Category: AIC’s Annual Meeting

The second group of presentations in the Architecture Specialty Group’s morning session covered a range of topics. Victoria Pingarron Alvarez of the University of Pennsylvania presented “Performance Analysis of Hydraulic Lime Grouts for Masonry Repair.” Ms. Alvarez described research carried out in 2005 and updated with current research to evaluate low-strength grouts used for adhesion. Moderately hydraulic lime grouts were formulated with different concentrations of El Rey Superior 200, an acrylic polymer emulsion, and subjected to tests of their mechanical and physical properties. A mix of 2 parts lime, 1 part fine mason’s sand, 1 part ceramic microsphere filler and 10% solution of acrylic emulsion in water yielded a grout with low shrinkage, moderate resistance to frost and compatible tensile and compressive strengths to historic masonry. Future research related to Ms. Alvarez’s work may address the suitability of test standards, as all of the test standards used in the evaluation of the lime grouts were modified in some way.

Ben Haavik and John Childs, both of Historic New England, gave the presentation “Revisiting Realty: A Changing Approach to Environmental Control in Historic House Museums at Historic New England.” Historic New England manages over 120 buildings and 1200 acres at 36 sites, and its collections include over 50,000 objects in its house museums as well as another 70,000 objects in storage. The introduction of environmental control systems at several Historic New England house museums in the 1990s quickly resulted in problems that are currently being addressed with a revised approach to environmental control. Two case studies were used to demonstrate Historic New England’s new approach to environmental control, which is a simplified approach applied incrementally. It includes a wider acceptable range of relative humidity, a monitoring program, humidistatic heating and simplification of equipment.

The final presentation of the morning by Avigail Charnov of Historic Resources Group was “A Review of 100 Years of Site Management.” The presentation, co-authored with Jake Barrow of Cornerstones Community Partnership and subtitled “Conservation of Earthen Sites in the American Southwest,” examined the creation of national monuments and parks in the southwest and the development of conservation efforts at these sites. While early conservation treatments were not well documented and were often undertaken in a trial and error fashion, a fundamental shift in conservation practices occurred in the 1970s. This shift incorporated laboratory material analysis, increased levels of documentation, monitoring of conditions, critical evaluation of treatments and a collaborative team approach.

The first trio of papers presented during the Architecture Specialty Group’s morning session all covered research on mortars. Brad Shotwell and Joshua Freedland, both of Wiss, Janney, Elstner Associates, asked the question “Evaluation of Historic Mortars: Is Petrography Ever Enough?” Mr. Shotwell presented a methodology for analysis of historic mortars beginning with petrographic examination. Petrography can be both qualitative and quantitative, incorporating techniques such as chemical spot tests to identify specific components and modal analysis to determine relative amounts of binder and aggregate. Several case studies were used to demonstrate the answer to the question posed in the paper’s title: it depends on the questions being asked and the goals of the project. Depending on the research goals and on the nature of the mortar being examined, ASTM C1324: “Standard Test Method for Examination and Analysis of Hardened Masonry Mortar,” which is weighted toward chemical analysis, may not be completely relevant. The approach to mortar analysis recommended by Mr. Shotwell is to begin with petrography and to supplement it with chemical analysis as needed.

John Walsh of Highbridge Materials Consulting presented “The Mortars and Concretes of Fort Jefferson: A Critical Examination of Effective Analytical Techniques for Unique Construction Materials.” The goal of the analysis was to identify the components of the mortar used at Fort Jefferson, constructed between 1846 and 1876. Mr. Walsh’s approach to mortar analysis, starting with qualitative petrographic examination and applying supplemental instrumental analysis, reinforced the first presentation of the day. As demonstrated by Mr. Walsh and Magdalena Malaj in the Fort Jefferson case study, petrography is also important to anticipate anomalies or interference that may arise during other analytical work.

In the third paper of the morning, chemical engineer Nora Perez presented her research on the mucilage additive to historic mortars in “The Application of Opuntia sp. Mucilage in the Pre-Hispanic Age, Today.” Polysaccharide extracts from the mucilage cactus has been used traditionally as an additive to Pre-Hispanic mortars to increase lime solubility, improve mechanical resistance and delay setting time. In a testing program conducted by Ms. Perez, the mechanical and physical properties of lime mortars prepared with different concentrations of mucilage additive were evaluated. Mucilage extract used as an additive to lime mortars does improve the physical properties of the mortars, makes injection mortars easier to apply and promotes the formation of a compact crystalline lattice. Biogrowth does not appear to be a concern with mortars having the mucilage additive, as the extract breaks down over time.

