Where a material becomes lighter in colour due to the action of various solvents or light. Sunlight, especially the ultraviolet component, can be particularly damaging.
Roughening or wearing away of an object’s surface due to repeated friction or contact with other surfaces.
A raised area, bulge or bubble on the surface of an object, often between adjoining layers of different materials. May be caused by a loss of adhesion between two layers, excessive heat, or pockets of trapped air or liquid.
Where an ink, paint or dye has become partially soluble and has wicked into surrounding areas of the support (usually paper or textile), resulting in a “blurry” appearance.
Where a previously clear and transparent surface (e.g. a varnish) has become white and/or opaque. Similar in appearance to bloom.
A substance capable of bonding materials to each other by chemical and/or mechanical action. Adhesives may be activated by water, solvents, pressure, heat or other means. Not all adhesives have good ageing characteristics and may become insoluble, yellow and brittle with time.
The transfer of acidic substances between two surfaces in contact with each other; often causing localised staining and discolouration. Also called acid transfer.
A solid piece of foreign matter attached to the surface of an object.
Describes where any element or piece of a surface or image is missing.