Relative being the key word in this talk, Steven Weintraub of Art Preservation Services, Inc., presented a checklist of critical thinking when making decisions about relative humidity (RH) microclimates for collections.
Question the accuracy of your RH measurement
Weintraub points out it’s really easy to be 5% off on measuring RH for a myriad of reasons including sensor locations relative vent locations, drift in the measuring equipment. While 40% to 60% is the usual goal, a conservator has to ponder how comfortable are you with 35% to 65%? Weintraub admitted those extremes make him less confident for preventive conservation; microclimates can be the answer when an object requires tighter control.
The talk ended on this accuracy theme as well. While technology has come to RH measuring systems such as blue tooth systems so the case no longer has to be opened, accuracy remains in issue. Before setting up an exhibit, compare all the meters so to have at least an internal standard for readings. Calibrating the meters before exhibitions is ideal, of course but not always feasible. If there is a large discrepancy in RH readings between the loaning institution and your institution, it might be worth having a conversation about calibration methods.
To seal or not to seal a case
Weintraub recounted the common reasons for not sealing a case: Avoid trapping off-gassing; gallery climate control is adequate; it’s harder and more expensive to construct an airtight case. However hindsight is harder to manage. It’s harder to retrofit a leaking case and make it air tight after the fact when too much dust is collecting on the objects or other problems occur. Thus it’s best to start with air tight cases and loosen if needed. Hence whether intentional or not, sealed cases are microclimates.
Microclimates: Active control, Passive control, or Nothing
Weintraub recommend building all cases to have the provisions for at least a passive RH control system regardless. Again the theme of enabling flexibility and avoiding retrofitting later applies. Building space for silica gel trays and not using it is easier than retrofitting the case later.
What is the rate of leakage for the case is the most important question for microclimates. The leakage rate will determine if a passive control is adequate or active control system is needed. Weintraub noted, no silica gel system in the world is adequate for a highly leaky case. Nominal leaking from a tight system then begs the question about why an active system is needed.Leakage assessment can be easily accessible. Weintraub feels it’s important and empowering for institutions to be able to conduct their own leakage rate tests. It will enable identifying when repairs are needed under service contracts and also make more informed choices about the steps needed for microclimates. A caveat on interpreting leakage rates when you’re shopping for cases No standard protocol exists for determining leakage rates; so manufacturers reported values are hard to compare. Leakage rates change over time as materials age and warp
Creating your own leak detector
Weintraub shared two easy ways to have your own leak detection system. Cans of dust-off contain small amounts of refrigerant. A refrigerant detector can be easily purchased from HVAC suppliers for about $500; the detector is akin to a Geiger counter. It’s a qualitative tool that helps locate the leaks. The second leakage assessment choice is monitor carbon dioxide levels. The carbon dioxide level in the case increased above ambient levels (600 to 2500 ppm) and use a meter installed in the case to monitor the change in carbon dioxide levels. Let the case reach equilibrium at before starting the leak test. Weintraub and students at the NYU conservation center are currently examining how long it typically takes to reach equilibrium. Weintraub likes to run his leak tests for 3 days. Basically it’s calculating the rate of loss of CO2 Thus the difference in CO2 measurements over the time period. Close to 0 for the rate means success as there is minimal leakage. A large rate indicates an issue. At that point, consider looking at the half-time decay, how many days it takes for CO2 levels to drop 50% in the case.
How much silica gel?
Answer: Leakage rate * number of exhibit days* buffering capacity of silica gel at your target humidity levels= weight of silica gel.
You can examine compare different silica gel types for your scenario as some silica gels perform better at high humidity and others at low humidity. For a maintenance-free case, Weintraub’s rule of thumb is double the exhibition quantity of silica gel. Another silica gel tip is to mix silica gels at different humidities to get the target humidity such at mixing 55% and 40% RH gel systems to get a target of 50%.
Also, mind the air gap in the case. An air gap is needed to make sure air flow is adequate in the case to get the benefits of silica gel actually reaching the collection objects.
Lastly, we as conservators need to do a better job of sharing our learning and experience about microclimate to develop a collective pool of knowledge
Weintraub’s article on Demystifying Silica Gel is available on Art Preservation Services website along with some of his work on LED.
Category: AIC’s Annual Meeting
Provides the membership with updated news about the annual meeting. Also announces themes, deadlines for papers, need for volunteers, etc.
43rd Annual Meeting- Heritage Health Information Survey Results Revealed, and The Past & Future of Conservation Funding Panel Discussion
I, like many others, had been looking forward to hearing the results of Heritage Preservation’s Heritage Health Information Survey, HHI 2014. Unfortunately, at the time of the meeting those results were not yet available for sharing. Despite my disappointment in not seeing those results the session was well conducted and highly informative.