The Conservation Project of the Manila Daguerreotypes

Caroline Barcella, Fifth Cycle Advanced Residency Program in Photograph Conservation

The second talk was equally engaging. This project was conducted during Caroline’s ARP study. These daguerreotypes were discovered at the Hispanic Society of America – 18 plates in passé-partout including 13 whole plates. This was a major discovery – very early for the Philippine Islands – images of Manila from a wharf to housing and water landscape. 2007-2009

Documentation and stabilization was goal. Many plates were loose. Result in greater understanding of their material housing and to develop documentation guidelines. English inscriptions on the reverse of housings. Owners were English speakers. American settlers who arrived in the islands. Plates are stunning. Passe partout housing presented for full understanding. Early 1840 paper mat – additional beveled mat added after 1840 (interesting time line on passé partout format presented) broadens our understanding of the dating of these related yet different formats.

Investigation to determine if plates were made at the same time by one photographer – comparative study of inscriptions indicated different hands and location. Probably that some plates are part of the same group owing to housing similarities. Demonstrates the clear value of analysis of housing using visual assessment and study or corrosion pattern to indicate past presentation. Front elements changed on some of these plates. Very nice example of in-depth analysis of collection using careful visual study.

Hallmarks were studied. They did vary. (15 hold the same stamp.) Plate holder marks on some but not all – different polishing systems used. Yellow fluorescence visible on some plates. Does this help with the assessment of processing? Whole plates appear to be processed the same way? All created in the same context. Possible conclusion. Documentation guidelines are important – method used can be secured from Caroline or final report on line.

An Early Daguerreotype by Henry Fitz. JR.

Hanako Murata, Assistant Conservator of Photographs, The Metropolitan Museum of Art

Hanako’s excellent, well illustrated, and comprehensive presentation addressed her work funded by the IMLS and the discoveries she made relating to the history and analysis of a Fitz daguerreotype – dated to 1840. Interesting points included:

The copper support of the plate was split which is quite unusual and rarely seen.

Uncertain how the plate was made. Investigation of the corrosion products required to further assess cause. There were breaks in the plates and UV examination in long and short wave undertaken. Plate may have been previously cleaned.

Owing to physical deformation a modified Z-tray designed for storage. Primary package was much deeper which required a replica case to be prepared with deeper tray. Fitz famous for his self portrait in NMAH Smithsonian. (This plate could not be analyzed because it was framed but it too may be on a brass support and certainly requires further study.) NMAH hold another 22 plates. Plus his workshop materials (including tools that demonstrate his frugal ways) which offer wonderful opportunities for learning and teaching. His studio established in Baltimore in 1840 – he continued taking images until 1842. In 1845 he moved to NYC. He made a telescope designed for astrophotography. His plates were roll welded.

Analysis included XRF at the Metropolitan which demonstrated only copper and zinc with traces of lead – 90% CU/10% ZN. Not gilded. Made on brass and not copper… questions relating to how unique this substrate was and why Fitz used brass and did he make this on his own? XRD on corrosion products in interlayer cleavage of the plate suggested that the plate may have been exposed to a pickling bath prior to joining. Clad welding may have been used in the manufacture which explains the lower Zn%. His background as telescope maker is important here but correlation between the metals used in scopes were not clear.

!9th century brass buttons were analyzed with XRF but there was not a strong link to the plate %.

Fitz plates – 22 at NMAH could be analyzed with portable XRF. Nine were made on brass! Zn% varied. These plates vary and visual differentiation based on color was not possible. Perhaps these were experiments? Brass only used for 1/9th plates. Deterioration did not vary considerably from brass or copper plates. Records of cleaning from NMAH do not exist. Additional delamination of plates observed where multiple layers are visible. Brass susceptible to stress cracking especially when in contact with ammonia.

