|AIC members from all specialty groups are invited to attend and participate in the event “A failure shared is not a failure: learning from our mistakes,” happening on Saturday, June 2nd, from 4:30 to 6:00 p.m. — click here to add it to your Sched. We will gather and share our cautionary tales, including treatment errors, mishaps, and accidents, with the idea of helping our colleagues not to repeat them.
Discussing mistakes is a hot topic that has already been embraced by others in our community. Two examples of events scheduled during the month of May are: “Mistakes were made,” a regular feature at the American Alliance of Museums conference, and the lecture “Conservation Confidential” hosted by our conservation colleagues across the pond in the Independent Paper Conservators’ Group.
Participants can speak for up to 5 minutes; if you prefer to remain anonymous, a reader will be happy to present your tale on your behalf. If you are unable to attend AIC’s Annual Meeting but would like to submit a tale to be read by one of our organizers or a colleague, please reach out.
Screens to project PowerPoint slides containing your images/video will be available (16:9 format), and a Dropbox folder will be made available for submissions. Please also bring your presentation on a USB Drive (highly encouraged). Time permitting, audience members inspired by their colleagues will be welcome to present. If appropriate (and acceptable to the speaker), the floor will be opened for questions and discussion following presentations. Extra points for suggesting safeguards and solutions!
Please note that this is a forum for sharing personal mistakes and solutions only. Participants are requested not to name other persons, organizations, work places, and avoid politics—institutional, national, and global!
The event will include a cash bar, so come, relax, unwind, share, laugh, groan, and learn. We plan to publish the event for those who wish to be included.
If you are interested in participating or have questions about the event, please contact Tony Sigel at email@example.com or by calling 617-767-1900 (cell), or Rebecca Gridley at firstname.lastname@example.org by May 10th.
Please include 2-3 quick sentences introducing your topic and indicate whether you plan to use a PowerPoint with images and/or video.
See you in Houston!
In her talk on ionic fixatives, Soyeon Choi, head conservator of works on paper at Yale Center for British Art, presented an overview of the history of ionic fixatives, an explanation of how they work, and the results of several experiments. I had been looking forward to hearing Soyeon’s talk, due to the potential usefulness of ionic fixatives for library and archives materials. As Soyeon emphasized throughout her presentation, this type of fixative is likely to be most useful in cases where saving the information is a higher priority over aesthetic appearance, such as in the case of modern and contemporary inks, which are sensitive to a wide range of solvents. Soyeon’s experiments focused on a wide range of inks and included a variety of tests with numerous ionic fixatives and several different contemporary inks.
Prior to this talk, I hadn’t realized that ionic fixatives had remained more popular in Europe than in the United States since they were introduced as a treatment technique in Germany in the 1980s. As Soyeon explained, ionic fixatives have been used for mass scale treatment in Germany since 1996, but simply have not caught on in the US, for a number of reasons. One of the main challenges in translating this technique into practice is that these fixatives are industrial products which are used in processing textiles, and are not commercially available on a small scale. A related challenge is that the names of the fixatives are proprietary, and therefore vary from country to country, so fixatives used for research and testing in Europe are either not available in the US or go by different names. And, as with all things industrial, the exact composition of these fixatives is proprietary and subject to change. Soyeon felt it would be useful to complete a study of ionic fixatives in the US, and having seen her talk, I agree!
Soyeon gave a brief and thorough description of the main categories of ionic fixatives, which can be either cationic or anionic, and explained how these differ chemically. Interestingly, it has been found that cationic and anionic fixatives work best when used in tandem rather than when used separately. She also explained that the main drawback of all ionic fixatives is that some permanent change in the color of the ink should be expected, and that these are most useful in situations where preserving legibility is the main goal. Her research focused on dye-based inks, and compared 13 different fixatives. The experiments included examining the effects of applying the fixatives, and then testing the efficacy of the fixatives using localized treatment.