Dr. Connie Bodner, Supervisory Grants Management Specialist, Institute for Museum and Library Services (IMLS) discussed support for programs addressing collection care priorities identified in HHI 2004 over the past ten years as well as her Institute’s continuing commitment in those areas.
The major priorities identified in the HHI 2004 report were:
• Institutions must give priority to providing safe conditions for the collections they hold in trust.
• Every collecting institution must develop an emergency plan to protect its collections and train staff to carry it out.
• Every institution must assign responsibility for caring for collections to members of its staff.
• Individuals at all levels of government and in the private sector must assume responsibility for providing the support that will allow these collections to survive.
Substantive progress has been made in responding to those priorities over the past ten years. Connie put forward as one outstanding example the Connecting to Collections – A call to action program which over four years raised awareness of collection care in many small to medium museums. In addition to distributing collection care ‘bookshelves’ to 3000 institutions, it created the internet based discussion list and webinar series that has now been adopted by FAIC as Connecting to Collections Care where it will be maintained and further developed.
Heritage Preservation’s Acting President Thomas Clareson provided a recap on the process of dissolution of Heritage Preservation set to occur on June 30, 2015. Many programs have been transferred to FAIC as detailed in our Executive Director’s communication in the May 2015 edition of AIC News http://www.conservation-us.org/docs/default-source/periodicals/aic-news-vol-40-no-3-(may-2015).pdf?sfvrsn=2. In addition, Heritage Preservation business archives are being transferred to the Smithsonian Institution Archives and the Saving Outdoor Sculpture (SOS) archives are being transferred to the University of Maryland. Digital resources for Heritage Preservation programs will continue to be made available through CoOL (even more good reason for each of us to financially support CoOL!)
The disposition of several programs is still being worked out. These include the Heritage Emergency National Task Force, HHI 2014, and the Conservation Assessment Program (CAP). There will be announcements about homes for these programs in the near future. The IMLS reiterated its commitment to continuing support for the CAP program.
Regarding the Heritage Health Information Survey, HHI 2014, while much of the 2014 survey was kept consistent with the 2004 version to allow comparison of results over time, there were some changes such as more information gathered on digital resources. The survey was sent out in October 2014 and data collection ended in February 2015. The response rate was about 20% based on 1800 responses from an estimated universe of 50,000 institutions.
The complete HHI 2014 report is now expected to be published in the fall of 2015. In addition to the report, brochures will be produced and press conferences scheduled. This could be an ideal time for collection care staff in institutions large and small to bring preservation issues and priorities to the attention of senior management and governance. Interestingly, survey response data files will be available on the IMLS website for download and further analysis.
High-level and long-term perspectives on foundation-based support for conservation training and practice were then offered by officers from three of our long-term, committed supporters: the Andrew W. Mellon Foundation, Getty Foundation, and Kress Foundation. Each discussed the history and underlying philosophy behind their ongoing support for conservation.
First, Alison Gilchrest of the Andrew W. Mellon Foundation outlined its 46 years of support for conservation beginning with a grant to support Dr. Robert Feller’s work on photochemistry and light damage at the Mellon Institute. Since then 310 grants with a conservation component have provided funding totalling $191,433,145 – an impressive investment indeed. These have been targeted through careful selection to support strength and potential, information sharing and networking. Alison has begun to explore how grant resources have been distributed over time and across the field with a view to ensuring there is collaboration across the Mellon foundation to fulfill its mission “to strengthen, promote, and, where necessary, defend the contributions of the humanities and the arts to human flourishing and to the well-being of diverse and democratic societies.”
Antoine Wilmering, Senior Program Officer then spoke of the Getty Foundation’s support for conservation which has included 1133 grants over the past 30 years and 287 grants over the past 10 years. The foundation is tending to support more broadly integrated projects which include research, development, training, capacity building, and dissemination. It is actively scanning the field for both what they read and hear and what they are not seeing and hearing to identify areas in which they can invest to best effect.
Max Max Marmor, President of the Samuel H. Kress Foundation was pleased to report his Foundation has supported more than 4500 Kress Fellows since 1961 and currently supports nine conservation fellowships each year. This is in addition to the substantial support associated with the conservation of the Kress collection itself, primarily through Kress Program in Paintings Conservation at New York University’s Institute of Fine Arts, and through such initiatives as the Summer Teachers Institute in Technical Art History (STITAH). Max believes that important priorities in the future will be sustaining the interest of young professionals in conservation and ensuring they will have adequate opportunities for development and employment, while also raising consciousness more generally in the importance of heritage preservation.
Numerous participants thanked the presenters and spoke to the benefits they had received through support from these foundations.
Robert Waller, Protect Heritage Corp.
