Call for topic-focused sessions and pre-sessions – AIC 2019

Greetings, colleagues! I hope your summers are off to a good start. We are now taking session proposals for AIC’s 2019 annual meeting. I know you get a lot of email, so in case you missed the call for proposals, all the info you need is below. Ruth and I hope to hear from you! We are both travelling this month, so if we don’t write you back immediately, don’t feel downhearted. We’ll be in touch as soon as we can.

2019 Meeting Theme

New tools, techniques, and tactics in conservation and collection care
Are conservation professionals innovators? We think so. From developing new approaches to conservation treatment and preventive care, to utilizing cutting-edge technological research, to examining how cultural heritage is defined and valued, conservation professionals are innovative, dynamic, forward-looking agents of change. And, how does collaboration with related fields and allied professionals influence the dynamics of the conservation – innovation process? We seek papers that explore all types of new work: practical, method-focused treatment projects; advances in collections care and management; discoveries in conservation science; and conservation initiatives that intentionally have a positive impact on communities.  In 2019, let’s come together to share new ideas for solving conservation and collections care problems large and small.

Call for sessions at the main meeting
Do you have an idea related to “New tools, techniques, and tactics in conservation and collection care” that would make a great, topic-centered concurrent general session? If so, please email AIC Vice President and General Session Program Chair Suzanne Davis at Include a tentative title, the program format, and a brief description of what subject(s) will be addressed; multi-disciplinary topics are encouraged. Members proposing sessions must be willing to serve on the General Session Program Committee. The deadline for submissions is June 28, 2018. For questions or to learn more, write Suzanne.

Call for Pre-session/Special event proposals
Do you have an idea for a pre-session event that is not exactly a workshop or tour? If so, please let us know! Just email AIC Meetings and Advocacy Director Ruth Seyler at with your thoughts on pre-session events. Calls for tours and workshops have gone out separately, but in case you missed those, please send them along to Ruth.

Abstract submissions should be no more than 500 words with an additional 300-word speaker biography and will be due on or before September 15, 2018. In mid-July, an email will be sent out with more detailed information including a link to AIC’s abstract submission portal.

For more info about the 2019 Meeting
View the results of our 2019 Annual Meeting Themes Survey to see how the theme was selected. For more information on the Greater New England location concept and the Mohegan Sun Resort, visit our 2019 Annual Meeting website.

45th Annual Meeting – Workshops, May 28-29, “Reading Between the Lines: Understanding Construction and Exhibit Design Drawings” – Collections Care Network

I participated in the “Reading Between the Lines: Understanding Construction and Exhibit Design Drawings” workshop along with 12 other conservators. During the introductions, we learned that the participants come from all over the country and as far away as Taiwan and Australia. Many had signed up in order to prepare ourselves for upcoming major renovations or new construction in our institutions. The workshop was taught by four instructors: Jeff Hirsh (Architect, Principal, Director of Cultural Practice at EwingCole), Bill Jarema (Principal, Mechanical Engineer at EwingCole), Angela Matchica (Principal, Electrical Engineer and Lighting Designer at EwingCole), and Mike Lawrence (Chief of Design at the Smithsonian National Museum of Natural History). EwingCole, an architecture, engineering, interior design, and planning firm, has worked extensively with museums and other cultural and research institutions. They recently collaborated with Mike Lawrence and Cathy Hawks (Museum Conservator at the NMNH and a participant and organizer of this workshop) on building the Q?rius Learning Space at the Smithsonian National Museum of Natural History, a permanent exhibition space in which visitors can engage with the museum collections through hands-on interactions. Much of the materials that were used in the workshop – drawings, specs, images, and group exercises – are documents from the Q?rius project.

The workshop covered a lot of ground, filling two full days during which we plunged into the complex world of construction projects. The workshop utilized a mixture of powerpoint presentations, tabletop exercises, and both planned and impromptu Q&A sessions to guide us through each step of the renovation process and help us to understand different types of construction and exhibit design documentation.

Day 1: Introduction to stakeholders, phases of design, basic terminology, reading mechanical and electrical drawings

We began with an overview of the stakeholders in a given construction project and the progression of projects from start to finish. I found it very helpful to learn about the types of documentation created during the various phases of planning and what level of detail can be expected from each phase. For example, a project starts from a concept report, which narrates the scope, timeline, and intent, progress to schematic designs, then to more detailed design development drawings, and finally to construction documents, which will go out to contractors for bidding. This lesson was supplemented by a tabletop exercise that asked the participants to find light temperature information among documentation from various phases of Q?rius design process. The exercise helped to drive home the importance of becoming a stakeholder and communicating preservation priorities at an early stage of the project, since it is becomes increasingly more costly and difficult to make revisions as the project progresses.

In the morning, we also learned basic terminology and symbols found in drawings. Because depicting the numerous things that are happening in a space – both inside and outside of the walls – is so complex, multiple drawings representing various levels of detail, multiple perspectives (elevation, plan, section), and specific categories of information are necessary. These drawings are supplemented by written documentations such as indices, keynotes, and specifications to convey the full scope of information. A reviewer must understand the system of symbols used as shorthand to indicate important information such as past edits, recent changes, the location of detail drawings, and demarcations of areas slated for demolition. At the start of the workshop, Jeff Hirsch had introduced the building as “a tool for preventive conservation”, and as the session progressed, I found it increasingly more helpful to think of the drawings as a set of instructions for using a very complex tool – in our case we are looking for ways to maximize the building’s ability to support collections preservation.

In the afternoon, we delved deeper into the different types of construction drawings by examining the general, architectural, mechanical, and electrical drawings, which each come with their own system of symbols that are used to communicate a wealth of meaning. Despite the sometimes daunting complexity of the drawings, it became clear that they follow a very specific and consistent order. I learned that when reviewing the drawings, it helps to understand them as both a set of instructions for the contractors and a legally binding contract for all stakeholders. As the latter, edits and revisions are closely tracked from version to version. Successful drawings clearly, thoroughly, and accurately communicate the scope of the project, including what is being demolished, what is being built, and what materials are being used for construction. Since each drawing can contain an overwhelming amount of information, approaching them with specific questions in mind makes them easier to navigate.

Some examples of information a conservator may need include: Do the edges of a demolition space impinge on existing collections? What are the fire ratings of the partitions slated for use in collections storage spaces, and will the fire rated partitions be fully enclosed (they must be in order to be successful)? Are there flammable materials sharing a wall with collections storage? Are smoke detectors and sprinklers located in appropriate areas? Are there enough outlets reserved for housekeeping, and are they readily accessible? What types of light sources are being used and how will they be controlled? If a new HVAC system is being installed, look to the mechanical schedules for the system’s ability to provide humidification/dehumidification and filtration information, and to the control chart for set points. Finally, with all systems that require maintenance and upkeep, it’s important to consider their proximity to collections materials, the frequency of maintenance, as well as space needs of associated personnel and equipment.

