Aging is a process by which an

art Art is a diverse range of human activity, and resulting product, that involves creative or imaginative talent expressive of technical proficiency, beauty, emotional power, or conceptual ideas. There is no generally agreed definition of wha ...

work, typically a

painting Painting is the practice of applying paint, pigment, color or other medium to a solid surface (called the "matrix" or "support"). The medium is commonly applied to the base with a brush, but other implements, such as knives, sponges, and ...

sculpture Sculpture is the branch of the visual arts that operates in three dimensions. Sculpture is the three-dimensional art work which is physically presented in the dimensions of height, width and depth. It is one of the plastic arts. Durable sc ...

, is made to appear old. It is meant to emulate the natural deterioration that can occur over many decades or centuries. Although there may be "innocent" reasons for it, ageing is a technique very often used in

art forgery Art forgery is the creating and selling of works of art which are falsely credited to other, usually more famous artists. Art forgery can be extremely lucrative, but modern dating and analysis techniques have made the identification of forged art ...

. Paintings deteriorate over time because they are created using essentially incompatible materials, with each having a different reaction to the changes in the environment, including light, temperature and

relative humidity Humidity is the concentration of water vapor present in the air. Water vapor, the gaseous state of water, is generally invisible to the human eye. Humidity indicates the likelihood for precipitation, dew, or fog to be present. Humidity depe ...

. An oil painting consists of several layers, comprising the base

canvas Canvas is an extremely durable plain-woven fabric used for making sails, tents, marquees, backpacks, shelters, as a support for oil painting and for other items for which sturdiness is required, as well as in such fashion objects as handbags ...

, a layer of

gesso Gesso (; "chalk", from the la, gypsum, from el, γύψος) is a white paint mixture consisting of a binder mixed with chalk, gypsum, pigment, or any combination of these. It is used in painting as a preparation for any number of substrates suc ...

base coat, several layers of the

oil-based paint Oil paint is a type of slow-drying paint that consists of particles of pigment suspended in a drying oil, commonly linseed oil. The viscosity of the paint may be modified by the addition of a solvent such as turpentine or white spirit, and varnis ...

and then several coats of varnish to protect the paint surface. With many different materials, it is understandable that each layer may dry at different rates and will also absorb and release moisture at different rates. When this occurs, expansion and contraction of the painting will result in a crazing of the varnish surface. This pattern of small cracks is known as craquelure. Along with the darkening or yellowing of the varnish surface, it is this visual representation of the cracking that is typically the primary indicator of ageing. The purpose for artificially ageing is to create a finished product that accurately reflects an era or is consistent with the environment (usually period) into which it is to be placed.

See also