The National Archives is the official government archives of the UK and Wales. The Archives has two buildings: Q1, a building built in 1978 with three main repositories in three floors, and Q2, a newer building built in 1996 with twelve repositories over four floors.
Ntanos started by looking into records from 1973-75 to see the decision-making of how the Q1 building was designed. During this time from 1973-75, the staff discussed the requirements of environmental control and determined that temperature was more important than relative humidity and felt that if you kept temperature at mid-range, the RH would be controlled, too! Seven to eight years of mold growth prompted investigation into this building. Intensive climate-mapping was done using data loggers to determine the differences in the environment, and they saw a big difference between the center of the room (50-55%) and the ends of the room (70%).
Ntanos also used environmental assessment permanence maps to demonstrate how the environment changes through the year (he gave a poster at this AIC meeting on the mapping of material types). Once they had collected 1-2 years of information, they started making changes.
They used Energy Plus Software and put in as much information as possible about the environment and the building. They also used HAMT (Humidity and Moisture Transfer) and saw a difference with and without HAMT because of the large collection of hygroscopic material. The aim of the model was to examine options in maintaining a sustainable preservation environment for the collection. They were able to reduce energy consumption in line with sustainability targets, build resilience in light of climate change predictions, and inform ongoing capital investment. Powering down the HVAC over the weekend saved up 22% without affecting the preservation environment.
Category: Specialty Sessions
Posts on talks that were presented as part of the specialty sessions at AIC’s Annual Meeting
42nd Annual Meeting – Photographic Materials Session, May 31, “Comparative Study of Platinum Prints in the Museum of Fine Arts, Houston Collection and the Early 20th Century Kodak Platinum Print Samples” by Saori Kawasumi Lewis.
Ms. Kawasumi Lewis presented research conducted at the Museum of Fine Arts, Houston during her third year internship. This project was joint with the National Gallery of Art’s Platinum/Palladium initiative. She was happy to close the conference with this talk, as it could serve as a teaser for the upcoming Platinum/Palladium Symposium.
Ms. Kawasumi Lewis had the unique opportunity to compare platinum prints in the MFAH collection to a platinum print sample set produced by Kodak c.1902-1910, owned by a private collector. The Kodak sample set is a great resource for this study because it was commercially produced and each product has been identified on the object. She hoped that characterizing these known samples would help identify unknowns, particularly artwork in the museum’s collection. To test this, she compared the Kodak sample set to a small group of prints in the MFAH collection. She used a variety of analytical techniques to narrow down the possibilities, finally resulting in a close match with one print in the collection: Lucille Tomajon, by Gertrude Käsebier.
Ms. Kawasumi Lewis presented this research in a systematic approach, showing us how each analytical method helped narrow down the field of possible matches. Each step ruled out some of the sample set and the MFAH group.
To begin, she led us through a bit of the chemistry of platinum printing, which is a semi-printing out process. Significant to the research, she detailed that an artist could add mercury in either of two distinct steps – sensitizer or developer. For greater effect, mercury could be added in both steps. Starting in the 1880s, mercury was added to commercially available papers. Palladium paper and platinum/palladium mixtures were also available.
Ms. Kawasumi Lewis described the analytical steps that helped her find affinities between the sample set and photographs in the collection. Comparison included: date, thickness, sheen, texture, color, and elemental composition. Ten platinum prints by Clarence White, Gertrude Käsebier, Fredrick Evans and others were chosen from the MFAH’s collection of pictorialist photographs as a comparison group.
First, X-ray fluorescence spectroscopy (XRF) was used to determine the elemental composition of the prints. Readings were collected from Dmax and Dmin areas using a Bruker handheld Tracer, and an Artex XRF unit. XRF data was analyzed using the counts from the instrument, which were normalized according to the Rh Kα line. In addition to platinum, mercury, palladium and lead were found in the prints. Some trends were identified: Mercury was abundant, though variable, so this required more investigation; palladium was present in several of the Kodak samples, but only one of the MFAH prints. This narrowed down the field a bit, ruling out the Kodak samples with palladium.
In order to determine if mercury variability was due to differences in the time of addition (sensitizer or developer), Ms. Kawasumi Lewis created mockups using a variety of methods described in the literature. She found that her mercury sensitized sample was most similar to the Kodak sample prints and most of the MFAH platinum prints. Not surprisingly mercury levels were highest in prints that had been sensitized and developed with mercury. This narrowed down the group a bit more by ruling out MFAH prints with high levels of mercury.
