Acid Burn: Brown discoloration on paper, resulting from acidic matting or mounting materials.
Adhesive Failure: Occurs when the adhesive deteriorates to the point of collapse. Can be found in works on paper (e.g., prints that have been mounted or collaged).
Biological Degradation: Any interruption in the original material due to current or previous biological infestation or insect damage, such as holes or remaining dust-like material.
Bloom: Occurs when moisture penetrates a varnished surface, causing cloudy areas to appear.
Broken / Separated Element: A broken element is part of an item that has been fractured into two or more parts. A separated element is part of an item that has been disconnected.
Canvas Relined: When the original canvas of a painting has been damaged or weakened, the piece is removed from its stretchers, backed in linen or canvas, and placed on its original stretchers or on new ones.
Canvas Re-stretched: When the original canvas of a painting has been tightened on its original stretchers, or taken off of its original stretchers and placed on new ones.
Check: A partial split in the woods grain. Occurs when there is uneven shrinkage, which most commonly extends across the rings of annual growth. These lengthwise separations usually result from stress due to air or kiln-drying.
Corrosion / Pitting: Corrosion is a chemical reaction between a material (usually metal) and its environment, which produces a deterioration of the material's properties. In some instances, corrosion can occur in a small or confined area in the form of pits on a metal surface. Pitting is an extreme, concentrated attack on a material which may take months, or even years, to become visible.
Crackle: The network of fissures or cracks in a finish layer such as varnish, lacquer, or shellac, due to age degradation, expansion and contraction from climate changes, and other causes.
Crazing: In ceramics, a mismatch in the thermal expansion between the glaze of an item and its physical body often causes small hairline cracks of the glazed surface, which can potentially compromise the pieces structural integrity.
Craquelure: A network of fine cracks on a paintings surface, typically due to elemental expansion, contraction , and age.
Creases: Occur when a material has been folded or bent, creating a line or ridge on the surface without breaking or tearing.
Deterioration: Any reduction of quality, use or aesthetics due to physical impairment.
Fading / Bleaching: Loss of brightness and/or brilliance of colour. Occurs when excessive ultra-violet light exposure causes the surface of the piece to become discoloured and loose brilliance.
Foxing: Reddish-brown spots that appear on paper and textiles due to water exposure or high levels of humidity.
Indentations: Any chip, dent, gouge, tear, abrasion, or loss occurring from force.
Inpainting: Application of paint to re-establish an item's visual continuity. Can be used to replace paint loss or disguise craquelure.
Instaining: Application of stain, typically to a wooden surface, in the area of a loss to re-establish an item's visual continuity.
Late Additions: When an artist authorizes a print re-strike with or without changes to the original plate.
Mat Burn: Improper use of acidic wood based matting materials will cause a "burn" or discoloration of the print where the acidic mat material contacts it. The acids will leech into the print causing the paper to turn brown or grey and to deteriorate.
Missing Element: Part of an item that has been lost.
Overpainting: Occurs when a restorer does not possess the correct skills to retouch a damaged area on an item and extends beyond the confines of a loss into undamaged areas.
Paint Loss: The absence of paint in areas where it was previously located, due to age and other influences.
Painting Varnished: During the restoration process, the restorer will often varnish the surface of an oil or acrylic painting to protect the image from dirt, dust, smoke, grease, or other pollutants.
Patina: The result of natural or artificial oxidation on a surface, which produces corrosion, texture, or a thin layer of colour that can range in hue. In bronze sculpture, patina specifically refers to the alteration of the surface by the sculptor with acid or other chemicals.
Remains of Hinges: Works on paper, prints, and photographs are often attached to a mat with paper hinges and a chemically neutral, non-staining, and permanent adhesive. Each hinge is attached to the piece and the back board, allowing easy removal from the board should the necessity arise.
Repurposed: An item that has been repurposed no longer performs its original function, and retains only aesthetic value.
Requires Cleaning: An item requires cleaning if there is an accumulation of unrelated matter on its surface (e.g., dirt, dust, grime, fungus, mould, wax).
Restoration: The process of halting the decay of a work of art and/or returning it to its original state.
Rippled Paper: When environmental influences cause disruptions, ridges, or buckling of paper.
Separation: Disconnection between two previously attached layers of a structure. For example, when varnish peels from the surface to which it was applied.
Skinning: Excessive cleaning. Occurs when a piece has experienced exorbitant intervention from a restorer or conservationist, removing a portion of the original media.
Staining: Occurs when foreign materials react with the surface of an item and create discoloration or spotting.
Surface Abrasions: Visible result of wearing, grinding, scratching, or tearing of a surface due to friction.
Surface Soiling: Accumulation of dirt, or other materials, upon the face of an item, including fingerprints.
Tears / Holes: Openings in a surface caused by forcibly pulling the piece apart.
Toning: Toning is the darkening or aging of paper over time, and exposure to humidity and the pollutants in the atmosphere. The toned area is surely acidic, and an indication that the rest of the sheet is probably becoming acidic. Toning appears even on pages or plates in bound books. It starts usually along the 3 unbound edges of a sheet, and slowly creeps inward.
Trimmed Margins: When the margins of a two dimensional work of art have been reduced. Typically occurs during the framing process.
Verso: Refers to the back or underside of a sheet of paper.
Water Damage / Warping: Includes any type of damage caused by contact with water or humidity such as staining, warping or loosening of material.