Mat Board: What Kind Should You Use For Your Photographs?
To Buffer, Or Not To Buffer, That Is The Question

The kind of mat board that you use for your photographs depends largely on how you plan to use them. If you are a beginning photographer and don't care about the longevity of your photograph, any paper mat will suffice. However, I would recommend that if you're going to the trouble to mat/frame your photo, you should at least use acid free board. However, for long-term storage of photographs, it is important to have a lignin-free mat board as well as one that is acid-free.

For archival storage, two kinds of mats are recommended:

  • Purified alpha cellulose, lignin-free, acid-free, and is often referred to as conservation board
  • Cotton rag is naturally acid-free and lignin-free, and is often referred to as museum board

Serious photographers should only consider matting with alpha cellulose or rag mats. Rag mats are considered the ultimate in archival storage, and they are also the most expensive (of course!). Rag mats are available as either buffered or unbuffered. The vast majority of rag mats (and most, if not all, conservation mats) sold contain alkaline buffers. The idea behind this is that most environmental pollutants are acidic, so the alkaline buffer neutralizes the acid pollutants. The main problem with this is the alkaline pH of 8.5 or so in these mats can have a negative effect on color prints. This has been demonstrated with color paper used to print from negatives (Wilhelm and Brower, The Permanence and Care of Color Photographs, p. 471, downloadable here). Ilford has recommended that Cibachrome (Ilfochrome) prints be stored in contact with materials near a neutral pH, as the dyes in the Cibachrome prints are most stable at a pH of 6.5-6.8 (Wilhelm and Brower, ibid). I have not found any such recommendations for any type of inkjet print. Eastman Kodak has stated that paper products in contact with prints should have a pH of about 6.5 (Wilhelm and Brower, ibid). Henry Wilhelm is currently the leading authority on photographic color permanence, and he and Brower have stated:

"Pending further research, the authors of this chapter, Brower and Wilhelm, discourage the use of alkaline-buffered mat boards and papers with all color products."

In addition, The Fine Art Trade Guild has formulated standards for conservation mats and rag mats. Many major mat manufacturers have complied with these standards. The Guild states on their website:

"However, it is worth noting that most authorities recommend unbuffered Museum Board for use with photographs."

Wilhelm also recommends unbuffered board for black and white, as well as color, photographs (ibid, p. 480). These statements certainly are in disagreement with the prevalent opinion that buffered boards are best for black and white prints.

In summary, I would have to conclude that there is a lot of misinformation in photographic circles regarding the kind of mat to use for photographs. The safest course to take until otherwise proven is to mat all photographs on unbuffered mat board. This is unfortunate, because it is harder to find unbuffered mat board, particularly pre-cut unbuffered rag mat board. Here is a list of suppliers that I am aware of. If you find a good source of pre-cut, unbuffered mats, let me know, and I'll add it to the list.

Sellers of Pre-cut Unbuffered Rag Mat Board:

  • - choose Super White Photo Rag; this is unbuffered cotton rag. Must buy packs of 10 mats.
  • - significantly more expensive than Matcutter, but more color choices. While you can order 1 mat, it is very expensive. Buy in quantities of at least 12 to get the price down.

You can special order Bainbridge Unbuffered Rag Mat (called Photorag Mat) from your local Aaron Brothers. They will cut the outside down for you, as well as cut a window, if desired. Crescent and Rising also make unbuffered rag mats. Suppliers of their uncut mats can be found by a Google search.

Finally, there is the issue of the mount, or backing, board material. Foamcore is very popular these days as a mount board because of its rigidity. It does come in acid free versions, which are sometimes labeled as "archival." However, this is not the case. The heart of foamcore is polystyrene, which is not stable and gives off acid vapors. Do you remember when negative sleeves were made with polystyrene? We dumped these for polyethylene years ago, so why are we using polystyrene foamcore to mount our prints? Some foamcore is also buffered, presumably to help with possible acidity. As we have seen above, the buffering creates yet other issues. Therefore, if you are going to mat with unbuffered board, it doesn't make sense to use a foamcore backing. Just use unbuffered cotton rag mat for your backing material.