Terms like “acid-free” and “archival” are tossed around fairly often in the art world, but what do they really mean? And how can you be sure that the materials in closest contact with your precious artwork won’t do harm over time? Well, you can start by consulting your friendly neighborhood custom picture framer!
Mats serve several purposes within a framing package. Visually, a mat creates a field between the artwork and the frame to give the viewer’s eye a resting space. Simply put, they help your art look great. And to be frank, looking great is a pretty important aspect in displaying your artwork. Mats can be the unifying factor that coordinates artwork and décor, or the “WOW” that distinguishes it. Mats can impart a greater physical presence on a smaller piece, or be a subtle contrast on a float mount. Mats are rarely a bad idea and we’re always eager to play with colors.
Less exciting but more important is the actual physical function that a mat performs. A matboard creates a small airspace that keeps your artwork from being in direct contact with the glazing, and having your valuable artwork against traditional glass isn’t archivally acceptable. Matboards come in a variety of grades, so let’s go over what differentiates them.
Many mats are made from wood pulp, which contains a plant material known as lignin. Over time this lignin will break down and oxidize, becoming acidic, and migrate to whatever it is in contact with. In this case, your precious artwork. To offset this process, an alkaline buffer (usually calcium carbonate) may be added during the manufacturing process. This helps to neutralize the acids that are created as the lignin breaks down. However, this is only a temporary fix as ultimately the buffer will be depleted and the lignin will oxidize and become harmfully acidic. Due to this, these mats are NOT recommended for art of any significant value, be it monetary or sentimental.
A better option is an alpha-cellulose mat. These mats are still made from wood pulp, but the potentially damaging lignin has been removed. Many of these lignin free boards still include an alkaline buffer as an added measure of protection against acid migration and atmospheric pollutants. These mats ARE acceptable for use in preservation framing.
Rag mats are made from pure 100% cotton fiber. They are naturally completely free of acids and lignin. As with alpha-cellulose mats, a buffer may still be added to prevent migrating acids from other sources. Rag mats are simply the best. Better than all the rest.
Even after all of these precautions, some mats still may have other potentially damaging components. The whitest of white paper and matboards are achieved using chemical compounds known as an optical brightening agents, or “OBAs”. These brighteners are added during the manufacturing process and absorb light rays in the ultraviolet spectrum. As a result, your eye is fooled into seeing a very bright white. However, these compounds break down over time, and what was once visually bright white will begin to appear yellow. OBA compounds are generally not considered appropriate for fine art, so we do not recommended these products for archival or conservation framing. Thankfully, with the use of a UV flashlight we can easily tell which of these matboards contain any brightening agents and choose the correct option for your project.
There’s a lot of science that goes into framing. We’re here to advise on best practices, thus leaving you free to just have fun picking out colors. Whether you’re starting from scratch on a new piece or replacing dated matting on an existing piece, we’ll help you make the right choice for your project.