The Abbey Newsletter

Volume 12, Number 8
Dec 1988


The ACS Symposium in L.A., Sept. 28-29

by Ellen McCrady

The Symposium on Historic Textile and Paper Materials: Conservation and Characterization II took place on four days (Sept. 27-30), but the presentations on paper were all on the 28th and 29th. The American Chemical Society's Cellulose, Paper and Textile Division has given other symposia on this topic before: 1976, 1979, and 1984. The well-edited but expensive proceedings (Advances in Chemistry Series 164, 193 and 212) appear a year or two later.

These events are significant because they offer conservators and scientists their best opportunity to get together and discuss matters of mutual interest. For several reasons, the symposia do not achieve their potential as a forum. They are so widely spaced that by the time the next one comes around, the conservators and scientists have forgotten each other's names, and there are no committees or other mechanisms for interaction between symposia. There was not even a list of participants with names and addresses, to help with networking afterwards. The Cellulose Division does have a semiannual newsletter, but its scope includes much more than preservation. Anyone can join the Division for only $5.00 (students free): apply to Dr. Tor P. Schultz, Mississippi Forest Products Lab, P0 Drawer FP, Mississippi State, MS 39762 (601/325-3136). Conservators would do well to join, meet scientists, make their own needs known, and do what they cam to help out the scientists when they call up with a conservation-related problem. It can be a two-way street.

By AIC standards, attendance was sparse, even among the speakers. About six out of the 24 or so speakers did not show up to give their papers. The audience was largest (50 or 60) on the afternoon of Sept. 29, when conservators and scientists in equal proportions assembled to discuss future directions. This included people from the fields of textile, wood and paper. The symposium I attended in 1979 was no bigger, though, so it seems that this is the natural size for symposia like this. No one got lost in the crowd or had trouble making themselves heard.

Some of the papers were too technical for me to follow, especially the ones in textile science and conservation (the wood people did not meet with us till the second afternoon), but they were all good, and some were plainly significant for book and paper conservators.

Two papers were on deacidification of books (David Hon and Don Sebera) and many of the papers involved accelerated aging of textiles and paper. William K. Wilson gave a paper on cornerstones, co-authored by Charleton C. Bard, in which he made recommendations for the container, contents (including film and magnetic records) and atmosphere inside the container.

Chandru Shahani gave one paper on alkaline reserve and one on humidity cycling. The Library of Congress lab's alkaline reserve work was to determine how much was enough: was it 3% calcium carbonate (the level they usually recommend), or more, or less? Results were inconclusive, but they did find out that a) methyl magnesium carbonate increased the life of newspaper over six times, b) for Allied Superior paper, a reserve of only 1.l3% was enough, and c) aqueous deacidification gave better life extension with lower reserves. The humidity cycling study replicated Cardwell's work in the 1960s, with variations, e.g. a higher relative humidity. Both books and paper were found to age faster at higher RH's and when cycled. In the discussion period, he mentioned that there is a big difference between aging of deacidified and nondeacidified paper if it is encapsulated, and that paper ages 8-10 times as fast if it is encapsulated. Someone in the audience made him promise to publish his work on this.

Robert Feller reported recent work at the Mellon Institute on the damaging effects of visible and near-ultraviolet light. They aged paper with heat as well as with light, and found that when light-aging at any of three wavelengths was followed by heat-aging, the paper just went on deteriorating at more or less the same rate as before, after a hiccup at the transition point; but when heat-aging came first, the rate of aging under light speeded up considerably and did not slow down for the duration of the experiment. If there is no lignin, he said, the paper lasts ten times as long. During the question period, he dropped a bombshell, saying that light-bleaching of wet paper, as done by conservators, does very little damage. He had used 40 times as much light as a conservator would use in light bleaching, and had not found that the light did a great deal of damage. (For background on the light-bleaching controversy, see p. 52 in the June 1987 issue of this Newsletter.)

It was too bad that neither Tim Barrett nor his coauthor B. H. Kusko of the Crocker Nuclear Lab in Davis could be there to read the paper they did on the analysis of old papers by particle induced x-ray emission (PIXE). This was the same effort for which conservators a few years ago submitted to Tim both very good and very bad examples of paper from the period 1400-1800. According to the abstract, the sulfur, chlorine, and trace metal content of 133 historical paper specimens were determined nondestructively. The papers that were in good condition had higher levels of calcium and zinc, and the papers in poor condition had more sulfur, chlorine, potassium and iron. Foxed spots sometimes had ten times as much iron as an adjacent clean spot. The sulfur values were higher near the edge, so could have come from exposure to air.

Mary Ballard, textile conservator from the Smithsonian's Conservation Analytical Lab, gave a significant paper on weighted silk. It was significant because she and Virginia Pledger found that the widespread 19th century technique of brightening colors in newly dyed silk by dipping it in sulfuric acid was probably more to blame than the various metallic weighting compounds usually blamed for the deterioration of silk. (Book conservators who have been puzzled by the unpredictable success of silking as a method of strengthening book pages may find that this answers some of their questions.)

The topic of lignin came up in the joint symposium on the 29th. Excerpts from my notes: "No one knows the formula of lignin.... The stability of lignin [in wood] is not determined by its chemical structure but by where it is.... Some very deteriorated woods are 100% lignin.... Lignin is inside of jute fibers and is not separable, so jute deteriorates in light, which is why it is outlawed in hatch covers. In linen you can separate the fibers from the lignin Lignin absorbs UV turns it into a free radical instead of heat. This is why antioxidants are effective: they shut down the free radical process."

The ongoing debate between textile and paper people about the proper aging temperature continued where it left off at the last conference, with no clear winner. The textile people reported aging at 125°C, 150°C and 190°C, temperatures at which the moisture content of the material is essentially zero, while the paper people reported moist (50% RH) aging at 90°C, which is even lower than the 100°C and 105°C levels common in paper research 20 years ago. The debaters are made anonymous in the following transcription from my notes:

A: You get the same chemical changes at any temperature below 125°C, wet or dry aging.

B disagrees.

C: The catalytic effects of metals, and reactions that depend on water and difference in moisture regain are missing in dry aging.

A: Name one reaction that requires water as a reactant.

C: I can't say; no one knows.

D: The wet strength is different after wet and dry aging.

E: You need water for hydrolysis.

(Others agree.)

A talks about specific reactions that don't require water, and says cellulose is never completely dry because of bound water.

C: But it's not labile.

F: You can get rid of all the water.

In the combined session on future directions, Sept. 29th, people suggested ways of getting through the communication harrier between conservators and scientists: round robin testing, electronic mail, collaborative projects and farming out conservation science problems to graduate students in universities. Problems recognized were lack of samples for testing and a recent drying up of funding from the Institute of Museum Services and chemical and dye companies for research. Conservators were urged to ask for goodwill analyses from university and forestry labs.

The speakers' addresses are all given in the program, for the convenience of anyone who wants to contact the speakers and can't wait till the proceedings are published. Readers can request addresses from the Newsletter office.

Any report like this, based on personal notes rather than a printed or taped record, is bound to contain inaccuracies. They will gladly be corrected if they are pointed out, and readers are requested not to take anything too literally in the meantime.

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