The goal of the first experiment was to determine if the fixatives leave any residue in the paper after washing, and to see if it made any difference to wash before or after the fixatives dried. Whatman filter paper was used, and the fixatives were applied to the paper on their own, as in not over any ink. Samples were left either unwashed, washed before the fixative dried, or washed after the fixatives dried. The fixatives tested included Polymin, Lupamin, Cartafix FF, Cartafix SWE, Cartafix WA, Cartafix WE, Cassofix FRN, Catiofast 159(A), Catiofast 2345, Mesitol NBS/Rewin EL, Nylofixan HF, Catiofast 269, and Appretan. The samples were washed for 15 minutes, and were examined for fluorescing residue and compared under UV light. There was a range of results in terms of fluorescence, and the fixatives which showed little to no fluorescence were chosen for further experiments.
In the next experiment, the effect of accelerating aging on the washed samples was examined. In this experiment, unwashed and washed oven-aged samples were compared. The oven-aged samples were aged at 70oC, 50% RH for 96 days. The fixatives used were Catiofast 159(A), Cartafix FF, Cartafix WA, Cartafix WE, Catiofast 269, Lupamin 9095, Catiofast 2345, Nylofixan HF, and Mesitol + Rewin. The samples were examined in visible and UV light. One fixative, Nylofixan HF, stained the paper even without aging. The not washed oven-aged samples developed significant amounts of fluorescence, but the washed, oven-aged samples did not, which suggests that washing did a good job of removing the fixative.
Based on these initial test results, three fixatives stood out as the most viable, including Cartafix WE, Mesitol & Rewin, and Cartafix FF. These three fixatives were then tested with contemporary inks. The inks tested, included Winsor & Newton Calligraphy Ink, Bombay India Ink, and Higgins ink. The fixatives were applied over fixed and unfixed inscriptions, again on Whatman filter paper. The fixatives were mixed with methyl cellulose and applied on a suction platen to both the front and back of the samples prior to washing. Both fixed and unfixed samples were washed. As expected, the unfixed samples bled profusely. Most of the fixatives gave acceptable results, and some fixatives worked better with certain inks. Higgins ink did not do well with any of the fixatives.
As Soyeon summarized, there are many factors to consider when using ionic fixatives, and their use requires a lot of fine tuning. The fixatives permanently alter the media to some degree in terms of hue and saturation, and rinsing is important for long term stability. The fixative names change fairly frequently. Future tests may include the use of ionic fixatives with blotter washing vs. immersion washing, gel vs. solution application, and air drying vs. quick drying. Overall, I thought the experiments were helpful and thorough. There was a lot more information presented than I was able to capture, so I hope that Soyeon publishes this work someday.
In her talk “Treatment 305: A Love Story,” Kathy Lechuga, book conservator at the Indiana Historical Society, described a deep relationship with a treatment technique that was years in the making. Kathy punctuated her talk with references to Prince lyrics, which she used to emphasis her love for the versatility of her new favorite treatment technique. Treatment 305 was originally developed at Princeton and was presented by Brian J. Baird and Mick Letourneaux in 1994. It is described in the Book and Paper Group Annual, in an article which may be found here.
The talk began with a summary of why Kathy has found this technique useful, what sort of books this treatment is typically used for, and how it relates to the Indiana Historical Society mission statement. Typically, she has found it useful for printed books from the late 18th to 19th century, which fit into the “medium rare” category. As this category of book treatment isn’t often addressed, I enjoyed hearing two talks related to medium rare books, including Quinn Ferris’ talk, “Medium Rare: An innovative approach to the space between special and general collections.” As Kathy described, the books in this category within her institution included collections that are used frequently for research and exhibits, and the ultimate goal of treatment was to improve mobility and durability while maintaining an aesthetic appearance that was harmonious with the books’ time periods.
Kathy was inspired by the Treatment 305 technique, because it helped in many ways to meet her desired treatment goals. She found this technique appropriate for books with a weak binding and a strong text block, and found that it would allow her to create a tight back structure while minimizing the inherent weakness of the historic structure. However, she did decide to experiment with deviations from the exact Treatment 305 technique as described in the original 1994 article, in order to better accommodate the needs of specific volumes, and to incorporate more contemporary treatment practices.