Day two: preventive conservation, exhibition design, and Q&A session

On day two, instructors began with an example in which the design team and conservators collaborated to identify an optimal pathway to move collections between the freight elevator and the Q?rius exhibit at the Smithsonian NMNH. An ideal pathway was not available, so the team mapped various options on the floor plan and used color coding to identify areas with issues such as security, access, and cleanliness. The drawing was supplemented by a filmed walk through of the actual path, which communicated potential issues with a clarity and immediacy that was difficult to convey through other media. I liked the way this example underscored the ways in which preventive conservation often relies on collaboration among parties with specializations beyond conservation, and that it focussed on an aspect of the environment – pathways – that is often overlooked when thinking about preventive conservation.

This followed with a tabletop exercise to find the outlets in the the drawings for the Q?rius space, which drove home how sometimes the little things can make a big impact on the maintenance of a finished space. In this case, it was important for us to consider the amount and location of outlets designated for a new space to make sure that enough are available for both display cases and for housekeeping use. In addition, we had to consider the accessibility of outlets for housekeeping and deduce from the drawings whether staff had to crawl into the base of display cases to reach outlets, for example. Through this exercise, we also learned that it was often necessary to switch between different sets of drawings (in this case, between electrical and exhibitions) because the information we needed was covered by overlapping specializations.

Moving further into the world of exhibition design drawings, we examined ways in which an existing space can be slightly modified to provide better climate collections objects. For example, Mike discussed an instance in which he built a vestibule as a means of limiting air exchange to an exhibit space that is located close to exterior walls and windows. In these instances the contractor schedule would be the place to look for information regarding the types of doors that are designated for use in a space.

Mike also walked us through the ins and outs of looking at drawings of custom exhibit cases, which provide detailed information on what can and cannot be done. I took a lot of notes here of factors that are important in the final product, such as: glass size (may be swapped to a different type without notice), acceptable deflection amount, potential need for levelers, desiccant chamber capacity (consider the climate of space that the case is going into), presence/type of lighting inside the cases, type of gasket used (does it actually press against the other side?), presence and composition of adhesives inside case. Getting custom cases sounded like a taxing process that was further complicated by the case builder’s use of proprietary materials.

The workshop concluded with a lively Q&A session that was populated by both questions that were pre-submitted by participants and by impromptu questions. Instructors and participants discussed questions relating to fire coding in collections and user spaces, condensation in air diffusers, preparing for a new building to be added to a museum, and considering the efficacy of using inhouse vs. outside consultants on construction projects. All in all, the workshop covered a lot of ground in two day period and offered a wealth of information that I was happy to bring back to share with my colleagues in preparation for our own renovations. I certainly felt more prepared and informed when our own construction drawings arrived at my desk several weeks later.

45th Annual Meeting – Luncheon, May 30, “Protecting the World’s Cultural Heritage: Identifying and Protecting Looted Artifacts” by Oya Topçuoglu, L. Burgess, and Dawn Rogala

Looted or stolen artifacts are a concern all over the world. The speakers at this luncheon focused on looting in the middle east, cases of illicit imports, and notable museum thefts. As a curator and conservator of Native American artifacts, however, I found much of the talk was relevant to the looting that happens right here in the U.S., albeit on a smaller, less industrial scale.

The first talk, by Oya Topçuoğlu, was riveting. For one thing, the demonstration of the sheer scale of looting happening in the middle east was incredible (see photo below).


On 4 August 2011 (left ), the soil at Dura-Europos is relatively undisturbed both inside and outside the walled city. On 2 April 2014 (right), however, very high-density looting is present inside the ancient city wall, while portions of the archaeological site beyond the city wall have been covered with thousands of individual pits. A number of vehicles (circled in red) are visible within the walls of the site. Coordinates: 34.74 N, 40.73 E. Image ©DigitalGlobe | U.S. Department of State, NextView License | Analysis AAAS. -

The scale of looting and tracking of antiquities is virtually impossible to quantify, partly due to the dangers of getting people on the ground in areas of conflict, but Oya and her colleagues have begun to address some key questions in the quest to put an end to such activities, including: Where does the looting happen? How do we identify it? Who is involved in looting, trafficking and sale of antiquities? Where do looted artifacts go, how do they get there? Who are the buyers? Where do sales take place? What is sold for how much? What can we do from the safety of our offices, universities, museums, etc.?

She noted that the so-called Islamic State (IS) is not the only party doing the looting but that such activities are most prevalent in IS controlled areas. Sales are conducted through online auction sites and the dark web. Documents are often falsified and regularly contain a stock phrase such as “Property of (or from the collection of) a London (German, Swiss, etc.) gentleman. Acquired in the 1980’s.”

The question I was really interested in was “What can we do?”. For tracking artifacts stolen from museums, for example, new substances are becoming available like “smart water,” an invisible polymer than can be traced back to a certain batch. She notes it is also important to adequately train law enforcement, both local and international, to recognize antiquities. Finally she discussed a project called MANTIS (Modeling the Antiquities Trade in Iraq and Syria) about which more details can be found here:

Looting at American archaeological sites is on a much smaller scale and probably does not fund major terrorist organizations but this talk made me think about how important it is to track the sales of antiquities and do whatever we can, including training law enforcement, to halt the illicit trade of the world’s cultural heritage.

The next speaker L. Burgess, was a lawyer who discussed issues that lawyers deal with like title, authenticity, and provenance. She highlighted some of the more famous art heist and illicit import cases. Again she pointed out the issue of falsified documents such as in the Steinhart case from the mid 1990’s in which a million dollar 3rd-4th century BC Sicilian gold phiale from Italy was claimed to be from Switzerland and worth only $150,000. She also talked a bit about repatriation and mentioned that she feels institutions are moving toward long term loans rather than transfers of ownership.

Finally, Dawn Rogala talked about some of the things to think about if you are approached to work with legal cases dealing with repatriation, art theft or forgery. She discussed what it means to be a subject matter expert, for example, you must be willing to testify. She mentioned questions you should ask yourself like, are you even allowed to testify or do job restrictions, for example, prevent it? Are you actually qualified? She says you must ask agents what is expected of you. And of course, ask yourself do you have time to do this? She also went over what language to use, how to write reports, and general things to be cognizant of.

