Paints
Humidity/temperature
The effect of humidity causes damage to works of art on fabric, wood, and paper, as well as sculptures. Humidity causes different effects to the various layers of an artwork. The repetitive effect of this process leads to bulges and to the lifting of the ground material, resulting in the separation and deformation of the supernatant layer of painting. The effect of temperature can be decisive in several types of damage. The fabric in oil paintings dries and weakens after a continuous stay in a very warm environment. Cracking of the color layer, lifting, deformation, buckling, cupping, or warping and cracking of wood wooden material is some of the most characteristic damage caused by humidity and temperature.
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Lighting/UV radiation
The ultraviolet radiation sunlight contains accelerates all damaging wear mechanisms.
It is partly responsible for the discoloration of varnishes, binders, pigments, the weakening of fabric, surface destruction and deterioration of the appearance of wooden works of art, including cracks, flaking.
Biological Factors
Biological factors are another cause of damage to buildings and museum artifacts. The acidic nature of animal and plant secretions, as well as infestations of lichens, microorganisms, bacilli and bacteria, affect stone and organic materials (paper, wood, cloth, leather) . Biological agents flourish in high humidity, in combination with high temperatures and minimal light.
Microorganisms have chemical and mechanical effects on the material, and cause disruptions to its surface, along with various corrosive results and the creation of discoloration and spotting.
Various insects and microorganisms have a direct effect on a variety of materials, such as fungi for example, which cause loss of material in wood artifacts, and can reduce the mechanical strength of the material until complete destruction.
One of the microorganisms that tends to infect oil paintings is usually fungi, the spores of which are found in abundance the air around us.
The organic materials used in the making of oil paintings make them a suitable source of nutrients for these infestations, especially if the fabric and ground material contain animal glue. The rear side of the fabric backing also creates a favorable haven for the growth of microorganisms. Damage to an oil painting can be caused by small animals, such as rodents, causing tears or make holes in the fabric of a work.
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Human Factor - paintings
The humans can cause damage to artworks in the following ways:
- Through direct contact: Human touch on an object transports sweat that contains fat and salts which can stain and corrode.
- By increasing relative humidity and air concentration of carbon dioxide: The human breathing cycle exhales air that contains more moisture from exists in inhaled air. Humans also expel humidity in the form of perspiration. For this reason, if a large number of people are introduced into a building, a significant increase of the relative humidity is observed, especially if the ventilation rate is relatively low.
- By producing vibrations: People walking in tandem causes vibrations, which are able to create shocks or dislodge an item from its base if not properly grounded. Also, the presence of visitors increases the level of the noise threshold.
- With theft: Many museums have announced that occasionally various objects have been stolen, either from storage areas or from the exhibition spaces themselves.
- By vandalism: Man can intentionally break, carve, paint etc. a work of art. Also, quite often the conservation procedures applied to an the artwork by untrained individuals along with the use of unsuitable maintenance materials causes irreversible damage.
There are also cases where significant damage, such as tears, damage, flaking etc., has occurred due to inappropriate packaging used during transport of artworks with highly sensitive fabric backing. Finally, hasty and inappropriate storage conditions can cause devastating effects.
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