The Abbey Newsletter

Volume 18, Number 8
Dec 1994



Thea Burns has a report of the IIC Congress in Ottawa, Sept. 12-16, 1994, in Paper Conservation News for December 1994, on p. 4-5. The Congress was titled "Preventive Conservation: Practice, Theory and Research," and it did have papers on all aspects of preventive conservation, including light, RH, temperature, pest control, storage of sensitive materials in inert atmospheres, and reduced handling and use.

The Proceedings themselves, 244 pages long, cost £20 from IIC.

Relative humidity, now a controversial topic, was a central concept in seven papers:

David Erhardt and Marion Mecklenburg, "Relative Humidity Re-examined"

Jonathan Ashley-Smith et al., "Let's be Honest--Realistic Environmental Parameters for Loaned Objects"

S. Staniforth et al., "Appropriate Technologies for Relative Humidity Control for Museum Collections Housed in Historic Buildings"

Jonathan P. Brown, "Hygrometric Measurement in Museums: Calibration, Accuracy, and the Specification of Relative Humidity." (He says that temperature and moisture content vary so much within a room, and it is so hard to measure RH accurately, that complexities of measurement should be acknowledged; measurement of RH is "emphatically not a substitute for monitoring the actual response of artifacts to their environment.")

Nathan Stolow, "The Preservation of Historic Houses and Sites"

T. Oreszczyn et al., "Comparative Study of Air-Conditioned and Non Air-Conditioned Museums"

Graeme Scott, "Moisture, Ventilation and Mould Growth" (2.7)


"Relative Humidity: A Discussion of Correct/Incorrect Values," by Stefan Michalski. ICOM Committee for Conservation, 1993, Preprints v. 1, p. 624-628. Like many other current publications, this one emphasizes physical stresses in museum objects, but it also touches on leather and paper at a couple of points, and it has an interesting section on the origin of today's environmental standards. Nine graphs and diagrams are reproduced from the literature to illustrate phenomena and relationships, e.g., "Lowest values of RH that will support mold growth" and "Effect of RH on rate of loss of strength in paper fibers."

On the basis of the research reviewed, he says that "a conservative limit for no mold, ever, on anything, would be to stay below 60% RH, but the practical danger for most situations begins above 75% RH. In either case, an excursion to 90% RH is tolerable (in terms of mold) as long as it does not exceed a day or two." He does not say how much mold would result within a year with several such excursions, or how dry materials would react that have been moldy in the past.

It is hard to believe the statement in the next to last paragraph that "Drops of 40% RH do not constitute an emergency for . . . most archival material"--unless it refers to fairly gradual drops. What about film? Parchment? Paintings on paper or parchment? Glass plate negatives? Coated paper?

What would the temperature be doing in the meantime? Although stories are told about how books and wooden artifacts stored in unheated buildings survived in wonderful condition for 100 years (and sometimes fell apart when they were later put into a museum), it is still not certain why they survived in an uncontrolled environment. Was it simply the lower temperature during the winter? What about the higher temperature during the summer? Outdoors, RH usually rises when the temperature falls, and extreme values are usually separated by 12 hours; in an unheated building, these fluctuations would be slowed down, but by how much? In libraries, museums and archives with HVAC systems, temperature and RH are separately controlled. Does this make a difference? There is much that remains to be explored. It is gratifying to see conservation scientists turn their attention to the knotty problem of relative humidity, but we need to see productive discussions and identification of the crucial obstacles to agreement among all parties involved: curators, conservators, and scientists. (2C1.3)


"The Determination of Allowable RH Fluctuations," by David Erhardt, Marion F. Mecklenburg, Charles S. Tumosa, and Mark McCormick-Goodhart. WAAC Newsletter, v. 17 #1, January 1995, p. 19-23. This is really quite a sensible article, written at the request of the WAAC Newsletter editor. It deals entirely with the types of damage that occur in museum objects that expand and contract as a result of changes in humidity, and omits consideration of the effect of high and variable RH levels on degradation of paper, film and so on. The authors emphasize that climate control should not be abandoned, even though some objects can withstand wider fluctuations than previously thought. There will always be some objects that require microclimates and buffered cases. "If anything, the relaxation of allowable RH fluctuations for the general environment requires more thought and a better knowledge of the materials, history, and requirements of the collection."