Overall the themes of the luncheon were crucial for many people in our field. It was odd to juxtapose the discussion of war-zone looting with the delicious lunch we were eating in the comfort of a plush conference room but the luncheon format did allow some good open discussion and, frankly, kept me from getting too depressed when thinking about the vast scale and impenetrability of the illicit antiquities trade.




45th Annual Meeting – Workshop, May, 29, 2017, “Effectively Using Portable IR and Raman Instruments for Art Object Analysis,” presented by Francesca Casadio and Tom Tague

My personal area of interest and intended future practice is in the conservation of historic interiors. Therefore, I am always keen on portability both in tools and materials as well as forms of analysis. The other advantage to the techniques presented in this workshop is that physical sampling is not required, which is always attractive and music to a curator’s ears.

The workshop met my personal expectations, but the title “Effectively Using…” could have suggested to some that this was going to be more of a “boot camp” for being able to implement these techniques back home. This style of workshop was more of an information/demonstration session and is great for anyone considering buying similar instrumentation and/or for gaining a better understanding of the general benefits and limitations of portable spectroscopy.

Given the short duration of this workshop, I was initially concerned that I might have signed up for a 2 ½ hour lecture without any hands-on component. Participants were encouraged to bring our own samples and indeed at least an hour was dedicated to looking at samples and exploring the instrumentation first-hand. Although we did run over the scheduled time, and were gently shuffled out of the room as hotel staff started to break down tables.

The workshop was led by Tom Tague, Ph.D. Applications Manager at Bruker, and Dr. Francesca Casadio, Director of the Conservation Science department at the Art Institute of Chicago. I really appreciated having these different perspectives. Tague did not assume the role of salesperson during the workshop, but as you would expect he was very positive in his description of the capabilities of the Bruker instrumentation. Casadio kept Tague grounded in the realities of our complex samples and what can be confidently identified using these techniques. At the same time, it was useful to have Tague there to speak to the specifics of the instrumentation and push Casadio a little bit to consider what some of the newer technology could offer. There was also a Bruker sales representative present to assist with running the instrumentation and software and offer information on pricing.

Overall the session was well organized. I know I was not the only attendee who was ecstatic that I got to take home a flash drive loaded with the presenters’ PowerPoint slides. The spectra from my samples that were analyzed were also loaded directly onto this flash drive before the end of the workshop.

The first part of the session did consist of pure lecture. Tague’s presentation focused on specifications of the Bruker portable instruments and descriptions of the techniques.

An interesting tip he offered was using sandpaper to take surface samples. He lightly abraded a painted surface and then placed the sandpaper in front of the portable FTIR (ALPHA)—no additional sample prep necessary.

Having just completed my Master’s degree in conservation I was able to follow the presentation fairly well, but I fear that it may have been overly technical and too fast for someone who does not work with these analytical techniques on a regular basis. Nonetheless, I anticipated this to be an intermediate-level workshop when I signed-up.

Tom Tague in front of demo table at the workshop. He has rotated the ALPHA in front of him so that the laser beam points downward and is working to raise the ALPHA up on some shims in order to fit the sample under the beam at the correct working distance.


As would be expected based on the organizers of the workshop, the instrumentation provided and discussed were all Bruker models. Two ALPHA portable FTIR spectrometers were present. The ALPHA is set up to receive different “snap-on” modules. The two modules available for demonstration were the “External Reflectance” module and the “Platinum ATR” module. The BRAVO Handheld Raman spectrometer was also available for interaction.


Here are some key facts about each instrument:


The base ALPHA starts around $14,000 and each module is on average $6,000 in addition.




ALPHA “External Reflectance”

  • Does not require direct contact with a sample/object
  • No size limitations as long as unit can be mounted/held in appropriate orientation to the sample

    ALPHA “External Reflectance” being used to analyze paper currency. This example was given in Tom Tague’s presentation.
  • Camera integrated in unit to help orient, find appropriate working distance/focus, and document sample location
  • Collects reflectance spectrum NOT absorbance
    • Can collect specular and diffuse reflection; reflective and non-reflective materials can be analyzed
  • Footprint of instrument is about 8” X 11”
  • Weighs about 13lbs.
  • Can be tethered to a laptop
  • About 6mm sampling area
  • Approximately 4cm-1 spectral resolution

ALPHA “Platinum ATR”

  • There is pressure/direct contact with the sample
  • The IR beam does penetrate into the sample

BRAVO Handheld Raman

  • $45,000-$55,000
  • Slightly narrower than 8” X 11” (looks like an oversized ELSEC environmental data monitor; less heavy than the Alpha)
  • Class I safe laser
  • 2mm sampling spot size
    • No camera or viewing capability to help align collection area
  • Object needs to be in contact, but no pressure required
  • Approximately 8cm-1 spectral resolution
  • Fluorescence mitigation built into software/data collection
  • Dual lasers built in and used/activated simultaneously
    • Optimal wavelength and reduced risk of damaging sample
  • Touch screen allows for control and data collection without tethering to laptop
    • Tethering also capable via WiFi to laptop
Example from Tom Tague’s presentation of the BRAVO being used to analyze medieval manuscripts at the Morgan Library and Museum.


In terms of the ALPHA “External Reflectance” one of the big selling points is that there is no size restriction or need to balance the object on a stage. The trade-off in allowing data collection without physical sampling is that the spectra generated are in % reflectance. The majority of reference spectra available for free and through the Infrared and Raman Users Group (IRUG) are % absorbance or % transmittance (its inverse). The Bruker software does offer the capability to convert the data using the Kramers-Kronig Transformation. Francesca Casadio seemed to prefer to analyze data from its original state in reflectance. Characteristic peaks for bonds are slightly shifted from their location in transmittance spectra, but at Casadio’s level of experience she is able to take these nuances into account with some ease. She was honest with the attendees summarizing that this form of IR spectroscopy is “not like portable XRF; one needs to have experience and repetition for familiarity with interpreting spectra.”

