This glossary's intent is to define specialized terminology used on this website as well as in condition and treatment reports. Some terms are more widely used than others and usage may vary according to individual conservators. See also ArtLex Art Dictionary at http://www.artlex.com for more art related definitions.

For more terms describing artist's techniques and media on paper refer to the following books: William Ivins, How Prints Look; Felix Brunner, A Handbook of Graphic Reproduction Processes and Paul Goldman, Looking at Prints, Drawings and Watercolours.

A
Abrasion - Damage caused by friction or rubbing action against the object’s surface by a hard, rough or tacky material. May occur accidentally, inadvertently or deliberately, including as a result of cleaning. Appearance of surface abrasion range from matte areas, to lifted fibers, to uneven and scratched areas.

Acid-free - Neutral or alkaline in pH; often used to describe paper based materials that are used to house art or artifacts.

Acidic - Less than pH7. For example, pure cellulose is initially slightly acidic, but on exposure to light, oxygen, pollutant gasses and acidic materials in its environment, its pH can drop lower and lower. As a result, the paper loses strength and flexibility, and sometimes changes in color.

Acid migration – The transfer of acids from one acidic material to another less acidic material, either by direct contact or by absorption of acidic gases from the surrounding atmosphere.  The less acidic material usually becomes stained and weakened. This is often seen with artwork that had been produced on good quality paper and then was framed with poor quality matboards and/or corrugated boards. As a result, the good quality paper becomes brittle and discolored with matburn and stains due to acid migration from contact with the acidic framing materials.

Acidity - Chemical state characterized by a pH below pH 7, where pH is a reciprocal logarithmic measure of the concentration of hydrogen ions. Acids are chemical substances with a pH below 7, which react with alkalis and can neutralize them. Acids in the presence of moisture degrade paper by causing acid hydrolysis of the cellulose molecule, breaking up the long cellulose polymer into shorter segments, resulting in paper which is weak and brittle.

Accretion - Foreign material attached to the surface of an object. In general, it is superficial and rests on top of the substrate; rather than being imbedded. An accretion may cause staining or planar deformation in the support. Examples include mold growth, food, or fecal matter of insects or rodents.

Acryloid (paraloid) B67 - Isobutyl methacrylate polymer. An acrylic resin produced by the Rohm and Haas Company that is used as a protective film by conservators.

Acryloid (paraloid) B72 - Ethyl methacrylate copolymer. An acrylic resin produced by the Rohm and Haas Company that is used as an adhesive, protective film, and fixative by conservators.

Acryloid (paraloid) B48N - Methyl methacrylate copolymer. An acrylic resin produced by the Rohm and Haas Company that is used as a protective film, that is especially known for its ability to adhere to raw and primed metals.

Adhesive - A material which joins surfaces together by adhesive forces. Adhesives may consist of starch, gums, proteins, rubber, shellac or synthetics. Each type has different working properties and chemical characteristics.

Aging cracks - Cracking caused by stress as a result of adverse environment conditions, mechanical or other causes that have developed over an extended period of time. The cracks are through all the layers of a painting beginning with the support. The individual cracks or fissures can form a network pattern of straight or barely curved lines.

Alligatoring - The upper paint layers pull away in a pattern similar to the look of an alligator’s hide when the drying process is compromised. The layer below is visible and the upper layer has a raised appearance. See also drying cracks.

Alkaline / Alkalinity - Chemical state characterized by a pH above pH7, where pH is a reciprocal logarithmic measure of the concentration of hydrogen ions. Alkaline compounds such as calcium or magnesium salts can protect the cellulose in paper from acid degradation by neutralizing acidity. Alkaline solutions also swell cellulose which can aid in the release of stains and discoloration. Very strong alkalis can degrade the cellulose polymer chain by the peeling reaction. Some colorants are pH sensitive and change color or are decolorized by alkalinity. Physical qualities and long-term strength of papers also depend on the pH of the paper and the percent of alkaline reserve present.

Alkaline reserve - Alkaline earth salts of calcium or magnesium, such as calcium or magnesium carbonate, introduced into paper at its manufacture or in conservation treatment. Calcium and magnesium carbonate are consumed in the process of neutralizing acidity. Their presence assures paper longevity as long as there is an adequate unreacted reserve to neutralize acidity in the future.

Anachronistic - 1. An error in chronology; especially: a chronological misplacing of persons, events, objects, or customs in regard to each other. 2. A person or a thing that is chronologically out of place; especially: one from a former age that is incongruous in the present.

Animal glue - An impure, brown protein-based adhesive made from boiling the hooves and cartilage of animals. Also known as hide glue.

ANSI (American National Standards Institute, Inc.) - ANSI facilitates the development of American National Standards (ANS) by accrediting the procedures of standards developing organizations (SDOs). These groups work cooperatively to develop voluntary national consensus standards. Accreditation by ANSI signifies that the procedures used by the standards body in connection with the development of American National Standards meet the Institute’s essential requirements for openness, balance, consensus and due process. www.ansi.org

Archival materials - This term should be used to describe materials that are intended to be long lasting due to their high chemical stability, neutral or slightly alkaline pH, good aging properties and inertness. The term currently has no standard definition or quantifiable method for verification and is therefore often used improperly on product packaging.

Art Conservation - See Conservation.

Art-sorb - A commercially available material that is used to balance relative humidity (RH) in enclosed environments. It has the ability to absorb moisture if RH is too high, or release it if RH is too low. Available as beads, cassettes or sheets, and commonly is preconditioned at 50% RH although this can be changed if required.

Aqueous - Water based solution.

Attachments - Integral items or materials (for example, labels, collage elements, etc.), which are adhered locally to the primary support rather than overall.

Auxiliary support - Structural materials that lend rigidity and support to the primary support, the surface which bears an image. Examples of auxiliary supports include stretchers, strainers, mats, etc. See Supports.

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B
Backing - Material(s) behind the primary support. Attachment may be with hinges, partial (edges) or overall. Backings may or may not be original to the support. See also secondary support and mount.

Batten - A piece of wood (or other material) used to reinforce joinery or align edge joined boards. Also known as a cleat.

Beva-371 Film Adhesive - A heat-activated film used to attach artworks to mounting supports.

Binder - The material which holds pigment particles or dye in a paint or other artist's material and which helps adhere it to the support. Examples of binders include linseed oil, acrylic, gum Arabic, honey, egg yolk, etc. Also called medium.

