Category: Topics

AIC’s 39th Annual Meeting – Research and Technical Studies Session, June 1, “The Macro, Micro, And Economics of Climate Control” by Dr. Fenella France, Library of Congress

Dr. Fenella France, Preservation Research Scientist at the Library of Congress, brought her expertise in preventive conservation to the topic of microclimates in cultural institutions, starting with the what, why, and where’s of microclimates, and ending with a presentation of an über-microclimate display and storage case: the “MOAC” (Mother of All Cases) for the iconic Waldseemüller map. Key points included:

  • A microclimate is a environment maintained in a small space that differs from its external environment. This might be at various levels of control within a building: the building itself, a room, a case, a box.
  • It is important to create specs for a microclimate based on an understanding of an object’s materials, history, and mechanisms of damage.
  • A specific object’s materials and cultural significance may dictate its need for a microclimate.
  • Issues which must be considered in planning a microclimate include the composition of the encasement, object access, environmental controls (active vs. passive), monitoring.

The Waldeseemüller map exemplified an object of highest cultural importance and value, which warranted an optimal microclimate for storage and display. Its fantastic encasement provided an anoxic environment, visibility of the object in storage and display, minimized handling, minimized oxidative and hydrolytic degradation, and access for monitoring of pressure, RH, T, and oxygen.  A few amazing stats about the case:

  • It was designed to maintain a 20-30-year seal.
  • It is a 2200 lb case within another case.
  • 92 bolts hold the tooled aluminum case together.
  • It has maintained 0-30ppb oxygen.
  • It has a flexible back to allow for changes in barometric pressure.

The encasement was an impressive, collaborative effort by conservators, engineers, architects, curators, and others. Although an estimated cost for the case was disappointingly not reported, I was impressed by the long-term planning that went into its design, as much as the elaborate, continuing monitoring and analysis conducted by the stewards of this object. Since the completion of the encasement in 2007, the durable case has proven to be effective and durable, as demonstrated by data generated by its monitoring systems. While I was duly wowed by the Waldeseemüller encasement, I would argue that France’s presentation of it as a “case study” was a little misleading. It was an exceptional feat of engineering and effort for an exceptional object. I was hoping for more discussion of more typical microclimate needs and solutions, probably covered in the Microclimate Workshop…

Open Positions on the ECPN Committee

The Emerging Conservation Professionals Network seeks three new committee members:

1-year term, beginning in September 2011, submission deadline August 25, 2011

Chair, Vice-Chair, and Outreach Coordinator

The Emerging Conservation Professionals Network (ECPN) works with various AIC committees to address the needs of conservation professionals with fewer than 7 years of experience. This includes pre-program students, graduate students, and recent graduates. The committee seeks to increase participation in AIC amongst emerging conservators.

The chair position coordinates monthly conference calls, writes agendas for these calls, oversees projects like: the mentoring program, the student research repository, and is responsible for editing all published material about the group. The chair represents the committee to the board of directors and at the Internal Advisory Group meeting, and collaborates on projects with other AIC committees and with representatives from conservation graduate programs.

The vice-chair is a new position that will oversee all of the ECPN activities at the AIC annual meeting (ECPN informational meeting, happy hour, portfolio session, and any new activities) and the yearly ANAGPIC meeting (there is a speaker each year from the ECPN who attends the ANAGPIC meeting). The vice-chair will also be a logical candidate for taking over the chair position after their one-year term.

The outreach coordinator is in charge of all social media communication including the ECPN blog, Facebook page, Flickr site, and other projects that involve outreach and communications. The outreach coordinator works closely with the communications coordinator, currently Amy Brost. The outreach coordinator may also take over the chair position after completion of a one-year term.

The ECPN communicates primarily via email correspondence and monthly conference calls. The committee meets in-person annually at the AIC meeting.

Please submit a brief statement of interest and your resume to Rose Cull, Chair, AIC-ECPN, (roseemilycull [at] gmail [dot] com) by August 25, 2011.

Questions about committee activities can be directed to Rose, or ECPN’s current outreach coordinator: Heather Brown (hnmbrown [at] yahoo [dot] com)

For more information about the ECPN see: www.conservation-us.org/emerging.

