Robin P. Croskery Howard, Objects Conservator at the Ah-Tah-Thi-Ki Museum, focused on how custom housing, in concert with climate control, can be effective preventative conservation. Three case studies highlighting specific housing solutions for different collection materials were shown.
Case Study #1: The Long Road Home/Speck Collection
Some housings need to provide safety for travel and long term storage. The Ah-Tah-Thi-Ki museum makes it a priority to repatriate any collection items that are not Seminole in origin. These items are returned untreated. The two housings used for this are either stacked layers of Volara cutouts, contoured to fit the object or ethafoam cavities lined with acid-free tissue.
Case Study #2: The Doll with the Broken Neck
The museum has a number of dolls made out of palmetto fibers. These fibers deteriorate over time and the limbs and necks of the dolls often detach. Any treatment would produce only temporary results as the doll continued to age and breakdown. Custom pillows and supports are used to support the dolls and relieve stress on their joints.
Case Study #3: Leaning Baskets
An oversized modern sweetgrass basket that had partially collapsed under its own weight was restored using an adaptive housing. The basket was put in a box with twill ties holding it in place. The ties were gradually tightened over several weeks to support and lift the basket and allow it to gently regain its shape over time. Other modern baskets are stored with ethafoam supports.
These were great, practical solutions for caring for objects by using housing to prevent or control damage. I realized while writing this post how much this session falls in line with Cordelia Rogerson’s “Fit for Purpose” talk. All of the items showcased here were cared for, but in a manner and level appropriate for long view of their “life” at the museum.
Category: Topics
42nd Annual Meeting, Textiles Session, May 29th: Analysis of Organic Dyes in Textiles by Direct Analysis in Real Time–Time-of-Flight Mass Spectrometry by Cathy Selvius-DeRoo, Ruth Ann Armitage
Direct Analysis in Real Time – Time of Flight Mass Spectrometry (DART-TOF) was shown to be a viable method of organic dye analysis in the presentation by Cathy Selvius-DeRoo. The beauty of the technique is that it requires only a small fiber sample, and no advanced preparation such as dye extraction, in order to get positive identification for a variety of dyes, both plant and insect based.
The project began with a grant to purchase the equipment. From there, various colorants were tested from a dye sample book, in order to develop the protocol. The sample was put in the ionizing gas airstream (helium) and heated to a temperature of 350 – 500 degrees. The result was fast and accurate identification of several dye classes, such as quinones, tannins and indigoids.
The presenter had a relaxed, personable style and shared some of her tips for success as well as lessons learned, including: better results were achieved with the higher temperature and with the addition of acid hydrolysis, which could be added just prior to putting the sample in the airstream using an eyedropper. The presenter confessed that flavonoids could be difficult to discern because the spectra are very similar for the various components.
After the method proved reliable, the technique was tested on textiles with undocumented dyes. The most satisfying was to substantiate family lore on a Civil War coat. The story was that a mother of a soldier dyed a Union issued coat to resemble a Confederate coat. Analysis revealed that the indigo was overdyed with Walnut (also referred to as Butternut). Cool.
Full disclosure – I signed up for blogging this talk because I’m a bit of a science junkie. I don’t always understand it, and in a small private practice, I certainly don’t have a Mass Spectrometer in the studio, but I appreciate knowing how to solve problems and who to go to for help.
42nd Annual Meeting – Health and Safety Session, May 31, 2014, "Unintended Consequences of Persistant Residual Vapor-Phase Chemicals within Collection Storage" by Catharine Hawks and Kathyrn Makos
This talk, given in Saturday’s Health and Safety session, was a summary of a project at the Smithsonian’s National Museum of Natural History investigating the vapors that staff were exposed to when opening old storage cabinets.
Chemicals that accumulate from pest management or other treatments can be harmful to people, objects/specimens, and even storage furniture through inhalation, repeated exposure, and adsorbing or absorbing onto their surfaces. Many pesticides are particularly retained in lipids in specimens and in the wood components of storage cabinets – this has the potential to be problematic for those working with collections that were subjected to these types of treatments in the past, particularly natural history collections. The goals of the project were to detect, identify, and quantify concentrations of organic vapors in cabinets that were known to have held treated specimens, thereby being able to determine the level of risk. Entering into the project, mercury vapor was expected. Heavy metals and non-volatile particulates were not investigated, with the idea being that proper use of personal safety tools and regular cleaning with HEPA vacuums will negate their effect on humans.