43rd Annual Meeting- Research and Technical Studies, May 16, The Technical Study and (Re-)Restoration of a Limoges painted Enamel Plaque, by Gregory Bailey
Gregory Bailey, Assistant Conservator of Objects at The Walters Art Museum, detailed the technical and historically-sensitive characterization of restorations on a Limoges painted enamel plaque at the Metropolitan Museum of Art (32.100.263), undertaken to correct the object and its record.
In this case, the correction required was literal. The oval plaque depicts Diana and Proserpina in a nocturnal scene, encircled by a border inscription. The object was accessioned by the museum in 1931 and thereafter underwent several treatment campaigns, during which repainting of the border yielded the nonsensical phrase “ESTES PARVBIQVITE.” Curatorial research identified the original motto as “POTESTAS PAR VBIQVE,” and Greg’s task was to restore this motto to the border.
To do so, he masked the incorrect text rather than replaced it. The mask was made by casting Orasol-toned HXTAL epoxy into a two-part transparent PVC mold. The PVC mold was created using a dental vacuum former over a cast plaster mold of the enamel area. Once cured, the epoxy was removed, trimmed, and adhered with Paraloid B-72 over the restoration at the plaque’s rim. The final fill is therefore removable with very little solvent, and the correct (original) motto was inpainted with acrylics. Simply over-painting the text would have compromised the solvent-sensitive 19th-century restoration areas, and erased this campaign from the plaque’s history.
Technical analyses that preceded this treatment provide information about the original and restoration materials, as well as their working methods. The plaque is composed of opaque and transparent enamels over a copper support, with surfaces partially silvered and gilt.
Greg notes that reflected long wave ultraviolet photography is not often used in object examination because it requires special quartz optics. The technique is useful for painted enamels because certain colorants and enamel compositions are partially or completely transparent to UV radiation, yielding information about the layered structure and sequence of enamel application . For example, the cobalt blues and lavender enamels on the plaque appear transparent under such radiation, making visible the underlying painted enamel structures and the silver foils. Short wave ultraviolet-induced visible fluorescence photography shows some fluorescence of the lead containing enamel colors, and of the restoration varnish. Long wave ultraviolet induced fluorescence shows the restoration varnish more clearly, as many early varnishes fluoresce bright green, suggesting the presence of a natural resin. (This plaque was also varnished in 1993 with dammar, also a natural resin, whose florescence instead appears faint milky blue due to the addition of light stabilizers to the varnish). Reflected near infrared photography shows the layered structure of cold painted restoration enamel, as again, certain enamel compositions and colorants are more transparent to infrared than others (ex. reds, yellows, oranges). Typically, those transparent to ultraviolet radiation are different from those transparent to infrared, making the two reflected radiation techniques complimentary. Greg also notes that reflected infrared is good for identifying cracks in counter enamel because cuprite often forms along these divides, which reflects strongly in the infrared range.
X-ray fluorescence spectroscopy (XRF) was used to signal compositional differences between the original and fill enamel materials. Generally, the restoration enamels contain a significant lead component as compared to the original enamel. The white restoration enamel contains lead arsenate, not in use until the 18th-century, and tin oxide as opacifiers. The green and blue restoration enamels contain chromium, a colorant not utilized in enamels before the 19th-century. The pink flesh tones contain zinc, which is associated with pink and red 19th-century enamels, but may have also been used as a low melting point flux of thin wash applied over the white enamel. Lastly, the translucent restoration red enamel is colored in part by antimony oxide, rather than the traditional use of copper oxide reds.
All of the restoration enamels are similar in composition and were likely applied during the same 19th-century campaign; however, different application methods were likely used. X-radiography illustrates a solder seam concealed by varnish at the lower edge where new enamel was laid over the copper support, which was then a common structural repair method. Elsewhere, however, enamel patches are set into losses over silver foil that appear neither soldered nor scored. These may have been painted and fired in place, cold painted in place, or painted and fired separately and then adhered in place. Greg notes that the plethora of active enamel restorers in the 19th-century surely led to the evolution of new restoration techniques. This plaque serves as an example and impetus to further document such developments.
Greg’s talk serves as a reminder that our understanding of an object, even one fortunate enough to have been previously treated and studied, is ever-evolving with the application of new analytical technologies and refreshed methodologies such as those expertly used here.
43rd Annual Meeting- Joint Session: Architecture and Wooden Artifacts, May 14, The Salon Doré from the Hôtel de La Trémoille: Conservation of the 18th Century gilded boiserie, by Natasa Morovic
Natasa Morovic, Conservator of Frames and Gilded Surfaces at the Fine Arts Museums of San Francisco (FAMSF), addressed the conference theme Practical Philosophy, or Making Conservation Work in her presentation of the immense gilding project undertaken over 16 months in an 18th-century period room, the Salon Doré, at the Legion of Honor.