For those interested in more on interpreting reflectance spectra of art objects Casadio recommended the following publications from a research group in Perugia Italy:

“Reflection infrared spectroscopy for the non-invasive in situ study of artists’ pigments.” C. Miliani, F. Rosi, A. Daveri & B. Brunetti, Appl. Phys. Mater. Sci. Process. 106, 295–307 (2012) (
“In Situ Noninvasive Study of Artworks: The MOLAB Multitechnique Approach.” C. Miliani, F. Rosi, B.G. Brunetti & A. Sgamellotti, Acc. Chem. Res. 43, 728–738 (2010) (
“Non-invasive identification of metal-oxalate complexes on polychrome artwork surfaces by reflection mid-infrared spectroscopy.” L. Monico, F. Rosi, C. Miliani, A. Daveri & B.G. Brunetti, Spectrochim. Acta Part -Mol. Biomol. Spectrosc. 116, 270–280 (2013)
“In-situ identification of copper-based green pigments on paintings and manuscripts by reflection FTIR.” D. Buti, F. Rosi, B.G. Brunetti & C. Miliani, Anal. Bioanal. Chem. 405, 2699–2711 (2013)


It is important to keep in mind the basis of data collection to understand the limitations of what can be analyzed with the ALPHA “External Reflectance” on a given object. For example, with a varnished painting the spectral reflectance of the varnish will typically only allow the varnish itself to be detected (with some exceptions depending on thickness of the varnish and underlying pigment composition). Similar reflective material properties make plastics easily detectable with this technique. Matte objects are still good candidates for analysis with the ALPHA, but the data will be collected via diffuse reflection. The ALPHA does not seem like an appropriate technique for discerning between individual layers within a given structure unless coupled with other techniques.

One of the ALPHA’s at the workshop was supplied by Casadio from the Art Institute’s lab, and she has extensive experience using the ALPHA. Her presentation was more about working knowledge of the instrumentation. She polled the attendees and focused on case studies mainly of pigment analysis and identification of plastics. Casadio emphasized the benefit of the ALPHA as a mapping tool that does not require sampling. Perhaps one or two samples could be taken from a work of art and more confidently characterized with bench top FTIR and/or GC-MS and then the use of specific materials could be mapped without additional sampling using the ALPHA. Casadio’s case studies often combined multiple analytical techniques. She finds the ALPHA to be a nice compliment to XRF. Overall, Casadio has found the ALPHA to be very useful in characterizing different plastics and also good at detecting deterioration surface products (e.g. zinc soaps) especially with modern and contemporary collections. Casadio noted that the ALPHA detects very strong signal and peaks for waxes and PVA coatings. Casadio has been able to use the ALPHA for collaborations with other institutions and collections, which is another boon of its portability.

I was disappointed that Casadio had not had previous experience with the BRAVO Handheld Raman. At the Art Institute she has a bench top Raman unit. She seemed skeptical about the BRAVO’s capabilities and some of the claims that Tague was making that it could “see” indigo and other organic pigments without surface enhanced Raman spectroscopy (SERS). Casadio stated that in her personal opinion with Raman it is better to bring the art to the unit than the other way around. By the end of the workshop she did seem impressed with the quality of spectra the BRAVO was generating, but there was not enough time to have further discussion and to tease out Casadio’s candid opinion on the instrument.

I was most excited for the practical demonstration with the instruments especially because I had come armed with over 10 samples. I was anticipating that I may not even get to analyze one sample, but was very pleased that I was able to look at 7 samples with the BRAVO portable Raman. This much time with the instrument was due in part to many participants not bringing samples.

If a similar workshop is organized in the future, it might be good to have participants sign up ahead of time for slots with the instrument if they are interested in analyzing a specific sample. It was a fairly large group – about 18 participants. Attendees that did not bring samples were still interested in watching the process of collecting data and interpreting the spectra. This was challenging; even with three instruments there tended to be 5-7 people crowding around a laptop screen. Dividing us into smaller groups, having the laptops hooked up to a projection screen, or further limiting the number of participants may be additional considerations for future workshops.

It seemed like the majority of participants were conservators rather than conservation scientists. I personally do not work with spectroscopic techniques on a regular enough basis to be able to confidently interpret spectra on the fly. Francesca Casadio was able to offer her expertise and interpretation while working with samples from the participants, but neither Tom Tague nor his Bruker colleague could offer specialized interpretation. Some of the participants seemed frustrated that the instruments were not connected to an art materials database for instant gratification and matching.

Both Tague and Casadio strongly emphasized the importance of each institution building its own reference database specific to the collection. The IRUG database was promoted, but as a supplement to an institution’s own reference database. Neither of the instructors felt that the database that comes with the Bruker software was appropriate for art materials.

My personal goal during the workshop was to pit these portable instruments against their stationary counterparts and to pit the two complimentary techniques against each other. Therefore, I brought known samples from my institution’s reference collection of traditional paints. All the paints were oil-based and mixed with some degree of lead white. The reference pigments I chose were mostly organics (indigo, madder, cochineal). Colonial Williamsburg has had the opportunity to partner with the College of William and Mary in order to perform SERS on objects in the paintings collection. My colleagues and I were curious to see how this portable unit compared to spectra produced with SERS. With the minimal time, I chose to focus on the BRAVO because our institution already has a bench top FTIR.

Tom Tague was set-up at the BRAVO “station” during the practical session, and as I stated previously he was not comfortable offering any interpretation of the data. I was excited to review the spectra we collected back at my home institution (Colonial Williamsburg Foundation/CWF) alongside Kirsten Travers Moffitt, the conservator in charge of our materials analysis lab. Moffitt performs a lot of FTIR analysis on our collection, but has less experience with Raman.

All the organic paint spectra from the BRAVO were certainly “neater” than what I am used to seeing in terms of raw data from a bench top Raman with oil paint samples. I personally would attribute the quality of the spectra to the dual laser capability. I’m not sure how much impact the fluorescence mitigation had because the spectra were still pretty noisy and it was challenging even for Moffitt to distinguish significant peaks. It appears that the fluorescence of an oil binder is still problematic with the BRAVO. In Tague’s presentation he showed an example of indigo detection with the BRAVO, but this was on an illuminated manuscript, where fluorescence of the binding media would be less of an issue.

At CWF we only have a reference database for IR spectra, but looking at possible peaks in the indigo/lead white sample spectrum, the characteristic peaks for indigo that Tague mentioned (545, 1463, 1578) do not appear to be present. It seems that the lead white is dominant, with a strong peak around 1050. In conclusion, Tague is partially right that the BRAVO can detect some organic pigments, but likely only if they are present in high enough concentrations (not mixed) and are not in highly fluorescent binding media (like oil).

Spectra (representing a shorter and longer collection time) from the BRAVO of the CWF reference of indigo and lead white in oil.tic peaks for indigo that Tague mentioned (545, 1463, 1578) do not appear to be present. It seems that the lead white is dominant, with a strong peak around 1050. In conclusion, Tague is partially right that the BRAVO can detect some organic pigments, but likely only if they are present in high enough concentrations (not mixed) and are not in highly fluorescent binding media (like oil).

The other samples I looked at were reproduction wallpaper samples from Adelphi. I was curious to see if we could detect anything useful about the pigments on an object that would normally be challenging to sample and could not be brought to the lab if it were installed in a historic interior.

The resulting spectra were less noisy than those of the oil paint reference samples, again likely due to the non-oil binding medium on the wallpaper.