Vapor data was collected via evacuated canisters using the USEPA TO-15 method, and a mercury vapor analyzer. Cabinets chosen for the survey were presumed to have not been opened recently (and some were known to have been left unopened for many years). Of the cabinets chosen, 55 held mammals, 100 held anthropological specimens, and 50 were empty but had held anthropological specimens in the past.
Results
Contrary to expectations, none of the cabinets were found to have mercury vapor! However, 39 other volatile compounds were found. Thankfully, these compounds were only detected in the ppb levels, and all volatile compounds detected were well below (often 100-1000 times below) workplace exposure limits (TLV).
Data obtained was not significantly different from the empty and the filled cabinets, which suggests that empty cabinets retain some chemicals, even after long periods of time. However, measurements of volatile compounds present in storage outside of the cabinets were not taken.
Though these ranges are safe for humans, they may not be safe for collections stored within the cabinets or for the cabinets themselves. Two chemicals are of particular concern: PDB (1,4-dichlorobenzene) and naphthalene are both highly toxic and will be retained in fats and other proteinaceous materials. They also increase mobility of unsaturated fats and are likely carcinogenic. In addition, PDB may crystallize onto surfaces, leaving a reside that can be quite sticky and difficult to remove.
Due to the results of the survey, the authors have a few key recommendations for collections that may contain such chemicals:
- Improve storage: Budget towards accelerated disposal of old cabinets. Do not reuse them, even with non-collection items. Re-house collections in metal cabinets, and segregate treated specimens from the rest of the collection.
- Implement an integrated pest management system: This reduces the need for future treatments and can be non-toxic! Heat treatment is not recommended for pesticide-treated specimens.
- Implement safe work practices and practice personal safetey measures: Wear gloves, minimize case-browsing, examine objects in a well-ventilated area.
- Work towards remediation: place scavengers in cabinets that can’t be evaluated or dealt with now.
- Above all, be aware and be safe!
42nd Annual Meeting – Collection Care Session , May 29 “Conservation Assessment at Schloss Leopoldskron in Salzburg, Austria: Promoting Sustainable Choices for the Adaptive Re-use of the Collection and the Site” presented by Rita Berg, Graduate Intern in Paintings Conservation, Brooklyn Museum and Crista Pack, Kress Fellow, Arizona State Museum.
Beautiful landscapes to boot, this talk illustrated how graduate students gained experience in preventive conservation by identifying the collections care needs of a prominent historic site that is also a busy event space/hotel.
In the summer of 2013, four students from New York University and the Winterthur/University of Delaware Program in Art Conservation — Rita Berg and Cybele Tom (NYU) and Crista Pack and Emily Schuetz Stryker (WUDPAC)—performed a conservation assessment of the historic collection at the Schloss Leopoldskron, under the supervision of Hannelore Roemich, Professor of Conservation Science at NYU and Joelle Wickens, Associate Conservator and Preventive Team Head at Winterthur. The talk was dedicated to Emily who passed away unexpectedly in February of this year.
Crista and Rita presented by discussing the building’s history, the goals of the project, the group’s workflow and theoretical approach, recommendations for the future, and lessons learned. The Rococo palace was commissioned by Count Leopold Anton Eleutherius von Firmian, and was once owned by Max Reinhardt. It is now an Austrian national historic site, and host of the Salzburg Global Seminar (SGS). The assessment project was co-sponsored by the Kress Foundation and SGS.
The Schloss is not only a magnificent edifice—it is familiar to many as the inspiration for the Von Trapp villa in The Sound of Music—but its historic collection includes paintings, works of art on paper, furniture, decorative arts and sculpture. Unfortunately the collection’s condition has never been systematically documented.
