Carolyn Tomkiewicz’s presentation began with a photo of a modest statue of Mary in the garden of a local church. It had been wrapped up against the oncoming storm—not by conservators, but by mindful parishioners. This protection had more in common with how you shield a plant from frost than how a museum usually guards against damage, but their effort and conscientiousness was rewarded when the statue survived the flood unscathed, a reveal that Tomkiewicz ended the talk with. These photos opened and closed the talk as a demonstration of how a community’s response, as much as a conservator’s response, is vital to the protection of the art in their midst.
Tomkiewicz begins at Westbeth Artists Residence, where studios and storage spaces in the basement were swiftly subsumed by the nearby and overflowing Hudson. When the artists were granted access ten days later, the salvage efforts began immediately. The rescue team—composed of the artists themselves, volunteers from AIC-CERT (Collection Emergency Response Team), and local conservation studios—took over the building’s courtyard and turned it into a makeshift triage center. Salvage operations rely on ingenuity: the team MacGyvered door screens into paper drying racks, applied toilet paper as facing for damaged paintings, used puppy training pads as blotters, and when faced with the unappealing prospect of leaving art unattended overnight, they stored as much as they could in a rental truck that they could lock up. Gaining access to indoor spaces at Westbeth improved the security of the artwork. However, as triage operations continued, more and more objects were brought to the team to be treated. The extent of the work to be done in those first few days never seemed to diminish, but the crew pressed on, even addressing the residents’ personal items as well as their art.
The Westbeth example typified an important part of the success of the Sandy response: educating artists on triage procedures to save their own artwork. This education came through including artists in the conservator-led salvage efforts as well as many informational sessions—specifically a well-attended public presentation at MoMA—and online support forums and resources. That AIC-CERT’s involvement was assisted by private conservators, public museums, and even conservation vendors who donated supplies, was what really propelled the Sandy response to be come an example of effective salvage outreach. Of course, few places worldwide rival the level of cultural saturation as Manhattan, but even cities and towns without MoMA should be able to construct a scaled-down version of this type of unified response within the local arts community.
The opening of the Cultural Recovery Center (CRC) in Brooklyn, run by FAIC to provide in-depth treatment at a secure facility, was the culmination of the volunteer effort to restore art after the devastation of Superstorm Sandy. Tomkiewicz discussed the treatment of three heavily deformed and flaking oil on canvas paintings at the CRC that required gradual-tensioning stretchers, humidity chambers, and a burnt-finger technique which utilized a lightbulb as the convex heat source. Given the type of damage Sandy left behind, she devoted special attention to the variety of ways to re-tension water distorted canvases, including Rigamonti stretchers and a “Gleitrahmen” (sliding frame) technique. Details of the treatments were published in the WAAC Newsletter Volume 35, Number 2 of May 2013, “A Tensioning Device for the Reduction of Severe Planar Distortions in Paintings,” by Carolyn Tomkiewicz.
She concluded her talk with the following advice: don’t store art in the basement in a flood zone!
Thanks to museums that publicize our projects and the growing acceptance of on-site treatments, conservation is increasingly in the public eye. But these efforts can only reach so many people, and they tend to be temporary events or installations. Nowadays, we have a way to spread information to the interested reader, however far away they might be, and to archive information for far longer than is usually possible in the physical world. Thus, the question becomes: since knowledge can be disseminated and stored this way, if it can’t be accessed that way, does that research really exist?
Hence, the growing importance of a conservation project website.
First to be discussed is the Kress Technical Art History website (artcons.udel.edu/about/kress). The site approaches a discussion of conservation by focusing on an in-depth exploration of methods and techniques, built around the painting reconstructions completed by Kristin and Brian. Each reconstruction has a section of the website, with a different page for each layer of the painting, but they also have a physical life that also educates: The originals are distributed to museums along with pigment kits, to be used as didactic tools in museum galleries. The website has additional informational pages that cover historical materials and techniques, examination and scientific methods, a vocabulary primer, and links to other resources, including painting reconstructions done by other people. The depth of the website is frankly astounding, as every page seems to link to more detail and further research: from the Historical Methods/Techniques, you can click “inorganic pigments” and find a slideshow of the raw materials being prepared, a PDF of a chronological list of pigment usage, and a link to a video showing the extraction of lapis lazuli. Not only is this a valuable resource for anyone diving into historical painting techniques, but interested pre-programmers will find its resources invaluable for Winterthur’s “copy, reproduction or reconstruction” portfolio requirement.