Next, surface texture was analyzed using Paul Messier’s texture scope and experimental design. This step helped to narrow down the list further by comparing the descriptions of surface (i.e. smooth, rough), to the MFAH prints. This further reduced the possibilities, so the field of possible matches was limited to only a few prints.
As the final step, Ms. Lewis used color to narrow down her final group of prints using a spectrophotometer to quantify red and yellow saturation. (As a note of caution, she mentioned that the color of platinum can be effected by more than just choice of paper. Temperature during processing, ageing and other factors can change the color of prints.) This narrowed her group down to just the Käsebier and the sample for Kodak Etching Sepia Smooth paper. This is strong evidence that Käsebier used this paper to create the print because the prints are alike in elemental composition, texture and color.
More research could help definitively characterize the paper Käsebier used for this print, but Ms. Kawasumi Lewis’ work gives us a good indication of the materials used by the artist.
42nd Annual Meeting – Architecture + Objects Joint Session, 29 May, 2014, “Preservation Planning and Mid-Century Modern Materials: Tools to Promote Strategic and Sustainable Building Conservation” by Lacey Bubnash and Katie Horak
In this presentation, I was looking forward to learning about the approaches that are taken in the preservation and conservation of modern built heritage.
Lacey Bubnash (Architectural Conservator at Architectural Resources Group) and Katie Horak (Senior Associate at Architectural Resources Group and Adjunct Lecturer at the School of Architecture, University of Southern California) shared their experience of preservation planning for The Village Green, also known as the Baldwin Hills Village, in Los Angeles.
Built in 1941-1942, the Village Green is a modern housing complex that includes residential buildings (today occupied as condos) with garages, community structures, such as a clubhouse and maintenance building, and large open spaces. The complex was designed with the idea of providing affordable housing for the pre-World War II community. On this account, inexpensive and mass-produced materials were used to construct the complex.
In their presentation, Lacey spoke about the site documentation that she and Katie prepared and reviewed during this phase, including the Historic Structure Report and Cultural Landscape Report respectively. These reports identify challenges for the site’s preservation and conservation, such as the presence of mid-century modern materials, and include recommendations for preservation and conservation treatments.
Lacey also presented about the application that she and Katie submitted for the Village Green’s inclusion in the Mills Act Property Tax Abatement Program. This Program is a financial incentive for historic preservation in California. It binds the participating city and the property owner in a contract that sees the reduction in property taxes in return for the property owner’s restoration and maintenance of the property. Their application was successful in obtaining a Mills Act designation for the Village Green.
I found this presentation to be a very interesting glimpse into the planning and preparations for the preservation and conservation of built heritage. I enjoyed learning about the process involved in such a large and multifaceted project – encompassing both built structures and designed landscapes – that bears the additional challenges of dealing with modern design concepts and materials.
42nd Annual Meeting – Book and Paper, May 31, Library Collections Conservation Discussion Group
The theme of this year’s Library Collections Conservation Discussion Group was “Options for Sustainable Practice in Conservation”, which tasked speakers to examine how conservators could lessen the carbon footprint of conservation work. Speakers included Brian Baird, from Bridgeport National Bindery, Danielle Creech of ECS Conservation, Julie Newton from Emory University, and Marieka Kaye of the University of Michigan Libraries. The speaker line-up was notably diverse, in that it included speakers from commercial binderies as well as those from labs within academic libraries.
Brian Baird had some good points about why conservators and labs should focus more on reducing waste, rather than just relying on recycling, to lessen their carbon footprint. For instance, recycling some items, such as ink cartridges, doesn’t do much good – the cartridges are shipped to China, where they remove the last few drops of ink, and the plastic cartridges still end up in the landfills. His ultimate take-away lesson was that no recycling program can be as efficient or cost-effective as simply reducing consumption of materials.
Danielle Creech spoke about the various iterations of ECS Conservation’s recycling program. Over the years, they’ve recycled everything from linotype and monotype waste, old equipment, old book covers, shrink-wrap packaging, and paper dust. They built a relationship with their County Solid Waste Management District, who helped partner them with a business-to-business recycling business called Quincy Recycling. With each iteration of their recycling program, ECS had to come up with creative solutions to reduce consumption as well as find ways to recycle various types of materials. Danielle made a very important point that recycling is NOT free, as it requires time and labor to train employees in the proper recycling procedures. She also mentioned that they have noticed some “recycling fatigue”, as employees constantly have to remember which of the 17 recycling barrels should be used for different kinds of waste.