Spectra collected from two different greens on a wallpaper reproduction from Adelphi using the Bruker BRAVO. Peaks are labeled, but a match has not been identified.



Despite the better quality of the spectra, we still did not have the resources (i.e. a good reference database for Raman and experience working with Raman spectra) to confidently characterize the pigments present. I am sharing this to illustrate Casadio’s point that the ALPHA and BRAVO require a certain level of expertise and do not provide instant answers.

One of the other participants, Ann Getts, a textile conservator at the De Young Museum in San Francisco, brought various sequins from a costume in storage with a suspicious vinegar odor. Getts had time to look at one of the sequins with both ALPHA modules, and her case study demonstrates some of the trade-offs with the non-contact “External Reflectance” module.

She began with the “External Reflectance” module and the first hurdle was getting the instrument positioned at the appropriate working distance from the sample. Without an adjustable stand, we had to use trial and error to shim up the ALPHA so that the camera could focus on the sequin. The resulting spectrum suggested cellulose acetate (as suspected by Getts initially), but even Casadio still felt insecure about drawing any concrete conclusions based on this spectrum. Then the sequin was analyzed with the “Platinum ATR” module and right away Casadio concluded that indeed it was cellulose acetate.

Each of these instruments has their advantages and disadvantages. Overall the ALPHA seems like a good bang for your buck given the duality of the modules. The price point is pretty reasonable also considering the portability.

The BRAVO is fairly new technology and the dual lasers seem promising, but at this point it does not seem like a must have for the average institution. I would encourage anyone thinking about purchasing any of these instruments to consult with both of the workshop leaders.

Francesca Casadio using the ALPHA to analyze a Roy Lichtenstein painting installed on the wall.


In general I would specifically recommend the ALPHA to:

  • Institutions that have a lot of sampling restrictions
  • Institutions with a lot of oversized works
  • Institutions that focus on modern and contemporary art (especially with plastics and large Color Field paintings)
  • Institutions with a conservation scientist on staff


In general I would specifically recommend the BRAVO to:

  • Institutions that have a lot of sampling restrictions
  • Institutions wanting to focus on analysis of paper-based art
  • Institutions with a lot of oversized works
  • Institutions that already have staff with Raman expertise
  • Institutions looking to purchase a Raman instrument

This blog represents my personal conclusions and understanding of the workshop. I would encourage any of the other participants and the instructors to post in the comments if they have differing opinions or think that I have misunderstood any of the technical aspects of the instrumentation.

45th Annual Meeting – Workshop, May 29, “Building Emergency Response Skills”

Three veteran National Heritage Responders delivered an emotional and highly persuasive workshop (abstract) during this year’s AIC Annual Meeting.  Susan Duhl, Bob Herskovitz and Ann Frellsen, having spent many hours of hard labor together in the field during disaster response, spoke seamlessly as a complementary team, not completing each other’s sentences, but oftentimes each other’s thoughts.  They mentioned having lived together in an RV in Louisiana, smelly and tired…and clearly they have cleaned up their act and can take this show on the road.

As an active collections emergency responder for a large academic library institution, here are my key takeaways:

When responding to a disaster, we need to get to know local government agents, whose word is law and yet whose language is foreign to most conservators.  We can prepare for this by taking the FEMA Incident Command training, which introduces the vocabulary and the hierarchy of the world of the First Responders.  What we’ll get out of it is the ability to communicate with others and to understand our roles.  By the way, conservators are NOT First Responders…that term is reserved for the fire, police, National Guard and other official personnel whose priority is human safety.

Personal health has to be our #1 priority, because we’re no good to anyone if we’re injured or sick.  When there’s no electricity, there’s no Nilfisk, no fume hood, no suction disk, no light table…so we are going to McGyver our way through this thing with all our appropriate PPE on at all times.  Fresh air and sunlight go a long way when the alternative is standing in the dark, knee-deep in “mud.”  (I put that in quotes because the components of disaster area mud should be assumed to be everything you don’t ever want to ingest.)

Mental health of those around you is going to be a bigger concern than you expect or, indeed, want.  You can provide the sympathetic shoulder, the gentle persuasion to take a break, or even the diplomatic persuasion to a leader to move sideways and let someone else shoulder that burden for a while.  It can be hard to wrap one’s mind around saving cultural heritage when people around you have lost homes and loved ones, but in fact our role in rescuing their patrimony contributes to their healing.

Conservators with a bit of grit can survive and, in fact, thrive, in the extreme environment of disaster response.  We have to “think outside the lab,” and get creative to make the best use of what is available.  To take on leadership roles in a disaster response we have to stay calm and focused, and accept that we are surrounded by confusion.  We may be the only ones on site who know how to assess what is possible and what is practical. But we also tend to become superheroes and work to long and too hard.  I am really grateful for the specific language the instructors modeled for how to remove an Incident Commander (let’s get used to that ICS term for team leader) whose energy if not competence is flagging. “How are you doing?  You’re doing such a great job!  I notice you’re looking a little tired.  You’ve been working really hard.  What we really need right now is someone to sit down over here and fill out this inventory…can you help out with that?  One of us can hold the radio for a little while.”  You can’t just kick them out…instead, move them sideways, and then they’ll see that everything is going to be ok, and they can take a real break without feeling like they’ve abandoned their responsibility.

Our fearless leaders gave a lot of good tips and tricks.  Here is a sampling:

  • A Uhaul makes a decent workspace during the day and secure storage at night.
  • Don’t touch sooty things…any contact embeds the soot.
  • Fire extinguisher powder is corrosive and in a damp environment (i.e. from putting out the fire) it can become intractable.
  • Got earthquake?…Bring Ziplocs to keep the parts together.
  • Just say no to the “natural oils” used by some vendors for deodorizing; zeolytes work well, and charcoal is ok. Ozone oxidizes collections as well as odors, and should be avoided.
  • Also say no to vacuum thermal drying.
  • Don’t pump out a basement until the floodwaters have receded, or the hydrostatic pressure from the outside water could collapse the foundation.
  • Need weights?  Try double-Ziplock-bagged water, which conforms well to 3D surfaces.
  • Document anything that is being discarded so insurance will pay for it.
  • The answer to the question “How much mold is there?” is: “Yes.”

Want to be a part of this action?  Well, some of the National Heritage Responders are nearing retirement, so new recruits will be needed.  You need training first, and experience second.  Take FEMA’s ICS 100.b online training.  Watch Tara Kennedy’s Facebook Live recording on working with disaster recovery vendors.  Go to your regional Alliance For Response group (might be under a different name…ask the AIC Office) to join up with a local training opportunity.  And get to know the National Heritage Responders in your area…let them know you’re willing and able to respond.

