Volume 9, Number 2
Jul 1996

Letters

[On page 5 of the last issue, there was a letter to the Editor from Dr. David Grattan, commenting on an article from the October 1995 issue, "Carbonate-Filled Groundwood for Cash-Strapped Publishers." I had written this article because I had heard that certain publishers who had switched from acidic groundwood to alkaline freesheet in the late 1980s had gone back to acidic groundwood when the price of paper nearly doubled last year. I wanted them to know that carbonate-filled groundwood, a recent innovation, is a better alternative. It is readily available, economical and apparently long-lasting, except for a tendency to yellow.

[One of the points Dr. Grattan made was that wood ages differently from paper, and that one could not conclude anything about the permanence of paper from the way the wooden implements I described had lasted. -Ed.]

Editor's reply to David Grattan:

The statement you referred to in your letter was the following paragraph:

In the last five years or so, however, alkaline groundwood grades have been appearing on the market. They contain calcium carbonate, which can preserve almost anything. Archaeologists have dug up rare wooden artifacts on the east coast of Canada that were over 1000 years old, preserved only because they were in a midden of discarded sea shells rich in carbonate. One can safely say that carbonate-filled groundwood is better than acidic groundwood, even if it does not meet the requirements of the ANSI/NISO or ISO permanence standards.

Notice that I have said nothing about the west coast of Canada, or waterlogged wood, or the relative keeping qualities of cellulose and lignin. The excavation I referred to was the subject of a science program on public TV last fall. The narrator emphasized that wooden implements like those found inthe excavations described, rarely last as long as these did, but these were in a calcium carbonate environment. Tools of bone and antlers, he said, are more often found in archaeological excavations, because they do not decay as readily underground as wood does. The archaeologists speculated, if I recall correctly, that these could have been the "red paint people" whose settlements have been excavated elsewhere in New Brunswick. At any rate, the implements showed that these people made their living by fishing rather than by farming or hunting.

I have tried to find a reference in the literature about this dig, but so far without luck. The public TV people cannot supply the information until they know the name of the program, because they do not index their programs by subject. However, I can refer you to Jim Tuck, an archaeologist in the Archaeology Unit at Memorial University in Newfoundland, who has worked in that part of Canada for a long timeand seen a lot of shell middens.. He may be able to confirm my statement about shell middens and wooden implements. There is also a book that I have not seen yet, which I suspect will bear me out: Archaeological Wood: Properties, Chemistry & Preservation, by Roger M. Rowell, published recently by the American Chemical Society.

I did not conclude from that TV program that groundwood paper would last longer if it was carbonate-filled. I have known this for many years, having seen how well deacidified newsprint performs in aging tests. I simply thought that the publishers would get the point more quickly if I drew a simple and dramatic parallel between that buried wood and the buffered groundwood I wanted them to use. Most publishers, after all, have never even heard of deacidification research involving groundwood. That article was written for the benefit of publishers.

There was a statement in that article, however, that I would like to correct right now. It is in the next paragraph: "Carbonate can not keep groundwood from yellowing, but for some purposes that may not be very important." In fact, there is evidence that it does retard darkening. The groundwood samples, for instance, in the second Lee/Bogaard/Feller publication (under 3B1.24 in the Literature section of this issue) darkened much less after light exposure when they had a high pH in the 9 or 10 range, which is where precipitated calcium carbonate would usually put it. So even if carbonate does not prevent yellowing of groundwood, it can slow it down considerably.