The Salon Doré was designed as a receiving room for guests in the Hôtel de La Trémoille (a family mansion) in Paris, but has since existed in six different locations and seven re-configurations. The Salon was donated to FAMSF in 1959 by the Richard Rheem family (of HVAC fame) and first displayed at the Legion of Honor in 1962. The room was reinstalled in 1996 as a ‘paneled environment’; that is, without its ceiling, window, doors, or floor. The original parquet floor was sold in the 1990s. Indeed, museum period rooms in this era often served as backdrops in which to display French objects and furniture not specifically related to the rooms’ histories. The re-presentation of the Salon Doré in 2012-2014 sought to revise this approach.
The Salon was returned from a rectangular to a square format based on original floor plans. A second 18th-century parquet floor, coved ceiling, windows, furniture, and new lighting were installed. Meanwhile, Natasa’s team was responsible for the conservation of the Salon’s gilt white oak paneling, or boiserie, including five dedo panels, four doors, four cornices with cast plaster ornaments, and high relief linden wood detailing.
Two hundred separate sections of gilt wood were deinstalled and relocated to an adjacent gallery turned temporary conservation lab, in view of the public. Visitors were thrilled to see the work in progress, remarking “you are our favorite exhibit!” iPad didactics introducing the conservation treatment steps and illustrating the Salon’s epic history were available in the galleries (see a preview here and don’t miss the French accent in the Kid’s Corner).
A dozen gilders, conservators, technicians, architects, electricians, and a master carver worked in the open lab daily. Accommodation of all the large paneling, work benches, and people within a tight space was challenging. All treatment steps had to be executed simultaneously due deadlines, with no running water and limited electrical. Gilding efforts were impacted by dust from the adjacent construction area, which quickly settled on the prepared surfaces, and drafts that caused the gold leaf to fly.
The condition of the Salon’s carving and gilding was extensively compromised by the room’s repeated moves, resulting in differing surface finishes as well as mold damage. Two gilding and inpainting campaigns were present: water gilding over orange-red bolle over gesso, water gilding over dark red bolle over new gesso, as well as brass powder and acrylic inpainting.
The treatment objective sought to preserve as much historic surface as possible. No aqueous solutions were used during surface cleaning so as not to interrupt the water gilding. Natasa received several questions after the talk on what materials were used. Here are the particulars: shellac coatings were removed with ethanol poultices, overpaint and soiling were removed with acetone:ethanol mixtures, and paint stripper was sparingly used in tenacious areas of oxidized brass powder paint. Flaking gesso was consolidated with <25% Paraloid B-72 in acetone:ethanol. Flügger was used for small fills, over which traditional gesso and gilding was applied.
Larger wood fills were freshly carved, based off of existing ornaments in the room, and water-gilded so as to replace ‘like with like’ (though it is acknowledged that oil-gilding would have sped up the process). The majority of fills were gilt before attachment; however, in situ re-gilding, or in-gilding, was done where necessary to match adjacent surface conditions.
In total, $22,000 of gold leaf (11,500 leaves) and 27 gallons of acetone were used during the campaign. The result is a glowing re-presentation of the Salon Doré’s opulence, reflecting – quite literally, due to the mirrors, rock-crystal chandeliers, and gleaming gilding- its importance as one of the premier examples of French Neoclassical interior architecture in the United States.
(A quirky review of the Salon project with working images can be found here).
43rd Annual Meeting – Collection Care Session: Beyond ‘No Food or Drink Allowed in the Gallery:’ Best Practices for Food in Cultural Institutions by Rebecca Newberry, Fran Ritchie, and Bethany Palumbo
Does the thought of blue martinis, smelly hot dogs, and live penguins in your exhibition space make you gag? The Society for the Preservation of Natural History Collections has sponsored a survey and development of best practices to help mitigate the risks posed by food service (and inebriated guests) in collections storage and display areas. This presentation summarized the survey responses, and illustrated them with a number of entertaining and apt case studies. The best practices document will be posted on the NHPRC website in the next few months.
The survey was initiated by Cathy Hawkes in 2011. In addition to answering questions, the survey also solicited written food policies from the respondents to reflect current practice. The top result of the survey was concern about not having a written policy; and 40% of respondents reported pest-related activity related to food in the building.
The best practices that came out of the survey have been well-proven through the experience of the survey respondents and the authors, and are generally agreed upon. The key is to develop a written policy on food management and get buy-in from all stakeholders to enforce it (e.g. administration, vendors, facilities, café/store staff, curators and collections management staff, security). The policy should address preparation, consumption, and disposal of food. It should explain the housekeeping and integrated pest management implications of food in collections areas. Staff should be well-trained in how to interact with the public to enforce the policy. And risk mitigation should be part of contracts signed with vendors; the contract can also reflect a “This event never happened” clause (i.e. leave no trace).