The major goals for the project included developing a long-term strategy for caring for the collection, as well as providing educational training for students who were able to test theoretical approaches in a “real-world” scenario (though it was admittedly hard to think of the bucolic, dream-like setting of this palace as “real-world”). However, major challenges quickly presented themselves to the students: food and beverages could be found throughout the house, candles were lit regularly, there were many open windows, objects vulnerable to theft, chaotic transportation and storage of objects during events, wildlife, dust and dirt accumulation.
The group worked in pairs to assess rooms, and three different types of object groups (prints, paintings and architectural elements) using photography and written survey forms that they had developed. They interviewed staff and local scholars, recorded patterns of use and consulted existing literature from the National Parks Service and the Conservation Assessment Program.
Among their recommendations were that the SGS articulate the presentation of the building and collection directly in its mission statement, appoint a collections manager, establish guidelines for events and handling. They also identified that the paintings, which were among the most valuable objects, are at the highest risk.
Although they found inherent contradictions in the house’s dual function as a historic site and event space/hotel, the students aimed to raise awareness among staff, owners and guests of the collection’s needs. This was done they maintained, keeping in mind the priority of the space’s functionality. This July a new team of conservation students will continue the project following the guidelines established by their predecessors. And judging from the Alpine landscape, lucky them.
42nd Annual Meeting – RATS Joint with Objects Session, May 30, “Technical Study and Conservation of the ‘Bat Wing Ship,’ Background, Challenges and Surprising Discoveries, Lauren Anne Horelick , Objects Conservator, Smithsonian National Air and Space Museum
The compelling object at the center of this paper is an experimental prototype of a Nazi German jet powered fighter aircraft discovered by the Allies at the end of World War II and brought to the United States for study. Designed by the Horten Brothers (Reimar and Walter), this craft with a steel structure, paper-thin plywood veneers, and no vertical tail is regarded as a design predecessor to the stealth bomber. The aircraft, a model Horten Ho 229 v3 (the third and final version of this particular airframe) was captured when it was near completion in the Gotha workshop http://airandspace.si.edu/collections/artifact.cfm?object=nasm_A19600324000 Charcoal was said to have been added to the construction adhesives to make the aircraft invisible to radar.
While always a favorite of air flight/military history buffs, this craft has never been exhibited and has been the subject of increased interest in recent years due to what the paper’s author describes as a “sensationalized” documentary entitiled “Hitler’s Stealth Fighter.” This video, available on YouTube, is replete with inaccuracies including the assertion that it is stored in a “secret government warehouse” when, in fact, its current home is the Smithsonian’s Paul E Garber Facility in Suitland, Maryland. However, it will soon be moved to another disclosed location – The Udvar-Hazy Center in Chantilly, Virginia where it will have its big reveal.
In preparation for this move, conservators at the Smithsonian NASM carried out a technical study to inform treatment protocol for the stabilization of the unstable and extensively delaminating veneers. They sought to characterize and identify the adhesives and other materials employed and, in particular, seek evidence for the presence (or apparent lack) of charcoal.
The aircraft is 55.4 feet wide with a tubular steel frame. The engine rests in the center of the craft and it is covered in a plywood skin. There is a clear canopy for the pilot. Due to complications of working on the object in its storage location, the decision was made to disassemble the damaged plywood portions to allow for treatment of the panels in the conservation lab. The composite materials that were examined and analyzed included the plywood board, structural supports and spacer blocks including the adhesives used to attach these portions to one another.
After a literature review of plywood available in Germany before WWII, reference materials were acquired for the potential materials. A sampling protocol was developed and the object and reference samples were examined under visual and Polarized Light Microscopy, FTIR, Raman, and for selected samples XRD was employed. (There may have been other methods employed that I missed in my notes– GC-MS and 3-D microscopy were mentioned in the abstract – sorry if I have omitted something significant.) The analysis was done in conjunction with the Museum Conservation Institute.
The analyses yielded some unexpected results as some of the wood sample results varied from those specified by the Horten Brothers (as reported in their interrogation). However the substitutions of European Beechwood/Scots Pine for the specified birch was not very surprising to the authors given the materials shortages at the end of WWII. The adhesives tested were identified as urea formaldehyde and phenol formaldehyde. Confirming the presence of charcoal in the black paint/adhesive layers proved elusive. The black particles were difficult to separate from the matrix. PLM examination did not support the charcoal identification and they were found to be amorphous with XRD. FTIR analysis pointed to the presence of cellulose, hemi cellulose and phenolics. This could mean oxidized or charred wood – or neither.