The second project to be covered was the two-year conservation of the monumental Triumph of David at Villanova. The project’s website (thetriumphofdavid.com) combines not only a timeline of the treatment but a walkthrough of its restoration steps, in-depth reporting on the scientific analysis done, and the ability to view different stages of work and analysis as segments of the whole image. Kristin pointed out that while many institutions are wary of publicizing such sensitive information about the state of their artwork, the Triumph had literally no reputation to uphold: its original assessment had marked it as an insurance loss. The transparency of the Triumph project is refreshing: discussing the decision-making process behind each step and explaining current methodologies. The website is an experiment in laying out a painting’s history on the table, pointing out where there’s room for more research, and inviting the next participants to the table.
Kristin closed the talk with the introduction of MITRA (Materials Information and Technical Resource for Artists). Conceived as a revival of the much-missed AMIEN forum, it will connect artists, conservators, scientists, and educators to discuss best practices. As an interactive forum, hopefully it will become a well of expertise to draw upon when confronted with the misinformation that plagues much of the internet. Though the forum will initially focus on paintings, it will expand as it grows to cover a wide range of topics—wider than its predecessor—including contemporary art materials and concerns, textiles, sculpture, storage, murals, photography, and whatever else the public clamors for, I expect. It will be hosted by the University of Delaware when it is launched, hopefully in the Fall of 2016.
I was drawn to this talk merely from the title, having worked in and visited Greece a multitude of times. Maria Lyratzi first introduced herself as the paper conservator for the Library of the Institute of Educational Policy/Greek Ministry of Education in Athens, Greece. She then dove right in to her talk, which covered quite a lot in a short amount of time. Maria was first influenced to begin her path to creating emergency response plans in Greece via the (former) American Institute for Conservation – Collections Emergency Response Team (AIC-CERT), now the Foundation of the American Institute for Conservation of Historic and Artistic Works – National Heritage Responders (FAIC-NHR). She admired how AIC-CERT showed emergency response plans in a systematic way to where she could adopt and adapt for Greece’s circumstances.
Maria gave a background of Greece and the types of natural disasters they experience (photo) as well as the legal framework that builds the foundation for protecting cultural heritage. Currently, the constitution of Greece, Article 24, states that “the protection of the natural and cultural environment constitutes a duty of the State. The State is bound to adopt special preventive or repressive measures for the preservation of the environment.”
The current State of Greece was established in 1830, and not too shortly afterwards in 1833, the Greek Archaeological Service was founded. And just one year following, the first archaeological law of Greece was established. Amendments to this law have occurred in 1899, 1914, 1921, and 1932. The current law, No. 3028/2002 is in effect and can be read here:
She then went over the main points of the archaeological law and the responsible authorities. The responsible authorities include:
Ministry of Culture
Responsibilities include: archaeological sites, historical sites, all types of museums, all types of monuments (Note: mentioned only ~30% of monuments are under the auspices of the Ministry of Culture)
Ministry of Education, Research, and Religious Affairs
Responsibilities include: Department of Government Archives and the Department of Libraries (Note: there is no specific department for the protection of libraries and archives)
Other Ministries (including Earthquake Planning and Protection Organization, EPPO)
Responsibilities include: Processes and designs the country’s earthquake policies, publishing informational and educational materials, and having a program of pre-seismic control of all public buildings (Note: only ~30% of public buildings are checked)
Public Authorities
Responsibilities include: Local organizations that collaborate with Ministries
Academic Institutes (indirectly)
Responsibilities include: Supervising postgraduate/doctorate projects, researching and scientific programs
Also mentioned were other authorities (General Secretariat for Civil Protection, GSCP) that should protect cultural heritage, but currently do not. As one can probably tell, the laws focus on mostly archaeological antiquities, rather than the wider cultural heritage.
Maria then gave an example of an online system that tracks risks of earthquake areas through the Institute of Geodynamics.