Some specific tips discussed include:
- Clean up immediately after an event
- Put out extra tables for dirty dishes (so they don’t go on top of exhibit cases)
- Provide space for staff to eat with proper waste containers
- Make clear signage for where to eat and not; include a simple educational message like “Food attracts pests which can damage our collections.”
- Determine the path that food and waste will take in and out of the collections space.
- Menu should consist of food that is tidy when eaten: no popcorn, red wine, ice cream, or round things that roll under exhibit cases like grapes
- Ventilation and fire suppression need to be accounted for
Following these steps will help you to avoid getting ketchup on your dinosaur (yes, it really happened!).
SPNHC Food Survey Report 2014
43rd Annual Meeting – Objects Specialty Group Session, May 16, 2015, "Silver or gold? Surprising Challenges in Cleaning a 19th-Century Persian Water Pipe" by Ariel O'Connor, with Julie Lauffenburger, Meg Craft, and Glenn Gates
In keeping with the conference theme of Practical Philosophy, or Making Conservation Work, Ariel O’Connor, currently at the National Air and Space Museum and formerly at the Walters Art Museum in Baltimore, presented a talk where an imperfect treatment method proved to be the best option. A nineteenth century Persian water pipe, or nargile, made of gilded silver and elaborately decorated with gemstones, was heavily tarnished and needed to be cleaned in preparation for an upcoming exhibit. The water pipe was first analyzed with XRF to determine the treatment; XRF indicated silver with copper, gold, and lead, but no mercury, suggesting the object was gilded with some process other than mercury gilding.
Test cleanings were done with several standard methods for reducing tarnish mechanically: cosmetic sponges, Duraglit polish, precipitated calcium carbonate, Long Shine silver polishing cloth, and Mars Erasers. Acidified thiourea, a chemical method of reducing tarnish, was not initially considered because of research showing the problems of thiourea – leaching of copper, microetching, and long-term detrimental effect of thiourea residues. (See for example, a recent article by Contreras-Vargas et al, “Effects of the cleaning of silver with acified thiourea solutions” in Conference Proceedings of Metal 2013.) While the mechanical methods, especially the erasers and sponges, were easy to use, the final appearance of the polished surface in the test cleaning areas was not as golden as expected.
Analysis with XRF led to a frightening conclusion: even the gentlest mechanical methods, such as a cosmetic sponge, removed gold from the surface. And as the object was gilded with a method other than mercury gilding, the gold layer was already very thing. Analysis after a test cleaning with thiourea, however, did not show the same loss of gold. The decision to clean the object with thiourea was reluctantly made. Steps were taken to use thiourea as safely as possible: dwell time was minimized, the surface was immediately rinsed with deionized water, and the work was performed in the fume hood because of the generation of poisonous gases. O’Connor introduced a novel technique for applying and rinsing the thiourea. Strips of non-woven cotton Webril Handi-pads were placed on the object then wetted with thiourea applied by dropper; rinsing was also performed with the handi-pads. Cotton swabs were used as little as possible because of the possibility of abrasion of the surface.
The treatment raised the important question of when is it acceptable to use a method that has been shown to be damaging. O’Connor articulated why, on this occasion, chemical cleaning with thiourea was the lesser of two evils. I look forward to seeing more research on the topic of cleaning gilded silver as well as discussion of the ethics involved in this treatment.
43rd Annual Meeting – Book and Paper Group Session, May 15, 2015. “Superstorm Sandy: Response, Salvage, and Treatment of Rare Pamphlets from New York University's Ehrman Medical Library" by Angela Andres
Angela Andres, Special Collections Conservator at New York University (NYU) Libraries, presented a case study of the salvage and treatment of a rare pamphlet collection from NYU’s Ehrman Medical Library. The collection consists of approximately 200 medical works, which sustained water damage when New York City took a direct hit from Superstorm Sandy in 2012. This presentation tied in well to the overall conference theme of Practical Philosophy, or Making Conservation Work, as the aftermath of the storm made the salvage and conservation of this collection particularly challenging.
Power outages and infrastructure disruptions were widespread in New York City in the weeks following Superstorm Sandy. Though conservators from NYU’s Barbara Goldsmith Preservation and Conservation Department were quickly on hand to assist with the Ehrman Library recovery effort, they were unable to enter some of the library spaces immediately after the storm due to flooding. Once the building was accessible, conservators worked with disaster recovery vendor Belfor and library staff to salvage water damaged materials, including this pamphlet collection. Due to concerns about mold growth and difficulties in locating a freezer or reliable power source, conservators interleaved the pamphlets with Tek-Wipe and packed them for removal to the Conservation Lab at NYU’s Bobst Library. Because of ongoing transit interruptions, it was necessary to transport the collection to the lab by taxi.