Blanching - An area of binder which has developed an unintended white or whitish appearance, possibly the result of exposure to moisture or fast-evaporating solvents. Also called bloom, especially in referring to varnish.

Bleeding - Physical movement of non-fast colorants. Usually occurs in the presence of moisture and results in a blurred or feathered appearance. Movement may occur laterally or penetrate to the reverse, which is also called sinking.

Bleaching - A cosmetic process done to works of art on paper which involves permanently changing the chemical structure of substances that are colored to yield substances that are not colored.  Bleaching of paper is considered safe if an appropriate bleaching agent is used under controlled conditions and thoroughly removed from the paper after treatment. There are both oxidizing and reducing bleaching agents. See also stain reduction.

Blister - A convex bulge on the paint or primary surface where the material has internally detached from the layer below.

Blocking - Condition in which adjacent sheets of paper, photographs, or other materials, become unintentionally adhered, often because adhesive or gelatin is present on one or more sheets and has been subjected to high humidity and pressure while the adhesive or gelatin has softened. In severe cases, the materials cannot be separated.

Bloom - Opaque or cloudy white appearance on a transparent film of varnish or lacquer which may be related to moisture absorbed in the film. This condition can also occur in the binder of various artist media. See also blanching.

Bole - A refined clay that is traditionally used in the gilding process. It is applied over gesso, mixed with glue, to act as a base for the gold leaf. The color can vary (typically yellow, terra cotta, and black), which may affect the final tone of the gold.

Break(s) - Scission of fibers due to physical weakness in the support; generally caused by simple handling and flexing or repeated folding of a very brittle support, in distinction to tearing or cutting.

Brittle - Description of an item that is easily cracked, broken, weak or inflexible. The characteristics of very low folding strength or tendency to break when folded are associated with adverse effects of acids, oxygen, light, heat and residual chemicals from the original manufacture of the paper or after manufacture. The term is usually associated with high levels of acidity in works on paper. Also known as embrittlement and desiccated. See also acidity.

Buckling - A random deformation in plane, usually concave and convex in appearance. See also cockling.

Buffer - A solution of ions and acids or bases which is capable of maintaining a nearly constant specific pH despite the addition of further acids or bases. In conservation, the term buffered is sometimes used erroneously to refer to the alkaline reserve. It is preferable to refer to the added substance as alkaline reserve and avoid the use of the word buffer in this context Nonetheless, matboard and paper goods with an alkaline reserve have a history of being called buffered paper or board. The term buffer is also used in describing the effect of certain materials to lessen the shock of sudden change. In discussing environmental conditions for artwork, packaging or housing can be designed and constructed to buffer sudden changes of temperature, relative humidity or shock.

Bulge - A planar distortion or protuberance characterized by a distinct convex formation.

Burnished - Surface area rubbed or polished yielding a shiny and/or smooth appearance. Burnishing may occur accidentally or deliberately.

Burn - Darkening, scorching, embrittlement or destruction caused by heat, fire or certain chemical reactions.

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C
Calender - Manufacturing process of pressing paper or cloth between a set of polished metal rollers in order to give it a very smooth, polished surface.

Card - A medium weight, stiff paper support which generally has a smooth, polished surface due to a manufacturing process known as calendering.

Cast / Casting - Involves pouring a liquid material (epoxy or polyester resins) into a mold to reproduce a form or shape. More viscous materials can be used for shallow molds. Casting is also performed with liquid metals such as bronze.

Cellulose - A long-chain carbohydrate polymer found in the walls of plant cells. It is the primary constituent of paper.

Check - An incomplete partial split along the grain of wood, resulting from uneven shrinkage.

Chip - A small loss with no discernible pattern resulting from force, tension or impact.

Cleat - See batten.

Cleavage - Separation or splitting between layers of media, for example, cleavage of paint from a support. See also flaking.

Coating -1. A material applied to the surface of an object during its manufacture which affects its surface characteristics and enhances its working properties. 2. Application of a material to a support and/or media for various treatment purposes, such as consolidation, fixing, sizing or varnishing. 3. Application of a material to the support and/or media, at the time the object is produced or at a later date in order to manipulate the visual or working properties of the support or media. (JEK)

Cockling - Deformation of a planar support, characterized by multiple alternate concave and convex distortions or ripples, often in parallel ridges.

Collector's mark - An identifying mark, generally a relatively small stamp - inked, embossed or perforated - or a marking applied by some other means, which denotes ownership or provenance.

Compensation - A restoration technique in which losses to the support and/or media are replaced partially or completely, to providevisual continuity and in some cases to enhance structural support.

Condensation - The conversion of a substance (as water) from the vapor state to a denser liquid or solid state usually initiated by a reduction in temperature of the vapor. This can occur when humidity is trapped in an enclosed area without air circulation (such as in a frame) and forms a vapor.  Condensation can result in mold growth, water stains and foxing.

Conservation - The profession devoted to the preservation of cultural property for the future. Conservation activities include examination, documentation, stabilization treatment, and preventive care in accordance with an ethical code such as the AIC Code of Ethics and Guidelines for Practice.

Conservator - A professional whose primary occupation is the practice of conservation and who, through specialized education, knowledge, training and experience, devises and implements all the activities of conservation including preventive care, examination, documentation, stabilization treatment and aesthetic treatment activities in accordance with an ethical code such as the AIC Code of Ethics and Guidelines for Practice.

Conservation Technician - An individual who is trained and experienced in specific conservation treatment activities and who works in conjunction with or under the supervision of a conservator. A conservation technician may also be trained and experienced in specific preventive care activities.

Consolidation - Reattachment or securing of media which is flaking, cracking and/or friable, by introduction of an adhesive and/or by application of heat, solvent, pressure.

Corrosion – Deterioration of a material (usually metal) from a chemical or electrolytic reaction. Rust is one type of corrosion.

Crack - Physical separation or break within one or more layers of a material, often the result of mechanical stress or contraction on drying.

Cracquelure/ Crackle / Crackling / Crazing - a network of fine cracks which develop in painting grounds, paint layers and/or surface coatings during the drying and/or ageing process.

Crease - A line, mark or ridge of paper caused by folding or crushing.

Cultural property - Objects, collections, specimens, structures or sites identified as having artistic, historic, scientific, religious or social significance.

Cupping - Islands of paint, bounded by cracks with upward curving edges.

Cut - A sharp-edged break in the support, caused by a sharp instrument or object.

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D
Darkening - A shift in color which is darker than the original appearance. May occur as a result of contact with poor quality materials and/or exposure to adverse environmental conditions. The appearance of darkening may be partial or overall.