They say that the rate of increase or decrease of RH makes no difference, only the differences in stresses between the outer and inner layers in an object. Conscientious conservators and curators, however, will recall that an object removed from cool or cold storage still has to be brought gradually to ambient temperature and humidity; and those in charge of protecting books will not be able to subject books on coated paper to rapid changes of RH without causing irreversible cockling of pages. (2C1.3)


"From Steaming to Seemly. . . Achieving Suitable Exhibit Climates." Technology and Conservation, Summer 1994, p. 5-7. The more successful an exhibition is, the harder it is to control the relative humidity with the existing HVAC system, because crowds raise the RH in a building. A high-profile exhibit at the San Diego Museum of Art kept things under control by renting equipment from Munters Moisture Control. (2C1.3)


"Relative Humidity in Museums,Galleries, and Archives: Specification and Control," by Stefan Michalski. In Bugs, Mold & Rot II, Proceedings of the Workshop, Nov. 16-17, 1993, p. 51-62. Edited by William B. Rose and Anton TenWolde. National Institute of Building Sciences, Washington, DC, 1993.

This paper supports a practice of maintaining highly individual micro- or sub-environments for artifacts, rather than having one broad range of conditions for everything. The graphs in Figures 1-4 show the effect of RH on mold growth, strength loss and fading of colorants for paper and photographs. He says, "Thus libraries and archives, which house predominantly unstable materials, have strong reasons to consider any humidity above 0% as chemically destructive."

On the topic of relative humidity control, he says that "in the day to day business of museum consultancy, building science suffers the same limitations as artifact science: at best the advice is up-to-date but complex, at worst it is obsolete but simple." New museums are built as elaborate showplaces, then "operated on a shoestring budget by mere mortals." The advice the Canadian Conservation Institute gives to small museums includes humidistatically controlled heating (that is, heating the air until the RH drops to 50%; uncomfortable for humans but, as he says, many smaller museums and historic houses are essentially unoccupied in winter). Another suggestion they make is to build a "cocooned room" inside the larger building. Another is "passive microenvironments" like book boxes or storage cabinets, or "active microenvironments" with humidity controlled by buffer salts or forced air. It is most important, he says, make sure the RH for most collections does not stray outside the bounds of the 25%-to-75% range, but for books on acidic paper, an RH as high as 50% only doubles the rate of decay during the winter. (2C1.3)


"Fungi as Contaminants in Indoor Air," by J. David Miller. Atmospheric Environment v. 26A, #12, pp. 2163-2172, 1992. This is a thorough review, very full of facts, well written, and important. There have been advances in several areas of epidemiological research on this subject in recent years. A more critical evaluation of indoor air with fungi is needed. The author works at the Plant Research Centre, Agriculture Canada, in Ottawa. (2C1.8)


"Health Implications of Fungi in Indoor Environments--An Overview," by Brian Flannigan and J. David Miller. In: Health Implications of Fungi in Indoor Environments. R. Samson, B. Flannigan, M. Flannigan and S. Graveson (eds.) Elsevier, Amsterdam, 1994. In press.

This covers recent research on health effects of fungi, including mycotoxins and volatiles produced by fungi, with a bow in the direction of bacteria, house dust mites and other organisms. The assessment of fungal populations gets a hard look, with its problems of sampling highly variable populations, selection of appropriate culture media, and identification of species. Alternative approaches are considered. The conclusion says, in part, "The mycological studies required for an understanding of the ecology of fungi in buildings and their role in determining the fungal flora of indoor air are not trivial. Thus far, most research published in this area is mycologically naive." There is a good long bibliography. (2C1.8)


"Deciding What is Worth Saving--New Directions in Archival Selection and Appraisal," by Ann Pederson. Preservation of Library Materials (Australia), #11, Nov. 1993, p. 3-12. The author emphasizes the differences between libraries and archives that make selection more crucial in archives. She reviews the different approaches or philosophies of appraisal, and says, "It may be that the best appraisal strategy will be for archivists to become unabashed experimenters, selecting the most promising and choice bits from each new scheme to form their own Dr. Frankenstein style customised appraisal strategy." She gives her own "Eleven-Point Customized Appraisal Strategy," admitting that David Bearman was right when he said in 1989 that there are not enough archivists in the world to appraise existing records in a lifetime. Her eleventh point is "Changing focus of modern records appraisal: from records to records keeping systems." (2D)


The Preservation Committee of the Canadian Council of Archives has a series of unnumbered and undated Information Bulletins, two of which were received at the Abbey office in February. One of them, entitled "What You Should know Before Deciding to Deacidify Paper Records," summarizes an article by Helen Burgess and Douglas Goltz, "Effect of Alkali on the Long-Term Stability of Paper Fibres Containing Lignin" (Archivaria, Journal of the Association of Canadian Archivists, #37, Spring 1994). The summary oversimplifies the article and previous reports in this project, saying that rag and lignin-free papers became more permanent with alkalization, while ligneous papers actually deteriorated. Actually, individual papers of all three kinds (rag, lignin-free, and ligneous) were sensitive to elevated pH levels, to some extent. In the most recent work reported in Archivaria, only one of the six older ligneous papers was adversely affected by alkalization; but the new cotton rag paper that was included as a control was quite adversely affected, as shown by the change in degree of polymerization after accelerated aging.