The pamphlets were frozen to allow for treatment in smaller groups over the next two years. Because the collection had been submerged in flood water containing sewage and medical waste, individual pamphlets were thawed and rinsed in a water bath. If mold was present, it was remediated after thawing with an alcohol solution. Dirt, fasteners, adhesive residue, and threads were removed while the object was in the bath. Each pamphlet was then dried, surface cleaned, mended, and rebound. Partway through the project, the Ehrman Library decided to digitize the collection, so the level of treatment was scaled back to accommodate imaging more easily.
In the wake of such a large disaster, the urge to assist can be overwhelming. Angela’s assessment of the positive and negative outcomes of this project was both practical and insightful. The active role taken by NYU Library leadership, as well as the effective division of labor, helped recovery efforts go as efficiently as possible. The Ehrman Library had a recently updated disaster plan with designated salvage priorities, and worked quickly to get a contract in place with a disaster recovery vendor when it proved necessary. The conservation treatment of this collection also afforded the Ehrman Library the chance to digitize and rehouse these materials as part of its long-term preservation strategy.
However, the in-house treatment of this collection significantly affected the conservation lab functions, and led conservators there to reexamine their approach to future salvage situations. Angela acknowledged that the strong desire to help in the aftermath of the storm might have prevented conservation staff from evaluating the situation more critically. In retrospect, Angela felt that it might have been useful to do a smaller pilot study prior to beginning treatment of the collection. That would have enabled conservators to get a better sense of treatment times, identify areas where treatment steps could be streamlined, and determine whether additional funding or staff would be needed to complete the project.
During the question and answer session, audience members asked Angela about specific salvage and treatment protocols. One participant asked why the Tek-Wipe interleaving was removed prior to freezing. Angela responded that the Tek-Wipe interleaving had become saturated with filthy water, and conservators wanted to get as much dirt away from the objects as possible. Pre-cut freezer paper is part of the conservation lab’s disaster kit and was readily available, so that was used instead. Another audience member noted the presence of iron gall ink on some of the pamphlets, and asked if any iron gall ink treatment was done. Angela responded that there were comparatively few iron gall ink inscriptions in this collection, and no additional treatment was done.
43rd Annual Meeting – Book and Paper Group Session, May 14, 2015. "Understanding and Preserving the Print Culture of the Confederacy" by Evan Knight
Evan Knight, Associate Conservator at the Boston Athenaeum, spoke about the Athenaeum’s multi-year project to conserve and digitize its Confederate Imprints collection. In the 19th century, the Boston Athenaeum was one of the premier libraries in the nation, and its librarian William F. Poole quickly realized the importance of collecting print materials from the Confederate States of America. The collection contains 4575 imprints in a variety of formats, including pamphlets, bound volumes, maps, and archival records.
The project’s objectives were to provide access to the Confederate Imprints collection through digitization, while improving its preservation and cataloging. Evan’s description of the project stressed the importance of conservator involvement, in order to balance the demand for digitization with the ability to effectively preserve the collection. The goals of treatment were to ensure that objects could be safely handled during imaging, allow for effective stabilization in a timely manner, and provide for a broader range of treatment options on important or rare items. As Project Conservator, Evan also had the unique opportunity to assess the entire collection, rather than seeing only those objects that came to the lab in need of conservation treatment. This allowed him to get a more comprehensive sense of both the condition problems and material characteristics of the collection.
The collection presented a variety of condition issues, including torn and creased pages, losses, planar distortion, and binding damage. However, because this was a three-year, donor-funded project, working efficiently was a particular concern.Evan spoke abouthow he balanced the treatment goals of reversibility, efficacy, and aesthetic concerns with the time constraints of the project. He streamlined his working methods and materials by batching similar treatments, only humidifying when necessary, using a relatively dry wheat starch paste for mending and flattening creases, and stabilizing losses without fills where possible.He also kept minimal paper treatment records, which were entered into a project spreadsheet at regular intervals. Only significant or unique items received more extensive written and photographic documentation.
Evan then discussed the material characteristics of Southern print culture, as well as identifying avenues for future research. He mentioned that though paper in the South during the Civil War is commonly presumed to be of inferior quality, he found great variety in the papers of the Confederate Imprints collection. All of the papers in this collection are wove and exhibit stitching patterns from the wire mesh screens used in the manufacturing process. With only 15 paper mills operating in the South during this period, Evan thought that some of these papers could probably be attributed to specific mills based on these stitching patterns. He also referenced technical studies in the Confederate Philatelist by Dr. Harry Brittain that have identified local fillers, additives, and ink compositions.