Deacidification - A general term used to describe treatment steps taken to raise the pH of acidic paper to pH7 (neutral pH) and to pH higher than 7 (alkaline pH). Also called neutralization and alkalization. Deacidification can be accomplished by immersion in or by spraying with an aqueous or nonaqueous alkaline solution or suspension, or by deposition of an alkaline earth salt on materials in a vacuum chamber. If deacidification is accomplished by immersion in an alkaline solution, it may also be accompanied by removal of soluble acidity, degradation products, and discoloration. See also acidity and alkalinity.

Deckle edge - A thinner, uneven accumulation of paper fibers at the edge of a paper sheet. It occurs because relatively less paper fiber is deposited along the deckle of the papermaking mold during the manufacture of handmade paper. An imitation deckle edge may be artificially created on machine made paper.

Degradation
Biological degradation - Deterioration caused by biological factors such as mold, insects, rodents, etc.
Chemical degradation - Deterioration resulting from reaction between primary support and/or media and other chemical species such as atmospheric pollutants, residues from manufacture and poor quality materials.
Physical degradation - Deterioration caused by physical factors such as wear and tear, use, handling, movement, etc.

Deionized water - A type of purified water, which has had ions of dissolved chemicals removed by being passed through one or more deionizing columns. Deionizing columns do not remove solid particles, so particulate filters are needed as well. Most ions removed are harmful to paper, such as iron and copper ions. Deionizing columns also remove calcium, a beneficial ion, which is sometimes added to deionized water for its beneficial effects. Deionized water is not sterile, in contrast to freshly distilled water. See Distilled water.

Delaminate / Delamination - Lateral separation of a once continuous support or surface into constituent layers. For example, in a painting, delamination could include separation of the ground, paint and/or varnish layers.

Dent - A depression of the surface and/or structure of an object.

Dimensions - The size of an object, customarily recorded in the order of height, width, depth. Generally, maximum dimensions are given if portions are missing or support is irregular.

Desiccated - State characterized by near or total loss of moisture content. Also known as embrittlement and brittle.

Destructive analysis - A type of analysis in which a sample of material is consumed during testing.

Dew point - When air is holding the maximum amount of water possible, any drop in temperature means that it must relinquish some, which results in the formation of condensation or dew.

Dimple / Dimpling - Any small, hollow place that has not penetrated through the layers. Dimpling often occurs when the primary support is partially affixed to a secondary support. Slight indentations in a paper support.

Discoloration - 1. A change or shift from the original color. 2. The chemical or degradation byproduct in the support which causes the color change.

Distilled water - Water which has been purified by distillation, a process in which water is heated to boiling, the resulting water vapors are carried through a distillation column where the vapors cool, condense and are collected. In distillation, dissolved ions and particulates are both left behind. Freshly distilled water is sterile.

Distortion - A deformation in the plane of the support and/or media.

Documentation - The recording in a permanent format (including written and/or photographic) of information derived from conservation activities.

Dog eared - Crease caused by a single or numerous folds in the comers of paper support.

Draw - Planar distortion usually located in the corners of support. Distortion is characterized by soft undulations resulting from tipped corners onto a secondary support or from being wrapped around a stretcher/strainer. This manner of attachment prevents free expansion and contraction of the primary support in response to fluctuations in relative humidity. It can also be caused by warping of stretcher or uneven stretcher pressure.

Dry cleaning - Removal of unembedded surface dirt or superficial dirt and grime by eraser cleaning techniques, as opposed to aqueous or solvent treatments. Erasers which might be employed include vinyl (grated or solid), kneaded, rubber or gum. Dry cleaning may also be performed with a brush, cloth or blower. Also known as surface cleaning.

Drying cracks - Curved and wide cracks that occur only in the paint layer(s) of a painting during the drying stage which are a result of the chemical processes and/or physical influences. Also known as alligatoring.

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E
Efflorescence - Dissolution, outward migration and precipitation of salts from within a material. These salts are visible on a surface as small crystals or white powdery or crusty deposits.

Embrittlement - See also brittle and desiccated.

Emulsifier - A surface-active agent such as soap promoting the formation and stabilization of an emulsion.

Emulsion - 1. A system consisting of a liquid dispersed with or without an emulsifier in an immiscible liquid. 2. A suspension of a sensitive silver salt or a mixture of silver halides in a viscous medium (such as a gelatin solution) which forms a coating on photographic plates, film, or paper.

Encapsulate - To create an enclosure with sealed edges around a paper sheet using two pieces of an auxiliary support, which is generally transparent The durable, flexible, and very permanent plastic film called polyethylene polyester terephthalate, better known in the U.S. by the brand name Du-Pont Mylar Type D. The edges may be joined or sealed by heat, ultra sound, 3M 415 double-sided tape or by machine sewing. Mylar Type D is no longer being manufactured; however there are a number of suitable alternative brands available.

Enzyme - A complex protein produced by living organisms that acts as a catalyst in specific chemical reactions, by inducing or speeding such reactions as breaking down and solubilizing starch (amylase), protein (protease), or fat (lipase), etc. Enzymes catalyze, but are not consumed in reaction, so very small amounts are necessary. Enzymes generally require moisture to be active, and, in theory, residual enzyme can be reactivated if moisture is supplied. Therefore, after an enzyme treatment step, a thorough rinsing is advised whenever possible and a deactivation step may also be advised in which any remaining enzyme protein is denatured by solvent, heat, etc.

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F
Facing - The adhesion of a protective layer such as thin Japanese paper upon the face of a fragile painting to prevent loss of the paint during conservation, or until conservation is performed.

Fading - Shifts of color in pigments or dyes, generally resulting from exposure to light, but occasionally from changes in pH or exposure to chemicals or pollutants.

False margin - A margin which has been adhered to the edges of the primary support. The margin may consist of individual strips of paper or a single sheet of paper in which the center area has been removed thereby framing the primary support.

Feather / Feathering - See Bleeding.

Figure - The pattern or appearance of a wood surface created by its distinct grain pattern, resulting from the anatomical structure, irregular defects or coloration.

Fill - A technique employed to replace a loss. Fills maybe considered stabilizing and/or restorative. In works on paper, fill techniques range from an insert of a like and stable paper, paper pulp or simply be provided by the mend or lining paper. Various combinations of filling techniques may be used in the same object.

Finger mark(s) / Fingerprint(s) - Mark(s), sometimes appearing as concentric rings, created by the handling of objects without gloves that leave oil, dirt or salt residues from the fingers that can reduce image densities on photographs and/or cause deformations, discoloration or corrosion on other materials.