AIC’s 39th Annual Meeting- Objects Session, June 3, “Balancing Ethics and Restoration in the Conservation Treatment of an 18th Century Sewing Box with Tortoiseshell Veneer,” by Lori Trusheim.

Trusheim’s presentation clearly guided listeners through the processes involved with the treatment of a sewing box in a private collection. This talk addressed the main conference theme of the AIC meeting and explored how the Code of Ethics can be applied to aid treatment decisions. I particularly enjoyed how thoroughly Trusheim outlined the steps involved with procuring replacement materials, as well as how the owner’s expectations have influenced the treatment.

 

New Sensor Network Protecting Art in NY Museum

In this photo provided by the Metropolitan Museum of Art, Paolo Dionisi Vici, associate research scientist in the Department of Scientific Research at The Metropolitan Museum of Art, left, and Hendrik Hamann, Research Manager at IBM, discuss a new environmental sensor system that will be deployed at the Clositers Museum in New York, Tuesday, June 7, 2011. Hamann holds an example of one of the sensors that will monitor the climate in the museum and help preserve its walls. (AP Photo/Metropolitan Museum of Art)

NEW YORK (AP)The Metropolitan Museum of Art is announcing Thursday that a network of wireless environmental sensors designed to prevent damage to the collection is being tested at its Cloisters branch.

Read more about the new monitoring program and the need for climate control for the collections in the June 8, 2011 Associate Press story by Jim Fitzgerald on the AP website.

39th Annual Meeting-ECPN Informational Meeting, May 31, 2011

The ECPN Informational Meeting had a wonderful turnout of more than 50 people.  Chair Rose Cull and AIC Staff Liaison Ryan Winfield indicated that there has been a good response across the AIC membership to what ECPN has accomplished so far, and recognition of its importance, vitality, and growth.

 

Announcements

Chair Rose Cull announced that there would be three upcoming vacancies on the ECPN committee: the Chair, Vice-Chair, and Outreach Coordinator positions.  Position descriptions will be posted online and will appear in the AIC News.  The positions will be filled in September.  The minutes from the previous meeting on 5/19 were also approved.  Minutes are published on the ECPN blog following approval.

 

Communications

Communications Coordinator Amy Brost asked everyone to take a look at the informational sheet about ECPN in the conference bag.  The sheet provides the URL of the group’s blog (emergingconservator.blogspot.com) and Flickr page (flickr.com/groups/conservators), as well as dial-in information for participating in the group’s monthly conference call (866-225-4944, conference ID 9992396916).  The call takes place on the 3rd Thursday of the month at 1 pm ET.  Everyone in the room was encouraged to take part in a future call.  The next call will be on June 16.

 

Amy advised that emerging conservators are being invited to help with the development of the Specialty Group Wikis.  There are also opportunities for emerging conservators to write book reviews for JAIC and other online publications as long as they have sufficient expertise on the topic.  This will be the topic of a future blog post on the ECPN blog.  Amy indicated that the group will work in the coming year to connect pre-program  and emerging conservators with regional conservation centers to enhance ECPN involvement in regional Angels Projects.  She encouraged everyone to see the ECPN poster in the Exhibit Hall and make a note of the contact information provided for the Chair and the committee Coordinators in order to follow up later with any questions, or to volunteer.

 

Outreach

Outreach Coordinator Heather Brown encouraged attendees to visit the Facebook page, which has roughly 325 members, 100 of whom have joined since August.  She also encouraged everyone to post their photos to the group’s Flickr page.  They could be photos from the AIC meeting, but they could also be photos from other AIC or conservation-related events or workshops.  The group would like to have a lively dialogue on the Facebook page and expand the assets on Flickr, so everyone was invited to contribute.  Heather urged everyone to consider blogging about their conservation experiences.  Rose indicated that anyone interested in creating content for the blog could reach out to her or Ryan to be set up as an author.

 

Heather is actively soliciting input from everyone about possible topics for webinars and podcasts.  Some initial ideas could include how to create a conservation portfolio, or how to set up a private practice.  She encouraged everyone to consider what they are hoping to learn through ECPN.

 

Education & Training Co-Coordinators Amber Kerr-Allison and Caroline Roberts shared an overview of the proposal to develop an online student research repository.  This repository is on the agenda for discussion with the graduate program leadership during this week’s annual meeting.  Some of the issues that will be discussed include: types of documents to be included (although the goal is to provide abstracts as well as full text), the submission and vetting process, hosting, and copyright issues.

