Conservation and restoration of paintings

Each of these materials requires specific care in handling, displaying, storage, added protective measures, and general environmental conditions.

Do not lift or carry a painting by its stretcher bar, or insert your fingers between the stretcher bar and the canvas[6] It is estimated that a lack of proper routine maintenance and care is responsible for 95 percent of conservation treatments; the remaining 5 percent results from mishandling objects[7] When developing display and storage methods for works of art, issues regarding relative humidity, temperature, light, pollutants, and pests need to be considered.

For example, during the Iraqi invasion of Kuwait, Saddam Hussein abused women, stole cars, damaged buildings and artwork.

Airborne pollutants which originate from atmospheric sources (ozone, hydrogen sulfide, sulfur dioxide, soot, salts), or emissive products, objects, and people (sulfur-based gases, organic acids, lint, and dander).

Preventive measures that may be taken to protect paintings from pests include upgrading building structures to obstruct pest entry, installing better cabinetry with good seals, better control of temperature and humidity in collections and storage areas, keeping food and other organic materials from collection areas, and treatment of outbreaks.

[14] Materials that are commonly damaged by pests include: natural fibers, wood, paper, starch adhesives, and egg tempera.

Due to the soft nature of the paint, it attracts and holds dirt and debris, creating difficulty when cleaning and resulting in darkening colors over time.

[31] Another of Jackson Pollock's paintings, Echo, endured yellowing at the top of the canvas due to strong museum display lights.

[32] Encaustic is a method of painting that involves dry pigments mixed with hot beeswax, then applied to the surface of a support such as wood or canvas.

The mold aspergillus versicolor can grow on frescos and consume nutrients effectively causing pigment discoloration and wall detachment from rot.

The many layers can deteriorate from the materials chemical compositions reacting to pollutants or environmental conditions such as humidity, temperature, light, and pH.

Conservators can remedy cracks and minor detachments of frescos with injections of epoxy resin containing micronized silica and lime putty.

The number of layers may vary, and each can be left in its natural transparent state, or colored with pigments to create lacquer painting.

[36] Treatment methods may include rejoining split wooden panels, mending torn fabric, or consolidating lifting paint flakes.

Pastels that are pigment particles bound together take on a more chalky and loose powdery characterization, and are secured to its supports using fixative or diluted resin in solution.

[1] In general, works of art on paper should be stored in a cool and relatively dry room with minimal exposure to light.

[41] Water color and Gouache paintings are pigments mixed into water-soluble gums that are applied onto paper or rigid board supports.

Damage to Watercolor and Gouache paintings can be prevented and mitigated by maintaining temperature and relative humidity within acceptable ranges, and low light conditions.

Tears and losses can be repaired with products such as wheat starch paste or methyl cellulose, and weakened paper can be strengthened by attaching a lining.

Scroll paintings often are multiple layers of paper and silk attached to wooden bars called a stave and dowel.

[46] Conservation treatments require significant research as the variations in technique and materials among Asian scroll and screen paintings is great.

In general some types of conservation treatments that may be conducted on scroll paintings and screens include remounting, consolidation of pignments, removing old backings, and in-painting and retouching.

[46] The material that makes up the support can have a major impact on the overall deterioration of an artwork, it can also determine the best method for handling, storing, and displaying an object.

Conservation treatments may take the form of reconstruction using traditional materials and techniques, and complete or partial coverings with protective layers.

[48] Canvas, typically made from linen, hemp, jute, burlap, and cotton,[49] is often stretched onto a wooden frame called a stretcher.

[19] The materials used in their construction are often a clay body, and some times mixed with sand, shell, chalk, mica, and ground-up fired ceramics.

Damage can be mitigated with proper relative humidity levels and storing of textiles in acid-free tissue or clean cotton sheets.

[19] Glass objects are not subject to the same vulnerability to environmental conditions as other types of paintings, but are most susceptible to damage from improper handling and inappropriate cleaning methods.

The paint on the surface of ivory is very delicate and can be easily rubbed off, small amounts of water (breath, condensation or residues from cleaning) can affect the image.

For imaging purposes of conservation, paintings are recorded in the wavelengths: ultraviolet (UV), visible (VIS) and infrared (IR).