The best conclusions to draw from this work are not that all ligneous papers are hurt by alkalization, but that lignin may be a contributing factor to alkaline sensitivity (p. 199) and that it is very hard to predict which papers will be damaged by alkali (p. 196). The authors were able to identify three probable factors in this adverse reaction to alkali: density of the paper, type and amount of size, and degree of oxidative degradation. The first two factors affect contact between the fiber and the solution, and the third increases the reaction between the fiber and alkali. (2D5)


"Book Printing and Electronic Publishing" is a section in GATF's 1995 Technology Forecast, a 24-page insert in GATFWorld, the newsletter of the Graphic Arts Technical Foundation, for Jan./Feb. 1995. Other sections cover "Trends in On-Demand Printing Technology," by Jeff Hayes, "Postpress Report" (which covers binding trends) by Werner Rebsamen, and other topics. (GATF's address is 4615 Forbes Ave., Pittsburgh, PA 15213.)

Short-run or "instant" book publishing is the largest growth area in book publishing. The digital master makes it easier to produce the paper version. At a June 1994 meeting of the Association of American University Presses, some saw CD-ROM and multimedia as direct competitors of book printing, while others saw it as an augmentation of their print work. Bulky directories become easier to transport and use on CD-ROM; also catalogs, encyclopedias, medical books and law books. (2E4)


"It's 10 O'clock: Do You Know Where Your Data Are?" by Terry Cook (director of the Records Disposition Division at the National Archives of Canada). Technology Review, Jan. 1995, p. 48-53. This was handed out by someone at ALA Midwinter this year.

This is about leaks and cracks in electronic record-keeping systems--not just the obvious ones of obsolescent software and hardware, but all the ways a system can go wrong just because humans are running it, working as they do in the context of an organization with turnover, mistakes and faulty communication. Security systems, including backups and offsite storage, may be absent or incomplete without anyone noticing.

Cook, as an archivist, speaks with authority when he explains the value of the system of control that we take for granted with paper records, a system lacking with electronic records: the signatures, letterhead, routing slips, attachments, acknowledgement-of-receipt stamps and so on, which are essential for some internal investigations or legal inquiries, and which are considered as part of the record. This article is a gold mine of horror stories. It ends with a summary of current thinking about ways to increase reliability of electronic records. (2E4)


"Ensuring the Longevity of Digital Documents," by Jeff Rothenberg. Scientific American, Jan. 1995, p. 42-47. The author is a senior computer scientist in the social policy department of the RAND Corporation.

This clearly-written and well-illustrated article not only provides a list of near losses or narrow escapes (the 1960 U.S. Census, tapes of the Department of Health and Human Services, P.O.W. and M.I.A. records for the Vietnam War, herbicide information needed to analyze the impact of Agent Orange, and more) and describes the basic characteristics of electronic records that are becoming familiar in the preservation community (obsolescence and vulnerability to stray magnetic fields and physical decay), but it also provides a full description of bit streams (the sequence of 0s and 1s that make up the electronic record) and the challenges they present to those who want to decode them, when the usual context is not present--as when a record in obsolete format must be read, but the software and equipment to read it cannot be found. The author suggests practices or standards that would provide the context in a form that is easier to read than the bit stream itself. He calls it "sealing bit streams in virtual envelopes." (2E4)


Accelerated Aging: Photochemical and Thermal Aspects, by Robert L. Feller. Getty Conservation Institute [1994]. 277 pp., soft cover.

Jim Druzik announced the appearance of this book on the Conservation DistList in January, saying:

"Ten years ago, late summer 1985, I was hired by the new Getty Conservation Institute to monitor the contract research program of the Scientific Program. I inherited three projects that had been negotiated by my supervisor Frank Preusser earlier that year. One of those projects was designed to 'capture' the wisdom and accumulated knowledge of Dr. Robert L. Feller on the subject of accelerated aging. That effort would turn out to be one of our most ambitious conservation science writing projects. Robert Feller's goal was simply to write the book he wished had been written when he was starting out in the 1950s. Now Accelerated Aging: Photochemical and Thermal Aspects is available to all. And frankly, it's the best source of information on the subject you can buy anywhere, anytime, at any cost. For ordering information call Getty Trust Publications at 800/223-3431 or (foreign) 310/453-5352."

There is little to add to this evaluation. The price is $33 postpaid. The book is well laid out, well written and illustrated, and is as simple as it can be, given the technical nature of the subject. Terms and concepts are defined clearly to give the novice a foothold in a new discussion, e.g. "Such a process would be called photolysis or the photolytic breaking (scission) of a bond." (p. 47) But concepts are never oversimplified; one can dive as deeply as one desires into any aspect of this subject, without being disappointed. (3B1.21)

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