A damaged or insecure work may be in the process of deterioration due to a weakening of materials, the structure or construction. When structural damages occur to a painting such as tears, flaking paint, cracks with lifting edges, or mold, consult a conservator to decide on possible courses of treatment. Special handling and immediate attention may be necessary.
Paint Layer Issues
Bleeding: One painted area spreads into an adjacent area; often caused by water or other solvents.
Blooming: An appearance of cloudy or dull spotting on a painting’s varnished surface as a result of exposure to moisture.
Discoloration: Changes of hue or value, often having uneven distribution and plainly detrimental to the prevailing tone relations.
Cleavage: Any separation or lifting of layers between the paint film and ground or between the ground and support. Active cleavage is generally associated with the cracking of paint and ground layers.
Blister: A protrusion from the painting’s surface as a raised area of paint indicating cleavage between the paint layer and the ground, or between two layers of paint.
Friable: An insufficient binding media causes the paint to become chalky and unstable.
Abrasions: Scratches, often resulting in a loss on the surface, extending to the paint and ground layers, caused by faulty cleaning, friction as well as where the frame touches the painted surface.
Crack/Fissure: Any separation in the paint layer, ground, or support perpendicular to the surface of the painting; not to be confused with cleavage.
Stress Cracks: Cracks caused by various types of pressure or impact in the ground and paint layers, eventually resulting in the cracking and flaking of paint film.
Traction Cracks: When the drying process is compromised the upper paint layer pulls away leaving bottom layer visible, giving the upper a raised appearance creating a pattern similar to alligator skin.
Mechanical Cracking /Spiral Cracking: Cracks caused by direct contact, resulting in the flaking and loss of paint.
Stretcher bar cracks: A line of cracks or crease in the ground or paint layer caused by repeated contact with the inner edges of the stretcher bar.
Crease: A line made by folding or wrinkling.
Aging cracks: Visible stress develops over time as a result of adverse environmental conditions, mechanical or other causes. The cracks are through all the layers of a painting appearing as individual fissures or a network of straight or barely curved lines, known as cracquelure.
Cracquelure: A network of cracks in a fine, overall pattern on the surface of a painting, usually a result of embrittlement of paint film due to age or by shrinking of the paint or varnish.
Crackle: A perpendicular disruption which causes a network of fine cracks in the painting’s layers.
Impact crackle: Cracks which form radiating circles are caused by impact.
Cupping: Aged paint, loosened by cracking, with edges curling to create cup-like formations.
Delamination: A separation of the layers of the ground, paint or varnish layers.
Interlayer Delamination: A separation of the paint and Varnish layers.
Tenting: The delamination of the paint or ground along cracks where the delaminated layers lift into a pattern resembling tent formations.
Flaking: Often through a combination of cleavage and extreme cracking, the paint or ground layer is dislodged from the support.
Lifting: The painting’s surface layers separate causing areas to lift.
Loose Paint: areas of the pigmented layer, which have lost adhesion, are no longer firmly fastened to the surface, but are still there.
Loss: A missing area in one or more layers of the painting; most frequently the result of flaking, abrasion, tears, etc.
Lacuna: A small cavity in the paint.
Surface and Coating Issues
Dirt/Grime: Dirt of any kind which accumulates on the painting’s surface.
Superficial Grime: An accumulation of dust, grease, smoke and particulate matter; generally accumulated through moisture or by transfer through inappropriate handling. Superficial grime can become imbedded, which can be difficult or impossible to remove.
Dust: Loose soil particles distributed on the surface of a painting.
Accretions: An accumulation of extraneous matter on the surface of a painting; altering the original design.
Spatter/Run: Dried droplets or splashes of foreign material.
Soil: A deposit of dirt or other materials upon the face of a painting; this may include fingerprints.
Stain: A soiled or discolored appearance caused by a foreign substance or uneven aging.
Smoke Damage: A deposit of partially combusted material, usually accompanied by an odor; generally resulting from an open flame or residue from a fireplace or a building fire.
Discolored Varnish: Natural or synthetic resin varnishes will become yellow (natural resin) or grayish (synthetic) as they age.
Canvas and Support Issues
Deformations: change or alteration of the overall form of a painting.
Warping: a structural distortion of the support whereby the support has become twisted, turned or bent out of shape, causing a planar distortion.
Buckling: A planar distortion caused by a canvas that has slackened on its stretcher, appearing as waves, ripples or bulges in the canvas. Draw: Wrinkles or bulges which radiate from edges and corners of a stretched canvas caused by an inadequate stretcher.
Cockling: A broad system of wrinkles or puckering formed on a painted surface.
Dent/Dimple: A slight depression in a painting’s surface caused by pressure, many times resulting in a puncture or hole.
Check/Split: A rupture or chink running along the wood grain; usually caused by stress.
Support Failure: Deteriorated canvas which no longer has enough strength to support a painting.
Embrittlement: The canvas has become perceptibly fragile to the point of snapping, crumbling or breaking.
Tear: A break in fabric or other sheet material as a result of tension.
Issues Caused by Previous Poor Restoration
Overpainting: Often a result of poor restoration, the repainting is extended beyond the boundaries defined by the damage.
Crushed Impasto: Heavy restoration can cause damage an artist’s distinct patterns and textural brushwork.
Skinned: Original paint is removed due to excessive cleaning.
Issues Caused by Outside Forces
Insect damage: Numerous species of insects feed upon materials in a painting, inflecting damage. Most damage occurs on the rear of the canvas, and in extreme cases can leave the paint layer unsupported, causing it to collapse. Signs of the working of insects include tunnels in wood or open gaps and holes in the fabric. Insect detritus: Debris and other feeding remains left by insects.
Water Damage: Lifting, delamination and loss of paint result from water saturation.
Tidelines: Staining on the front or reverse of the canvas caused by water coming into contact with the canvas and subsequently drying.
Shrinking: Once canvas becomes damp, drying causes the material to become smaller or more compacted.
Mold/mildew: Fungi caused by moisture, which produce enzymes that degrade the host material; until mature, neither may be detectable except by the characteristic musty odor.