Thank you to this team of veterans who have saved so many collections, and are now sharing what they know to give us all the tools to respond effectively.

P. S. I also attended the National Heritage Responders meeting after the workshop, and witnessed the official retirement announcement for Bob Herskovitz.  He’s retiring to his boat, so the group gave him a life preserver emblazoned with the name of his boat, “Ça Va Encore Bien.”

Improved Respirator Fit Testing at the AIC Annual Meeting

The Health & Safety Committee is happy to announce NEW and IMPROVED respirator fit testing for the Annual Meeting in Chicago! We have listened to your feedback and have modified the process to make fit testing more accessible.  The new program includes:

  • An online lecture–no more conflicts with Annual Meeting programming!
  • More options for medical evaluations. Medical evaluations will be provided through AIC (and are included in the price of the fit test) OR you can still see your own doctor.
  • CIPP members get a discount! FREE Fit Test if you sign up for the CIPP Seminar.

Appointments are limited, so register now!

Why Get a Respirator Fit Test?

The AIC Fit Test Program is specifically designed for conservators, particularly those who are self-employed or who do not have a respiratory protection program provided through their employer.

Whether you are using hazardous chemicals in your laboratory or working with mold-infested artifacts after a flood, you need to be sure you are protected with a properly fitting respirator. Do the elastic straps still pull tightly? Do you need a new type or size due to facial changes resulting from weight gain or loss or surgery? Are you using the right kind of protection for your hazard?

OSHA requires individuals be fit tested on an ANNUAL basis to assess the condition of both the respirator and the user. If you perform work that requires the use of a respirator your employer MUST provide the appropriate respiratory protection, medical evaluation, training, information and fit testing–even disposable dust masks are considered by OSHA to be respirators requiring proper fit testing.

It is important to be proactive in your own health and safety and to follow OSHA recommendations and protocols, even if you are your only employee.

What is Involved?

The AIC Respirator Fit Test Program consists of three parts in order to be compliant with the OSHA standard:

(1) An OSHA Respirator Medical Evaluation Questionnaire completed by the registrant and reviewed prior to the fit test either with the Chicago-based clinic contracted by AIC (included in the registration fee) or with their own healthcare professional (at their own expense).

(2) An informational lecture (~ 1 hour) and quiz, which can be completed online prior to the meeting.

(3) An individual fit test (about 15-20 minutes/person) at the Annual Meeting.

Fit test appointments will be available on Tuesday, May 30 (9am-5pm) and Wednesday, May 31 (8:30am-11:30am).

Both the lecture and fit test will be conducted by a qualified Occupational Safety Professional or Certified Industrial Hygienist.

Registrants can bring their own respirator if they already use one and/or try on a selection of sample respirators. They will be contacted directly by the Health & Safety Committee to provide the link to the online lecture, to discuss medical evaluation options and to schedule appointments.

How to Register:

Registration for a fit test can be completed through the AIC Annual Meeting online portal.

This year, the Conservators in Private Practice (CIPP) Specialty Group is generously funding fit testing for its membership.  CIPP members who register for the CIPP seminar, Innovative ‘Tools’ to Enhance Your Business, can also sign up for a FREE fit test. Can’t attend the seminar? You are still eligible to sign up for a fit test for the reduced rate of $30 (a 50% discount from the regular registration fee). If you aren’t currently a member, add CIPP to your AIC Membership Renewal to receive this benefit ($25).

From the “Sessions” checkout screen, select the “Respirator Fit Test” option and the appropriate registration status (Regular, CIPP Member or CIPP Seminar Attendee) and proceed to checkout. AIC will confirm your status eligibility prior to contacting you about scheduling a specific appointment.

We look forward to seeing you in Chicago!


The Committee would like to thank all the members who completed our online survey!  Fit Test organizers are making sure to address all the helpful comments, questions and concerns. 


44th Annual Meeting – Workshop, May 14, "Gellan Gum Applications for Paper-based Objects"

I was very excited to see Gellan Gum Applications for Paper-based Objects listed on the workshops for AIC/CAC, but I was also a little worried about signing up. My familiarity with gums in paper conservation was limited to reading the odd DistList posting. Would it be too technical? Would I be in over my head?
Gellan Gum 4
I shouldn’t have worried. The facilitators from Library and Archives Canada and the Canadian Conservation Institute put me at easy immediately, and the group introductions reassured me I wasn’t the only novice in the group.
We began the morning with a presentation covering both a theoretical and practical introduction to gellan gum. Crystal Maitland did an excellent job of explaining the science behind the use of gellan gum without overwhelming us with too much technical detail. After the getting the theoretical grounding Doris St-Jacques, Greg Hill and Anne Maheux took over and shared some of the practical treatments which had been performed at CCI and LAC.
From there we headed down to the Canadian Centre for Architecture’s inviting lab. It’s always exciting to visit another institution “behind the scenes” and CCA’s facilities did not disappoint. Despite the large group everyone had their own workspace prepared for them with all the tools and samples we’d need for the day.
One of the real strengths of the workshop was exactly how much hands-on experience we gained. We split in to two groups to watch Doris and Greg prepare batches of gellan gum and then in to groups of three to give it a try ourselves. The process proved to be fairly simple, especially with the help of the excellent workshop leaflet. It included clear instructions and my favourite kind of diagram – one which does all the ratio math for me! In addition to the recipes the leaflet also included figures outlining the order of layers for different kinds of gellan gum cleaning and instructions for bleaching and deacidification. All together a very useful document.
Gellan Gum 5Gellan Gum 6
Every participant was provided with a print which had been cut in to four sections for testing cleaning, deacidifying and bleaching. Many participants also brought their own samples. This was an excellent bonus, allowing everyone to see the effects on a wide variety of materials.

Each group began by mixing up their own batch of gellan gum. These set by the end of the day, allowing us to test our handy work, but the facilitators had also prepared a large number of sheets of with a variety of concentrations and additives. It was very informative to be able to play around with the assortment. Very few institutions have to resources to create such a wide variety of gels just to allow their conservators to gain the experience of the different properties, making this an invaluable experience
.Gellan Gum 2
The gellan gum workshop accomplished something I was sure was possible at the start of the day. It allowed me to leave feeling confident enough in my skills that I’m looking forward to trying out gellan gum in my own lab. And if turning an intimidated rookie in to a confident tester isn’t the sign of a great workshop then I don’t know what is!
Gellan Gum 3

Joint 44th AIC Annual Meeting and 42nd CAC-ACCR Annual Conference–Workshops, Saturday May 14, 2016, "Identification of East Asian Papers for Conservation" by Nancy Jacobi and Megumi Mizumura

When I saw the “Identification of East Asian Paper for Conservation” workshop, I began to review what I knew about the subject and decided I could benefit from further education on the matter. I signed up for the workshop hoping to become more confident in my understanding of East Asian papers and I was not disappointed. Besides, what is more exciting than dedicating three hours to talking about paper?