The site has several different tools, including a map with various options, a list of all the monuments and their associated risk, and an area for local research. It maps various monuments, but not nearly enough. The Institute of Geodynamics’ method of collecting data covered monuments and their condition in regional, seismotectonics, and geological data. They then conducted a hazard assessment for each monument. A map was developed where the user is able to choose a multitude of categories to determine associated risks. Maria had been proposed by the Institute of Geodynamics to be a part of their team to expand their map to include locations of libraries and archives. She was also asked to educate local authorities and the personnel of museums, libraries, and archives in Greece for disaster planning.
Maria had additional support from the Library of the Institute of Educational Policy to publish the first disaster plan in 2009 on their website, to organize and run a three day Greek-American seminar in 2013, and to publish her first book on disaster planning in Greece, a culmination of 5-6 years of work, released 2009. The topic of the three-day seminar in 2013 was Disaster Response and Conservation. There were two days dedicated to lectures of disaster preparedness and salvaging art, libraries, and historic collections with one day hands on in disaster recovery training.
She then went on to discuss two surveys given to Greek scientists. The first covered the recorded catastrophic events to cultural institutions from 2002-2012 and the second presented the degree of readiness of major cultural institutions in the prevention and handling of natural and manmade disasters. The data was collected by the Hellenic Statistical Authority (ELSAT) and the Fire Brigade, neither of which have kept formal records of disaster-affected institutions.
Results of the first survey include: 255 cultural institutions calling the fire brigade to assist in fire and flood incidents. Most of them were incidents on archaeological sites. ELSAT has no data for fire brigade assistance for earthquakes. The fire brigade gave no descriptions of the flood or fire incidents that have occurred in cultural institutions. There are no records for disaster incidents to buildings or collections. It is unknown if the files even exist. From the first survey, most floods reported were on archaeological sites (~71%), with, not surprising, rain water being the main cause. Most fires reported were on archaeological sites (~73%), versus museums (~15%). The cause of fires in museums was of unknown origins.
The second survey, the very first of its kind in Greece, was sent electronically to representatives of all types of official museums, private museums, libraries, and archives:
103 public museums, 77 private museums, 188 libraries, and 1 archives
With an allowance of one month to complete, the response rate was 21%
Maria shared various survey questions with the results, below are a few of those slides:
Plans for the future include(d) a one-day seminar on May 28, 2016 in Nafplio with The Center of Hellenic Studies and Harvard University on how to prepare a disaster plan for your institution. Maria is planning to prepare a five-day seminar for the Bank of Greece in Athens inviting the FAIC-NHR representatives and representatives of all the Greek authorities who should be cooperating in the prevention and response of disasters to cultural heritage. She would like to conduct additional research on the degree of preparedness of libraries and archives in the prevention of disasters, to hold disaster prevention seminars all over Greece, to build a volunteer team to confront disasters all over the country similar to the FAIC National Heritage Response, and to create a website with instructions on disaster preparedness.
The audience was very captivated and supportive by the fact she has taken on this giant task by herself. She hopes to have help from volunteers and is trying to contact Greek ministries almost every day. With the current state of Greece and having seen it in person, I am not surprised on the bulk of the results from the surveys. I am surprised that Maria is able to undertake this responsibility for her country and expand disaster preparedness to libraries and archives and wish her the best of luck.
Stephanie Porto, Owner and Paper Conservator at Niagara Art Conservation, presented an engaging talk on the conservation of maps depicting the rapid growth of Buffalo, New York from 1805 to 1909, which were exhibited in “You Are Here: Buffalo on the Map.” Stephanie’s talk perfectly balanced the technical treatment aspects with contextual information on the maps themselves. Image and exhibition outline found on: http://www.buffalolib.org/content/now-display/rare-book-room/buffalo-on-the-map.
Stephanie outlined the history and interesting facts of each map requiring conservation treatment. From the 1833 map, which detailed the area one year after Buffalo had been incorporated as a city, to the 1847 map which demonstrated the increase in commerce on the lake, and the 1893 Christian Homestead Association map, which included the salacious representation of 75 houses of ill fame.
