Nehushtan - the first recorded antique meaning a "brazen serpent" made by Moses.
Recommendations for the Matting, Framing, and Display of Art on Paper

Laura Downey, Conservator, University of New Mexico Art Museum

Please note: These recommendations are for art on paper, not photographs

Conservation Matting And Framing
Ask your framer for 100% rag fiber, acid-free, alkaline-buffered matboard, sometimes called "museum board."

Ask your framer what will be used to attach the artwork to the mat. The best solution is to use corners or edge-strips of acid-free paper or good quality paper, so that nothing needs to be attached directly to the artwork. Another method is to use "hinges" of Japanese paper (sometimes called "rice paper") attached with starch paste or methylcellulose. Sticky tape (also called "pressure-sensitive tape") should NEVER be used. Some tapes are called "acid-free" or "archival" but still they can damage artwork and be difficult to remove. In a pinch, acid-free gummed linen tape is less damaging than other tapes, but it is too heavy and brittle to make a first-rate hinge.

A proper mat has both a window and a back mat that are the same size and the same material. The artwork should be attached to the back mat, NOT to the window. Another sheet of acid-free cardboard or Coroplast® is usually placed behind the mat within the frame, to give extra support. Avoid using foam boards for this purpose even if they have acid-paper on the exterior. It is the foam on the inside that is the source of the off-gassing of damaging materials. If your frame isn't deep enough for all these layers, it probably isn't strong enough to do its job.

Ask for Plexiglas or other acrylic sheet plastic for glazing in the frame. Standard glass is a hazard since it breaks easily, which can damage artwork and injure people. Glass also lets through damaging ultraviolet radiation, which can cause - fading of colors and yellowing of paper. Ultra-violet filtering acrylic gives the most protection against light damage, although it is more expensive than regular acrylic sheet.

Hanging And Display Of Artworks On Paper
When hanging artwork, avoid exterior walls (walls with the outdoors on the other side). The temperature and humidity changes more near these walls than they do elsewhere, and this will cause damage to the artwork over time.

Avoid hanging valuables near evaporative cooler vents. “Swamp coolers” add moisture to the air, which lowers the temperature but can be damaging to artworks.

Consider storing your artwork and documents in archival boxes, rather than framing them. This avoids light exposure that can fade colors and yellow paper. Carefully stored, paper artifacts last much longer and can still be taken out, looked at and enjoyed by you and your family.