The majority of the talk centered around four case studies which incorporated slight variations on the Treatment 305 technique. The books included in the case studies were similar in that all were missing significant portions of their original binding components, such as their spines, one board, or both boards, and dated to the late 18th century or 19th century. The treatment was varied slightly in each case study, in order to accommodate the needs of each particular volume. All four case studies varied slightly, although common features included minimal spine linings and new boards constructed from two pieces of 4-ply board which had been laminated together.
One component of one case study which really caught everyone’s attention, and resulted in a few audience questions, was Kathy’s use of a screen-printing kit to replicate the title information on the spine of a book. I also thought this was a great new tool to consider, because replicating an original spine is called for on occasion, and using new materials to replicate an aged aesthetic can be a challenge.
The final talk of the June 1st RATS session was by Jana Dambrogio, Thomas F. Peterson (1957) Conservator, MIT Libraries, Curation & Preservation Services. Jana has been working for several years on the subject of “letterlocking,” the many techniques by which a letter can be folded to form its own envelope. Some of these letters are folded very simply while others are outfitted with complex security features that indicate if a letter has been opened by someone other than the intended recipient. Jana’s research has even suggested that a single individual might have had more than one technique for folding letters.
Most of this research has been carried out by studying unfolded letters, examining folds, cuts, and other physical evidence in order to reverse engineering the original folded structure. Now, Jana and a team from Queen Mary, University of London are using Computed Microtomography (CT scanning) to discern the interior structure of unopened letters. A collection of 600 such letters is held by the Museum voor Communicatie in The Hague, Netherlands.
The letters are part of a group of 2,600 that came to the Museum stored in a 17th century trunk. Jana explained that in the period when the letters were written, the mail operated on a “cash on delivery” system. The letters in the trunk were never retrieved, and thus remained in the custody of the postmaster. While about 2,000 have previously been opened, the “Signed, Sealed & Undelivered” project team are studying the 600 that have never been opened, using a novel application of CT imaging.
During the talk, Jana shared many videos from the project website, demonstrating techniques for letterlocking and showing the potential of the imaging technique.
For more information visit:
It’s probably safe to say that most book conservators have encountered at least one oil-stained textblock. In many cases, the source of the oil was leather dressing, historically applied in an attempt to improve the suppleness, appearance, and longevity of leather bindings. Many different formulae of leather dressing have been documented, but one of the best known is a roughly 1:1 mixture of neatsfoot oil and lanolin.
Treating this staining is challenging for a number of reasons: while conservators can speculate about the type and age of the oil causing the stain, they can’t always make a definitive identification, so extensive testing is often necessary; oil-based printing inks can be susceptible to the same solvents that will act on the stain; treatment of any stain in a bound textblock is difficult; and finally, depending on the amount of oil still saturating the binding, there is the potential for the stain to return or expand over time.
Holly Herro, Conservation Librarian for the History of Medicine Division at the National Library of Medicine presented on the development of a process to remove oil stains from book paper. The project was carried out in collaboration with paintings conservator Scott Nolley, Chief Conservator at Fine Art Conservation of Virginia, and paper conservator Wendy Cowan of Richmond Conservators of Works on Paper. Tests were conducted on a blank modern paper endsheet from a 15th century book. The sheet was stained with what the conservators suspected was a combination of neatsfoot oil and lanolin, applied approximately 30-40 years ago. Several protocols were tested, but the most successful at reducing the staining was as follows:
Pre-wash the affected page in a 50/50 solution of deionized water and ethanol buffered to pH 9 with ammonium hydroxide. In the tests, the samples were washed in three baths totaling one hour and air dried. Using suction, first apply a pipette filled with petroleum ether, a low polarity solvent that solubilizes the lanolin. Then apply acetone with a pipette, a high polarity solvent, to solubilize the neatsfoot oil. Continue alternating these solvents in a 1:1 ratio, changing the blotters regularly, until the oil is visibly reduced. Periodically view the substrate using a ultraviolet light checking for any oil residue. After the oil is reduced, wash the paper in a deionized water buffered to pH 9 with ammonium hydroxide.