Paper sampler given to workshop participants.
Paper sampler given to workshop participants.

The aim of this workshop was to help participants recognize the characteristics that denote paper quality to aid them in selecting good quality East Asian papers that meet conservation standards.

Megumi Mizumura, a paper conservator at The British Museum, presented first. In addition to providing historical context for Japanese, Chinese, and Korean papermaking, she went into great detail about the Japanese papermaking process. Mizumura’s presentation illustrated how different steps of the papermaking process may affect paper quality.

Slide from Mizumura's presentation: 'Various Alkalies for Cooking Kozo.'
Slide from Mizumura’s presentation: ‘Various Alkalies for Cooking Kozo.’

 She revealed that some papers thought to be of good quality by conservators may actually be poor quality due to changes in fiber furnish and manufacturing processes. The fiber furnish may be a blend of low grade, cheap kozo from Thailand, wood pulp, or other plant fibers. (Thai kozo is the lowest grade kozo because it grows quickly causing the fibers to be less flexible and contain oils that are difficult to remove during the cooking process.) Aggressive chemical steps to quickly cook fibers and bleach pulp are also detrimental to papers, decreasing stability of the fibers after aging. Mizumura highlighted some important details for conservators to be cognizant of when selecting papers:

  • the source of the kozo fiber–Japan, China, Thailand, or Paraguay
  • preparation of the fibers–the degree of detail used to separate bark layers when preparing the fibers, hand-beaten or machine-beaten
  • alkaline cooking processes used to prepare the fibers–wood ash, slaked lime, soda ash, or caustic soda
  • bleaching processes–no bleaching, natural bleaching with sunlight, or chemical bleaching with chlorine based bleaches or hydrogen peroxide
  • method of manufacture–handmade or machine made
  • drying methods–wooden boards, stainless steel plates, or metal rollers
  • Possible additives–sizing, fillers, dyes

Mizumura’s presentation provided conservators with a foundation for making better informed selections of papers for treatment.

Slide from Mizumura's presentation: 'Factors to Consider When Choosing Japanese Paper.'
Slide from Mizumura’s presentation: ‘Factors to Consider When Choosing Japanese Paper.’

Nancy Jacobi, head of The Japanese Paper Place (, followed Mizumura’s presentation expanding upon Japanese papermaking. She emphasized the beauty of a well made sheet of paper and the endangered nature of the papermaking profession in Japan. Jacobi then discussed the introduction of East Asian papers to the West and their uses by artists and, later, conservators. She shared two recurring degradation issues observed during her work at Cape Dorset, Canada in identifying Japanese papers used for relief prints by the Inuit since the 1950s. Jacobi noted oil stains in the supports caused by oils leaching out of the fibers which is characteristic of Thai kozo. She also observed pervasive, small foxing spots in papers caused by the use of uncoated metal dryers to quickly dry finished sheets of paper. Jacobi’s observations reiterated the dangers of not knowing materials, and manufacturing processes of East Asian papers used for conservation. The changes in paper quality may be a reflection of the pressure on the dwindling number of papermakers to meet high demands for East Asian papers. Takao Moriki, third generation president of the Moriki Paper Company (, was also present and supported the workshop material with knowledge of the subject gained from personal experience and research of these materials.
Paper Identification Exercise

During the hands-on portion of the workshop, we put our knowledge of East Asian papers and observation skills to the test. Using the sample books received for the workshop, we examined several samples at a time. Jacobi prompted our observations with questions requiring us to differentiate between some of the following characteristics:

  • quality
  • fiber furnishes
  • fiber preparation
  • cooking or bleaching processes used 
  • drying methods used
  • handmade or machine made papers
  • additives

Once we had done our best to distinguish the various characteristics of our samples, we checked our answers against the key provided. The answer key contained a detailed break down of the papers listing the name, the region it was from, fiber furnish with fiber origin and percentages for fiber blends, machine made or handmade, fiber preparation, cooking process, bleaching, drying methods, additives, weight, and original sheet dimensions. The workshop organizers also brought their study collection with many other samples of East Asian papers for us to examine in addition to those in our sample books. Additionally, discussions related to experiences in using East Asian papers were cultivated amongst workshop participants.
Below are images of some of the papers in our sample books that I find really interesting.

5-A Kurotani #4 from Kyoto: handmade, japanese kozo, soda ash cooking, no bleaching, dried on stainless steel sheet. 5-B Okawara from EhimeL handmade, Thai kozo, caustic soda cooking, chlorine bleaching, dried on stainless steel sheets.
5-A Kurotani #4 from Kyoto handmade with Japanese kozo, not bleached
5-B Okawara from Ehime handmade with Thai kozo, bleached

8-C Kaji Natural from Ehime: Hand made, thai kozo 90% and wood pulp 10%, caustic soda cooking, chlorine bleaching, direct synthetic dye, and stainless steel sheet drying. 8-D Matsuo Kozo from Fukuoka: handmade, japanese kozo, caustic soda cooking, chlorine bleaching, direct synthetic dye, and stainless steel sheet drying.
8-C Kaji Natural from Ehime handmade with blended fibers and synthetic dye
8-D Matsuo Kozo from Fukuoka handmade with kozo and synthetic dye

3-A Sekishu Mare from Shimane (UNESCO grade): handmade, Japanese kozo, hand beaten, soda ash cooking, no bleaching, dried on wooden boards. 11-C Xuan paper made at Red Star--tan tree and rice straw fiber, grade is special bark made, Mian Lian (thinnest paper thickness) used for caligraphy 11-A Hanji made in Korea with kozo fibers
3-A Sekishu Mare from Shimane (UNESCO grade) handmade with japanese kozo fibers
11-C Xuan paper made at Red Star with tan tree and rice straw fiber
11-A Hanji made in Korea with kozo fibers


This workshop raises awareness for the necessity of thoroughly understanding the materials used for conservation treatments. The hands-on exercise was a good challenge and essential for learning the characteristics that mark good quality paper. The workshop provided a good foundation and clear direction for conservators to work towards mastering the identification of East Asian papers.
The information I learned through this workshop will be very useful for guiding my decisions when selecting papers in the future. I truly appreciated the organizers’ passion for East Asian papers. It was a pleasure to peruse the additional samples in the study collection while talking about paper with all workshop participants.