Marieka Kaye outlined how both the library and her lab play a large part in promoting sustainability in the overall University of Michigan community, via the Library Green Team program. This program encompasses more than just recycling bins, by providing avenues for both staff and students to creatively reduce consumption as well as reuse materials within the library. For instance, their library staff intranet has a Craigslist-style office furniture swap listing, and the library sells reusable water bottles which can be used with the recently-installed water-bottle refill stations. In the conservation lab, they replaced the incandescent bulbs in the overhead lights with energy-efficient compact fluorescent bulbs.
Julie Newton started her talk off with the statement that “a box of lab scraps is a hundred tiny art projects waiting to happen”, which will resonate with anyone who loves to collage or make other types of paper-based art. Through her vigorous efforts, Julie was able to extend the life of many materials before they went into the recycling bins. She noted that while conservators are usually very frugal with their materials, such as Japanese tissue, they tend to be less frugal with more plebian materials such as box-making board or paper towels. She encouraged her staff to re-use scraps in creative ways, either within the lab or outside of it. She also acknowledged that you do have to ask yourself on occasion if the effort and time it takes to accumulate and repurpose scrap is worth it, versus just getting new materials. Making scrap useful is again, not a “free” activity, as it requires staff time to sort and organize it in a useful way.
I’ve made a list of the some of my favorite creative uses for scraps and “waste” that were presented by these speakers:
- Several thousand pounds of paper dust were repurposed as horse bedding when it was donated to an Amish farm by ECS.
- Excess rubber bands were donated by ECS to a teacher in Indiana, who is trying to break the record for the largest continuous rubber band ball.
- Some materials can be composted, such as paper towels, old paste, used tea bags.
- Scraps of board and paper can be donated to schools or local art programs and clubs.
All in all, the speakers acknowledged that recycling and reducing consumption requires some effort and staff time, but in the end it can make a big difference by improving the environment and providing a positive impact on our society. In addition, contributing to sustainability efforts helps strengthen our relationship with our surrounding community, by forging partnerships with local businesses and environmental groups.
What creative solutions for repurposing “waste” or reducing material consumption has YOUR lab undertaken? Share them in the comments!
42nd Annual Meeting – Photographic Materials Session, May 31, “Technical Research on The Diane Arbus Archive” by Janka Krizanova
Janka Krizanova’s fascinating talk on her work with the Diane Arbus Archives at the Metropolitan Museum of Art in New York City provided an overview of the first eight months of her two-year-long research scholarship. The Diane Arbus Archives contains 600 vintage prints, 800 work prints, 6,200 rolls of film, 6,500 contact sheets, and the artist’s library and equipment. Krizanova’s goals for the project are to characterize the materials in the archive, assess the stability of materials in the collection, create a long term plan for the preservation of the archives, and create guidelines for the exhibition of materials in the collection.
In her research, Krizanova examined:
• technical and historical literature on 20th century photography
• manuals and books of samples of photographic papers issued by the industry (in addition to Paul Messier’s Historic Photographic Papers Collection)
• other characterization studies, such as that on the Thomas Walther Collection at the Museum of Modern Art
Krizanova began her study by conducting a survey of the collection. She found that Arbus’ body of contact prints had the widest variety of photographic processes and the most varied condition states. Arbus worked primarily with silver gelatin prints, but also utilized the stabilization process for contact sheets and temporary proofs, as these prints were much faster to process than silver gelatin prints. However, they were not designed to be long lasting.
Stabilization prints are made by using a special photographic paper with an incorporated developer. Arbus used Kodak Ektamatic Paper (boxes of which are housed in the archives). A negative in an enlarger is used to expose the paper, which is then fed into the processer. It first passes through an alkali bath, which activates the developer in the paper. The paper then moves directly into an acidic stabilization solution, which complexes the unexposed silver. This silver is “stabilized”, but not fixed. The whole process is over in a matter of seconds. In addition to describing this photographic process, Krizanova discussed the intriguing condition issues seen in the collection, including spotting, darkening, lightening caused by applied pressure, and discoloration even when stored in an ambient room environment. Krizanova is working on establishing a set of terms to describe the condition issues presented.