The samples were examined under UV and visible light before and after treatment to determine the effectiveness of each treatment. The alternation of a polar and non-polar solvent over a suction table seems to have been an effective way to reduce both suspected components of the stain. The protocol was also tested on an endsheet in a bound book using a suction platen.
Leather dressing stains in books continue to be a common problem faced by book conservators and additional tips and tricks are always useful to have on hand. A great next step for this work would be testing of the impact of the protocol on printing inks.
To read more about the project and about techniques for reducing oil and leather dressing staining on paper, consult the following resources:
“Oil on Paper: A Collaborative Conservation Challenge” by Kristi Wright and Holly Herro: https://circulatingnow.nlm.nih.gov/2015/06/16/oil-on-paper-a-collaborative-conservation-challenge/
“Treatment Options for Oil Stains on Paper” by Denise Stockman: http://cool.conservation-us.org/coolaic/sg/bpg/annual/v26/bp26-22.pdf
“The Removal of Leather Dressing from Paper” by Brenna Campbell: http://cool.conservation-us.org/coolaic/sg/bpg/annual/v28/bp28-22.pdf
At the 2017 AIC Annual Meeting in Chicago, we, Katherine Kelly, Denise Stockman, and Alex Bero, gave an overview of the 2016-2017 developments in the BPG Wiki and sought feedback from an audience of about 60 interested members about how to move forward in 2017-2018. We want to thank the BPG Officers, who made certain that this discussion group had a place in a very busy schedule!
There have been a lot of changes to the BPG Wiki in the past year. We followed through on our promise to increase communication with the BPG membership, and this has led to much greater participation in return. We have a long list of contributors to thank, which we have included at the end of the post.
We undertook a reformatting campaign across the wiki. Standardization is crucial to allowing for the future growth of the Wiki, so we created a template to choose among the many variations of page design. We resolved many issues along the way, such as how to reduce numbering but differentiate between sections, how to include links and references, and how to thank new and old contributors without top-loading the page. The elimination of the original numbered outline format makes it much easier to grow and move information around.
All of the shared BPG pages and all of the Book Conservation pages have been updated in this way. For the pages derived from the original Paper Conservation Catalog, 10 pages have already been reformatted. We are looking for volunteers to re-format 16 other pages. See our Call for Reformatting on the Help Wanted Page.
The first contributors to the Wiki this year were the Tips presenters in Montreal, who shared images and PDFs from their 2016 presentations. This was a great way to quickly share new techniques. These contributions were available within a month of the Annual Meeting and are now gathered together with Tips from 2013 and 2014. (There were no Tips Sessions in 2015 or 2017.)
Alex Bero spoke about the activities of the Bibliographies subgroup. A recent priority has been to update the format of bibliographic entries of the wiki, in order to bring them into line with the JAIC Style guide, with a few modifications for the online format.
For 2017-2018, we intend to build a new Guide to Resources page with information on how to get resources that are not freely available online, and on resources that are underutilized.
If you have suggested improvements to any BPG Bibliography, please consider becoming a wiki editor or sending your citations or annotations to email@example.com, who will format them and post them on the wiki.
It has long been our goal to get more images on the Wiki pages. This year, progress was made on several pages, including the Fiber Identification page. Jennifer McGlinchey Sexton offered us the images she had created for CAMEO, the Conservation & Art Materials Encyclopedia Online, and Xiaoping Cai offered to add them to the Wiki. The result is a much more appealing and useful page.
Adhesives Recipes and Tips
The first call for content this year asked for contributions to Adhesive Recipes and Tips. This is a companion page to Adhesives for Paper, which offers a more in-depth and technical discussion of adhesive properties. With contributions from seven book and paper conservators, Adhesive Recipes and Tips now offers recipes for making methyl cellulose, Klucel G, funori, isinglass, and wheat starch paste in a variety of ways. There is also an annotated bibliography on remoistenable and pre-coated tissues.
