While protecting works of art and valuable paper items, such as diplomas, with acid-free folders and archival-quality boxes may be appropriate for storage - it isn't logical for items you wish to display.
One of the best ways to preserve your art for the future while being able to view it is to mat and frame it using conservation-quality materials. You can bring it to a professional or do it yourself. If you choose to have a professional do the work, be sure to choose a reputable framer and specify the materials used.
Whether you or a frame shop frames your art, all mats, backing materials, and adhesives should be chemically stable and acid-free. Adhesives that come in contact with artwork should be permanent but reversible. When handling your art, use cotton gloves to keep from soiling the paper.
If your artwork is already matted and framed, check the cut edge of the window mat for browning, and look for brown cardboard backer or brown paper sealing the back. Any of these indicate inferior materials. Reframing the art is typically recommended.
Artwork should never touch the glazing, a window mat and backer board are essential.
A window mat and the backer board should be made of acid-free, high alpha-cellulose purified wood pulp or cotton rag board.
When cutting out window mats, save the cut-out board to use with smaller prints as backer boards or the top window mat. It is best to plan out cuts from largest to smallest, to get the most out of each sheet of board. Don’t dispose of the remaining strips; they can be used as dividers in drawers and boxes or as stiffeners in bags containing small objects.
Use a stable adhesive to hinge the window mat to the backer with acid-free tape, such as linen or Tyvek.
Art should never be mounted on the backer with an adhesive such as a dry mount. Instead, small items can be fixed to the backer board with acid-free corners or transparent mounting strips. Larger items should be hinged to the backer with Japanese paper and starch adhesive. Use a T-hinge if the artwork doesn't show through the window or a folded V-hinge if it does.
When framing, the choice of whether to use glass or acrylic is often one of personal choice. Some prefer the clarity of glass, while others choose acrylic to avoid the possibility of breakage.
Either wood or metal frames can be used. They should be deep enough to hold the mat/picture "sandwich" and a frame backing board.
Once you have placed your matted picture in the frame, keep pollutants and insects from affecting your artwork by placing a well-fitting sheet of acid-free corrugated board in the back of the frame, sealed with stable sealing tape.
When choosing a frame, make sure it has a rabbet deep enough to accommodate the thickness of a mat, backing board, and glazing material. For backing board, use 100% rag content mat board, double-walled plastic board like corrugated polypropylene, or material with paper surface layers and a central foam layer. Never use Masonite, corrugated cardboard, wood, or other materials that are not acid-free. Seal the frame with adhesive tape to keep out dust and pollutants.
One of the safest methods for protecting photographs and prints is to mount and mat the item using two pieces of archival-quality mat board. The general rule is for the backing board to be sturdy enough to support the piece while the top or "window" mat should be thick enough to protect the item from any surface damage.
When preparing a print for display, use a minimum of 4-ply mat board for the window mat. This should be thick enough to keep the surface of the print from touching the glass in the frame. Some prefer a 6 or 8-ply board, to enhance the overall appearance of the print and also to provide an additional space between the print and the glazing.
When preparing a print for storage, 2-ply is sufficient and also allows more space to fit additional matted prints in the storage box or drawer. It is advisable to cover the surface of the print with an interleaving tissue or paper before stacking.