The technical characterization of some of the silver gelatin and stabilization prints will involve:
• Measuring paper thickness
• Documenting printing on the verso
• Microscopic documentation of the surface texture
• XRF in the D-max and D-min areas
• UV examination
• Paper fiber sampling
• Spectrophotometric measurements
• Microfadometer readings
Krisanova has begun the first four categories of characterization. I really look forward to hearing the results of her work and her characterizations of the interesting and complicated condition issues seen in the stabilization prints.
Here are two excellent questions asked (and answered) at the end, loosely paraphrased:
Q: Will you fix and wash the stabilization prints?
A: No, they are to be preserved as is.
Q: Would you consider freezing the stabilization prints in an attempt to preserve them?
A: No one is doing that right now, as far as anyone knows. Currently, it is not an option for us, but we will certainly address this question again later in the study.
42nd Annual Meeting, Objects Session, May 31, Pine Pitch: New Treatment Protocols for a Brittle and Crumbly Conservation Problem by Nancy Odegaard, et al.
In this paper presented at Saturday’s Objects Session, Nancy Odegaard, Marilen Pool and Christina Bisulca described a new treatment protocol they established, along with their colleagues Brunella Santarelli, Madeleine Neiman, and Gina Watkinson, for treating baskets with deteriorated, pine pitch coatings. The treatment protocol was devised after conducting a survey of the basket collection at Arizona State Museum, where the majority of the pitch-coated ethnographic baskets (70 out of about 100) had unstable, blanched, cracked and brittle surfaces. The baskets required treatment so that they could be moved to a new location.
The majority of the baskets were Apache and were made using a twining or coiling technique. The pine pitch, obtained from the piñon pine would have been applied to the surface of the baskets as a waterproofing measure. Two colors of pitch were observed on the exterior of the baskets, each with different condition issues. Some baskets were covered with a red pitch that appeared translucent. The other baskets were covered with a dark brown to black, opaque pitch. Both colors of pitch had suffered degradation due to factors such as UV, temperature and pollutants, however the red pitch appeared more unstable and had a formed a series of fine cracks. The darker pitch had deeper cracks.
Because the baskets had to be moved, a treatment protocol was established to stabilize the surfaces so the baskets could be safely transported to a new storage area. Previous treatments for deteriorated pitch had included consolidation with solvents or the use of heat (using a butane torch!) to reintegrate the cracked, crumbly surface. The ASM team was looking for another treatment option, and one that took into consideration the vast numbers of objects that required treatment. Borrowing from methods used to clean aged varnish in the field of paintings conservation, the conservators decided to reactivate the pitch using a solvent to stabilize the flaking material and reattach the crumbly surfaces.
Prior to any treatment, the conservators wanted to get a cultural perspective on the treatment since they did not want to add material, alter the pitch or appearance of the basket and wanted to make sure the objected retain their cultural integrity and significance. Nancy consulted with a Navajo weaver who said that pitch baskets should always look shiny and therefore reactivating the pitch, and the subsequent shiny appearance the material would take, was acceptable.
Treatment
Because of the success in the use of ethanol in cleaning aged, pine-based varnish from paintings, that was the solvent chosen for the reactivation of the pine pitch on the ethnographic baskets.
- The first stage of the treatment was to place the baskets (many supported by foam rings or, if they fit, by large glass beakers) in an ethanol solvent chamber for 24 hours. This would condition the surface and prepare it for further treatment.
- The baskets were then removed from the solvent chamber and areas of the surface sprayed with ethanol using a Dahlia sprayer for a more direct application of the solvent.
- Brushes, foam swabs wrapped in PTFE (Teflon) tape and Kim Wipes (lint-free wipes) soaked in ethanol were then used to relocate any loose flakes.
- After one side was treated, the pitch was left to air dry for a few hours, then the basket was turned and the other side sprayed with ethanol and flakes reattached.
- When the entire pitch surface had been treated, the basket was left to air dry for about 24 hours or until the pitch no longer felt tacky.
During treatment the conservators noticed that the transparent red pitch reacted faster to the ethanol. The darker pitch was less soluble and more pressure was needed to re-adhere fragments. They also noticed that for areas with damaged basketry elements, the reactivated pitch served to reinforce those areas of the plant fiber so that no further stabilization of those woven elements were required.