Non-Western Bookbindings and Their Conservation
This year’s blockbuster success was a new page on Non-Western Bookbinding Structures and Their Conservation. This topic was identified as one that had very little coverage in the wiki, but that might interest many of conservators. Immediately after the Call for Content, this page took off, and in a month, ten conservators had contributed more than 130 citations on Armenian, Chinese, Korean, Japanese, Islamic, Palm-Leaf, Thai, and Tibetan manuscript and bookbinding traditions.
In addition to the benefits of many minds coming together to create good content, there were collaborations between well-established and emerging conservators. This type of collaboration can combine deep experience, the perspective of someone new the field, and wiki-editing skills – with excellent results.
Culturally Sensitive Treatment
One of the contributors for the Non-Western Bookbindings page, Marieka Kaye, from the University of Michigan, saw an opportunity for an offshoot page that focuses on the Culturally Sensitive Treatment of book and paper objects. The aim of this page is to discuss the conservation ethics involved in treating materials from a wide variety of cultures and help identify components of those artifacts that should not be lost during treatment. The page currently focuses on East Asian materials, but we hope to expand into other cultures.
Related AIC Wiki Pages
The BPG Wiki is part of the larger AIC Wiki. A long-term goal is to connect BPG pages to those in other Specialty Groups, and to contribute to pages of common interest. These efforts are in the early stages, but there are some good successes to report, including Conservation Supply Sources, Oddy Testing Results, History of Conservation, and the recent ECPN page on Gels, Thickeners, and Viscosity Modifiers.
Following the presentation, we asked the audience for feedback on how the Wiki should grow in the coming year.
There were discussions about the appropriateness of moving content around to allow certain topics to grow (for example, iron gall ink might benefit from having its own topic page), removing excessive information, updating out-of-date or inappropriate terminology, improving bibliographies with software like Zotero, and soliciting images.
There was also an enthusiastic debate about how the wiki should deal with outdated treatment techniques. The pages on Alkalization & Neutralization and Bleaching have several examples of treatments that, while accepted practice at the time of their writing, have fallen out of favor (e.g. Diethyl Zinc). It was agreed that outdated techniques should be indicated within the wiki. There was a suggestion from the audience that keeping information on the same topic page was better, ideally in a separate section for historical or superseded techniques. Another audience member stressed the importance of adding a date for when techniques were moved to that section (or when the technique was in common use).
Another audience member pointed out that treatments change and are updated all the time. She recommended a review cycle for pages (perhaps every 10 years) to review the content of a chapter and provide updates.
We are grateful for the thoughtful debate on these issues and feel that this year’s discussion group has provided excellent guidance and direction for the year ahead.
How You Can Help
If you have ideas about how you would like to get involved in the Wiki, please send the Wiki Coordinators an email. You can also look at the page called BPG Help Wanted, where we list topics in need of attention, recent Calls for Content, and ideas for future growth. Please also join the AIC-Wiki listserv as this is the main way that Wiki editors communicate among themselves.
Denise Stockman, Paper Conservation Wiki Coordinator, New York Public Library
Katherine Kelly, Book Conservation Wiki Coordinator, Library of Congress
Alex Bero, Wiki Bibliographies Team, New York University
2016-2017 BPG Wiki Contributors
Amélie Couvrat Desvergnes
Debora D. Mayer
Jennifer McGlinchey Sexton
Tina C. Tan
Yana van Dyke
For the first BPG Session of a treatment-themed AIC Conference this year, Adam Novak, a paper conservator at Daria K. Conservation, LLC in New York gave his presentation on a topic that is very important but not often discussed in the field: using one’s senses to determine the appropriate treatment for an item. With a multitude of treatment options available, the conservator is (ideally) able to control the outcome and intensity of the treatment by understanding the effects of time, moisture, conductivity, and expansion on the item. Adam referred to the thorough research and presentation at last year’s AIC meeting by Amy Hughes and Michelle Sullivan on minimally invasive treatments using gels as an example of how the conservator can control the treatment.
