A letter to the editor of the March 26,1992, Nature, from B. Singh of McMaster University and H.W. Taylor of the University of Toronto, broke the news that "fine papers used in high-quality printing, photocopying and writing are indeed radioactive." Not very radioactive, but indisputably so.
"Using standard gamma-ray spectroscopic methods with a shielded large-volume HpGe detector," the authors say, "we have measured the gamma-rays emitted by various paper samples, mostly in the form of unbound scientific journals, magazines and newsprint.... These data establish the presence of easily detected radionuclides in fine papers." They believe the radiation comes from the clay fillers in the papers. The dose of radiation received by a person standing in front of a bookcase of these journals is comparable to that received by a person living or working in a brick or masonry building. Some of the journals, e.g. Journal of Environmental Radiation, had low radioactivity, but the authors did not know why.
The Dard Hunter Paper Museum has been renamed the American Museum of Papermaking, and the IPST, its owner, has hired Ms. Evelyn E. Garlington, an experienced museum curator, to take care of it. She will be responsible for expanding the former Dard Hunter Paper Museum into a nationally recognized museum depicting the processes, artistic values, and importance of paper and papermaking processes through the centuries. New artifacts will be added. Although the museum will not move from storage to its new quarters until later this fall and will not open until next spring, a new inventory has been begun and an exhibit schedule for 28 interpretative exhibits is already being drawn up. Exhibit conditions will be as non-stressful as possible, with very low lighting (paper degrades readily in light, more rapidly than any other type of artifact). A storage study area is also being planned. The museum will occupy about 2500 square feet in the IPST Paper Tricentennial Building.
The Encyclopaedia Britannica, which is revised and reissued yearly, has been printed mostly on alkaline paper for a number of years, but 1990 was the first year when all 32 volumes were on alkaline paper. A source at EB headquarters in Chicago says they like to use alkaline paper, because some of their customers ask about permanence.
Because of the size and complexity of the printing job for this venerable reference work, they always have to have several paper suppliers lined up, to prevent disruption of the production process in case of strikes, market conditions and so on. For a while before 1990, one of the suppliers was acid.
Since paper permanence standards will soon start specifying a lignin level of 1% or less instead of the presence or absence of "groundwood or unbleached pulp," it is reassuring to learn that this 1% level is not hard to reach. A mill source sent in this information last March:
Basically speaking, unbleached mills would have a problem reaching the 1% or less lignin levels, since pulp coming from a digester may be 2 to 3% or more lignin content. The 1% level is probably achievable by most modem bleached pulp mills, with hardwood grades being at a lower level than softwood grades.
The Mishima Paper Company makes a 30-120 gsm water-soluble paper using carboxymethylcellulose salts. It is printable yet capable of dissolving in 5-20 seconds. It is one of the Mishima specialty papers described in J. Jpn Soc. Col. Mater. 64(11), Nov. 1991, pp. 696-701. Unfortunately it is in Japanese. The abstract appeared in the June Paper & Board Abstracts.