Plans for treatment do not include repainting damaged areas as the author mentioned a growing trend toward exhibition of aircraft in a less heavily restored state. Beech veneers will be employed in areas of loss but were unavailable in the United States in the <1mm thickness required so must be ordered from Germany. Because the urea formaldehyde has cross-linked with age and become insoluble, the conservators are not as concerned as they might have been about adding new materials when they choose an adhesive to stabilize the veneers.
Details and updates on this research project and the treatment are available on the on the National Air and Space Museum’s Airspace blog http://blog.nasm.si.edu/restoration/horten-h-ix-v3-bat-wing-ship-may-2014-update/ The Bat Wing Ship is poised to be a popular attraction when it goes on exhibit – I know my interest has been piqued by this interesting talk!
42nd Annual Meeting (Objects Session 5/31/14) – "Testing and implementation of microclimate storage containers for small metals and plastics" by Dana K. Senge
Dana’s talk – the last of the Objects session talks given at AIC’s 42nd Annual Conference in San Francisco – presented the results of multiple tests conducted by the National Park Service (NPS) Intermountain Region Museum Services Program, evaluating several readily available materials for their ability to protect sensitive objects from less-than-ideal climate conditions. Tests sought to identify the best methods for long-term storage of two distinctly different categories of collections materials: archaeological metals and historic plastics. The ideal solutions would be cost effective and easy-to-use, would allow for easy monitoring and access, and could be consistently applied across all NPS sites.
Archaeological Metals
Various storage systems for archaeological metals have been employed at NPS sites in the past, including Stewart boxes, 2-4 mil polyethylene (PE) bags with twist ties, and heat-sealed Marvelseal enclosures in combination with desiccants and/or scavengers.
Following the work done by JP Brown (2010) and Alice Paterakis (2011), Dana did some short experiments to confirm that resealable PE containers with silicone gaskets held a microclimate better than similar containers without gasketing. This being established, she added data loggers and twice the calculated amount of desiccant recommended for the container’s volume, and conducted a longer test in three locations – Arizona, where storage conditions were generally dry (about 35% RH); Montana, where conditions ranged from 25-45% RH; and Texas, where conditions fluctuated around 50% RH. Even under the most humid conditions in TX, the worst-performing silicone-gasketed PE boxes only allowed an increase of 2% RH over the course of the year-long test period. Measurement of the TX test box after a second year registered only another 2.7% increase in RH. Based on this set of experiments, Dana calculates that this particular setup would only require recharging with desiccant every 5 years if a change of less than 15% RH was desired. In addition, Oddy testing of the materials involved in the system confirmed that there was nothing harmful being off-gassed.
Historic Plastics
To find an ideal solution for historic plastics, Dana started by consulting Yvonne Shashoua’s 2008 publication, Conservation of Plastics. She learned that different polymers have wildly varying requirements for safe storage: cellulose nitrate (CN) and cellulose acetate (CA) need ventilated or scavenged environments to slow deterioration, while natural rubber fares better in anoxic environments, and polyvinyl chloride (PVC) calls for only non-absorbent glass or Mylar fabrication materials. The deep trays with Tyvek covers that had been in use at NPS since the 90s were not effective, so alternatives were sought.
For use with CN and CA, several box designs were evaluated for their ability to ventilate the space and prevent dust accumulation inside the box. Acid-free board boxes were made with slatted or screened walls and were tested without lids, with Hollytex lids, or with acid-free board lids. Inside the prototype boxes, Dana placed a deteriorating CA shower curtain ring along with a sticky surface to determine how much dust found its way in, and A-D Strips to monitor for the buildup of harmful acetic acid vapors. Findings supported the use of a blue-board lid, as it prevented the most dust over a month-long period. Though screened and slatted boxes did equally well, the screened boxes were found to be easier to construct. No harmful buildup was detected by the A-D strips in any of the boxes.