The bindings in the collection encompass pamphlets, trade bindings, and publisher’s bindings. Regional variations exist, with covering materials, decorative tool patterns, and sewing structures often traceable to specific publishers or cities. In this collection, Evan noted that certain sized books are associated with specific binding features or subject matter. He also found repeated use of particular stamping dies and repurposed cases in some of the collection’s publisher’s bindings. Evan then discussed the wallpaper covers associated with literary fiction published from 1863-1865 by S. H. Goetzel of Mobile, Alabama.
The project was a success and finished ahead of schedule, with all but three objects in this collection digitized. Two were bound volumes with unopened pages, and the third had significant mold damage and was set aside for later treatment.
During the questions session, Evan was asked if he’d found any photographic maps in this collection, and he described one that had gotten minimal treatment and was encapsulated. Evan was then asked to elaborate about his stabilization and storage methods for maps that were folded into wrappers. He mentioned that they wanted to store these objects flat, and many could be opened mechanically without humidification. The folds on other documents proved to be more stubborn and needed to be humidified prior to flattening.
Another audience member asked about Evan’s observations on imported papers in this collection, particularly blue writing papers. He responded that though blue stationery was common in this period, he didn’t see it used for imprints. Rather, he most often encountered this type of paper pasted into volumes. Evan also mentioned papers and books that were imported through the Union blockades.
Many thanks to Evan for a particularly interesting and useful talk. For additional information, please refer to Evan’s bibliography on his BPG Wiki user page: http://www.conservation-wiki.com/wiki/User:Ev-knight
43rd Annual Meeting – Paintings Session, May 15, "Rediscovering Renoir: Materials and technique in the paintings of Pierre-Auguste Renoir at the Art Institute of Chicago" by Kelly Keegan
Renoir is one of those art historical giants that I’m sometimes guilty of overlooking, simply because of how frequently his imagery appears in contemporary culture. An upcoming treatment of a Renoir painting at work, though, meant that it was high time to take a closer look. Fortunately, Kelly Keegan of the Art Institute of Chicago gave a fantastic presentation on “Rediscovering Renoir” at the 2015 AIC conference, which was brimming with details about the artist’s materials and techniques, and beautiful photomicrographs and graphics.
The presentation was a summary of findings from the in-depth technical study of Renoir’s 15 paintings at the Art Institute of Chicago, conducted as part of the Online Scholarly Catalog Initiative. Examination techniques included x-radiography; infrared, transmitted light, and ultraviolet imaging; x-ray fluorescence spectroscopy; scanning electron microscopy/energy dispersive x-ray spectroscopy; polarized light microscopy, surface-enhanced Raman spectroscopy; thread counting; and, of course, lots and lots of looking under the microscope.
Renoir was both less and more methodical than I expected. For example of the former, he didn’t have a reliable art supply merchant. His canvases ranged in fineness, and thread counting demonstrated that they never came from the same bolt of cloth. Although most of the paintings are now lined and on non-original stretchers, seven canvas stamps from four different suppliers were found. His ground layers were usually white or off-white, with dragged inclusions and palette knife marks indicating application by the artist. The use of the palette knife often exposed the tops of the canvas weave.
Renoir’s compositional planning shows his meticulous side. Even the highly impressionistic work Chrysanthemums includes a graphite underdrawing with individual petals. The artist varied his preparatory drawing medium, using dry media, blue or brown paint, or red lake washes. Slight adjustments were common, and a dramatic change was discovered in Lunch at the Restaurant Fournaise, the catalog cover image: an isolated two-person encounter was initially depicted, but the final product has three figures. Later in Renoir’s career, infrared examination shows the debilitating effect that rheumatoid arthritis had on his once-confident draftsman’s hand.
Renoir’s color palette included vivid pigments, including emerald green, cobalt blue, various bright yellows (see image above), vermilion, and red lakes, in addition to iron oxides. One color he considered an “unnecessary purchase” was yellow ochre, which he ironically preferred to mix himself using much more expensive pigments. Although he did a lot of blending on the painting, he kept his brush clean to prevent muddying of the colors. In contrast to most other Impressionists, Renoir’s paint layers are quite thin relative to the ground layer. The influence of his teenage training as a porcelain painter is evident in his use of thin glazes, especially with luminescent red lakes over white ground. He used a palette knife at times to scrape away layers and create texture in the interstices of the canvas weave.
This presentation was chock full of technical information and interesting quirks about Renoir that not only make me feel more prepared to approach a Renoir treatment, but also give me a much better appreciation for an artist that deserves a close look. His work shines under the microscope and when considering the individual behind the paintings. The Online Scholarly Catalogs are a wonderful resource, and I’m grateful to have gotten Keegan’s dynamic overview of the Renoir content.