The primary concern in conservation is obviously the effectiveness of a treatment, but the possible repercussions of the treatment on an object in the future is a concern. Adam spoke of how every treatment carries with it both risks and benefits, and as conservators we can control how invasive (and how effective) we would like a treatment to be. Drawing from conservation’s relatively short past, it is apparent that reversibility is key and often “less is more.” The less invasive the treatment, the better the longevity for the object. This is of course balanced with the efficacy of the treatment as well, which Adam mentioned.
Adam gave a few examples of different paper treatments involving different kinds of media in excellent detail, describing how he approached each object with the idea that one’s “senses are as important as the science.” Which is to say, if you can detect the subtleties of the paper surface, quality of the ink, etc. then you are more able to control your treatment in such a way to retain the integrity of the work. Ideally, if the conservator is honed in on the subtleties of the item being treated, then the overall outcome of the treatment will have little trace of invasion. This quote was integral to the message of the presentation, and appeared twice(!):
As the treatment “toolbox” grows and changes moving in to the future, taking a closer look at qualities of an item to be retained after its treatment and cleaning will become more important and certainly more achievable.
Emily Hishta Cohen presented a technique for repairing case bindings, where the case has detached from the textblock along one or both board joints. This technique was developed in the MIT Libraries Preservation Department, and continues to be used there frequently in the repair of books belonging to both special and (more recently) circulating collections.
The technique is essentially a modification of a hollow tube repair, except that the tube is gradually constructed on the book using layers of tengucho (or other very thin Japanese paper), adhered with a mixture of wheat starch paste and methylcellulose. Silicone-coated Mylar is used to prevent the tube from adhering to itself as the repair dries. After the spine hollow is reconstructed, internal hinges of tengucho are adhered along the inner board joint(s) to reinforce the repair. Notably, this technique preserves all existing spine linings. Rather than cleaning them off, as with traditional re-backing techniques, here they are left in place and re-adhered as necessary. The best way to understand how this repair is executed is to watch a very thorough step-by-step video created by the MIT Preservation Department, available at this link: http://bit.ly/MITRBBS.
This technique is reversible, minimally interventive, and preserves all existing components of a binding, all of which are admirable qualities in a conservation treatment. It appears perfectly suited to cloth covered case bindings of a relatively small size (such as the one that appears in the video). The abstract mentions that the technique can be modified for larger, heavier books by using cloth in place of Japanese paper. I would be interested in seeing how this would be done without removing existing spine linings to make room for the extra bulk of the repair cloth, which would be significantly thicker than tengucho.
Regardless of how it might be adapted to more substantial books, this “re-engineering” technique is a reminder that sometimes, the weaker repair material is the ideal choice. I’ll certainly keep this technique in mind. A conservator can never have too many tricks up her sleeve.
In her talk, Quinn Ferris discussed a new conservation workflow recently implemented at the University of Illinois at Urbana-Champaign Library, called “Medium Rare Conservation.” This new workflow was initiated in response to the realities and limitations facing the conservation staff at the UIUC. The library’s holdings are massive (24 million items, including 13 million volumes), and must withstand frequent use (1 million patrons visit the library annually). Meanwhile, recent budget cuts have eliminated the possibility of hiring additional permanent staff, while services are never allowed to be reduced.
The “Medium Rare Conservation” workflow is a response to the problem of inadequate resources facing so many university libraries. It is a streamlined approach to treatment that combines elements of special collections conservation (ethical and logistical considerations) and general collections conservation (speed and efficiency).
The term “medium rare” is not new. It was used in 1987 by Stephen Ferguson to describe a category nineteenth and twentieth-century books that, while not considered rare, were “endangered” in the sense that the poor quality of their materials resulted in rapid decay, and finding replacement copies was difficult and expensive. In contrast, the term “Medium Rare” is used at the UIUC to indicate the appropriateness of a specific conservation treatment approach. It does not describe an item’s value, priority, or rarity. A book designated “Medium Rare” in this context could, for example, belong to either special or circulating collections. Because the term has been used in both ways in recent years, it can be problematic and cause confusion. Ms. Ferris addressed this, explaining that she supported the development of more precise terminology. Specifically, she suggested more neutral or objective language for categorizing based on complexity of treatment required, such as numbers 1, 2, and 3.