As a space-saving alternative to ventilated storage, Dana next evaluated several common scavengers in conjunction with the previously described resealable PE containers. In order of their performance (worst to best), they were Kodak Molecular Sieves, a single MicroChamber board, Getter Pak, two MicroChamber boards, and Zorflex. The most effective adsorbent, Zorflex, prevented acetic acid build-up in the container for 18 days. Interestingly, each scavenger tested lowered the humidity in the box to some extent initially, though it did eventually rebound. A second round of tests that doubled the amount of scavenger found no benefit to doing so. Future work will include evaluating activated carbon cloth, and rerunning the above described scavenger tests on boxes containing a larger amount of deteriorating CA to see if the products can keep up with increased volumes of off-gassed acetic acid. She would also like to test resealable glass containers in this capacity.
Although storage for PVC objects was not extensively discussed, Dana mentioned that she has been using and is pleased with heat-sealed 1 mil Mylar enclosures. She prefers the use of a single-impulse heat sealer to a double-impulse model to make the enclosures.
Finally, Dana made a point to address a few limitations of the systems she evaluated for this paper, including size (the largest silicone-gasketed PE containers she’s been able to find only measure 9 x 12 x 6 inches) and the need for a robust monitoring/maintenance plan.
Questions/comments after the talk:
- One talk attendee mentioned that she had found much larger gasketed PE boxes, but that they didn’t necessarily seal well because of the distance between the clamps, especially on the long edges. She recommended testing the container with water – if it’s not watertight, it won’t be airtight either!
- A question was posed about the efficacy of these systems compared to non-gasketed PE boxes that were sealed with aluminum tape instead. Dana stated that aluminum tape was not evaluated in this round of testing.
- Dana, though she didn’t mention brand names, cautioned that some brands of containers definitely held a better seal than others. Test your enclosures first!!!
I really enjoy hearing about research with practical applications. Thank you, Dana, for a well presented and interesting talk!!
42nd Annual Meeting – May 30th, "Sustainability Roundtable" hosted by the Sustainability Committee
What does it take to get your institution to do something about sustainability? The Sustainability Committee roundtable sought to create a space to discuss facilitating change at our institutions. In full disclosure, I am on the Sustainability Committee, however my role at the Annual Meeting did not include organizing the roundtable. Jia-Sun Tsang and Sarah Stauderman lead a discussion of five sustainable issues, focusing on the Smithsonian Institution (SI) as a case study. This was followed by a discussion amongst the audience, who were divided into groups of two.
The five sustainable issues were recycling, reuse, making a difference/activism, preservation environment, and lighting. After the presentation of these five, the audience was invited to add additional issues they would like to discuss, which included planet sustainability (especially water consumption, CO2 emissions, exotoxins emissions).
- Key factors for improving the success of recycling at the Smithsonian were improving communication between housekeeping and facilities and educating the staff about how to recycle.
- Reuse of materials occurs at an individual level, through units, and across museums. For example, the SI has a process for reusing equipment, exhibition cases, etc. that are no longer needed at a particular branch. A
- Activism was profiled through the experience of Eric Hollinger, an employee at the SI who has had a major impact on green issues. He sees himself as an “agitator,” “assistant,” “advisor,” and “advocate.”
- Making changes to the preservation environment occurs best when all the relevant constituents are at the table (facilities, conservation, curatorial, etc.). An example of effective change to preservation environments was a Smithsonian wide summit that occurred last year.
- Colonial Williamsburg recently worked across departments to make changes to their lighting system and switch to Light-Emitting Diodes (LEDs). Further information on that case study can be found on the Sustainability pages of the AIC wiki. Another case study for successful changes to lighting is the partnership between the Smithsonian American Art Museum and the Department of Energy.
Sarah Stauderman gave us a crash course in management theory to give us the tools and mindset necessary to create change. Learning to frame the conversation to effect change takes practice. These conversations work best if you have a defined purpose and engage multiple perspectives. Change happens most quickly when you can collaborate, compromise, and negotiate with your colleagues. Keeping things simple and aiming for small outcomes will help to get the momentum going on your project. When you do get a meeting, think carefully about where the meeting will be held and if you can make it an experience or in some way engage the constituents in the issue.
We then broke into pairs to discuss the following three questions. The goal of this section was to help participants practice the dialogue and thought processes that facilitate change.
