The Five Types of Mat Board (at a glance)
• Regular Mat Board (sometimes called Paperboard) offered by Bainbridge and Crescent a 4-ply acid neutralized mat board, the industry standard and the most popular kind.
• Alphamat Artcare by Bainbridge is a conservation quality archival mat board made of alpha cellulose fibers. 100% acid and lignin free throughout.
• Rag Mat Board by Crescent is an acid free, lignin free cotton core mat board. Archival quality. Face papers are acid neutralized.
• Museum Rag 100 by Crescent is a 100% cotton mat board. Both the core and face papers are acid and lignin free. Archival. Conservation quality.
• Black Core Mat Board, a subcategory of regular mat board with the same acid-neutralized core but black rather than cream color.
Is Regular Mat Board Safe for My Artwork?
Regular mat board is made of wood pulp based paper. Untreated regular mat board could be a threat to art but it is no longer possible to buy mat board that is untreated. All paper mat board manufactured for picture framing is put through a bath of calcium carbonate to neutralize it against the acidity that occurs when lignin, the binding polymer in wood, breaks down.
Neutralization renders the acid content harmless for a period of time, perhaps as long as a hundred years. Today, all Bainbridge regular mat board (called Paperboard) and Crescent regular mat board (called Decorative Mat Board) has been acid-neturalized in this way.Regular mat board is recommended for easily reproducible art that is expected to be exhibited for just a few decades. Most posters, digital photography and unsigned, unnumbered prints fall into this category.
If Regular Mat Board is Safe, Why Does Anyone Need Archival Mat Board?
The problem with acid is that it migrates. Once it seeps out of an acid bearing material it can contaminate anything it comes into contact with. Museums and others who handle valuable heirloom art are concerned that while neutralization can keep acid neutralized for a period of time, once it breaks down it becomes the source of the problem, not the barrier against it. For them mat board should be a barrier and hindrance to acid migration. The way to achieve this is to make mat board out of a material that cannot become potentially acidic in the future. Crescent Rag Mat Board is made of 100% acid free, lignin free cotton. Alphamat Artcare is made of 100% acid free, lignin free alpa cellulose fibers. Neither can become acidic over time due to the breakdown of neutralization at the mat board’s core. Conservation grade, archival quality mat boards are recommended for items that have the potential to increase in value over time due to rarity and demand. This may include limited edition prints, signed and numbered prints, and some original art.
What Exactly is Museum Board and Why is it so Expensive?
Museums have the most exacting standards when it comes to safeguarding art. They are uneasy with any material in proximity to art that has the potential to be harmful. To that extent they often view Rag Mat Board as inadequate for the framing of priceless art because, even though its core is made of 100% acid free, lignin free cotton, its face papers are wood pulp papers that have been acid neutralized. They demand a higher grade of cotton mat board where the face papers are also made of cotton, where, so to say, the mat board is 100% acid free, lignin free cotton throughout. Museum Rag 100 is that mat board. Making a board entirely of cotton is pricey, which makes this the most expensive mat board available, but also the safest. Museum grade rag is recommended for rare and valuable art that requires protection for generations to come.