Firing flaws - Bubbles, crazing, crawling, pinholes, gaps or imbedded foreign matter in a glaze.

Fixative - A coating applied to protect a soluble or friable medium while undertaking other treatment procedures. The fixative coating prevents bleeding or transfer of the medium.

Flaking - Lifting and detaching of clusters of pigment and binder which occurs when a medium loses it’s binding properties or when it has undergone physical stress. Flaking often results in losses.

Fluorescence - The emission of radiation, generally as visible light, during exposure to a source of radiation of a different wavelength, such as an ultraviolet lamp. In conservation examination, the ultraviolet lamp, also called a black lamp, is used to look for the emission or absorption of fluorescence for a variety of materials including oils, varnishes, protein glues and sizes, certain pigments or dyes, mold and foxing growth, iron deposits as well as previous restoration materials.

Flyspeck - A dark brown or black accretion of fecal matter produced by insects. Flyspecks appear as a, round, convex droppings; they are often found in dusters. The material is quite acidic and damage caused by staining and deterioration of the support is often irreversible.

Fold - A bend in an object in which one part of the support is laid over onto itself that can lead to cracking, breaking or fragmentation in the image layer or support. Creasing may or may not accompany a fold.

Footcandle - An English system measure of the intensity of light, based on the light of one candle at distance of one foot. Used to express recommended light levels for light sensitive media and paper, often in the range of 5 to 10 footcandles. A metric measure of light uses a unit called the lux, which is approximately 10 times greater than a footcandle, resulting in recommended ranges of 50 to 100 lux.

Foxing - Reddish-brown spots associated with mold growth or metallic specks. Foxing can vary in size and may be round, diffuse or discrete spots. Sometimes the centers of foxing are darker than surrounding areas. Under ultraviolet examination, areas of mold growth fluoresce brightly, while iron rich spots and specks absorb ultraviolet without fluorescence and appear black.

Frass - Chewed material dropped by feeding animals or insects.

Friable - Nature of a material characterized by a loosely bound powdery state. Some media are friable by nature including fabricated and natural chalks and charcoal. Friable states may result from deterioration or desiccation of binder. See powdering.

Fumigation - Treatment to expose an object to smoke, vapor, or gas for the purpose of disinfecting or of destroying pests. Fumigation, once a standard treatment for mold and insects, is now seldom used because chemical fumigants can have adverse effects both on works of art and on personnel. Moreover, fumigation is ineffective in the long run if the objects are returned to storage conditions that were responsible for the mold or pest infestation in the first place.

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G
Gelatin - A purified, water-soluble animal protein used for emulsions and coatings obtained from animal tissues (typically bovine) by boiling. Gelatin is more carefully processed and refined during manufacture than animal or hide glue. See also animal glue.

Gesso - A white priming layer traditionally prepared by mixing calcium carbonate or gypsum with size (animal glue) to use on the surface of an object to provide a smooth surface to receive painting or gilding.

Gilding / Gilt - The application of gold (or other metal) leaf onto the surface of an object.

Glassine - A thin, smooth translucent paper used for temporary protective enveloping and interleaving works of art on paper. This paper is often at a neutral pH when first produced, but will become acidic over time. It is not considered an archival material, thus should not be used for long term storage.

Glaze - Clear or colored glassy coating/sealant on the surface of a ceramic body.

Glazing - Protective transparent material used in framing, such as glass, polycarbonate and acrylic sheeting. A UV blocking material or film is sometimes incorporated into the glazing to prevent ultraviolet rays from hitting the artwork. This coating will not block visible light from damaging the artwork.

Gloss - Surface quality of being very smooth, shiny and reflecting light.

Gouge - Physical damage to support and/or media appearing as a discrete concave distortion, generally accompanied by a spot or linear disruption of the surface. Often the result of sudden impact on a surface, such as with a tool or broken glass.

Graining - A faux painting technique used to replicate the appearance of a desired grain of wood (figure) or stone surface.

Grease - A substance which is oily in composition and can penetrate, stain and/or visually disfigure the support and/or media on contact.

Grime - Dirt of a greasy nature. It may be imbedded or superficial.

Ground - The opaque coating over the painting support (e.g. canvas) on which the image is painted. See also gesso.

Gum - A natural secretion from certain plants with adhesive properties. Gums are used as binders and adhesives.

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H
Hairline crack - A very fine isolated crack.

Handling creases - Small dents/creases, often arc-shaped, in a paper support usually resulting from careless handling practices.

Handmade paper - Paper made in the traditional technique, in which a vatman dips a papermaking mold into a vat of paper pulp, catching a fiber slurry which drains to create a mat of intertwined fibers. These fibers, on drying, form a sheet of handmade paper.

Heat-set tissue - A thin tissue paper coated with an acrylic adhesive layer which becomes tacky when heated, for example with a handheld tacking iron, and is adhered with light pressure. This material was developed as an alternative to traditional paper mending techniques.

Hide glue - See animal glue.

Hinge - A piece of Japanese paper (or other similar material) used to attach a paper artifact to a mount or mat. This attachment system can provide good structural support, yet allows safe, ready access to the attachment when it is desired to remove the artifact. Care must be taken in the application method of the hinges to prevent causing damage to the object.

Humidify / Humidification - Treatment procedure in which moisture is introduced either as a mist or water vapor to expand the material to relax creases and/or planar distortions. This treatment is often followed by restricted drying to prevent the previous condition from returning.

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I
Imbedded - Physical state of a foreign material being irreversibly ground into the support. The material may be intended or unintended.

Impasto - 1. The thick application of a pigment to a canvas or panel in painting. 2. Raised decoration on ceramic ware usually of slip or enamel.

Incident light - Light falling onto a surface.

Inclusion - Foreign material included within a paper support or other support layer, generally added inadvertently in manufacture.

Indentation - A depression in the plane of an object that doesn’t necessarily break through the surface. See also dent or dimple.

Infrared radiation - The portion of the electromagnetic spectrum which lies below or beneath visible red, which is invisible and which results in heating when it is absorbed by surfaces. Generally infrared radiation is not useful for visibility and its heating effects are not generally desirable. Infrared examination however can be part of a conservation examination in which carbon based underdrawing is suspected but concealed by heavy layers of paint. As a long wave radiation, infrared is better able to penetrate visually opaque paint layers. When it strikes underlying carbon based drawing, the infrared is absorbed, while it is reflected back by underlying white ground. This differential absorption/reflection can be seen on a vidicon screen and captured by camera, to reveal carbon underdrawings. Digital technology can also be employed to capture these underdrawings.