Their conservation treatment needed to be completed in a limited timeline, and while six out of eight of the maps required linings due to poor quality paper, Stephanie found that traditional wet paste lining was not going to be possible in most cases. She included some great references that she had consulted on dry lining techniques: Sheesley, Samantha. 2011. “Practical Applications of Lascaux Acrylic Dispersions in Paper Conservation”. The Book and Paper Group Annual 30: 79-81. Jamison, Jamye. 2013. “Tip: Lascaux Linings in the Treatment of Park Plans for the Cleveland Public Library”. The Book and Paper Group Annual 32: 82-83.
Stephanie’s lining mock ups initially had an issue with sheen and planarity, but she was able to solve both problems using cellulose powder and a combination of Lascaux 303 HV and 498 HV. She outlined the specs of each adhesive, noting their difference in sealing temperatures (498 HV is higher) and final film elastic description (498 HV is hard and 303 HV is tacky). Stephanie described her preparation of the lining paper, beginning with rolling a 2:1 Lascaux 498 HV and 303 HV mixture onto silicone release Mylar with a brayer, allowing to dry, and ironing the dried adhesive film onto the lining paper, and using a printmaking baren to apply pressure after the film and paper were cooled. The map was placed recto up and the prepared lining paper was aligned underneath, the sandwich was flipped and smoothed by hand, then ironed from the center out. After being cooled, the lined map was pressed between Tycore panels. She then discussed the specific treatments of particular maps requiring linings.
The 1850 map depicting an 1805 Buffalo rendered in ink on watercolor paper required the removal of pressure sensitive tape, suction washing and cleaning, dry lining, and overall stretch-mounting.
The 1888 relief printed map could not withstand a backing removal, and so the treatment went forward with consolidation of delaminated paper with wheat starch paste set with a tacking iron, and a dry lining was applied with the original textile backing still in place.
The 1909 relief printed map was heavily water-damaged and retained evidence of previous conservation intervention. The map was consolidated with methyl cellulose, and was lined overall with the backing still in place with a Beva 371 film, and stretch mounted onto a foam board.
The 1893 color lithograph map required the removal of pressure sensitive tape, a temporary facing of 4% w/v Klucel G in ethanol during the backing removal, and a dry lining.
The 1833 hand colored lithograph was in the poorest condition with many detached fragments and a varnish layer. After the varnish was removed with ethanol, and the same temporary facing was applied, the backing was removed dry and the verso was then sanded to remove the adhesive residue. After lining with the Japanese tissue Okowara, the backing paper itself was hand toned with acrylics to integrate losses.
All the temporary facings were removed and loss compensation was completed by pouncing the Japanese tissue with cellulose powder and dry pigments. Finally, we got to see an excellent use of old chemistry textbooks in the pressing and flattening of the maps!
Examples of chromogenic prints, at the Graphis Atlas website, with 10x magnification. Left: Kodacolor (1958); center: Kodak Royal Paper (May 1998); right: Fujicolor (1960s-early 1970s)
Heritage conservation tends to focus on what has been admired for many centuries. Other specialties, such as photographic materials, have only been around for a relatively short period of time. Photography is nonetheless a compelling medium with an array of different processes and variants within them. Research in this field shares the same goals as the one done for other materials: to better understand how, when and where objects were made, what conditions caused them to deteriorate and ultimately how to best preserve them. Studies such as the one presented by Christine Andraud at the AIC-CAC conference aims to bridge the knowledge gap in the field.
As Andraud states in her abstract, color photographs, particularly those classified as chromogenic, lack the kind of study that black and white processes have already received. This is exactly what caught my attention: why is that? Although we are now in the digitally born media age, color photographs have been commercially available since the late 1940s. Until not that long ago, they were the most common type of photographic technique, used by artists and amateurs alike. Today we can find examples of chromogenic prints in fine-art museums as well as in personal archives. Their widespread use is exactly the reason why they should be studied further.
For the purpose of identifying these types of prints analytically, Andraud used fiber optical reflectance spectroscopy (FORS). This is a non-destructive and non-contact technique that has long been used to analyze pigments in paintings. The same technique can also help us in the identification of dyes used in photographic emulsions. Better results are obtained when the device is placed in contact with the sample, but according to Andraud, this doesn’t seem to cause damage.
