Foxing refers to oxidation spots in paper that are
similar to tidelines. No one has been able to
make foxing appear in paper, so no single agent can be identified as causing these spots. Their similarity to tidelines suggests that they may
result from accumulation of oxidized parts of the
paper that collect as the wetted paper dries.
Elmer Eusman was able to demonstrate that tidelines do occur in that fashion, with the
drying concentrated at the edges of the wet spot.
Why this accumulation occurs in spots in not
clear, but it may have to do with the presence of impurities (such as included metal) or damage from mold that has occupied those spots.
This problem can be avoided if paper is kept dry.
One sure way to get foxing in paper is to hang
the sheet in a frame that is not sealed on the
back and allow that frame to be hung on a damp wall. The glazing will trap moisture from the
wall and the relative humidity in the frame will
be higher than the relative humidity in the room.
Thank you for the good information, I was talking to a lady who use to work for our local museum and she corrected me on the myth that foxing was a form of mould, Preservator what book would you recommend to learn the truth of some of the myth that may not be correct in todays framing industry.
Here are some good books, but they are more about
art than framing, per se.
CLAPP, ANNE F. Curatorial Care of Work of Art on Paper. Oberlin, Ohio: Intermuseum Laboratory, 2d rev. ed., 1974.
DOLLOFT, FRANCIS W., and PERKINSON, Roy L. How to Care for Works of Art on Paper. Boston: Museum of Fine Arts, 1971.
ELLIS, MARGARET HOLBEIN, The Care of Prints and Drawings. AltaMira P 1995.
GLASER, MARY TODD. "Framing & Preservation of Works of Art on Paper." New York: Parke Bernet Galleries, 1971.
JAMES, CARLO et al., Old Master Prints and Drawings: A Guide to Preservation and Conservation. Amsterdam: Amsterdam Univ. Press 1997.
KING, ANTOINETTE. "Care and Conservation of Prints" in Castleman, Riva. Modern Art in Prints. New York: Museum of Modern Art, 1973.
ZIGROSSER, CARL, and GAEDHE, CHRISTA M. A Guide to the Collecting and Care of Original Prints. New York: Crown Publishers, 1965.