Inherent vice - Existing condition, which causes deterioration of the object as a result of its original construction.

Inlay - To set pieces of wood, ivory, bone, metal or stone (etc.) into a surface or ground material, at the same level as the surface to produce a decorative pattern. Marquetry, parquetry and boule are examples of inlay.

Inpainting - A technique in which areas of loss in the media and in some cases in the support are compensated to provide visual continuity. Various artist's media may be employed. It is preferable to use a reversible inpainting medium that is different from the media of the original surface when possible.

Inscriptions - Information bearing marks or writing which are considered original to the object or which have been added over time.

Insert - A technique used to fill a loss in a paper support, in which a similar weight paper or paper laminate is physically shaped to the contours of a loss, often with a bevel or shelf margin that slightly overlaps the edges of the original thus permitting strong adhesive attachment to the original. Occasionally, inserts are not adhered to the original, but instead attached to a mat backboard directly behind the loss.

Insect damage - Physical damage to support and/or media as a result of destructive contact with insects. Damage may appear as surface thinning, losses or as accretions, such as flyspecks.

Intaglio print – Engraving, etching, drypoint, aquatint and mezzotint are all intaglio processes.  The word “intaglio” means incising or engraving in Italian and was first developed in the early sixteenth century. The image is engraved into a metal plate using a sharp tool and/or etched into the surface using chemicals. Ink is applied and then excess is wiped away from the surface so that it remains in recessed areas. The plate is put through a press under very high pressure to transfer the image to a sheet of dampened paper (or other substrate). A platemark will often be seen around the edges of the image for this method of printing (unless the paper is cropped), formed by the impression of the edge of the plate into the paper. The plate can be re-inked a limited number of times (depending upon type of metal) before the quality of the image is reduced.

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J
Japanese (tissue) paper - A paper support made by traditional Japanese hand papermaking techniques (or by machine in some cases), using traditional Japanese papermaking fibers of kozo (paper mulberry), mitsumata, or gampi. Japanese paper is very strong (has a high tear strength) even in thin weights, because of the very long fibers used to make the paper stock. It generally retains its strength on aging. Japanese paper may be encountered as the primary support, in Eastern or Western art, or as a conservation material. Japanese paper is valued in conservation treatments because its thinness and translucency make it less obtrusive, while its strength and stability on aging lend long-term support to the original.

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K
Keys - Thin, triangular pieces of wood tapped into the corners of a stretcher to tighten the canvas

L
Lacuna - Loss of paint (or other material) in a small area.

Laid paper - Paper which is characterized by a grid-like variation in thickness apparent in both raking and transmitted light. The grid consists of chain and laid lines. Chain lines are spaced further apart than laid lines. Laid lines are very dose together and run perpendicular to the chain lines. True laid paper is hand made, though machine made paper can be given an impression resembling chain and laid lines through use of a dandy roll in manufacturing. The texture of Western papers is created by the closely spaced copper wires of the papermaking mold surface, while the chain lines result from the fine wire stitching that holds the surface flat. The distribution of paper fibers is thinnest where the laid and chain lines intersect.

Laminate - A layered structure of parallel sheets of various materials fused or adhered together into one entity. In paper conservation, laminates may refer to layered paper as found in board construction or used to make paper inserts.

Light damage - Reduction of stability of paper support and media caused by (long term or high intensity) exposure to light and ultraviolet radiation. Wavelengths in the ultraviolet region of the electromagnetic spectrum are considered most harmful to objects, however all wavelengths of light are damaging. Light damage is cumulative and its effects may continue in the dark, after intermittent exposure.

Lignin - Polymer which binds together the long cellulose molecules in woody plants. When the plant structure is disrupted in papermaking, lignin becomes unstable, especially on exposure to light or pollutants. Paper and paperboards containing lignin discolor and become increasingly acidic as they age.

Liquid stain - Describes a stain caused by water or moisture. A liquid stain is often characterized by a tideline. See also Tideline.

Loss - Area of the support and/or media which is physically detached or missing.

Lux - See Footcandle.

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M
Marvelseal 360 - This material is an aluminized polyethylene and nylon barrier film which resists the transmission of water vapor and other atmospheric gases.

Mat - As recommended for conservation purposes, a type of protective rigid enclosure for a paper artifact, which is made from a relatively rigid paper board called matboard. While a number of mat structures are possible, the most common structure has two pieces, a front window mat, which has a "window" or opening cut to make the paper artifact visible, and a back board, a solid piece of mat-board the same outer dimensions as the window mat. Generally the window mat is attached to the back matboard with a folded hinge of linen tape applied along the length of one entire side, so that the mat can be readily opened. A mat is always supposed to be larger in length and width than the paper artifact enclosed within it, so that it can protect all edges of the paper. Similarly, the thickness of the window mat is to be greater than the maximum thickness or most protruding part of the artifact, so that the surface of the artifact is also entirely protected from contact or damage. A paper artifact is attached to the back mat using hinges and/or folded comers of acid-free paper (or polyester) slipped over the corners of the artifact. Varying qualities of matboard are available. Only matboards made with 100% rag or alpha cellulose should be used for long term preservation. See also mount.

Mat burn - A brown line of staining on the support within the aperture of a mat window opening cut from mat board containing lignin. The staining results from the migration of acidic components in the mat board. Also called mat stain.

Matte - Surface appearance which has no shine, reflectiveness or gloss.

Medium / Media -1. Material(s) which comprise the image bearing components of the object. 2. The binder which holds together pigments in a material used to make images.

Mend - A technique used to provide physical stability to a tear or otherwise vulnerable site, generally consisting of a thin reinforcing repair paper and an adhesive to attach it securely to the artifact.

Metamerism – The effect which occurs when colors which appear the same under one set of lighting conditions [e.g. daylight], appear to change when viewed under different lighting [e.g. fluorescent]. The effect is caused by the different dyes and pigments used to create the colors.

Methyl cellulose - Cellulose ethers are water soluble polymers derived from cellulose. They can be used as an adhesive, sizing, thickener, binder, emulsifier, surfactant or suspension agent, etc. In conservation, methyl cellulose is most commonly used as a consolidant, sizing and/or adhesive due to its chemical stability and reversibility.

Mitre joints - An angle cut in the end of a piece of wood or other material for joining two or more elements. An example would be seen in the joins in the corners of a frame.

