Through the use of UV-glass, acid free mats, and backing material, the damaging effects of light can be reduced. These products are available to protect valuable, original and irreplaceable art. Conservation framing is the use of the highest quality rag material to surround the artwork. Special techniques and procedures are used to protect the work with regards to mounting. It is a process that is always reversible; therefore the artwork's integrity is never compromised. While conservation framing is generally used for paper borne art and documents of high monetary value, conservation framing should be used anytime a high degree of protection and preservation is desired for a framed piece. Examples would be historical documents, present day as well as antique photographs, and mementos.
The general components of a conservation-framing job consist of the frame, the glazing, the mat or spacer, the backing and the hinging. Mats, backing, hinging and glazing must consist of 100% acid free material of conservation quality approved by the library of congress. Hinging should be of acid free materials with a water-based activated adhesive. Under no circumstances should pressure-sensitive adhesives be used on paper as these adhesives change character over time and the adhesive is known to migrate into the paper. To retain the original state of the artwork, it should not be cut, folded or mounted or glued to backing boards. Museum grade (dahle) corners can be also used. This method resembles photo corners and does not require any sort of adhesives to come in contact with the artwork.
Everything will deteriorate given time and exposure to the environment. Conservation framing is designed to minimize deterioration and to avoid contributory deterioration by the materials that surround the artwork. High temperature and humidity levels can accelerate the growth of mold inside the frame. Mold is often seen as a ghostly image on the glazing material. Mold formation cannot be totally eliminated and as a result the frame should be disassembled every 3–5 years to remove mold that has formed. Artwork should be spaced from the glazing materials to provide an air space to prevent the condensation of moisture onto the paper and allow a small air space for the inside frame atmosphere to adjust for increased levels of moisture in the air. Spacing is achieved by the use of a mat or spacer between the glazing and the artwork. Sudden changes of temperature and humidity should be avoided as heavy condensation may wet and damage the artwork. Foxing is red or brown spots that appear on the surface of the paper. While the exact cause of foxing is not totally understood, it appears to accelerate under high temperature and humidity conditions. Atmospheric pollution or dirt or dust may combine with moisture in the air to form harmful acids that will attack the artwork. The effect of light on art is insidious and not readily apparent. Ultraviolet rays damage artwork in two ways. Strong fluorescent lighting or direct sunlight may fade color. Paper also tends to absorb high-energy photons, which cause a chemical reaction in the paper, breaking it down and causing it to turn brittle. The effects of light on materials can be reduced by the use of glazing that filters out harmful ultraviolet rays.