Analytical Investigations
In addition to the treatment, instrumental analysis was conducted to characterize the two types of pitch and determine if there were any changes in the pitch before and after treatment. The analysis was conducted using Fourier Transform Infrared Spectroscopy (FTIR) and optical microscopy.
The first investigations looked at the two types of pitch and whether there were any changes observed before and after treatment. Analysis showed that there were no differences before and after treatment and therefore reactivation and exposure to ethanol did not alter the material chemically. There were differences, however, noted between the red and dark pine pitch. The transparent red pitch had a low aromatic component as opposed to the dark brown-black material, which had a high aromatic hydrocarbon content.
A series of experiments were then conducted in order to figure out what accounts for these differences and it turns out it has to due with how clean the pine pitch is and at what temperature it was initially heated to during application. Using optical microscopy, the dark pitch seemed to contain woody materials and had inclusions of bark. Could this be the explanation for the differences in the aromatic content?
Samples of resin from piñon pines in the Navajo area were collected and heated to different temperatures and then examined using microscopy as well as FTIR. It turns out that if the pitch is clean and does not contain any woody components, there are little to no aromatics. However, when bark is present in the pitch, the aromatic content is similar to that seen on the pitch coating the ethnographic baskets. The heating temperature also plays a role not only in the color, and a temperature of 180° C produces pitch similar to that seen on the ASM baskets.
This was a really informative talk describing a new approach to not only the treatment of crumbly pine pitch, but also a protocol for treating large numbers of unstable baskets. The talk was of particular interest to me because some close colleagues and I have often encountered similar types of condition issues with different resinous materials on archaeological objects (for example bitumen coatings on ceramics, bitumen or pitch on baskets, natural resins on Egyptian funerary objects and mummies) and have often discussed the need for approaches to the stabilization of these materials other than consolidation using synthetic resins. The literature is a bit lacking in terms of the treatment of these types of materials and it’s wonderful that Nancy and her team at ASM are adding to this body of information by sharing their treatment methods and findings (and hopefully publishing them in the OSG Postprints or another publication!).
The next stage of the pine pitch/basketry project will be to work on the archaeological basketry collection and I looked forward to hearing about their approaches to the stabilization of pitch on those artifacts.
42nd Annual Meeting – Paintings Session, May 29, "Eclectic Materials and Techniques of American Painters: 1860-1910" by Lance Mayer and Gay Myers
Gay Myers, with the support of Lance Mayer, presented research on American artists gathered from primary sources including artists’ interviews, notebooks, letters, manuals, and suppliers’ catalogues, periodicals, and advertisements. Their presentation focused on a period when more Americans began traveling to Europe.
The influence of instruction from French academics like Thomas Couture (1815-1879) was particularly strong. The American painter Elizabeth Boott (1846-1888) wrote manuscripts about European techniques that delineated Couture’s studio instruction in Paris, William Morris Hunt’s (1824-1879) classes in Boston, and Frank Duveneck’s (1848-1919) practice in Munich. Couture advocated the method of painting thinly over brown underlayers (these paint layers become more transparent over time, and so, this method has sometimes led to problems). He influenced several nineteenth century American painters including Eastman Johnson (1824-1906), Winslow Homer (1836-1910), and Thomas Eakins (1844-1916). Hunt and his pupil Helen Knowlton (1832-1918) believed that caring too much about one’s technique was stifling. Duveneck employed large amounts of oil media in his paintings to achieve a “buttery” application and sealed his works with extremely glossy varnishes. Duveneck’s varnishes were so thick that the American painter John Singer Sargent (1856-1925), who preferred light varnishes, advised others not to let “D” or any of his boys varnish their paintings.
The Art Amateur (1879–1903), an American magazine edited by Montague Marks (1847-1905), used the artists’ advice columns to document Thomas Dewing’s (1851-1938) use of matte varnishes, the growing popularity of the shellac-based Soehnée’s varnish as both a retouching and final varnish, and the early beginnings of the tempera revival in America. The American author Albert Abendschein (1860-1914) was among those in opposition to the tempura revival and has been quoted stating “the egg is more useful taken internally and kept out of the studio.” Abendschein instead advocated for indirect painting in which glazes are layered onto a monochromatic underpainting. In his 1906 book, The Secret of the Old Masters, Abendschein documented the growing tempura revival, commercially-produced paints containing wax, as well as other art trends.