Mold - A surface growth of fungus which may have varying color, shape and configuration. It generally proliferates in damp conditions (60% relative humidity or greater) where there is little air circulation. Damage caused by mold includes staining and loss of strength.

Monotype / Monoprint – Usually a single or unique work typically created by painting or drawing an image (often using printing ink but not limited to) onto an unprepared plate such as copper, millboard or acrylic which is then transferred to paper (or another support) by rubbing or passing the items through an intaglio press. This process can generally only be used to create a single print, however artists such as William Blake were able to produce as many as three impressions of some of his monoprints. It is important to note that the second (and possibly third) impressions would have a different appearance from the first impression and may have been enhanced after printing. Technically the terms monotype and monoprint do have different meanings. A monoprint is generally considered to be one of a series and generally begins with a more typical type of relief, intaglio or planographic printing process and then individual impressions are altered to give them unique properties within the series.

Mottled / Mottling - Uneven and diffuse discoloration which may appear on both support and media.

Mould - A flexible or rigid material applied to an object to create a negative form from which castings can be produced (see casting).

Moulding - A profile such as a cyma curve, half-round, quarter-round, etc., cut in wood or other material. Used in frames, furniture and architectural elements.

Mount - Auxiliary support to which the primary support is partially affixed for storage and exhibition purposes. A window mat may be attached to the mount. It is also the term used in England for mat. (JK)

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N
Newsprint - A smooth, lightweight paper made from unpurified wood pulp fiber stock. Newsprint is acidic and high in lignin. These components contribute to its physical instability and predisposition to darkening with the simple passage of time, and especially when exposed to light and pollutants.

Nick - A small triangular loss from a direct blow.

Non-aqueous - A liquid, solvent-based system used in treatment in which water is not present.

Nondestructive analysis - A type of analysis during which a sample is not consumed during testing. Nondestructive analysis includes testing done in situ, without removing a sample from the object, such as some types of x-ray fluorescence (XRF) analysis. Alternatively a sample may be removed from the artifact but is not consumed during the analysis (so that it can be returned to the artifact or used for other analysis).

Normal light - Light which strikes a surface perpendicularly, e.g. at a 90 degree angle to the surface.

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O
Obverse – The front of an object.

Offset - A mirror image of a paper artifact created by transfer of media or binder to an adjacent sheet of paper, glass, board or plastic film, or by chemical migration of constituents in the paper or medium, such as oil in printer's ink or lignin derived staining.

Oxidation - The chemical action of electron removal from one atom or molecule by another atom or molecule or to dehydrogenate a material especially by the action of oxygen. Oxidation is implicated in the deterioration of paper and photographic materials.

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P
Panel painting - A painting on a wood support.

Paper - A support, generally flexible, made from a liquid suspension of beaten plant fibers deposited on a surface. The primary constituent is cellulose. Paper characteristics vary depending on the quality and chemical stability of fibers and additives and procedures employed in the manufacture.

Papyrus - Support made from overlapped parallel strips of reed plant stalks.

Parchment / Vellum - Support made from one of a variety of animal skins, which have been dehaired, soaked in lime, stretched, scraped, and allowed to dry under tension.

Paste - A type of adhesive prepared by cooking starch in water until it forms a thick translucent white suspension. When prepared from purified water and when free of additives, paste has excellent aging properties and can be easily reversed. The sources of starch can vary; rice and wheat starches are common.

Pasteboard - Semi-rigid support consisting of several sheets of paper pasted or adhered together.

PAT Test / Photographic Activity Test - The Photographic Activity Test was developed by the Image Permanence Institute to test the quality of photographic storage materials. It is the subject of International Standards Organization standard 14523:1999 subsection (E) Photography-Processed photographic materials-photographic activity test for enclosure materials. The standard describes the test as a "predictive test of interactions between storage enclosure(s) and photographic image(s). It can also be used to evaluate possible photographic activity caused by components of enclosures such as adhesives, inks, paints, labels, and tape." Essentially, the test indicates whether a material is likely to damage photographs, negatives, slides, motion picture films, etc. It looks for chemical interactions that manifest as discolorations of photographic material. If a product fails the test, it should not be allowed near photographic materials; however, a pass result in the PAT is not necessarily an indication that the material is completely photo-safe.

Patina - 1. A surface appearance that has been created by environmental factors and/or use over a prolonged period of time. 2. A surface finish or appearance artificially induced by chemicals or other means to create a desired finish. An example of patina is the green colored, corrosion product layer formed on copper and bronze after exposure to certain environments or produced on the metal surface chemically, intentionally and artificially (as by acids). This corrosion layer is often valued aesthetically for its color.

Pigment - A finely-divided colorant, which may be derived from a wide variety of substances, organic and inorganic, natural and artificial. Pigments are insoluble in the binder in which they are used, distinguishing them from dyes which are coloring matter that form solutions.

Pith - A smooth, white, paper-like support which is cut in a spiral from the soft, spongy tissue found in the center of certain plants. Found in Western collections as the support for souvenir depictions of Chinese life. Also erroneously called rice paper.

Planar - Smooth or flat two dimensional surface.

Planographic print – Lithographs and collotypes are examples of planographic printing processes. Lithography was invented in 1798 by Alloys Senefelder. These processes take advantage of the antipathy between grease and water. Certain parts of a semi absorbent surface (metal or stone) are made receptive to printing ink while other parts (which will remain blank) reject the ink. In the case of a traditional lithograph, the image is created by drawing onto a stone with a grease crayon or brushed with greasy ink. The stone is dampened and then inked. The ink clings only to the greasy marks. The image is transferred to paper (or another substrate) using some pressure. Generally the stone or plate can be re-inked many times. No platemark is formed during this process.

Platemark – A slight indentation of the paper around the edges of an intaglio print which is formed when the paper and plate are passed though an intaglio press under great pressure. This indentation may or may not have ink on the surface depending upon how well the printing plate was wiped. Sometimes platemarks are trimmed away or a false platemark may be added to a reproduction.

Polyvinyl Acetate (PVA) - A thermoplastic, synthetic, vinyl resin produced from its monomer by emulsion polymerization. Available in the form of an emulsion, it is usually used in adhesives, which are themselves also referred to as PVA or PVA adhesive. There are dozens of PVA adhesives, some are “internally plasticized” and are suitable for use in conservation, due to greater chemical stability among other qualities.