 

Another exciting program that was established a few years ago but is now hitting its stride is the Mentoring Program.  Ryan Winfield indicated that the mentor-mentee matches made so far have generally been successful, but that there is a shortage of mentors.  Roughly 20 more mentors are needed to match to the current mentee applicants.  The AIC meeting presents a good opportunity to ask someone you admire to consider serving as a mentor.  Mentors need to have Professional Associate or Fellow status in AIC.  Ryan encouraged anyone who had applied to be a mentee but had not heard back to please be patient until more mentors could be identified.  They can also get in touch with Ryan or Rose to discuss further.

 

In the coming year, the group is hoping to identify one or more Graduate Student Liaisons to each of the American training programs.  This will give AIC and ECPN a “point person” for reaching current students about opportunities.  As ECPN becomes more visible and productive, more of the AIC membership thinks of reaching out to the group, and having designated liaisons will help streamline communication.  This designated liaison model may be effective for connecting ECPN to the regional conservation centers as well.

 

Lastly, everyone was especially encouraged to participate in the Portfolio Session on Thursday, June 2 during the morning and afternoon breaks.  This is a rare chance to see portfolios from all stages – pre-program, graduate, and emerging professional.  This event is new for 2011.

 

Q&A

There were many questions about the online student research repository, but because the idea is still in the proposal phase, many details of how it will work are not yet known.  The outcome of the discussion with the graduate program leadership may be discussed in ECPN’s June 16 call, in which everyone was invited to participate.  Others were curious about the group’s connections to emerging professionals in related fields, and indeed, strengthening those connections is a goal for the coming year.  Some inquired about the international reach of ECPN.  The group has a liaison to the ECC-CAC, Stephanie Porto, but aside from Canada, ECPN does not have a liaison to any other country.  Some asked about qualifications for involvement in ECPN.  The committee coordinators range from pre-program to graduate students to emerging professionals, so anyone is welcome.

 

Closing

Amber and Amy encouraged everyone in the room to find some way to be involved, whether by taking on a position on the committee, or by helping with one specific project.  The group welcomes new ideas and is made better by ongoing input from everyone in the room.  The more people who get involved, the better ECPN can be.   Rose collected everyone’s email address and will send a follow-up survey to see how everyone felt about the ECPN sessions and events at this year’s meeting.  Everyone was invited to ECPN’s Happy Hour on Friday from 6-10 at McGillin’s Olde Ale House.

39th Annual Meeting – Architecture/Research and Technical Studies Joint Session, June 3, Consideration of Infrastructure in the Assessment of Historic Fountains by Thomas J. Podnar

Thomas J. Podnar opened with a picture of an anonymous fountain to illustrate the beauty of these structures and their ability to bring beasts together (displayed by horses drinking from the fountain). The talk consisted of three case studies which are summarized below.

The Probasco Fountain in Cincinnati, Ohio (c. 1887) was the subject of the first case. The fountain consists of Quincy granite with a polished bowl and a bronze top. The fountain was located precariously close to an existing roadway, and Podnar was hired to evaluate the condition of the fountain and explore the feasibility of moving it to a safer location. During an investigation of the interior cavity, he found a water main running through the chamber and an electrical box, which was added for display lights. Research of historic photographs revealed that the water display had been diminished and that it was missing elements such as drinking cups. In the end the city decided that it was cheaper to move the alignment of the road (slightly), and the fountain remains in the original location.

The second case study subject was the Athena Tacha in Cleveland, Ohio (c. 1985). The stepped granite fountain was designed to be ½ wet and ½ dry (the latter for students to perch upon). After running for eight years, the fountain was shut off due to issues with water leaks. A condition assessment found that the adhesive sealant, used to control water, had failed and resulted in water leaking to the dry side. Mineral deposits were also found on the stone’s surface, other conditions included broken pipes, corrosion, and inadequately sized equipment. The client also shared photos taken during the installation process, and Podnar noticed that it was the middle of winter. Low temperatures had also caused poor bonding of the stone to the continuous mortar bed. A full re-installation and equipment upgrade was recommended and subsequently executed. Stones were removed and labeled, and when re-installed provisions were made for water seepage to flow to the pool (at the base) and stainless steel clips were added to reinforce connections. Custom-fit pieces of sheet metal were installed to separate the wet and dry sides. The mechanical system was fully replaced (upgraded) and the access grate was designed to match the existing (granite) in galvanized metal, rather than stone, to facilitate maintenance with a lighter unit.

