Glazing, Mats, Backing Board, Adhesive
Glazing, mats and backing board
The glazing should be UV-protective glass or acrylic (Plexiglas, Lucite, etc.).
Glass is best used for art that has a friable (easily crumbled) media that might separate from the paper or canvas, such as chalk, pencil, colored pencil, pastel or charcoal. Acrylic can build up a static charge which can lift the media from the paper.
Glass can also be better for photographs.
While the backing that comes with pre-made frames cannot be used for preservation framing, you can use it as a pattern for cutting the front mats, the back mat, and the backing.
All of these items should be acid-free, lignin-free and pH-neutral. DO NOT use foam core, wood or cardboard, as they contain acids or other dangerous chemicals that are harmful to the art.
The artwork itself will be sandwiched between the decorative front mats and the back mat. The front mats can be made of cotton matting board, which is available in many colors at art supply stores.
Photographs are best double matted to ensure sufficient space between the glazing and the emulsion of the photograph, as photographs easily stick to glass in humid weather.
Double matting is also a good idea for friable media to prevent the glazing from smearing or touching the art. Choose two mat colors that complement each other and the artwork.
Adhesive
Many framing centers use spray adhesives or dry mount to attach the art to a backing board. This is not safe for your art. It will make it very difficult to take the art off the backing board if ever you want to, nor will it last forever.
Although it prevents the art from buckling when first mounted, over time the adhesive will become dry and brittle, allowing the artwork or photograph to come free.
Acid in spray adhesives and dry mount can also stain the back of the art or photograph and over time might even leach through the paper and discolor the front.
Adhesives used in preservation matting are either acrylic-based or are made from wheatstarch paste. Acrylic-based linen tape is a good solution for attaching a photograph or piece of artwork to a backing.