These plates by Fitz are only known images on brass. May have been experimentation. Others may exist. Many discussions on who took the first image of a leading figure in the US. His self portrait is dated 1839… and it may be one of the earliest known self portraits. This is very significant. During the discussion Dr. Susan Barger notes that this may be roll clad plates that have failed. See her dissertation for more details on manufacture process. Correspondence about how to use materials – and debate about earliest plates. Cornelius made his own plates but that was his business.

Wednesday’s afternoon talks began with Gretchen Guidess who lectured on Finding Support: Reassessing & Developing a New Support System for Original Upholstery. The talk focused on a recent conservation treatment of a slip seat with surviving original under upholstery. Gretchen conserved the slip seat during her second year at the Winterthur/University of Delware Program in Art Conservation. The upholstery dates between 1780-1789, and resided in the Gardiner Mansion on Gardiner’s Island. Due to the original stitching along the under upholstery, the show cover and under layers were conserved for future study. Damages from the removal of previous repairs caused deformation of the under upholstery and tears along the back rail that needed support. Gretchen decided she needed a supportive, transparent material in order to show the under upholstery layers of the seat. She chose Vivak, a co-polyester sheeting, that is cold/heat formable, comes in a variety of thicknesses, can be cut with scissors/saw, and can be shaped with a hair dryer. Please see the following link for more details: null. A user guide can be found in pdf form at www.curbellplastics.com/petg-fabrication-vivak.pdf. Vivak could be shaped using heat to form to all the concave areas of the under upholstery, and the edges of the material were turned down to prevent tearing. The needlework was supported using dyed bobbinet. The support was held in place using c-clips attached to fabric covered Vivak supports. Vivak has also been used to produce clear costume mannequins in Santa Fe. Any further questions about Vivak and the product can be directed to gretchen.guidess@gmail.com.

Ann Frisina, Textile Conservator at the Mennesota Historical Society, gave the second lecture entitled: Not Much Left: Digitally Printing Replacement Upholstery as a Group Effort. Ann focused on the intricacies related to interpreting and representing a piece of upholstery from the James J. Hill House in St. Paul Minnesota. Two wingback chairs were sent to the conservation lab with several layers of secondary upholstery. There was little physical evidence of the original upholstery remaining. The tracking edge of the first chair was analyzed to reveal a late 19th century Jacquard woven cotton warp and wool weft. The second chair had no visible repeat, and was only depicted in an old photograph of the room that was hard to decipher. Consultations with upholstery designers specializing in historical furniture came up with a line rendering of the design that could be repeated in Adobe Photoshop. The image was first depicted in gray scale, and then a limited color palate was added to represent the original upholstery. In order to represent the original upholstery, a digitally printed fabric was produced as a replica fabric for the two wingback chairs. The replica upholstery was printed at L.T.S. in New York on various smooth to textured cotton samples at 7-8 yrd. legnths. In order for the colors to be manipulated for printing, they must be indexed in Adobe Photoshop. Therefore, each color can be manipulated separately. Identification, analysis, and replica reproduction for the original upholstery of these wingback chairs involved a collaboration between many artisans.

The third lecture of the afternoon was given by Catalina Hernandez, Private Practice Conservator in Bogata Columbia, entitled: The Uses of Nonwoven Fabrics in Conservation. Catalina began her investigations of nonwoven materials as part of her dissertation at The Textile Conservation Center in the UK. During an archaeological materials conservation project at the Gold Museum in Bogata, Columia, she continued to investigate alternatives to Tyvek and Acid Free tissue, due to such a limited budget for the project. While Tyvek and Acid Free tissue are commonly used in the U.S. and Europe, they are very expensive and hard to order in Columbia and other Latin American Countries. Catalina compared four readily available, cost-effective, nonwoven fabrics available in Bogata. Two nonwoven fabrics, generally used as car covers, were Kimberly-Clark Block-It 380 and Dustop Soft as Flannel car Cover. The other two nonwoven fabrics were Bonlam 90B4 all purpose fabric and Bonlam all purpose fabric available from Polymer Group International. All fabrics were very light, but the Bonlam nonwovens were breathable with a high tensile stragnth. Bonlam 90B4 proved to be the best alternative to Gore-Tex. It could be used in humdification, solvent, and adhesive application treatments. During the chemical resistance testing, the pH of the fibers in Bonlam 90B4 is not affected by exposure to chemicals. The car cover fabrics were too light, let liquid water in, grabby, and shrank during the lint production test. While all the fabrics were too light for some conservation treatments, Bonlam 90B4 all purpose fabric proved to be a successful alternative to Tyvek and Gore-Tex as a breathable nonwoven material.

