The following are the important factors involved in archival framing.
Of the many types of mat board available, one should use only 100% cotton rag mat board when framing a print. Cotton fiber is 99% acid-free; it is then buffered to pH 8.2 with an alkaline reserve of 2-3% to counteract environmental acids and air pollution which may come in contact with the art. The most deceptively named boards are some "acid-free" mat boards made from wood pulp. While the acid content of these boards has been reduced from that found in the raw pulp, it has not been eliminated. The buffering agents used on the surfaces are only effective against airborne compounds, and do not protect against heat and light activation of acidic elements remaining in the board. For the short term they can be alright, but there is a considerable risk over time.
A spacer is used to keep the paper surface away from the glazing. This procedure is important because high or changing humidity can cause condensation to form on the interior of the glazing surface, and without the air space between the art and the glazing material, this condensation will be in contact with the art work. This may lead to mold, mildew and water spots on the art work or may cause the art work to stick to the glazing.
Hinges are the invisible attachments between your art work and the backing board. It is important that these not have any acidic content and that the hinges be easily removable without damage to the art work.
Manufactured to filter out 97 to 99% of ultraviolet rays, conservation quality glazing will protect your art work from fading due to sunlight and bright fluorescent or incandescent light. The advantages of acrylic are that the material is lighter and safer, especially when art work is to be shipped. Conservation glass has the advantage of being less likely to bow in a large frame and being less susceptible to scratches.
This prevents dust particles and tiny insects from gaining access to your art work. At the same time, the porous quality of the paper will allow the art work to breathe within the frame.
Consistent 70 degrees Fahrenheit and 50% humidity are optimal. Some slow variation in these factors is acceptable over a period of months or years, but any sudden change can be harmful. It is advisable not to hang or store art work on a damp wall, a wall that has been recently plastered, over a working fireplace, or in any area subject to excessive sunlight, heat or dampness.
Be sure to take the frame off the wall. In order to prevent the moisture of the cleaner from seeping into the frame and onto your art work, it is best to clean the glazing in a horizontal position. Use a non-abrasive cleaning product, spraying onto a soft, lint-free cloth, rather than directly onto glazing. Never use glass cleaner on acrylic. While the frame is off the wall, check the dustcover on the back of the frame. If it is missing or has been ruptured in some way, the frame should be taken to a frame shop to determine whether any damage has occurred and to replace the cover.
Over time, acids and dirt in the environment can have a harmful effect upon your art work.