Choosing the right Mat Board
One of the most frequently asked questions regarding archival products is about mat board. Which board should be used for the display of photographic work? Conservation board or museum quality rag board? At one time, mat board was made from re-used cotton rags, hence the name rag board. Today, both conservation board (made from wood pulp) and museum board (made from cotton linters) are archival.
Conservation board is the lower cost solution for archival mat board.
It does not have the long history of archival reliability that museum board has, however all modern day testing has proven its archival reliability. Although it does not have the rich surface quality of museum board, there are times when this is not an issue or perhaps seems an easy sacrifice to make for the price difference. Museum board, if you can afford it, remains the best possible choice.
Buffered or non-buffered is a simple decision.
If you are not dealing with traditional color prints, cyanotypes or albumen prints—choose a buffered board. The buffering agent in the board (usually calcium carbonate) sets up a long term alkaline reserve that will continue to absorb and neutralize acids from the environment for many years. Traditional color prints, others named above, must be matted with a non-buffered board. They can be backed with either type board.
Choosing the correct thickness of mat board is based on function. If you are dealing with small prints (8x10 or smaller), a 2-ply board should be adequate if the work is to be framed. Artwork larger than that, needs the stiffer 4-ply. A cost savings approach for small prints is to back the print with a 2-ply and overmat with 4-ply. The overriding rule, however, is common sense: if the print seems flimsy on 2-ply, mount it on 4-ply.