After the afternoon coffee break, Allison McCloskey, Assistant Conservator at the Williamstown Art Conservation Center, gave a lecture entitled: Revisiting Treatment of 12th Century Mongolian Deels. Allison assessed the conservation treatment of three 12th c. deels (traditional Mongolian cloaks) that were unearthed in an archaeological dig by the Center for Cultural Heritage of Mongolia. Allison, and fellow conservator Cynthia Luk traveled to the Mongolian capital of Ulaanbaatar as part of a bilateral exchange funded by a Trust for Mutual Understanding. The Deels were originally treated an isopropyl alcohol bath of 70% ethanol and 30% distilled water to address the soling and microbial activity. After the initial immersion, an aqueous cleaning was carried out with Johnson’s Baby Shampoo to separate the Deels. They were dried under glass weights to prevent distortion and creasing. Once dry, the Deels were stitched to a padded board support. Narrow fabric wrapped piping was inserted between any areas of folded edge to prevent creasing. Nylon net was stitched over the surface for additional support. The conservators analyzed the deterioration of the sericin coating on the Talas hair silk fibers by using SEM and FTIR on the Deels. Mass Spectrometry and Gas Chromatography were used to detect detergent residue remaining after the previous wet cleaning treatment. After analysis, it was decided thatno harmful residue remained after wet cleaning that would require further cleaning treatments on the Mongolian Deels.

The final talk of the afternoon was given by Patricia Ewer entitled: Cultural Exchange Programs: Sharing Conservation Information in Azerbaijan. Patricia, a Textile Objects Conservator in Mound, Minnesota, discussed the details of her trip to Azerbaijan to visit their museum and conservation department. The trip was funded by the Fund for Arts & Culture, with an emphasis to share ideas and practices. An initial objective for her trip was to meet find an individual to offer an museum conservation internship in the U.S. While preparing for her trip she researched travel to Azerbaijan, and was presented with very limited literature. Patricia also reviewed literature and communicated with other conservators such as Mika Takami, Julia Brennan, and Frances Lennard, who have all traveled to foreign countries to carry out conservation lectures. Once arriving in Azerbaijan, and meeting the individual museum workers, she realized the intense desire, craftsmanship, and interest among the community to preserve their cultural history. They had a team for textile analysis and fabric re-weavers carrying out treatments on a variety of carpets. After her visit, Patricia proposed an alternative to picking one individual from Azerbaijan returning for an internship in the U.S. She suggested a team of conservators for the U.S. travel back to Azerbaijan and collaborate with the museum workers for a longer period of time.

This concluded the textile group lectures on Wednesday afternoon. The textile group business meeting was carried out after the talks.

[I apologize that the reports on the individual General Session talks are not longer and in greater depth. At the Wednesday morning sessions I had the dual role of blogger and time keeper for the speakers so my attention was split. I am delighted that another blogger has posted detailed reports on the talks by George Wheeler and Steven Weintraub. ]

George Wheeler opened the meeting with his talk, “Identity Crisis– Critical Identity: The Future of Conservation and the Role of AIC in its Development”. Wheeler’s premise was that conservation is an act of criticism and interpretation. Conservators must think about how they think and must make a connection between thought and action. He suggested that conservators look to other fields like literary criticism for models on how to do this. He spoke about four books and one journal that have helped him advance his theoretical thinking. The books are Cesare Brandi’s “Theory of Restoration (Enligh trans, 2005), Salvador Munoz-Vinas’ “Contemporary Conservation Theory” (2005), Paul Eggert’s “Securing the Past” (2009), and Alison Richmond and Alison Bracker’s “Conservation Principles, Dilemmas and Uncomfortable Truths” (2010), and the journal is “Future Anterior”.