J.G. Vibert (1840-1902), Edward Dufner (1872-1957), Mary Louise McLoughlin (1847-1939), and other significant members of the art community discussed varnishing practices, pigments, added media, and supplementary topics in a series of interviews conducted by DeWitt McClellan Lockman (1870-1957). The French author Vibert advocated a preference for petroleum solvents, and similarly, the American artist Dufner began using kerosene oil instead of turpentine because it dries without a glossy sheen. Dufner considered glossy surfaces so undesirable that he wrote on the verso of one of his paintings: “This picture being in a light key is meant to be matte surface and should never be varnished.” Vibert was also a staunch believer that lead white was not compatible with vermillion or cadmium and offered zinc white as an alternative. Concern about the toxicity of lead white also lead many artists, including McLoughlin, to start using zinc white. Since that time, technical analysis has confirmed zinc white is more prone to cracking than lead white.
This presentation effectively demonstrated the extent to which American painters experimented during the late nineteenth and early twentieth centuries. If you would like to learn more about the materials and techniques of American painters, Mayer and Myers have authored multiple publications including American Painters on Technique: The Colonial Period to 1860 (2011) and American Painters on Technique: 1860-1945 (2013).
About the Speakers
Lance Mayer and Gay Myers graduated from the Oberlin College conservation program (1977 and 1978) and work as independent conservators to private collectors and public institutions including the Lyman Allyn Art Museum. The authors are fellows of the American Institute for Conservation of Historic and Artistic Works (AIC) and have each served as chair of the AIC Paintings Specialty Group. They have collaborated on conservation and research projects for over thirty years, were awarded the Winterthur Advanced Research Fellowship (1999), Museum Scholars at the Getty Research Institute (2003), and College Art Association/Heritage Preservation Award for Distinction and Scholarship in Conservation (2013).
42nd Annual Meeting – Photographic Materials, May 31, "László Moholy-Nagy: Characterization of his Photographic Work at the Art Institute of Chicago and his Working Practices" by Mirasol Estrada
Mirasol Estrada, the Andrew W. Mellow Fellow in Photograph Conservation at the Art Institute of Chicago, studied the work of László Moholy-Nagy in the museum’s collection for two years. Her talk was a comprehensive look at the photographer’s working practices as well as the specific characteristics of his photographs in the collection at the Art Institute of Chicago. Ms. Estrada was drawn to the work of Moholy-Nagy because of the experimental nature of his working practices, and his philosophy of photography.
Moholy-Nagy always thought of himself as a painter but he also produced drawings, film and photographs. He came to Chicago in 1937 to direct the New Bauhaus, which then became the Institute of Design. He was an influential teacher, including teaching his philosophy about the practice of photography, published in his book “Vision in Motion”. This philosophy was summarized very nicely by Mirasol, who described Moholy-Nagy’s idea that there are eight varieties of seeing.
The first variety of seeing is “Abstract”, which includes photograms, which are direct records of shapes and shadows. The second is “Exact”, which is straight-forward camera photography. The next is “Rapid”, which shows motion, followed by “Slow”, his description for long exposures. “Intensified” was using chemical manipulation such as solarization. “Penetrative” described x-rays, “Simultaneous” was the term for his photomontages, and lastly, “Distorted” was the term for mechanical or chemical manipulation of a print or negative. This was an interesting summary of Moholy-Nagy’s ideas about the variety of seeing correlated to his photographic method – a good window into the photographer’s thinking process and the categorization of his themes.
Ms. Estrada then took us through the characterization, both physical and analytical, of the thirty-nine photographs in the Art Institute’s collection. She grouped the prints physically by their size, tonal range, surface texture, finishing (coatings) and thickness. These groupings were displayed in a very clear, easy to read chart detailing the characteristics, including thumbnail photos of each object overall and in detail to show tone, surface texture, etc. Analytical data for each object was also included (XRF, FTIR) to complement her visual observations. Using her chart, one could compare the date clearly and easily, looking at tone, texture, and subject of the image.
