tom rand , Nov 11, 1999; 12:11 p.m.
I've recently started shooting color and having Ilfochromes and C-
Prints made of my images. Having shot B&W for twenty years, the
mounting/presentation of color photographs is new territory for me.
I have some confusion with the difference between buffered and non-
buffered board for matting of color prints. I am aware that I must
use acid free board, and on top of that it should be cotton rag board.
But now I understand that for *color* prints, I need to use non-
buffered board due to the acids in the color photographs mixing with
the "buffers" in a buffered mat board and possibly causing a color
shift?? Can someone explain this?
What board do I use for the archival mounting of color photographs -
both Ilfochromes and C-prints? Do I need non-buffered for both types
of prints? Do I need non-buffered at all, and what is non-buffered?
Any info would be appreciated.
Joe Miller , Nov 11, 1999; 12:35 p.m.
There is supposedly a tendency for a board to drift toward acidity because our environment is acidic. An alkali can neutralize an acid and may be added as a buffer offset this drift toward acidity. Think of a buffer as an alkali reserve. I think the most common buffer is calcium carbonate. There is not supposed to be a problem with black and white prints and buffred board, but chromogenic prints (as well as dye transfer and albumen prints) are themselves slightly acidic and a buffer could affect this. Hope this helps
Robert P. Boner , Nov 11, 1999; 12:42 p.m.
This problem was addressed in the Nature Forum. As I recall, the Ilfochromes require a non-buffered board. Dan Smith seemed very knowledgeable about the subject. If you can't find the thread, try searching under his name.
Adam Squier, NW Columbus, OH, USA , Nov 11, 1999; 12:46 p.m.
Always use rag mats. These are 100% cotton. You can usually see the 4 layers of board in the bevel. That's why they're also called "4-ply" boards. You can also get 8-ply boards that are twice as thick -- useful if you're matting a large picture as the glass (or plexi) is less likely to come in contact with the picture. They're the same color all the way through.
If you're not as paranoid, regular "acid-free" mats will do the trick. You'll have more choice in colors, too. These mats are made of wood-based paper that has been bleached and treated to remove the "bad stuff" <-- technical term. These are probably the "buffered" boards you wrote about.
Remember that the mounting and backing are as important as the mat. Usually, the pictures are mounted using plastic photo corners to the backing paper -- often 2-ply rag. Then the over mat is hinged to the 2-bly backing at the top using acid-free linen tape. Then, acid-free fome-cor is used for the backing. If they're not being framed right away, you can put the whole thing into a plastic sleeve made for this and taped on the back.
Hope this helps.
Terry Carraway , Nov 12, 1999; 02:33 p.m.
To be technical, something buffered uses a mixture of acid and base to maintain a constant pH. The way it works is the two are picked and mixed such that the result is at a point where there are plenty of excess ions around to void pH drift with the addition of more acid or base.
They are commonly used biochemical laboratory processes to maintain the pH.
Bill C , Nov 15, 1999; 02:40 p.m.
Tom, my standard recommendation for this kind of info is Henry Wilhelm's encyclopedic book, "The Permanence and Care of Color Photographs". Chapter 13, by Carol Brower and Henry Wilhelm is titled "Composition, pH Testing, and Light Fading Stability of Boards and Papers". See especially pages 469-472 for discussion regarding the pH and buffering issues.
Apparently it's a complex issue and research is far from complete; if you just want to hear "yes" or "no", this book will frustrate the heck out of you. However, I doubt that you will find a better source of information than this book.
The "Museum and Archive Collections" part of "Summary of Recommendations", starts out, "Given the lack of unbiased information on which mount boards and papers are most suitable for photographic applications, and on what pH levels are best, the authors believe the safest course for museum and archive collections to follow at present is to chose nonbuffered 100% cotton fiber boards and enclosure papers for all types of important photographs.".
The authors make it clear that their recommendations here are their "best opinion" based "on a studied examination of available information".