Shelly Smith, the second speaker of the morning followed Wheeler with a very animated talk, “With Patience and Fortitude: Keeping Conservation Relevant in a Changing Institution”. Smith is Head of Conservation at the New York Public Library, an institution with a permanent collection comprised of enormous numbers of objects housed in multiple branches. In 2008, the Library changed its mission statement dropping conservation from its mission at the same time that it made plans to move its conservation department to a new, much larger custom designed laboratory offsite, and that it transferred the department from its technical services division (where it was sometimes looked at as a high end book repair shop) to the collection strategy department where the curatorial department resides. Confused by the mixed messages it had been given about its importance to the institution, the conservation department decided to become proactive rather than wait to be told what it should be in the new scheme of things. It has encouraged the Library think about the transportation of collection materials now that all items must be moved offsite for treatment. It is working to show how stewardship of the collection serves the Library’s new mission “to inspire lifelong learning, advance knowledge and strengthen communities”. One of its the first initiatives in that regard was the production of a five minute video, geared to school children, on the treatment of library materials which was incorporated into a recent Library exhibition.

Patricia Silence, speaking on behalf of the AIC Green Task Force (GTF) presented the last paper before the coffee break– “Challenges of Sustainable Conservation in the 21st Century”. The information she presented will be available in greater depth on the AIC website. Silence stated that the GTF’s aim is provide a methodology for reducing the individual conservator’s impact on the environment. It does not presume to tell anyone how he or she must work. Among the areas Silence spoke about were solvents, water purification systems, treatment options requiring less water, the use of reusable rather than disposable materials, recycling of materials, and travel. She discussed how the AIC itself is working to be more environmentally conscious including choosing meeting tote bags that were made from recycled materials. The GTF is collecting ideas on how to make conservation practice more sustainable. Silence asked that ideas and tips be sent to green@conservation-us.org

The first presentation in the second of the Wednesday morning sessions was Steven Weintruab’s “The Evolution of Environmental Standards: The Struggle to Quantify and Simplify Risk in a Complex World”. Weintraub dedicated his talk to Carolyn Rose and Toby Raphael. Weintraub’s premise was that environmental control is a complex issue and there is a danger when it is simplified to a list of specificiations. He noted that when Garry Thomson first published “The Museum Environment” he did not include a list of environmental specifications. Rather he gave explanations for why certain numbers or ranges of numbers made sense. Weintraub also noted that today conservation is one of a number of fields– the construction industry being another– that are tring to establish performance guidelines rather than prescriptive guidelines. Weintraub said that environmental control can be seen as a matter of risk and cost benefit analysis–i.e., what is the level of risk that an institution will tolerate and what will it cost to prevent a certain amount of damage. Weintraub spoke at length about lighting. He noted that in the old days lighting was simple– one used just enough light to see the object and no more– but that lighting has become more complex as we have come to understand that 50 lux of light directed at an object 8 hours a day for 90 days has a very different effect than 150 lux directed at an object 8 hours a day for 30 days. Weintraub ended his presentation with the reminder that we should be thinking about problem solving rather than about applying standards.

The next presentation, “p3: Pen, Preservation, Political– Establishing a Longitudinal Study for the Exhibition and Storage of Herblock Drawings”, was divided between Holly Huston Krueger and Fenella G. France, with Krueger providing background ablut the collection and France describing the longitudinal study of seven drawings from the collection. Krueger noted that when Herbert Block, the Pulitzer Prize winning cartoonist Herblock, died in 2001, he left his entire archive of 14,460 finished drawings and 50,000 rough sketches to the Library of Congress with the stipulation that some part of the collection be on display at all times. While Herblock was fairly consistent in his choice of materials throughout his career (1941- 2001)– graphite and India ink– in the 1960s, he did begin to try a variety of other materials of varying stabilities. The Library of Congress’s curators were concerned about how exhibition and storage conditions would affect the works, so Krueger and France developed a study that used selected drawings to provide baseline data on this. The works chosen for study were examined with hyperspectral imaging before, during, and after they went on display and will be studied while in storage. In addition, sample sheets were made using drawing materials taken from Herblock’s studio. They will be used in natural and accelerated aging tests.