The “Medium Rare Conservation” workflow was established as a way of increasing efficiency, but as with any major change, its implementation required significant time and patience. The designation needed to be clearly defined and given a list of criteria that would allow for easy identification of collection materials to be channeled into the new workflow. For example, items requiring basic mending, flattening, or simple book repairs (such as those performed regularly on circulating items) could be categorized as “Medium Rare,” while any treatments involving leather work or the use of solvents, could not. Treatment documentation guidelines needed to be created. This involved building a new interface within the existing treatment documentation database, and developing a regimen of abbreviated photo documentation.
Once established, the workflow yielded a number of benefits, some more surprising than others. Treatment turn-around time was decreased, and a greater number of collections were served. Closer working relations with colleagues were established. Treatment opportunities were expanded for conservation technicians, interns, and student employees, who are now able to perform simple treatments on special collections materials. Meanwhile, conservators are allowed to focus their treatment time on items requiring greater care and more complex interventions.
The “Medium Rare Conservation” workflow at UIUC is still in it’s infancy, and will continue to be fine-tuned. Still, it was clear during the lively Q&A session at the end that the issues raised by this talk are on the minds of library conservators. How should Medium Rare treatments be prioritized? Should items be treated if they are available in alternate formats? Stay tuned to see how this kind of hybrid conservation work develops at UIUC and other library conservation labs over the next few years…
Andrew began his talk by very graciously acknowledging that many other people have contributed data that informed his paper. Andrew’s work is based on research began by William Barrow, a paper chemist at the Library of Congress until the 1960’s. Barrow’s research on books tried to draw a connection between physical properties and chemical content. He had collected about 1000 books published between 1500 and the 19th century, and he took various measurements such as fold endurance, pH, alum content, etc. He tried to draw connections between those sets of data to predict the ageing characteristics of the paper. This collection was obtained by LoC in the 1970s, and are still used for destructive testing today. But where Barrow used macro and micro scale measurements, Andrew looks to the middle ground: polymer chemistry. For that, he uses size exclusion chromatography, or SEC.
SEC measures the degree of polymerization of cellulose using a roughly 1mm squared sample size. (It may be helpful to think of degree of polymerization as the molecular weight.) The degree of polymerization of a sample can be compared to known references. It should also be noted that papers have a mixture of molecules of different sizes, and SEC provides a distribution curve. The more large molecules in a sample, the less degraded the cellulose, meaning that the paper is in better condition. Andrew discussed several examples of treatments of iron gall ink on paper where SEC was used to show the effects of those treatments on the papers.
Barrow’s research indicated that pH was the best indication of the future physical properties of paper. Andrew took about 80 samples from Barrow’s collection and confirmed that the molecular weights of paper correlate with pH (when the pH drops, the molecular weight drops). Andrew then looked to see if the molecular weight corresponded to physical properties; with newer papers, the molecular weight does tend to be smaller. Poor tear resistance also corresponds to low molecular weight. In general, he found that the molecular weight determined by SEC is a better indicator than pH for future physical properties for both newer and older books.
SEC certainly has advantages. The sample size is ridiculously small. Tells you about the physical building blocks of the paper, giving a better idea of what’s in it and what state the cellulose is in. There are some disadvantages to overcome before this technique is in every lab. The test itself takes a week to do. It requires extremely expensive equipment and organic solvents, and one must have the technical knowledge to interpret the data. Andrew’s ultimate goal is to turn this into a rapid technique that’s affordable, so that the molecular weight distributions of an object can be included in an object’s record and be pulled up by a barcode. That’s an exciting prospect!
Andrew’s work presents a very interesting analytical option that future conservators might have access to. It would be nice to have a predicting model for the degradation of library objects. But it would be even more interesting to see the effects of treatment on paper. It is important that conservators continue to check our own work, and I’m glad to have assistance with that from scientists like Andrew.