A few interesting observations that were made following the study were that Moholy-Nagy most likely did not process his own photographs – he has been known to have explained that he was allergic to the development chemicals. This may explain the diverse body of work and materials choices, since his students, wife, and daughter may all have been a part of the processing of his artwork. Moholy-Nagy used many different types of paper and other materials, especially noticeable on his move from Europe to the US, reflecting the marketplace at each time and place. Ms. Estrada offers that it was perhaps more important for the artist to express his ideas, his complex categories of “varieties of seeing”, in the Bauhaus tradition, instead of focusing on the fabrication of his artwork.
42nd Annual Meeting – Collection Care & HVAC, May 31, "Some trends in examining six years of utility and climate data at the Museum of Modern Art" by Jim Coddington
Jim Coddington, the chief conservator at the Museum of Modern Art (MoMA) in New York, presented some trends that were found from analyzing the environmental data that was collected at MoMA over the past six years. This was particularly interesting because it compared two relatively new or newly renovated buildings with different types of usage/functionality and HVAC systems. The building on 53rd street, Jim admits, is very leaky from a number of sources, including the many doors through which thousands of people pass, and has a steam and electric HVAC system. The building in Queens (QNS) on the other hand is mostly concrete with very little glass and has a gas powered HVAC system. The data that Jim presented was collected from across the museum including finance, operation, conservation, and vistor services. Needless to say there are a lot of people invested in this.
Jim showed mostly graphs and charts. These included data showing the temperature and %RH outside, inside the buildings, dew point, and comparing this energy usage. I’ve included images of the graphs that I found most interesting or informative.
In QNS there is a large expenditures of gas in august and dips in winter. This is because that are able to use free cooling to extract excess heat for 8 or9 months, or 3 out of 4 seasons, through a heat exchanger on the roof. In this process, heat is absorbed from the condenser water by air chilled water. The length of time they are able to use free-cooling is based on set points of T and RH (see second image) and is affected by air temperature, relative humidity, and water supply temperature. Non-free cooling with the RH set at 50% happens over the summer and is longer at lower temperatures. So during the summer the temperature set point is allowed to drift to 22 degrees C. Jim mentioned that having a narrower set point may actually equal cost savings, but they have no data for that.
On the analysis for the 53rd street building, Jim highlighted that this is a very different situation. It is a high use building, with lots of leakage points and demand on the systems- steam and electric principally. Therefore, the energy usage is much higher.
It has been asked whether heat from visitors is significant? In Chris McGlinchey’s calculation, the 360 kJ/hr given off by the visitors with a typical stay of 4 hours, this is not a huge contributing factor.
In Jim’s summary and conclusions- The expected was stated that they are consuming more energy in the 53rd St building than QNS. This is mostly in winter (see the third image). The QNS building is more efficient because of the free cooling, lower set point temperature and equates to lower energy usage thanks to an efficient building design. Online Resources:
- Steam- natural gas utility converter: http://www.coned.com/steam/default.asp
- NIST Guide for the Use of the International System of Units (SI) 2008: http://physics.nist.gov/cuu/pdf/sp811.pdf
- Humidity converter: http://www.cactus2000.de/uk/unit/masshum.shtml
- Dewpoint calculator: http://www.decatur.ed/javascript/dew/index.html
- NOAA, National.ncdc.noaa.gov/
42nd Annual Meeting- OSG, May 31, "Restoration by Other Means: CT scanning and 3D Computer Modeling for the Re-Restoration of a Previously Restored Skull from the Magdalenian Era by J.P. Brown and Robert D. Martin"
After collaborating with JP at the Field Museum on rendering CT scans a few years ago and seeing his article about this work in the spring MRCG newsletter, I was excited to see some images about this in person. JP has been working with CT scanners since 2006 starting out by taking advantage of the kindness of local hospitals and more recently renting a portable unit that came to museum on a truck.
As many of us know, CT scanners can look inside objects non-destructively and provide accurate images with 3D geometric accuracy. JP started the talk be reviewing some of the physics of getting a CT scan done, the benefits, and limitations. Here’s a run-down:
1. The scanner has a donut shaped gantry consisting of a steel ring containing the X-ray tube and curved detector on the opposite side, so your object has to fit within the imaging area inside the steel ring.
2. On each revolution you get lots of images scanned within 30 seconds to 5 min- this is very fast.
3. The biggest logistical challenge is moving objects to and from the hospital safely.
4. During the scanning you immediately get slices, which are cross-section images from three different directions. Volumetric rendering is done from the slices and there is free software for this.