44th Annual Meeting—Gap Filling for Ceramics Workshop

The Gap Filling for Ceramics workshop brought together conservators from various backgrounds to experiment while learning practical tips from Rachael Perkins Arenstein, Conservator at the Bible Lands Museum, and Elisheva Kamaisky, Head Ceramics Conservator at the Israel Antiquities Authority in Jerusalem. The day passed quickly as the workshop was packed with PowerPoint presentations and hands-on activities with spackles, plaster, epoxy techniques suited to archaeological and fine arts contexts. Like many participants I took the class as an opportunity to learn from others and practice without the pressure of working on a museum object. Having focused on ceramics this year, I am familiar with the materials and techniques discussed, but I found it an opportune chance to break out of my familiar habits, review the properties and different reasons for choosing plaster versus bulked Paraloid B-72, for example, or ways of manipulating Milliput and refining plaster.

Elisheva Kamaisky demonstrating how she uses a balloon attached to the end of a plastic tube to create a backing inside a jug with a small neck and rim, which blocks easy access to the interior.

The program moved through the various stages of the filling process beginning with discussions of how to protect the surrounding surface from ghosting. For porous unglazed surfaces, common in archaeological contexts, Elisheva often uses masking tape or low-tack painter’s tape, pinching around the edges of fills to prevent the infiltration of plaster. Using tape is always evaluated on a case by case basis depending on the stability of the surface and its ability to withstand tape. Elisheva also showed different strategies she uses for backing of plaster fills, such as layering masking tape to conform to the shape of the ceramic, heated wax, and balloons.
My experimental flower pot generously broken and reassembled by Elisheva and Rachael. Here I have used masking tape to protect the edges and build a backing for fills.

Elisheva showing an example of a tinted plaster fill before drying

The class then discussed tips for mixing and refining plaster, such as how to use a rasp appropriately, when to begin shaving down a fill, and when to stop working it and allow it to dry for wiping down and sanding. Rachael talked about different uses for ready-made spackles and their different properties, pros and cons of using Modostuc, Flugger and PolyFilla. She also referred to different uses of Milliput and gave tips for how to refine it with water before it is dry. This I found particularly useful because refining as much as possible while it is still pliable saves an immense amount of time wasted with sanding or grinding excess material afterwards. I also found the discussion of problems related to B-72 fills helpful as Paraloid is not always easy to work with, and can be difficult to compact. At the end of the day I was very glad to have taken the workshop, and could tell that other participants felt the same as it was a great opportunity to discuss strategies, problems and challenges with conservators with a breadth of experience, and other conservators ranging from those in private practice, to museum conservators who brought expertise with other materials such as wood or stone. It was also a fun way to prepare for the conference, reminiscent of being in graduate school, and getting your hands dirty.

44th Annual Meeting, May 14th, "Ferrous Attractions: The Science Behind the Magic" by Gwen Spicer

The workshop Ferrous Attractions: The Science Behind the Magic was led by Gwen Spicer (Spicer Art Conservation, LLC) and Van Wood (Small Corp Inc.).  The program was outlined in three sections: introduction to the magnetic system, hands-on testing, and a brief summary of testing results.
The magnetic system includes four components:

  • the strength of the magnet,
  • the type of ferromagnetic material receiving the magnet,
  • the space between them (occupied by the artwork),
  • and gap materials (those in contact with the artwork: fabric, Mylar, twill, batting, paper, or suede).

Magnetic systems can be assembled in several different ways:

  • Two-part (point fastener): magnet/magnet or magnet/ferromagnetic material.
  • Three-part (sandwich): ferromagnetic material/magnet/ferromagnetic material or magnet/magnet/ferromagnetic material.
  • Large area pressure: flexible magnet/ferromagnetic material or magnetic slat/ferromagnetic material.

The ferromagnetic material, commonly 24 gauge steel, is called a “soft magnet” because it is magnetized in the presence of a permanent magnet.
Conservators typically use neodymium permanent magnets. Neodymium magnets are considered the strongest, yet their sourcing is ethically problematic – details of their mining and trade were addressed in Gwen’s 2015 AIC Sustainability session talk.  This table compares other types of magnets you may encounter.
Hands on testing was done in pairs using a wooden jig, bucket, weights, and a kit of various magnets, metals, and gap materials. The test: choose a type of magnetic system, suspend the bucket, and fill it until the system fails (ie. the bucket drops).  Images of the jig and testing results from a previous workshop are found on Gwen’s blog.

Many factors influence the strength of a permanent magnet including:

  • shape (disc/cylinder, sphere, block, ring)
  • size (diameter, thickness)
  • grade (“strength” of the magnet – the higher the N# the stronger – N42 and N52 are common)
  • pull force (force required to separate the magnet from steel or another magnet)
  • pole orientation (axial or diametrically magnetized)
  • Curie temperature (temperature at which the magnet is demagnetized)
  • intrinsic coercive force (resistance to demagnetization).

K & J Magnetics Inc. discusses these aspects in detail in their blog and glossary. They also offer a Magnetic Pull Force Calculator to aid in selecting magnets for appropriate use!
Tips from the summary discussion:

  • Do not use hot glue or irons near magnets because the heat can demagnetize them. For example, the Curie temperature for neodymium magnets is considered low: 310-400 degrees Celsius.
  • Do not put cell phone near strong magnets!

Magnets –

  • Axial magnetic attraction is stronger than diametric (side to side) attraction. Always check the pole orientation when purchasing.
  • Match your magnets! Magnets of similar diameter and pull force will behave the most regularly. Magnets that differ by more than 1/8″ diameter will slip because the magnetic field is not evenly distributed.
  • Neodymium magnets corrode easily and therefore require a coating. They are brittle and chip easily. They are hard to demagnetize, but they can easily demagnetize other magnets!
  • Three-part systems are the strongest. Magnets can be bundled to increase pull force.
    • Is the pull force additive or logarithmic?

Ferromagnetic materials –

  • Steel powders were deemed ineffective by the group overall – you need A LOT of it.
  • 24 gauge steel is the sweet spot – higher gauge steel is only minimally stronger.
  • Using a thinner magnet on the artifact surface and a thicker one behind reduces the total pull force of the two magnets.
  • Beware of steel washers. The hole significantly reduces the pull force and causes the magnet to slip.

Gap materials –

  • The best gap material is decidedly Benchmark suede (to cover the magnets) due to the suede’s friction and slight give – better than Mylar or cotton. Polyester batting was the worst because the gap is too big.
    • What is the optimal or minimal gap for your magnetic system?

Gwen Spicer is writing a book on magnets in conservation, supported by the AIC Kress publication fellowship. If you have a Case Study you would like to share, please get in touch!