Dyes used in photography were not always the most chemically stable. In fact, their formulas changed often precisely to change this trend and improve their reliability. The appearance of these photographs can be quite different from the one they had when they were made. Consequently, their visible spectra have almost certainly changed. It is therefore considered more accurate to characterize these dyes in the near infrared region, where the organic functional groups’ fingerprint can more accurately be identified.
Using samples from known manufacturers and dates and the Fischer criterion’s statistical model, the author created a chromogenic processes database, to which other samples of unknown provenance can be compared to. So far, data has been collected for prints made from the 1960s up to the 2000s, by different manufacturers. Kodak samples seem to be the ones that yield better results so far (within 3% error). The author’s goal is to continue this project by analyzing more samples (particularly produced in the 1950s to 1970s) and therefore increase the accuracy of the obtained results.
This method seems to be very promising and I personally hope to hear about it again in the future.
Christina Bisulca presented a fascinating paper that not only described the source of and uses for pine resins and insect lacs but also detailed various methods of testing for these substances in the lab. The Arizona State Museum is home to a collection of 35,000 objects representing every major cultural group in the southwest from Paleo-Indian to the historic period. As part of a conservation and rehousing project made possible by a Save America’s Treasures grant, conservators hoped to analyze and identify adhesive resins present within the collection. Map showing regions mentioned in the talk
Certain plants and insects are found only within particular regions of Arizona due to the huge range of elevation and environmental biomes within the state. Since three of the most prolific cultures, the Hohokam, Mogollan, and Ancestral Puebloan occupied very different biomes, it was assumed their use of natural adhesives would vary according to location.
The Hohokam, for example used creosote lac, a polyester resin derived from an insect on the creosote bush found in desert lowlands. On the more northerly Colorado Plateau, where the Ancestral Puebloans lived, piñon pine was a plentiful source of diterpenoid resin. In general, Bisulca and her team assumed insect lac was used in the south and pine resin in the north.
Initial analysis was done with Fourier Transform Infrared Spectroscopy (FTIR) but researchers had trouble gathering reference plant material. They also realized these high tech, expensive tests are not readily available to many archaeologists, so they used microchemical tests in addition. Since no reliable microchemical test existed for shellac the team developed one based on the pH dependency of color in anthraquinone dyes, which are extracted from lac insects in Asia. In alkaline conditions the dyes turn from orange to purple. The test worked 80% of the time even in their archaeological collection. Where it did not work the resin had likely been charred or highly heated. The results of the tests challenged their assumptions about pine resin being used primarily by the north. In fact the team found more insect lac in the Ancestral Puebloan collection than pine resin. The lac would only have been available to these regions through trade. The researchers also investigated the use of each material. Bisulca used arrows, common to all three cultures, to highlight the different uses for each adhesive. Insect lac is stronger and less brittle so was used by each culture, regardless of location, for hafting the arrowheads to the shaft.
Overall, Dr. Bisulca’s talk was extremely informative and used excellent images to portray her ideas. The images she used of the lacs and resins as they are found in nature and on ethnographic objects helped to clarify the differences between the source and use of each. I have to admit I had not considered the significance of these resins in terms of their use in tracing trade routes and cultural practices. I am curious to know what similar substances would have been used by Eastern and Plains area cultures and how well such resins would be preserved in damp archaeological environments. This will certainly change the way I approach native material at my own site.
All images are from a poster on insect lac by Christina Biscula available here.
Information about the authors is available from The Arizona State Museum’s website.
Lucy-Anne Skinner spoke about the conservation of human remains at the site of Abydos, Egypt. Working for the Institute of Fine Arts, New York University project, Lucy had to engineer some novel solutions when two unusual burials needed to be block lifted. Lucy explained that block lifting an entire burial is not common at Abydos, as most graves are fully excavated in the field. Two graves excavated in the 2012 season in the North Cemetery presented unusually complete assemblages of grave goods, with one wearing a beaded headdress over well-preserved hair, and these factors prompted the conservators to block lift rather than to try to treat the components in situ.