Voyage of Ulysses on Sixth Street in Philadelphia (c. 1977) was the subject of the final case study. The stainless steel fountain was fabricated by Lippincott and designed by David von Schlegell. During the condition assessment, Podnar found that the clear coating (applied to the metal’s surface) is failing and that the water display has been diminished (when compared with historic photographs). The fountain installation is located over a parking garage, and is leaking into it. The mechanical system consists of separated pumps for the two different display elements (high water throw on one side and a continuous waterfall on the other). Other findings include that the screen strainer has never been removed during maintenance and that over the years pumps were replaced with smaller ones. Podnar shared historic photographs taken during fabrication of the artist testing the water flow at Lippincott, emphasizing the importance of water flow in this fountain’s design. Conservation treatments are planned and have not yet been executed.

39th Annual Meeting – Research and Technical Studies Morning Session, June 2, “Acoustic Emission for Tracing Damage Directly in Works of Art” by Lukasz Bratasz

Acoustic emission measurements use microphones, amplifiers, and computers to detect and record the release of elastic waves during stress relaxation processes within materials, such as crack propagation at both the macro and micro scales. This talk discussed how acoustic emission (AE) has been used to track these processes in wooden and stone objects under varying levels of relative humidity and outlined how such studies have been used to generate and validate RH guidelines.

During AE experiments, the microphones are positioned against objects mechanically, without the need for glues or clamps, and environmental noise can be determined when there is sufficient distance between two sensors. It is important to note that recording AE monitors internal stress-relieving processes in real-time but is not able to predict when damage may occur.

The AE from wooden cylinders was found to depend on both the change in RH and the rate at which this change occurred. Mild changes in RH applied over 48 hours, for example, did not lead to detectable acoustic emissions. Monitoring the AE of a wooden altarpiece in a church lead to the establishment of expanded RH guidelines of 35 – 60% RH.

AE studies have also been performed on clay-containing sandstones similar to those found in medieval cathedrals. The studies monitored the sandstone’s response to damaging wetting-drying cycles and detected a linear AE increase with the number of cycles. The results of this study, in conjunction with predicted climate data, were used to anticipate areas of Europe in which clay-containing sandstones may be at particular risk for damage.

39th Annual Meeting – Research and Technical Studies Morning Session, June 2, “Listening to Art: An Exploration of the Use of Photoacoustic Infrared Spectroscopy in the Forensic Analysis of Artists’ Pigments” by Ian Butler

Dr. Butler described in this talk the potential use of Fourier transform photoacoustic infrared spectroscopy (FTIR-PAS) to identify organic and inorganic pigments. In their commercially available device, the sample is placed in a gas filled cavity and exposed to periodic flashes of infrared light. The sample absorbs the radiation and heats up, causing the surrounding gas to expand. The expansions can be detected as sound waves by a microphone at the end of the cavity.

The technique has been used to obtain reproducible IR spectra of pure pigments in the range of 400 to 4000 cm-1 with a resolution of 8 cm-1. Samples from lab-prepared frescoes have also been analyzed. In some cases the background noise from the plaster overwhelmed the pigment spectra, but in others the spectra could be used for pigment identification. Dr. Butler mentioned the possibility for depth-profiling, which may allow for more complex samples to be analyzed. Such work has not yet been carried out.

This method can also add some useful peaks to a regular FTIR spectrum, making it another useful option in conservation science’s identification tool-kit. Only small samples are needed and minimal preparation is required, an advantage over the commonly used ATR (Attenuated Total Reflectance) technique that may call for the sample to be crushed.

39th Annual Meeting – Research and Technical Studies Morning Session, June 2, “Medical Computed X-Ray Tomography and Volumetric Reconstruction for the Technical Examination of Organic/Composite and Ceramic Objects” by JP Brown

This talk presented case studies to demonstrate the application of computed tomography (CT) scanning to archeological objects. According to Dr. Brown, CT is usually available in most hospitals and can often be used for free in the evening. JP recommended first taking a regular x-ray of the object to elucidate its general construction. He did not go into details about the technical aspects of CT and image processing; however, this topic was covered by Hai-Yen Nguyen’s talk earlier in the session (An Open-Source Workflow for the Visualization of CT Data in Art Conservation and Archaeology).