1) What do you need to achieve the goal?
2) What in your organization is keeping you from your goal?
3) What training/resources do you need?
Personally, I found it helpful to have a framework to start thinking about change. Talking through ideas with my partner was encouraging and provided valuable insight. I hope that the other audience participants were able to take away a feeling of optimism about their ability to implement new sustainability initiatives at their institutions.
42nd Annual Meeting – Opening Session, May 29, "The Long and Winding Road . . . Effective Advocacy, Fundraising, Networking, & Collaboration: Promoting Sustained Preventive Conservation Globally" by Debra Hess Norris
Across the globe, people are united in the desire to preserve tangible and intangible cultural heritage during catastrophic natural disasters, warfare, economic collapse, and other crises. Photographic collections, for example, are considered valuable to many cultures yet traditional photographic processes are disappearing. These collections are incalculable in number, many exist under poor conditions, and only a small percentage of them are inventoried systematically.
As professionals, we are accustomed to evaluating the condition of collections such as these and perform analytical research. While these pursuits are essential to the field, Debra Hess Norris reminds us that we must engage in intercultural dialogue, advocacy, and fundraising in order to effectively care for global cultural heritage.
We must not operate in isolation but rather promote education and training through hybrid and certificate programs. We must build public awareness and advocate for our cause through traditional media, social media, bilingual platforms, and crowd sourcing. We must pursue external support from organizations such as the Giving Pledge, Clinton Global Agenda, Gates Foundation, Luce Foundation, and US Ambassador Fund. The American Institute for Conservation of Historic and Artistic Works and FAIC should facilitate communication with the Institute of International Education, Department of State, and the Alliance for International Education and Cultural Exchange. In addition, AIC and FAIC must participate with ICCROM, ICOM, IIC, and UNESCO.
In closing, Norris reminds us that our projects – small and large, local and global – must be significant. She demonstrates this through a slideshow featuring John Lennon’s “Imagine” and images of photographic preservation projects from the Middle East, Africa, Latin America, Europe and Asia.
About the Speaker
Debra Hess Norris earned an interdisciplinary B.A. degree in chemistry, art history, and studio art (1977) and M.S. degree in conservation (1980) from the University of Delaware. She has taught more than 100 workshops and seminars for conservators and allied professionals, has authored more than 35 articles and book chapters on the care and treatment of photographic materials, conservation education, ethics, and emergency response, and has collaborated on a series of Worldwide Photographic Preservation Projects with conservation professionals, organizations, and agencies.
Norris has served as chair of the AIC Ethics and Standards Committee (1990-1993), as president of the AIC (1993-1997), on the National Task Force for Emergency Response (1995-2000), and chair of Heritage Preservation (2003-2008). Currently residing as Chair of the Art Conservation Department at the University of Delaware and Professor of Photograph Conservation, she serves on the board of the Conservation Center for Art and Historic Artifacts (CCAHA) and the Advisory Committee for the FAIC Hermitage Photograph Conservation Initiative.
Related Lectures/Webinars
ECPN Webinar: “Conservation Education, Outreach, and Advocacy” with Teresa Myers, Richard McCoy, and Sarah Barack. April 2013.
ECPN Webinar: “Self-Advocacy and Fundraising for Personal Research” with Debra Hess Norris. July 2012.
42nd Annual Meeting – Research and Technical Studies Session, May 31st, "X-ray Micro Tomography Analysis of Western Red Cedar Secondary Phloem by Peter McElhinney"
What factors contribute to the deterioration mechanisms for cedar bark? Peter McElhinney’s presentation on work completed as an Andrew W. Mellon fellow in object conservation at the National Museum of the American Indian in Washington D.C. addressed this question. His project was inspired by encountering labels on storage boxes for objects in the collection with the words “Inherently Fragile: Will Have Continued Loss.” Peter set out to better understand why cedar bark deteriorates so rapidly and dramatically.
