Selecting the right matboard requires consideration of the conservation needs of the art itself, along with the form of presentation. All artwork to be matted does not have the same protection requirements. And, there are varying views on what is acceptable in conservation matting. Matboard may be divided into four general categories:

1) Standard matboard is made of wood pulp. Lignins (and other materials) found in wood pulp, cause paper to become acidic and eventually to disintegrate. Note the quick deterioration of newsprint which is acidic.

2) Neutralized matboard is usually made of wood pulp that has been buffered with calcium carbonate to make it non-acidic.* Buffering slows the deterioration of paper by temporarily neutralizing its acid content. Buffered matboard lasts longer than standard matboard and the bevels won't yellow as quickly. It is important to use acid-free matboard to prevent acid-burn, which will yellow artwork, photographs or needlework. Buffering agents may damage some photographs,** silk and wool.

Standard matboard is not made into museum quality by neutralizing it (even though it becomes non-acidic or is called acid-free) because the acid-causing agents are not removed. Over time due to UV light and pollutants in the air, the matboard will return to its acidic state, turning yellow to brown.

3) 100% rag board is made from cotton and contains no wood (lignins). Little pulping or purification is required because cotton is the purest natural form of cellulose. Rag board is also called Museum Board, is acid-free and meets the standards set by the Library of Congress for museum quality matboard. It is available with or without buffering.^

4) 100% Alpha Cellulose is matboard made from wood fibers that have been extensively pulped and chemically purified to remove lignins and other acid-causing materials to make it acid-free. It is then buffered for an alkaline reserve to protect against airborne contaminants. 100% alpha cellulose meets the Library of Congress standards for museum quality matboard.

Standard matboard is acidic and should not be used with any work of monetary or sentimental value. Crescent offers a standard matboard with acid-free cores and backing papers. Neutralized matboard, 100% rag board and 100% alpha cellulose board are all non-acidic. 100% rag and 100% alpha cellulose both meet the Library of Congress standard for museum quality board. Non-acidic matboard is more expensive than standard, with museum board being the premium line. Acid-burn will decrease the value and appearance of an artwork. When framing an original artwork or limited edition print of value, use only museum quality matboard. For many applications, neutralized matboard will provide satisfactory results where museum quality preservation is not required.

Ask your local art store about the several brands of quality matboard available.

For more detailed information read:
Home Book of Picture Framing by Ken Oberrecht
Picture Framing Magazine Special Conservators Issue February 1993
For more information click here

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*In chemistry pH is the measure of acidity or alkalinity. The pH scale runs from 0 to 14. Seven is pH neutral; boards under 5 are highly acidic; buffered boards usually have a pH over 7.5. Acid-free is having a pH factor of 7 or higher. Museum quality matboards must have a pH between 8.5 and 9.5 to allow for an alkaline reserve against acidity.

**There is matboard specifically designed for photographs that is acid-free and does not contain buffering. Some, not all, conservators prefer unbuffered acid-free mats for albumen, black and white gelatin prints, and chromogenic color prints. Dye transfer prints and cyanotypes should only use unbuffered matboard. Colored matboard may have components in the dyes that may cause damage if in direct contact with photographs.

^Some rag board is buffered for an alkaline reserve. Alkaline-sensitive articles and certain photographs need unbuffered matboard.

TYPES OF MATBOARD REVIEW
Matboard is a special paperboard made specifically for mounting artwork. It comes in a variety of textures and colors with a white, black or colored core. Because the mat comes in direct contact with the art, it must be of the proper quality for the art being matted. For example, a "WELCOME" sign set up for a weekend conference might be matted with an inexpensive piece of poster board, while fine lithograph, signed by the artist, requires a mat made of the highest quality materials.

STANDARD MATBOARD
Made of wood pulp. This type is acidic and will eventually turn yellow due to acid-burn. Use only for works of temporary value.

NEUTRALIZED MATBOARD
Made of buffered wood pulp, it is non-acidic but not acid free. Eventually the buffer will become acidic. Use for craft projects, student work, presentations or posters. After several years this type may yellow and may need to be replaced.

100% ALPHA CELLULOSE
Made from wood fibers that have had all potentially acidic materials chemically removed. This type of matboard is acid-free and meets the Library of Congress standards for MUSEUM QUALITY matboard. Use for fine art and signed prints.

100% RAG BOARD
Made from cotton fibers, this type of matboard contains no wood. It is acid-free and buffered to prevent acidity after long exposure to the atmosphere. It meets the Library of Congress standards for MUSEUM QUALITY matboard. Use for fine art, signed prints and needleart.

NONBUFFERED 100% RAG BOARD
This is a special rag board made without buffering agents. Use it for certain types of photographs (albumen, dye transfer and chromogenic prints) and textiles (silk and wool) because buffering in regular rag board could react to the acidic dyes used in these processes and fabrics, altering their colors.