Resolutions of 0.3-1.0 mm can be obtained by CT. The results are presented in Hounsfield units (HU), a scaled measure of the attenuation of radiation due to the material. Water is defined to have 0 HU, while air is defined to have -1000 HU. Typical HU values for metal and bone are 3000 HU and 1000 HU, respectively. Many image-processing techniques, such as the application of false-color, rely on the different HU values of different materials.

Case 1: Animal mummy

The CT images clearly showed that a piece had been inserted into the mummy, probably to hold the head at a desired angle. The detail obtained of the skeleton allowed for the species to be identified as a type of gazelle common in Egypt.

Case 2: Polychrome Japanese sculpture

The CT showed the grain of the wooden object in great detail, enough that non-invasive dendrochronolgy could be possible. This piece demonstrated the problem of having highly attenuating materials in the object – the bright images caused by leaded glass eyes obscured some of the nearby details. However, false-color rendering was able to show areas of gesso and older conservation treatments on other areas of the sculpture.

Case 3: Moche pottery

One of the aims of this study was to check for the presence of organic residues inside the vessels. This was done by comparing the HU values of the pots to those obtained from samples of various modern food residues. Although the CT of one of the pots did not indicate that food residues were present, the image showed a pattern of holes suggesting that the vessel was designed to produce sound from blowing air. A second pot was simply a conch shell, and the CT confirmed the expected internal structure. Interestingly, material inside a third pot did indeed exhibit attenuation values matching those of the test food samples. The material was subsequently collected on a swab, and SEM images indicated that the organic material was likely charred plant stems.

Case 4: Restored archeological stucco (possibly Sasanian)

The sculpture depicted the head of a king. The crown portion of the object, the shape of which could be used to identify the specific king, had been largely restored. Although it was possible to visualize only the original material by manual segmentation of the restored portions, not enough of the original remained for the identity of the king to be determined.

Several interesting points were raised during the question portion of the talk. It is known that x-rays affect the results of thermoluminescence (TL) dating, though it is not known to what extent. As a precaution, JP recommends removing a sample before CT scanning if TL may be performed later. Another interesting question regarded recommendations for approaching a hospital. JP suggested contacting the chief radiologist first, or ideally, finding a teaching hospital with a research radiologist. He mentioned that eventually an administrative/financial person will also need to be contacted and that having an exciting story about your proposed work will increase the chances that the hospital allows use of their CT machines.

39th Annual Meeting – Research and Technical Studies Morning Session, June 2, “An Open-Source Workflow for the Visualization of CT Data in Art Conservation and Archaeology” by Hai-Yen Nguyen

This talk discussed how open-source image-processing software can be used to manipulate data obtained from computed tomography (CT) scans of objects. In this technique, radiographs are taken around an axis of rotation, and the three-dimensional volume of the object is virtually reconstructed. From JP Brown’s talk (Medical Computed X-Ray Tomography and Volumetric Reconstruction for the Technical Examination of Organic/Composite and Ceramic Objects), we learned that it is relatively easy to gain free access to CT equipment at local hospitals. However, as  Hai-Yen pointed out, the proprietary software for processing the data can cost around $15,000. By using several open-source programs, she and her co-workers were able to obtain quality images highlighting various aspects of the object under study.

CT images of a corroded metal artifact in a tub of water were presented at various stages of processing with different software programs. A median filter was applied in ImageJ to reduce noise. Most other processing applications were performed in ImageVis3D, including thresholding, slice analysis, and manual segmentation. The 16-bit raw tiff file formal was considered the most user-friendly for transfer between the software systems.

After the initial data processing, Hai-Yen demonstrated the use of false color to clearly show different types of material and used clipping (masking) to isolate certain features. Once a complete 3D rendering is obtained, it could potentially be used to create a physical model of the artifact without the need to dry out and clean the original.

Disclaimer: Neither of us bloggers has ever done CT or this type of image processing, so we may have missed salient details. Feel free to add information in the comment section below.