43rd Annual Meeting – Architecture Session, May 15, "The Power of Light! Using the Newest Laser Technology to Clean New York’s Oldest Outdoor Monument: The Obelisk of Pharaoh Thutmose III" by Bartosz Dajnowski
The obelisk of Pharaoh Thutmose, also nicknamed Cleopatra’s Needle, is New York’s oldest outdoor monument. Matthew C. Reiley, Associate Director of Conservation and Senior Conservator at the Central Park Conservancy, began the talk by providing background information on the history of the obelisk. The stone monument was commissioned around 1450 BCE by Thutmose III to celebrate his 30th year of rule. The red granite was quarried in Aswan and carved with hieroglyphs. It was one of a pair of obelisks that stood at the sun temple in Heliopolis. The monuments were purportedly toppled during a Persian invasion around 525 BCE and were later moved and re-erected in Alexandria by Romans around 12 BCE. In the 19th century, one of the obelisks was given by Egypt to the United States. William Vanderbilt paid for the transportation of the monument to New York City. It traveled across the Atlantic Ocean in the hull of a ship and was raised in Central Park in 1881.
The first condition study and treatment of the monument came in 1885. The study noted damage from freeze-thaw cycles. Salt migration and deposition occurring over time, while the monument was in Egypt, had created microcracks in the substrate. Water infiltrating into these areas and expanding during freezing caused surface loss. Workers removed unstable fragments, and the surface was impregnated in paraffin wax, which over time trapped dirt and pollution. In 1983, the Metropolitan Museum of Art performed a scientific study, which found that the monument was stable and not aging at an accelerated rate.
In 2011, an Egyptian Antiquities official threatened to take back the obelisk, claiming it was not well cared for. This prompted the Central Park Conservancy’s project to document, clean, and stabilize the monument. Photographs were taken and color annotated to document condition issues. Cleaning tests, using aqueous methods, micro-abrasion, and lasers, were performed in order to find a suitable method for removing years of accumulated soiling and atmospheric pollutants that obscured the carvings. Based on these tests and in situ mockups, laser cleaning was chosen because it was controllable, effective, and did not damage the stone.
For the second half of the talk, Bartosz Dajnowski, Vice Director and Objects Conservator at the Conservation of Sculpture & Objects Studio Inc., described the laser cleaning methods. He listed some of the benefits of laser cleaning: no chemicals, no abrasives, no loud noises, and no public hazards or contamination to the surrounding areas. Unlike a laser pointer, the beam of this laser is focused to a point and then it spreads out so that the radiation diffuses past the focal point. The cleaning process is called laser ablation, and it works discriminately as it excites one material so that it separates from the substrate. Since laser cleaning is not a mechanical process, it is safe to use on fragile substrates. Bartosz noted that it is important to use the correct settings because if the laser is used incorrectly, it could damage the substrate, for example by melting bronze or shattering quartz and melting inclusions in stone. He also pointed out that adding water to a surface during laser ablation has a micro-steam cleaning effect as the laser turns water into steam. The water also helps reduce the effects of plasma formed by the laser, minimizing the possibility of phase changes in the iron within the stone.
Bartosz spoke about his prior experience and research with lasers, including work done during his graduate studies at Winterthur. Extensive testing and analysis was done on stone samples before laser cleaning began on the obelisk. Small fragments that had previously fallen off of the obelisk were cleaned and then examined by George Wheeler at the Metropolitan Museum of Art to confirm that safe laser cleaning parameters were being used.
Seven lasers were used to clean the entire stone monument and the four bronze crabs around its base. One of the lasers, called the GC-1, Bartosz built himself using a new design. With the other lasers, the pulses are emitted as line scanning, with a mirror alternating left and right, so the pulses come out like a machine gun firing back and forth. This creates hot spots at the edges, which can result in overcleaning or damage. Optical shields and other methods can be used to cut off the hot spots, although this decreases efficiency. In Bartosz’s new design, the laser pulses are emitted in a circular ring pattern, so the beam is constantly moving around in a circle. In this formation, there are no hotspots, and when the instrument is moved across the surface, the coverage area is exposed twice, which increases efficiency. Since this unit is also smaller, Bartosz was able to take it up to the top of the scaffolding. As others on his team used the line scanning lasers and worked from the bottom of the monument up, Bartosz worked from the top down. With his new laser, he was able to clean the same sized area in half the time!
With lasers, the level of cleaning is controllable, and Bartosz mentioned that the team was asked to try leaving some soiling in the recesses of the carving to increase the legibility of the glyphs. However, the soiling was uneven, and the carving had suffered previous damage, so it was not always easy to distinguish. An overall cleaning was carried out, although a few areas of soiling were left near the top of the monument for future analysis.
Following laser cleaning, fragile and unstable areas of the stone monument were consolidated. The 3,500 year old, 220 ton obelisk now stands cleaner and more stable for the future. In a fitting end to the talk, Bartosz noted the appropriateness of using light to clean and revive an ancient monument that was originally built to honor the sun.