Poultice - A malleable mass or material which absorbs water or other solvents and can be applied to an artifact surface, to slowly release solvent and/or to absorb solvent and matter dissolved in it. Poultices can be applied to hold water, solvents or solutions in intimate contact with a surface to soften accretions or adhesive. In addition, poultices can function as absorbers of matter dissolved in a solvent, drawing out soluble matter from a surface by virtue of capillary action.

Powdering - Physical state characterized by a loosely bound material. May be used in describing the inherent properties of a media (see Friable) or to describe the appearance of a condition or damage.

Pressure-sensitive tape - See Tapes.

Preventive care / Preventive conservation - Non-interventive actions taken to prevent damage and minimize deterioration of an object. These include monitoring, recording, and controlling environmental conditions; inspecting and recording the condition of objects; establishing an integrated pest management program; practicing proper handling, storage, exhibit, housekeeping and packing and shipping techniques; integrated pest management; emergency preparedness and response; and reformatting/duplication.

Preservation - The protection of cultural property through activities which minimize chemical and physical deterioration and damage, as well as prevent loss of informational content. The primary goal of preservation is to prolong the existence of cultural property.

Primary support - The sheet or surface which bears the image directly. The primary support may be a simple sheet of paper or may be adhered to a secondary support, another sheet or surface, which gives additional rigidity and support. See Supports.

Puncture - Structural damage to support and/or media. Punctures are generally caused by an impact to the surface and may penetrate, causing a hole.

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Q

R
Rabbet - A channel, groove, or recess cut out of the back edge of a frame to receive the glass and matted object or painting. Also known as a rebate.

Raking light - Light source positioned on one side of the support so that the light rakes across the surface from a low angle. This position creates strong shadows which accentuate textures and deformation of plane. Raking light is distinguished from normal light.

Recto - The front face of a sheet of paper or the right hand side of a book opening.

Relative humidity - The amount of water vapor held by a volume of air relative to the maximum amount which air at that temperature could hold. Expressed as a percentage of the actual water vapor held divided by the maximum water vapor which could be held at that temperature.

Relief print – Woodcut, linocut, collograph, letterpress, embossing and stamping are all forms of relief printing. Relief prints are the oldest method of printing seen in China around the 9th century and in Europe around 1400. The non-printing areas of a wood block (or other material) are carved away, leaving raised areas which form the image. After the block is inked, the image is transferred under pressure from the raised surface of the block to the paper (or other substrate). Embossing from the printing surface is sometimes visible from the verso behind the design areas. The block can be re-inked many times.

Repair - Various treatment techniques which restore structural stability and/or visual continuity to a damaged support or media.

Residue - Remaining portion of a substance after a process, a by-product of a process, not intended as part of the finished artifact. The residue is generally the remains of an attachment that has been removed.

Resizing - Treatment technique in which a sizing material is restored to the support by means of brushing, spraying, or immersion.

Restoration - Restoration is often a component of a conservation treatment which addresses the aesthetic appearance of an object and is intended to return cultural property to more closely resemble its original appearance, often through the addition of non-original material. Care is taken that restoration treatments are reversible when possible, maintaining the integrity of the original object.

Retouch - See Inpainting.

Reverse – The back of an object.

Reversible - A preservation process or treatment that can be undone without damaging the original material of an object.  Certain treatments such as cleaning can not be reversed.  Once removed, the same dirt can not be put back on the piece! Consolidation is another treatment which is often not considered to be reversible.

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S
Scratch - Physical surface damage which is narrow and sharp-edged. Scratches often involve a loss of support and/or media.

Screenprint / Silkscreen / Serigraphy – Form of stencil printing. A screen (made of silk or other fine weave, synthetic fabric) is stretched over a frame. Areas of the screen are blocked out by a masking material (painted on or photo-produced). The screen is placed in top of the paper (or other substrate) and ink is forced through the open areas of the screen using a squeegee onto the substrate below. The screen can generally be reused after the masking material is cleaned out.  Often more than one color is printed to create the image using separate screens for each color. Andy Warhol is best known for his screenprints.

Secondary support - An additional material, often paper or fabric, adhered to the primary support which gives additional rigidity and support, for example, a chine collé print in which a small, very thin paper is adhered onto a thicker, larger sheet, or a map or poster mounted onto linen. A secondary support may be adhered partially, such as around the edges or overall to the primary support. See Supports.

Size / Sizing - A water-resistant material which is added to paper or textiles. Sizing may be added during manufacture or as a coating after the material is formed. Sizing may also be added in a conservation treatment step as a coating on the surface of paper. Sizing inhibits the absorption of liquid into the fiber matrix, making the paper less susceptible to moisture or the feathering of ink and aqueous media. Sizing substances include gelatin, alum rosin, methyl cellulose, etc.

Skinning - A form of physical damage in which the surface of the paper in an area appears to have lifted up in a continuous thin surface flap.

Smudge - A streak or smear caused by movement of a friable medium or transfer of dirt or grime from another surface or object, i.e. finger smudges. Smudges are generally accidental in nature although they may be intentional.

Soiling - Deposits of embedded dirt, adhesive residue, etc.

Solubility - The tendency of aqueous or nonaqueous solvents to dissolve, soften, or swell a substance. Solubility may be complete, as when salt crystals totally disappear into water, or a matter of degree, in which less soluble materials are swelled or softened. Solubility may be desirable in a treatment when a stain, degradation product, or adhesive needs to be removed, but may be problematic when there is undesired vulnerability of media, coatings, collection marks, annotations, etc. which can also be affected by the solvents under consideration. For these reasons, solubility testing should be carried out and documented prior to any solvent treatment.

Spatter - Refers to dried droplets or splashes of foreign material on a surface.

Split - Physical damage to the support caused by contraction of the support which is held under restraint or when the support sheet ruptures along a previously weakened area such as a fold. Splits usually have the soft-edged appearance of a tear.

Spot test - A small local test using water, solvents, or other materials being considered for use in treatment, which are applied in inconspicuous places on the artifact to determine the possible positive or negative effects on the support, media, adhesives, etc present in an artifact.

Spur marks - Marks on the bottom of ceramics left when grinding away excess glaze or firing cones.

Stabilization - Minimal treatment procedures intended to maintain the integrity of an object and minimize deterioration.

Stain - A discoloration which lies in the matrix of the object.

Stain reduction - Stain reduction that does not respond to washing can sometimes be done by bleaching. This is a time-consuming and sometimes complicated procedure. It is warranted only in the case of disfiguring staining on objects of aesthetic value. Bleaching may be done by exposure to artificial light (oxidizing) or with chemicals (oxidizing or reducing). See also bleaching.