Frank Matero presented the final paper of Wednesday’s General Sessions, “Conservation as Revitalization of Cairo’s al Darb al Ahmar”. Matero

began his talk by proposing that conservation is creative, progressive, and subversive– the last because it goes against the trend to replace anything old with something new. The conservation plan for the Darb al Ahmar district of Cairo, a district that was listed as a World Heritage Site in 1983, gave that socially and environmentally fragile area a means of revitalizing itself and its economy. The restoration of the crumbling district wall, parts of which were buried under rubble, took what had been a dangerous structure and turned it into a unifying element of the district. So much material was required for the repair of the wall that quarries were reopened to fill the need. Local workmen were hired and taught historic construction techniques providing meaningful employment. The revitalized district has seen an influx of visitors who provide an additional boost to the local economy.

Drawing on that rare commodity, common sense, is what Steven Weintraub has built his career around. That he has highly honed reasoning skills was evident in his AIC general session presentation on the evolution of environmental standards. Weintraub starts his presentation with reference to Gary Thomson’s The Museum Environment. According to Weintraub, the environmental recommendations that Thomson made in this book reflect a practical knowledge gained over time and based on common sense. Since that time, the conservation profession has place environmental controls that move us farther away from the target.

Weintraub advocates that environmental requirements to preserve artwork are complex systems that have been over analyzed or over simplified. Environmental controls should be based on risk assessment concepts. What level of risk is your institution willing to tolerate? In conservation, our risks should be like insurance actuarial – our environmental controls should be driven by costs and practicality of implementing environmental standards. We must be wary of the one size fits all type of environmental standard, recognizing that conditions that are right in Santa Fe will not apply to New York.

Environmental discussions have circled around recommendations like 40%-60% RH versus 45%- 55% RH, and 16-25 deg C versus 20-24deg C. One approach is to look at the way materials respond to humidity and choose the best set point for all materials – this leads to that 40% RH to 60% RH range. But other factors need to be considered. Environmental standards do have some positive influences. In existing buildings, the ability to maintain such standards has an impact on the operational procedures that may lead to operational and physical improvements. These standards influence the construction of new buildings.

Weintraub then addresses lighting issues and the display of artwork. Originally, light issues were driven by defining the lowest amount of light needed to accurately see the artwork and nothing more. Again this was a practical and common sense approach. Then we moved away from this way of looking at lighting issues and turned to the concept of annual exposure. But annual exposure is a managerial tool, not a conservation tool. For example an object exposed to 50 lux for 8 hours a day for 90 days does not experience the same amount of possible light damage as object that receives 150 lux for 8 hours a day for 30 days. The most important concept to take away is to make every photon count. In moving forward we must return to the common sense past.

The recent trend is studying artwork using microfading testers continues to focus on damage issues. Weintraub feels that this emphasis is overrated. When you use a microfading tester to study artwork, where in that lifetime prediction curve are you for the object? Instead he advocates going back to the idea of lighting the object just enough to see the object without doing damage.

He points to the Harrison report from the early 1950’s that shows that the damage to an object is relative to the wavelength of light to which it is exposed. Spectral damage calculations can be made based on this work that allow you to calculate the amount of damage per lux based on wavelength and specified material. Then you can choose your light source. For example, daylight has two times more damaging than tungsten light.

Next, Weintraub turns to environmental monitoring systems noting that these are really problem solving tools. But what should our metrics be? We need to keep in mind that there is a hierarchy of conditions that affect visual appearance that we perceive. This hierarchy can be things like color temperature or color rendering. These are the conditions that Weintraub feels we should monitor.

In the end, Weinstraub states that we are looking at complex systems that have a pattern. We need to sit down and look at all the data, consider the risks, and try to perceive the patterns.

In a new format, the Architecture Specialty Group (ASG) held a morning session devoted to presentations by students and recent graduates of architectural conservation programs. These papers presented recent research work carried out by the students on a variety of thesis topics.

Jennifer Schork, a recent graduate of Columbia University now working with Integrated Conservation Resources, presented “New Insights into Dolomitic Lime Mortar.” Ms. Schork carried out a laboratory testing and instrumental analysis program to better understand the constituents and properties of dolomitic lime mortars. Dolomitic lime dominates the North American market for repointing mortars, although some may not be aware that they are using it or the affects that it has on the mortar. Ms. Schork’s research showed that dolomitic lime mortars can be 45% stronger than high calcium lime mortars, with the uncarbonated material (brucite: Mg(OH)2) perhaps contributing to this strength.