The team of workmen working with the conservator helped build a wooden frame and slide metal sheets underneath, so that the entire burial could be lifted. Foil was used as a barrier layer, and expandable spray foam was used to lock components into place so that the burial could be transported back to the lab and eventually (in another field season) flipped over to work from the bottom to stabilize the lower portion of the coffin before addressing the human remains and other components. Lucy showed many details of the extraordinary finds including beautiful hippo ivory clappers. Though this project began in 2012, conservation of the burials was only completed a few days before this talk was presented (really!). Political instability in Egypt and the extraordinary logistical challenges surrounding excavating in a country undergoing political and social upheaval complicated the timeline and created extra challenges for the conservators.
Transporting a block-lifted burial to the depot at Abydos, Egypt (image courtesy Abydos excavations, Institute of Fine Arts, New York University)
For me, the big takeaways were that conservation in the field requires a great deal of planning and then a lot of on-the-fly creativity. Many digs lack a field conservator, but clearly the planning and execution of this complicated project really benefited from having Lucy on site over the course of multiple seasons. The project took several years to complete, so communication and planning in the off-season was needed for a successful outcome. Particularly challenging issues of working within Egypt while in the middle of a period of crisis were dealt with admirably by Lucy and her colleagues.
In the morning session on May 16th, Ron Spronk, Professor of Art History in the Art Conservation Program at Queen’s University, shared his experiences with several recent endeavors to standardize the technical documentation of paintings and to make the resulting information both accessible and user-friendly.
Followers of the Rembrandt Research Project will be familiar with the missions of the projects Spronk describes in that they each generally aim to comprehensively study the oeuvre of a single artist. However, the crucial difference is that the more recent ventures are web-based, open-access, and shareable, and they are highly reliant on the compilation and comparison of images obtained using consistent methods across institutional boundaries.
Spronk spoke first about Closer to Van Eyck: Rediscovering the Ghent Altarpiece, an initiative made possible through the partnership of many organizations, including the Royal Institute for Cultural Heritage (KIK/IRPA), the Getty Foundation, and the Netherlands Organisation for Scientific Research. During the presentation, Spronk briefly toured the audience through the website, which is beautifully user-friendly and self-explanatory. Definitions are available for each of the analytical techniques used, and it is also possible to download condition, materials research, and dendrochronology reports.
The follow-up website, Even Closer to Van Eyck, is set to launch shortly and will focus more on the treatment of the altarpiece. As the Getty Foundation website pronounces, “This second phase of the Van Eyck project will incorporate high-resolution images produced during and after the full conservation of the altarpiece, which is currently underway. The web application is expected to set new standards for digital projects related to art history and conservation by providing access to the decision-making process for the treatment of the altarpiece and by disseminating the open-source technology behind the website to the museum community.” Another extension of the Closer to Van Eyck website is VERONA, or Van Eyck Research in OpeN Access, which has aimed to study and document all paintings securely attributed to Van Eyck in a standardized manner. The resulting scholarship will be published online.
The Bosch Research and Conservation Project similarly attempts to consistently document the entire oeuvre of Hieronymus Bosch and includes restoration of nine works. Several structural treatments were supported by the Getty Panel Painting Initiative. The Bosch website shows three works represented by high-resolution photographs in normal light, infrared images, and X-radiographs, with a three-pane slider moving between them. Spronk described the method by which all of the images were obtained using a window frame, which lets the camera remain completely parallel, and showed a video demonstrating the documentation process. A larger website application is set to be launched at an indeterminate date.
Although not covered during the presentation, the abstract also lists the “Hand of the Master on panels by Pieter Bruegel the Elder,” a comprehensive workshop on Bruegel that took place at the Kunsthistorisches Museum in Vienna from November 24-25, 2015. The workshop program and a presentation by Angela Cerasuolo on The Parable of the Blind and The Misanthrope in the Museo Nazionale di Capodimonte, Naples may be found on Academia.edu.
In searching for these websites after Spronk’s presentation, it became clear that these projects are all very much in progress, and only partial information is, as of yet, available. However, these endeavors appear to be extremely promising. The Even Closer to Van Eyck website in particular is eagerly anticipated because it will share the methodology used to treat the altarpiece. Much as the altarpiece during treatment is itself on display, this website should set a new precedent for transparency and should further raise public awareness of conservation activities. The founding concept of comprehensive, standardized, and open-access documentation on which these projects are based presents an encouraging model that will hopefully one day become more common practice, providing greater opportunities for interdisciplinary research and collaboration.