Stress cracks - Cracks that have appeared (such as in a paint film) which are a result of various types of external pressure such as impacts which create stress (such as in the ground and paint layers).

Stretcher crease / marks - Impressions or creases in the ground or paint layer of a painting, which follow the inside edges of the stretcher or the edges of cross-members caused by the support touching or resting against the stretcher.

Strip lining - A partial lining confined to the outer edges of the painting when it is necessary to strengthen the edges but not yet necessary to line the entire canvas.

Substrate - The structural material of an object. See also supports.

Superficial - Resting on the surface of the support or media, not imbedded.

Supports - Conservators distinguish between the sheet or surface which bears the image directly (primary support), an additional material which may be adhered to that image bearing sheet (secondary support), and extra materials which lend further rigidity to the former (auxiliary support). Every object has a primary support but only some have secondary supports or auxiliary supports. See Primary support, Secondary support, Auxiliary support.

Surface cleaning - Removing the obscuring material such as dirt and grime from the surface of an object. See Dry cleaning.

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T
Tapes - A variety of adhesive-coated materials manufactured in strips and often found on paper art and artifacts as previously-applied mounting or repair materials. Typically, a tape structure consists of a carrier strip of paper, cloth, or plastic, which has an adhesive layer coated on it. Gummed tape has an adhesive which requires moistening to become tacky. Pressure-sensitive tape has a natural or synthetic rubber-like adhesive which is tacky at room temperature and requires only pressure to become adhered to a surface.
Adhesive Transfer Gun (ATG) tape - an adhesive film without a carrier layer, dispensed from a handheld "gun" which transfers tacky adhesive from silicone release paper onto a surface.
Archival tape - so-called "archival tape" varieties are formulated of adhesives which are more stable than typical commercial tapes. Because they can be misused, they are not generally recommended for application on paper art or artifacts.
Cellophane tape - an early form of pressure-sensitive tape, which had a carrier of cellophane, a glossy plastic made of regenerated cellulose and an unstable adhesive layer very prone to causing oily discolored stains on paper and other surfaces.
Double-sided tape - a form of tape with a very thin carrier that is coated on both sides with pressure-sensitive adhesive. See 3M 415 double- sided tape.
Glassine tape - an early form of gummed repair tape with a carrier of glassine paper, a glossy tan transparent paper.
Linen tape - a form of cloth tape, typically a gummed tape, though some pressure-sensitive varieties are now available.
Masking tape - a form of pressure-sensitive tape with a tan crepe paper carrier. Designed for temporary application, as in masking out areas prior to painting, so generally not stable.
Magic (Mending) tape - a form of tape with a cellulose acetate plastic carrier that has a matte rather than a glossy surface, and an adhesive layer of acrylic adhesive, less prone to discoloring than cellophane tape. Also called frosty tape.
3M type 415 double-sided tape - a form of tape with a very thin carrier that is coated on both sides with a pressure-sensitive adhesive. This adhesive tape has been specified as the recommended adhesive for tape encapsulation. See encapsulate.

Tear - Physical damage which results in a linear or branched separation of the support into partially or completely separate pieces. The resulting edges along the separation have a soft fibrous "feathered" edge, in distinction to a sharp cut edge.

Tenting - Upward lifting in a tent-like curvature of layers which have cleaved, often as a result of shrinkage of the primary support.

Thinning / Thin spot - A form of abrasion with marked loss of paper fibers, that makes the paper more translucent to light in the affected area. May be associated with skinning.

Tideline - A stain which occurs when a liquid dries, depositing dissolved material at its perimeter. A tideline is characterized by a discrete edge which is often darker than the remainder of the associated stain.

Traction crackle - Cracks in a paint or varnish film caused by differential drying of two layers where one dries more quickly than the other resulting in the tradition of one of the two (or more) films splitting, or cracking, the layer.  Also called Alligatoring.

Transmitted light - Light source positioned beneath or behind the support so that the light shines through the fiber matrix and media. This lighting position allows one to see distribution and density of paper fibers and media, watermarks, chain and laid lines, etc.

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U
Undulation - Planar deformation consisting of soft, gradual distortions which are convex and concave in appearance.

Ultraviolet, UV - A high energy portion of the electromagnetic spectrum, which lies above violet light in the visible spectrum. Ultraviolet radiation is invisible to humans, hence is incorrectly called light. It is not necessary for vision and is capable of causing photochemical degradation of many organic materials including cellulose, as well as causing fading of dyes and pigments. For these reasons, ultraviolet radiation present in daylight or the light produced by common light sources such as fluorescent tubes or halogen fixtures should always be filtered to remove ultraviolet in order to help prevent photochemical damage and fading of art and artifacts exposed to light. Often abbreviated as UV. See also Fluorescence.

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V
Varnish - A clear surface coating of resinous material(s) used to protect the surface of an object (such as a painting or furniture). Some varnishes yellow with age.

Verso - The back of a sheet of paper or painting. The left hand side of a book opening.


W
Warping - Deformation of a typically planar object such as a painting or frame to twist or bend out of plane.

Washing - A treatment step in which the paper artifact is immersed in or saturated with water in an attempt to remove soluble degradation products or discoloration and to restore its flexibility.

Watermark - A design created in paper made in a papermaking mold with wire shapes sewn onto its surface. The design is visible in transmitted and/or raking light because paper fibers are more thinly deposited in this area. Machine-made paper can be given an impression resembling a watermark through use of a dandy roll in manufacturing. Chemical watermarks are made by impregnating the manufactured paper support with a transparentizing medium. Watermarks are useful in identifying the origin and age of paper.

Wheat Starch Paste - See Paste.

Wove paper - Paper which is manufactured (either by hand or by machine) on a screen or with an even mesh. Paper fibers form an evenly distributed matrix of uniform thickness. The sheet may exhibit a faint pattern similar to fabric which is due to the transfer of the texture from the screen or web. Wove paper was introduced in the West around 1750.

Wrinkle - Sharp deformation of paper, angular and irregular appearance, often with broken fibers. (JK)

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X Y Z


A variety of resources were used to develop this glossary including:
1. Book and Paper Catalog. Published by the Book and Paper Group of the American Institute for Conservation of Art and Historic Artifacts (AIC). Chapter 5.6, pages 15 to 29.
2. Merriam-Webster Online Dictionary: www.m-w.com
3. SITES. Standardized Reference Terminology. (Smithsonian)
4. http://en.wikipedia.org/wiki/Main_Page