Casey Gallagher, a recent graduate of The University of Texas at Austin now with the Texas Historical Commission, studied “Biological Growth on the Alamo.” Ms. Gallagher posed three crucial questions in her research: 1) what is the biogrowth? 2) is the biogrowth damaging to the stone? and 3) do cleaning treatments previously carried out affect the stone? Through lab cultures and DNA analysis, species of cyanobacteria were identified on the Alamo stone. This can be particularly damaging to the stone because they are endolithic, penetrating underneath the surface of the stone, and they secrete amino acids, leading to stone deterioration. In addition, cyanobacteria have a hard sheath that is difficult to remove and they can tolerate long periods of desiccation and extreme heat, leading to recolonization. One year after the application of in situ cleaning tests using D2 Biological Solution, BioWash and water, there are not signs of recolonization. However, photographic records show recolonization after previous cleaning of the stone, and recolonization has also occurred in laboratory culture samples.

A testing program to evaluate “Fatigue Behavior of Adhesives for the Repair of Marble” was presented by Laura Michela, a current student at Columbia University. Ms. Michela’s research compared thermoplastic adhesives (Paraloid B-72, Paraloid B-48N and a 3:1 blend of Paraloid B-72 to Paraloid B48N), thermosetting adhesives (Epo-Tek 301-2 and Akepox 2000) and a sandwich of Paraloid B-72 used as a barrier coat with Epo-Tek 301-2. The broken portions of cylindrical samples of Vermont marble were readhered using the different adhesives and then subjected to repeated vibration to simulate fatigue. Some samples broke during the vibration, but the remaining samples were tested in 4-point loading. Some of the observations from the testing program are that all samples subjected to the repeated vibration experienced loss of strength, the samples repaired using thermosetting adhesives had higher strengths than the thermoplastic adhesive samples, and that some samples broke at an area of the cylinder where the adhesive was not present. The research built on previous work carried out by Columbia University conservation students. Areas of further research include looking at different thermoplastic blends, different solvents with the thermoplastic resins, different marble types and different load testing mechanisms.

Alex Kim, a 2009 graduate of the University of Pennsylvania conservation program who now works in the programs Architectural Conservation Laboratory, presented “Soft Vegetative Capping of Architectural Masonry Walls.” Although “hard” mortar capping is often used on exposed masonry ruin walls, mortar capping is prone to cracking, which allows moisture and vegetation ingress, leading to further deterioration of the wall. Mr. Kim’s presentation examined another approach to protecting exposed masonry ruin walls. “Soft” vegetative capping uses geosynthetic membranes, soil and gravel and vegetation to prevent moisture infiltration. It has the benefits of low maintenance cost, improved aesthetics and legibility and retractability. In situ tests performed at semi-arid sites in the southwest United States and central Anatolia show that there is reduced temperature fluctuation with soft capping compared to hard mortar capping. However, moisture infiltration below the waterproofing membrane was noted at one test site, pointing to the need for improved design and installation procedures.

The final paper of the student session was given by Jessica Kottke, a recent graduate of the University of Pennsylvania conservation program. Ms. Kottke presented “Three-Dimensional Laser Scanning for Imaging, Quantifying, and Monitoring Micro Stone Surface Deterioration at Heritage Sites.” Using the case study of work documenting two lion sculptures at the Merchant’s Exchange in Philadelphia, PA, Ms. Kottke showed that three-dimensional laser scanning was useful in creating a background image that could be annotated for condition surveying. However, given the limitations of resolution, it may be impractical to use the three-dimensional models created from laser scanning programs for monitoring changes over time.

Dr. George Wheeler, Director of Conservation at Columbia University, Fran Gale, Senior Lecturer and Director of the Architectural Conservation Laboratory at The University of Texas at Austin, and Frank Matero, Professor of Architecture at The University of Pennsylvania, made several key points that put the student research presentations in context. The thesis research presented during the session is typically only one part of on-going research and is often followed by additional research by other students as part of their theses. The research also often depends on partnerships with organizations such as the National Park Service or academic departments outside of the preservation programs.

