, are the same. The binding mediums differ in each: water-soluble gums and glues for watercolor; wax for encaustic; egg yolk plus water and/or oil for tempera; drying oils for oil paints.

Panel​: stiff primary or secondary support of wood, metal, or composition board. Pentimento​: phenomenon in paint involving translucency of upper layers and emergence

of tones beneath. As the index of refraction rises, more light can penetrate through the paint layer, and the drawing and underpants once concealed show through.

Priming​: layer following the ground layer providing a modified color base and/or textured surface on which to paint. Today, priming and primer, meaning in preparation coating for canvas, are synonymous with ground (see ground).

Raking light:​ light rays directed parallel to the surface of an object or picture, used in examination of objects, especially paintings, to indicate buckling and other irregularities of conformation.

Relining​: removal of the old lining canvas and adhesive and mounting on a new lining canvas with new adhesive.

Size​: in its broadest sense, any material that is used to seal a porous surface; frequently applied to a glutinous mixture of gelatin, skin glue, starch, resin, or gum in water. Raw canvas is normally “sized” before application of the ground or painting.

Split​: rupture in wood running along the grain from and to end of a panel or board causing complete separation.

Stretcher​: wooden frae over which canvas paintings are stretched, often with jointed corners; may be expanded ad the canvas tightened by driving in keys or various kinds of springs.

Stretcher crease​: appearance on the paint surface of the form of the stretcher bars as area of relatively uncracked or uncured paint (generally in a picture where the surface exhibits crackle). The edges of the stretcher are marked in the paint surface by fairly continuous parallel straight cracks.

Support​: physical structure of a painting which holds or carry the ground and paint film; can be any material such as fabric, wood, metal, or paper on which a painting is executed.

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; consists usually of natural or artificial resins, waxes, or oils.

Transfer​ (or transposition): removal of the support from the reverse of the paint and ground layers and subsequent mounting of these on a new support. In some cases the ground is removed where it is in bad condition and a new ground is applied to the reverse of the paint film.

Varnish​: surface coating containing resinous matter either dissolved hot in a drying oil (oil-resin varnish) or in cold in a solvent (solvent-type or spirit varnish).