Objects made from cedar bark come from Western Red Cedar trees that grow in the North West coast region of North America. Native groups in that region harvest and weave cedar bark to make baskets, hats, mats and other objects. Cedar trees can grow to between 65-70 m tall and 3-4 m in diameter. One of the unusual features of these trees is the way that the bark is made and the type of cells present on the exterior of the bark. Peter focused on four aspects of cedar bark that play a major role in the way it deteriorates: the disruption of the cells on the exterior bark, calcium oxalate crystals, dehydration of pectin, and phenols.
Peter demonstrated the changes to the bark’s cellular structure using diagrams and CT scans. Cedar bark, called phloem, is made up of sieve cells, parenchyma cells and fibers. Cross sections of bark examined with a Skyskan 1172 micro CT scanner from Micro Photonics Inc. enabled the differentiation of inner and outer phloem. The cells in inner phloem, the section of the bark closest to the tree, are orderly, more rectilinear, and less disrupted. As the cells are pushed towards the outside of the tree, they become outer phloem, and develop a more disordered, compressed, less rectilinear appearance. The fibers in outer phloem have stronger cell walls, whereas the parenchyma and sieve cells tend to be crushed or squished. These changes in the phloem relate directly to the shedding characteristic of objects made from cedar bark.
The CT scan also revealed the presence of a large bio-mineral crystal in the bark sample. These bio-minerals form as part of the normal function of cedar trees based on minerals absorbed from the soil. Scanning electron microscopy with energy dispersive spectroscopy identified small, shard-like crystals as calcium oxalate and the large particle as a silica aluminum crystal. The small shard-like crystals were most abundant in the cell walls in the middle and outer phloem. This corresponds with literature that cedar trees have 10-20 times as many calcium oxalate crystals as other trees. These crystals may cause cell wall abrasion during manipulation of the cedar bark, which could contribute to the bark’s rapid deterioration.
The dehydration of the pectin and phenols also affect the cells. Cedar bark used for objects loses moisture over time, which can cause the dehydration of the pectin in the bark. Dehydrated pectin may reduce the ability of cells to adhere together. Significantly higher numbers of phenols are present in the outer phloem than in the inner phloem. The phenols protect the bark from ultraviolet radiation damage. This characteristic could influence lighting requirements for objects made from cedar bark if we can determine whether they are made from inner or outer bark.
Conservation applications of these findings help to improve understanding of how cedar bark deteriorates. The cells in outer bark are already structurally compromised, which can contribute to the shedding associated with cedar bark objects. Calcium oxalate crystals can further damage cells during handling of the object. Dehydrated pectin reduces cell adhesion within the bark. Finally, phenols present in high quantities in the outer bark may project the material from damage due to Ultraviolet radiation. Overall, this talk applied complex information about cellular biology to develop a better understanding of cedar bark deterioration mechanisms. This information is essential for developing better preventive care handling procedures for these fragile objects. I’m looking forward to reading the post prints for this talk and studying the figures and images in more detail.
42nd Annual Meeting – Interest Session, May 31, “Syllabus Sharing Session”. Chaired by Emily Williams.
This was a pretty informal session but it was attended by a lot of really enthusiastic people. When I arrived in the room shortly before the start time the discussion had already started. By the time Emily Williams arrived (one issue with this session was a lot of competing interests at the same time) only 5 minutes later, we were already well into it and she had her work cut out to herd the syllabus-sharing cats.
The initial premise of the meeting was for people either teaching or interested in teaching conservation to allied professions to get together and share their ideas for teaching. This arose from interest expressed at the last annual meeting. Emily Williams, who guided the session, explained that there wasn’t a big plan for it, they just wanted to provide a space for discussion and she wanted to distribute a short questionnaire to determine interests (see end of blog for the questionnaire questions; please send your answers to the questions listed to Emily Williams)
When I came in, the discussion centered on what kind of sharing was proposed. Some participants were unwilling to post their syllabi online for various reasons, although they’d be willing to share them with interested people via email. The group seemed pretty evenly split on this topic but even without general consensus on that topic there were a lot of interesting ideas and useful resources discussed.
One suggestion (sorry, everyone, I was having a hard enough time jotting down the ideas that were coming fast and furious and didn’t always note who said what) was a list of who was teaching what, where, and whether to undergrad or grad students, so that we could see who was teaching something akin to our interests and reach out to them. Another participant was interested in adding information on class size and whether the instruction was compensated. At this point, Emily came in and let us know that AIC’s e-editor Rachael Perkins Arenstein and she had just discussed setting up a Wiki page that could host just this sort of info, so that was great. This ‘Teaching to Allied Professionals’ wiki page would be akin to the existing Exhibiting Conservation .