Following the presentations of recent student research and answering of technical questions posed to the presenters, there was a discussion on the possibility of developing an annual forum for student presentations. All present in the session seemed to agree on the usefulness of the presentations by students and recent graduates from architectural conservation training programs of their research. A forum for presenting the work of recent student research is valuable to the development of both the emerging professionals, who get feedback from their more established colleagues, and to the experienced practitioners, who learn about recent research that may affect their work.

Two points of inquiry on the organization of a session for recent student research were debated: what venue is appropriate for a presentation of recent student research and who should participate at presenters. On the first point, most people present for the discussion agreed that a half-day session or even full-day session of student presentations held in conjunction with the ASG session of the AIC Annual Meeting is an appropriate venue. This year, funding to cover all student costs to present at the session was provided through the George Stout Memorial Fund, and it is hoped that similar funding will be available in future years.

The question of what criteria should be used to select potential presenters is more contentious. As presented by Frank Matero in his introductory remarks to the session, there are 24 programs that lead to a Master’s degree in historic preservation, and another 20 or so graduate programs in related fields that award certificates in preservation or conservation. There are ten Master degree programs with one or more courses in architectural conservation, but only a handful of these have a full curriculum in architectural conservation. A number of questions were left undecided, such as whether the opportunity to present papers at a student and recent student session should be limited to just those trained in a program with a full architectural conservation curriculum or open to those doing architectural conservation research in other programs, and whether the universities should preselect the papers submitted for presentation or the papers should be submitted by the students to a ASG program committee. These questions will likely be revisited during the ASG business meeting on Friday, May 14, and in future discussion by ASG members.

It’s not often that conservators and conservation scientists have a chance to sit down and think about the theory behind our work. Usually the plethora of tasks we face each day gets in the way. Today, Dr. George Wheeler, Columbia University, treats us to a lively lecture on the theory of conservation.

He opens his discussion by talking about the growing pains of the profession. AIC has come through a difficult time with the recent unsuccessful efforts towards certification. He feels that there were lessons to be learned here as we attempt to define ourselves, now and in the future.

Wheeler structures his presentation around “four books and a journal” in a take-off of four weddings and a funeral. He began the discourse with the book, Theory of Restoration, (2005 English translation) by Cesare Branch. In the book, Branch states “restoration is carried out in order to reestablish the critical text of the work of art. . .” Thus all that we do should be defined by the need to reestablish the artwork. Wheeler feels that another important insight from this Italian scholar was the concept that the work of art is recognized as a physical object with dual historical and aesthetic value to be transmitted to the future. Wheeler also points out that only the material of a work of art is restored. We cannot restore a spirit of a work of art.

Next, Wheeler discusses issues in the definition of conservation, based on the work, Contemporary Theory of Conservation, by Salvador Munoz Vinas (2005). He contrasts the AIC definition of art conservation with one offered by Munoz Vinas. AIC’s definition of conservation is “The profession devoted to the preservation of cultural property for the future.” Munoz Vinas states that conservation as we know it today is a complex activity. Wheeler thinks conservation is about defining and developing our activities over and above the professionalism of the job. Another important point that is made is the uncomfortable relationship between conservators and conservation scientists. Conservators mustn’t look to scientists for validation in what they do. Instead, they should look within for authority to guide their actions.

The third book that Wheeler highlights is Securing the Past, by Paul Eggert. Eggert who is an English professor, explores underlying theories behind the different arts and practices of restoring historic objects and texts. Wheeler notes that a key issue addressed in the book is the subject-object relationship. Ultimately, we must define the boundary between who we are and what we work on.

Wheeler introduces us to the journal, FutureAnterior by way of shifting preservation and conservation away from nostalgic antiquarianism towards active involvement. Again, the emphasis is on our actions in relation to the artwork.

Conservation Principles, Dilemmas, and Uncomfortable Truths, a compilation by Alison Richmond, is the fourth book highlighted in the presentation. Within these pages, Wheeler chooses to quote Jonathan Ashley Smith, stating that conservation is in its adolescence. We can’t become a grown up profession simply by saying we are grown up. We cannot mature without the growing pains.

Wheeler concludes by telling us that we must mobilize the creative activity within this organization to determine where we are going in the future.