Preventive conservation is becoming an increasingly important part of our work as conservators, but it often seems that many important questions about environmental control have yet to be answered. Questions such as to what degree are fluctuations of temperature and RH humidity damaging to collections, and are they more or less damaging than strictly maintained but not ideal conditions?
Jean-Louis Bigourdan addressed some of these uncertainties in his talk on temperature and moisture equilibration in storage spaces containing significant quantities of hygroscopic materials. He focused on reconciling the need for climate-controlled storage with the quest for sustainability and the pressure of budgetary limitations. His introduction was reassuring: the current thinking on storage climate is that relatively stable low temperatures are desirable (“cool storage”), but there is little benefit to maintaining a perfectly stable climate (i.e. without fluctuations). Rather, a certain degree of cycling is acceptable, so long as the shifts are not extreme.
Following from this fact, Jean-Louis presented the concept of “dynamic management” of HVAC systems. Dynamic management entails shutting down the HVAC for short periods, such as overnight, and adjusting climate set points seasonally. This would save on energy, and thus reduce the environmental impact and cost of operating such systems. Of course, we as conservators are immediately concerned with the effect on collections materials during such shutdowns: How extreme are the fluctuations in temperature and RH resulting from periodic shutdowns of the HVAC?
This is the questions Jean-Louis attempted to answer through two phases of testing. He was particularly focused on the possibility that collections containing large quantities of cellulosic and/or hygroscopic materials might buffer against large or sudden shifts in temperature and RH. Jean-Louis undertook two phases of testing to understand the extent of the self-buffering capabilities of such materials. The first round of testing was conducted in the laboratory, and the second in library and archive collections storage rooms.
In his laboratory tests he exposed different types of materials to large fluctuations in temperature and RH. The materials included things like closed books, matted photographs and drawings in stacks, and stacks of unmatted photographs. He also tested the effects on these materials when they were placed inside cellulosic microenvironments, such as archive storage boxes, measuring the temperature and RH at the surface of objects, and at their cores. His results indicated that the RH at the core of books or stacks of cellulosic material does not change as rapidly as the exterior environment. Temperature equilibration occurred over a period of hours, and moisture equilibration occurred over the course of weeks or even months. Microenvironments increased the time to equilibration, mostly by controlling diffusion of air.
Another useful result of this laboratory experimentation was that it demonstrated that the moisture content of paper-based and film collections was more affected by environmental temperature than by environmental RH. In other words, at the same exterior RH, the moisture content of the collections object was lower at higher exterior temperatures. The laboratory testing therefore suggested that storage spaces with significant quantitates of hygroscopic materials will be buffered against large changes in RH and temperature due to moisture exchange with the collections materials.
Jean-Louis found that field testing in collections storage spaces returned many of the same results as his laboratory tests. 6-8 hour shutdowns of HVAC systems had little impact on environmental RH, and many of the systems they examined were already following seasonal climate cycles without causing dramatic shifts in the temperature or RH of storage environments. He encouraged conservators to take their collections materials into account when evaluating the buffering capacity of their storage environments.
I was very encouraged by these findings, although I have some remaining questions about the potential effects on collections materials. How much moisture is being exchanged with collections items in such a scenario? Is it enough to cause dimensional change in hygroscopic materials, especially on exterior surfaces, and will that contribute to more rapid deterioration in the long term? Regardless, I was happy to be prompted to remember that collections materials are an active part of the storage environment, not an unreactive occupant of it.
The talk wrapped up with Jean-Louis raising a few areas of further research. He hypothesized that changes in storage climate which are achieved through a series of small but sharp changes would result in slower moisture equilibration between environment and collections than would a change made on a continuous gradient. He also raised the possibility of predicting the internal moisture fluctuations of collections materials using their known hygroscopic half-lives. Both of these areas of research could be extremely helpful to conservators attempting any dynamic management of their climate control systems.