Several participants offered useful resources; these came up at various points in the discussion but I’m going to lump them together here:
- Chemistry in Art is the first web-based community launched by the NSF-sponsored Chemistry Collaborations, Workshops and Community of Scholars program (cCWCS) . The CiA community is primarily designed for college-level instructors to network and to collaborate; and to access, share and develop curriculum materials.
- GCI has a lot of good teaching resources. “The GCI is pleased to make available didactic resources that have been produced and used in the Institute’s courses, workshops and field training. These resources include outlines of teaching sessions, bibliographies, exercises, case studies, and technical notes that can be downloaded and used by conservation educators and students in the classroom and by professionals for informal, personal learning according to the terms described below.” GCI puts everything up under a Creative Commons License. Kathleen Dardes mentioned that she was particularly interested in getting feedback on this resource.
- NEDCC also has resources available freely.
- UCL has a very detailed online syllabus for their Conservation for Archaeologists course:
- Renee Stein and Katherine Etre at the Carlos Museum have worked with science teachers to develop a resource for high school science labs based on art conservation. Carlos.emory.edu/science-art-conservation
There was some discussion of how to write a syllabus; Emily put forward the view that we should think of a syllabus as a contract between the student and instructor. Some felt that this might lead to a voluminous syllabus and suggested adding a generic paragraph that everything is subject to change. There was general agreement that it was important to communicate fully with students to understand their expectations and to explain your expectations. List outcomes and rubrics (this was unfamiliar use of rubric for me so I turned to Wikipedia for explication: “In education terminology, scoring rubric means “a standard of performance for a defined population”.” Live and learn). The students need to understand that taking one course will not transform them into conservators. Instructors in a university setting may need to follow institutional guidelines for syllabus-writing but also may be able to get help from their Centers for Learning Excellence.
At our request Emily explicated what the relationship was between ETC (the AIC Education and Training Committee of which she’s also a member) and this syllabus sharing group. In short, the ETC is tasked with overseeing AIC’s education initiatives (mostly directed at conservator education) whereas our adhoc group was directed at conservation education for allied professionals.
At this point, we went around the room and introduced ourselves and talked about our specific interest in the topic. It was fascinating to learn how many different ‘allied professionals’ were interested in or could benefit by an academic introduction to conservation basics: art students (who could learn how to make their artworks more permanent or definitely ephemeral); museum studies programs; collections managers; archaeology and anthropology students; art history students; library scientists and archivists; programs for chemistry, materials science or engineering students, and others I’ve probably left out. One participant was especially interested in identifying and accessing online resources that could be used by students in the Developing World.
Emily polled the room to see if there was interest in a session for the next Annual Meeting on how to teach. If you weren’t there but would are interested, please fill out the extremely short survey at the end of this post.
I have not yet taught a full semester University level course, just classes in other courses and workshops in host countries. But I hope to do so in the next year or so as our Museum starts an exciting new initiative for teaching archaeological science to undergraduates. Having long felt that most American archaeology and anthropology students need to understand more about conservation, I’m pretty passionate about this topic and it was great to be in a room with others who share that passion.
SURVEY DISTRIBUTED AT SESSION:
We are hoping to organize a formal workshop on teaching for the Miami AIC meeting. To help us plan this and future events please answer the following questions and return this form to either Emily Williams (ewilliams@cwf.org) or Suzanne Davis (davissl@umich.edu)
- What resources would you most like to see AIC develop to aid you in your teaching. These resources might include items for the soon to launch “Teaching to Allied Professionals” wiki page, continued education courses for conservators engaged in courses, course materials for use in the classroom or other items. Please write down anything you think might be useful.
- Is there a particular challenge that you feel you or other conservators face in teaching Allied Professionals that you particularly wish to see addressed through workshops or the wiki page.
- Have you developed course materials or other teaching aids that you are willing to share with other conservators? If so, what types and how may we contact you?