A mat is a paper based border that is sometimes part of the visual presentation of a framed work of art. In addition to functioning as part of the presentation of your art, it also creates a barrier between the art and glazing (glass or plexiglass). The characteristics of a mat include its thickness, acidity, core, and surface. The thickness of a mat is referred to as ply; it comes in 4 ply, 6 ply, and 8 ply. The thicker the mat, more of the bevel cut is visible; it is sturdier, and more expensive. The acidity of a mat impacts its years of longevity. A standard mat board consists of wood pulp, which contains natural materials such as lignin. These materials create acidity in paper, which causes paper to disintegrate. For example, newspapers have a high amount of acidity, which accounts for its short life span. For those still familiar with the newspaper, you probably have noticed how it quickly it becomes brown, brittle and disintegrates.
Acidity is a factor in the surface and core of the mat board. The surface of the mat refers to its outer color and paper. Mats come in a versatile number of colors. Its outer paper can be smooth, highly textured, patterned, fabric such as suede, or linen. The core is the center of the mat board that is revealed when a window (opening) is created in the mat with a bevel cut. It looks like a thin line or border inside the window of the mat. Most mats typically have a cream, white or black core. There are however some mats with bright color cores. White, black, and bright color cores are acid free; cream cores are not.
The two main problems with acidity are discoloration (fading of the mat surface) and the acid’s possible damage to the art. The mat board manufacturing industry addressed the issue of potential acidity in mats by placing mat boards through a neutralizing process. Neutralization can make acid harmless for many decades.
Different types of mat board include the regular mat board (sometimes referred to as paper board), rag mat board, and museum rag. Regular mat board is suggested for reproducible art, such as posters and digital photography that is expected to be exhibited for only a few decades. Rag mat board is recommended for items that have the potential to increase in value (rarity and demand) over time. This may include limited edition prints, signed and numbered prints, and some original art. Museum grade rag is the most expensive mat board, and is recommended for rare and valuable art that requires protection for generations.
The next time you step into a framing business, you will have basic knowledge of the mat. You and the framing designer can have fun selecting the mat or combination of mats that best present your art.