A particularly thoughtful question by an audience member provided the opportunity for more climate control wisdom. A Boston-area conservator of library and archive collections wondered whether it made sense to use dew point as the set point on HVAC systems in the winter to save money on heating costs, but during the summer to use RH as the set point to insure against mold growth. Jean-Louis felt this would be an unnecessarily complicated method of control, but offered a general rule for the storage of hygroscopic collections. He suggested thinking of lower temperatures as the primary goal, and of RH as important to maintain within a broader range. Lower temperature slow degradation reactions inherent to such materials, and so generally lower is better. However, RH need only be high enough so as not to embrittle material, but low enough to prevent mold growth. Essentially he suggested that if your RH and temperature are too high, you are better off reducing temperature slightly, which will slow degradation reactions, and as a side-effect your collections may absorb a small amount of moisture, thereby lowering the RH in the building environment.
Jean-Louis’s talk left me intrigued and excited about the possibility of taking advantage of hygroscopic collections materials to provide a more stable and sustainable storage environment.
Conservation scientists at the Canadian Conservation Institute (CCI) continue to examine artists’ works and contribute each year to the growing database of information on Canadian artists’ working methods and materials.
One of their latest projects is the characterization of the materials used by painter J.E.H. MacDonald (1873-1932). The study looks at the supports, grounds and paint formulations MacDonald used during the period 1909-1922. This study compliments an important retrospective of the artist’s work planned for 2018 at the McMichael Collection of Canadian Art.
MacDonald was a founding member of the famed cohort of Canadian landscape painters known as the Group of Seven, and was closely associated with the celebrated painters, Lawren Harris and Tom Thomson
In all, 32 works from Ontario museum collections were examined, comprising 11 oil paintings and 21 oil sketches. The goal of this study is to gain a better understanding of the artist’s working methods and materials, and to assemble some reference data to help attribute works of uncertain date or origin. This particular presentation focused on observations and results from 13 of these works.
Throughout the period under study, MacDonald used a variety of rigid painting supports, including fiberboard, pulpboard, laminated pulpboard, and thin bookbinder’s board, which may have been his preferred support.
The study reveals that there was a shift in the size of the support he favoured through this period. Early works before 1914 were varied in size, often small, less than 7 x 9 inches. Through the years 1914-1917, he often chose a standard 8 x 10 inch format, and after 1918 he chose a slightly larger size, 8.5 x 10.5 inches, which was also the size favoured by his friend Tom Thomson, who died mysteriously in 1917.
This change in size of the support was also paralleled by a gradual change in his preparatory layers and painting technique. A variety of materials were found in the grounds of his early works. Sometimes he employed coloured double grounds. After 1918, he abandoned traditional grounds, preferring simply to seal the board surfaces with shellac. It was noted that this layer could prove to be solvent-sensitive during future varnish removal operations.
There was a gradual shift in his painting technique as well: his palette changed from muted colours, layered wet into wet, to a bolder paint application. By 1918 in his Algoma paintings, the brushstrokes are more confident and vigorous, often applied using complimentary-coloured paint strokes. An interesting feature of these works is the fact he often left the support or underlayers visible at the edges of his brushstrokes. Bold outlines of oil paint underdrawing are also sometimes seen through the brush strokes of the upper layers of paint.
Paint pigments and fillers were also characterized for the paintings and sketches studied. MacDonald’s paints were generally complex mixtures made of multiple colours, composed of 2 or 3 main colours, adjusted by the presence of small amounts of 2 or 3 more colours. A distinguishing element of his favoured palette include a characteristic mixture of lead sulfate and zinc oxide for his whites – a mixture that was commonly used by Tom Thomson and members of the Group of Seven. This particular white is likely the new “Flake White” paint manufactured by the renowned British colourmen, Madderton & Co. (founded by A.P. Laurie) used for its Cambridge Colours paints that were sold worldwide in the first three decades of the 20th century. Viridian was the only truly green pigment the artist used, while various blues and yellows were also combined to make other shades of green. Yellows, blacks, reds and blues were also characterized. Of interest is the bright yellow paint, likely a Winsor and Newton tube paint, since it contained chrome yellow and a magnesium carbonate filler, materials not found together in the Cambridge paints line.
The publication of this information on MacDonald’s materials will be a welcome contribution to the advancement of our knowledge of the artist’s working methods. This information will also be essential as scientists begin to examine and ponder the materials used in a controversial group of small oil sketches that were purportedly buried for decades on the artist’s estate, before they finally entered (in recent months) the collection of a major Canadian institution. Tip of the iceberg indeed…