5. Apparently it is relatively easy to do segmentation, segment out regions of interest, and extract wire frame models, just time consuming. From there you can get images of the surface and texture and can even print the models. It is relatively easy to go from slice to wireframe, but harder to achieve a manufacturing mesh to produce a 3D print, which can be expensive in comparison to traditional molding and casting.
6. PROs of scanning and printing: there is no contact with the object, complex geometry is not a problem, the scans and volumetric rendering are dimensionally accurate, you can print in lots of materials; prints can be scaled to make large things handleable or small things more robust for handling or increase visibility; subtractive manufacture, in which you can use a computerized milling machine to cut out a positive or negative, is also a possibility.
7. CONs of scanning and printing: printing is slow, the build volume is limited, a non-traditional skill set is required of conservators to produce the final product, and only a few materials age well. The best material is sintered nylon, extruded polyester may also be safe, but it doesn’t take paint well; it is hard to get the industry to think about permanence.
The object at the center of this project was a Magdalenian skull. The skeleton itself is of considerable importance, because it is the only magdalenian era skeleton of almost completion. A little history: it was excavated, quite professionally, in 1911 when they lowered the floor of the site. Unfortunately the burial was discovered when someone hit the skull with a pickax. Needless to say, the skull did not come out in one piece. In 1915 the full skeleton was removed in two blocks. My notes are a little fuzzy here, but basically at some point between the excavation the skull was restored and then went from being 2 pieces to 6 pieces, as it is documented in a 1932 publication by von Bonen. It appears that at that point the skull was also skin coated with plaster. Thankfully (?) those repairs have held up. Great, so why, did they need to scan and reconstruct the skull? Well according to Dr. Robert Martin, JP’s colleague at the Field Museum, the skull doesn’t look anatomically correct. Apparently during the time period when it was put together there was an interest in race and the skull fragments could have been lined up incorrectly accentuating cultural assumptions.
A previous x-ray showed that two fragments in the forehead are secured with a metal pin. In 2012, when the mobile CT scanner came to the museum, they were all geared up to start with the Magdalenian skull. Unfortunately there was not much difference in attenuation between bone and plaster making it tricky to define between the two materials in the scans. JP consulted a cranial reconstruction group and asked them to pretend this was a pediatric car crash victim with a cranial injury; they asked, why aren’t you using the mimics software package?
JP and his team also imaged the skull with a micro CT scan that has a 0.1 mm resolution versus the normal modern setting of 0.3 mm. They had previously identified 36 fragments of bone from the previous scan. It was hard to tell if some of those separations were just cracks or actual breaks between fragments. The hope was that the micro CT scanner could better define these areas. The micro CT scanner works opposite to the industrial/medical scanner. As you can see in the image to the left, the tube and detector are fixed, while the sample is rotated. Other differences are that it is slower, one scan takes 30-90 minutes and because of scanner geometry the skull had to be imaged in two scans . Because of this, JP used the previous scan to mill out a contoured support to hold the skull in the exact position. JP noted that digitally filling in the holes of the skull to create the support was the most time consuming part of that process and suggests using different radio-opaque marker dots to identify left and right for orientation during the later stitching process. With the new scans at least three separations were identified as cracks vs. breaks.
Now for the virtual reconstruction… the biggest obstacle in this stage was how to achieve something more anatomically correct using the virtual fragments when they have no boundaries. The fragments don’t push back in the computer- and the fragments can easily move into each other. With the software JP used mostly the translation and rotation functions and the free animation software Blender (which has a high learning curve and took several days to get accustomed to) to create hierarchical parent child relationships between the fragments as he joined them together. Just like putting a vessel together, right? In the virtual world at least there is no worry about lockout. They had a 3D printed of the final skull reconstruction and had an artist do facial reconstruction, which JP thinks always look related to Jean Luc Picard… So how successful was this? From a conservation perspective- awesome, it’s fully reversible! Scientifically though, it’s decent, well documented and scientifically justifiable- However, someone else could go through the same process and come up with a different reconstruction because of their reliance on left right symmetry for this reconstruction…
So what did I take away from this talk? This was a very cool project and if I have a question about CT scanning and 3D renderings, I will call JP! The scans can be extremely informational and there seems to be a lot of potential in their use for mount-making, crates, and storage, and possibly virtual reconstructions. Hopefully at some point in the future the software will become more intuitive and easier to use so that more of these types of projects can be done.