For the highest protection for your artwork, you should only use mat boards that are preservation or museum grade. There are three basic types of mat boards used in picture framing. The first is a regular or paper mat board. These mat boards, while being cost effective, contain a product called lignin. Over time lignin breaks down creating an acidic gas that can leave a burn mark on your artwork. The color will also fade over time, and the cream-colored bevel will begin to darken. Some paper mats have a bleached white core, but the overall degradation of the mat will be the same. The second type of mat board is made using alpha cellulose. Cellulose is the chief material in all plant life. Alpha cellulose is the purest form of this material. These mats are buffered to maintain a neutral pH. They are considered to be preservation quality. They will not harm the artwork, nor will they fade or “bleed” over time. This type of mat is the primary, in-stock mat at FastFrame. The third type of mat is a rag mat. Made from cotton linters, rag mats are naturally lignin-free. They are made with a colored surface paper, which are preservation grade, or can be 100% rag mat, which is museum grade.