June 2016 – Page 7 – AIC Blog Archives: Conservators Converse

Joint 44th AIC Annual Meeting & 42nd CAC-ACCR Annual Conference, Breakout Session: Emergency, May 16, “Disaster Plan in Greece,” by Maria Lyratzi

I was drawn to this talk merely from the title, having worked in and visited Greece a multitude of times. Maria Lyratzi first introduced herself as the paper conservator for the Library of the Institute of Educational Policy/Greek Ministry of Education in Athens, Greece. She then dove right in to her talk, which covered quite a lot in a short amount of time. Maria was first influenced to begin her path to creating emergency response plans in Greece via the (former) American Institute for Conservation – Collections Emergency Response Team (AIC-CERT), now the Foundation of the American Institute for Conservation of Historic and Artistic Works – National Heritage Responders (FAIC-NHR). She admired how AIC-CERT showed emergency response plans in a systematic way to where she could adopt and adapt for Greece’s circumstances.
Maria gave a background of Greece and the types of natural disasters they experience (photo) as well as the legal framework that builds the foundation for protecting cultural heritage. Currently, the constitution of Greece, Article 24, states that “the protection of the natural and cultural environment constitutes a duty of the State. The State is bound to adopt special preventive or repressive measures for the preservation of the environment.”
The current State of Greece was established in 1830, and not too shortly afterwards in 1833, the Greek Archaeological Service was founded. And just one year following, the first archaeological law of Greece was established. Amendments to this law have occurred in 1899, 1914, 1921, and 1932. The current law, No. 3028/2002 is in effect and can be read here:

[http://portal.unesco.org/culture/en/files/25587/11113354823nomos4en2.pdf/nomos4en2.pdf]

She then went over the main points of the archaeological law and the responsible authorities. The responsible authorities include:

Ministry of Culture

Responsibilities include: archaeological sites, historical sites, all types of museums, all types of monuments (Note: mentioned only ~30% of monuments are under the auspices of the Ministry of Culture)

Ministry of Education, Research, and Religious Affairs

Responsibilities include: Department of Government Archives and the Department of Libraries (Note: there is no specific department for the protection of libraries and archives)

Other Ministries (including Earthquake Planning and Protection Organization, EPPO)

Responsibilities include: Processes and designs the country’s earthquake policies, publishing informational and educational materials, and having a program of pre-seismic control of all public buildings (Note: only ~30% of public buildings are checked)

Public Authorities

Responsibilities include: Local organizations that collaborate with Ministries

Academic Institutes (indirectly)

Responsibilities include: Supervising postgraduate/doctorate projects, researching and scientific programs

Also mentioned were other authorities (General Secretariat for Civil Protection, GSCP) that should protect cultural heritage, but currently do not. As one can probably tell, the laws focus on mostly archaeological antiquities, rather than the wider cultural heritage.
Maria then gave an example of an online system that tracks risks of earthquake areas through the Institute of Geodynamics.

Measures of Our Cultural Heritage Protection Against Strong Earthquakes

The site has several different tools, including a map with various options, a list of all the monuments and their associated risk, and an area for local research. It maps various monuments, but not nearly enough. The Institute of Geodynamics’ method of collecting data covered monuments and their condition in regional, seismotectonics, and geological data. They then conducted a hazard assessment for each monument. A map was developed where the user is able to choose a multitude of categories to determine associated risks. Maria had been proposed by the Institute of Geodynamics to be a part of their team to expand their map to include locations of libraries and archives. She was also asked to educate local authorities and the personnel of museums, libraries, and archives in Greece for disaster planning.
Maria had additional support from the Library of the Institute of Educational Policy to publish the first disaster plan in 2009 on their website, to organize and run a three day Greek-American seminar in 2013, and to publish her first book on disaster planning in Greece, a culmination of 5-6 years of work, released 2009. The topic of the three-day seminar in 2013 was Disaster Response and Conservation. There were two days dedicated to lectures of disaster preparedness and salvaging art, libraries, and historic collections with one day hands on in disaster recovery training.
She then went on to discuss two surveys given to Greek scientists. The first covered the recorded catastrophic events to cultural institutions from 2002-2012 and the second presented the degree of readiness of major cultural institutions in the prevention and handling of natural and manmade disasters. The data was collected by the Hellenic Statistical Authority (ELSAT) and the Fire Brigade, neither of which have kept formal records of disaster-affected institutions.
Results of the first survey include: 255 cultural institutions calling the fire brigade to assist in fire and flood incidents. Most of them were incidents on archaeological sites. ELSAT has no data for fire brigade assistance for earthquakes. The fire brigade gave no descriptions of the flood or fire incidents that have occurred in cultural institutions. There are no records for disaster incidents to buildings or collections. It is unknown if the files even exist. From the first survey, most floods reported were on archaeological sites (~71%), with, not surprising, rain water being the main cause. Most fires reported were on archaeological sites (~73%), versus museums (~15%). The cause of fires in museums was of unknown origins.
The second survey, the very first of its kind in Greece, was sent electronically to representatives of all types of official museums, private museums, libraries, and archives:

103 public museums, 77 private museums, 188 libraries, and 1 archives

With an allowance of one month to complete, the response rate was 21%

Maria shared various survey questions with the results, below are a few of those slides:

Plans for the future include(d) a one-day seminar on May 28, 2016 in Nafplio with The Center of Hellenic Studies and Harvard University on how to prepare a disaster plan for your institution. Maria is planning to prepare a five-day seminar for the Bank of Greece in Athens inviting the FAIC-NHR representatives and representatives of all the Greek authorities who should be cooperating in the prevention and response of disasters to cultural heritage. She would like to conduct additional research on the degree of preparedness of libraries and archives in the prevention of disasters, to hold disaster prevention seminars all over Greece, to build a volunteer team to confront disasters all over the country similar to the FAIC National Heritage Response, and to create a website with instructions on disaster preparedness.
The audience was very captivated and supportive by the fact she has taken on this giant task by herself. She hopes to have help from volunteers and is trying to contact Greek ministries almost every day. With the current state of Greece and having seen it in person, I am not surprised on the bulk of the results from the surveys. I am surprised that Maria is able to undertake this responsibility for her country and expand disaster preparedness to libraries and archives and wish her the best of luck.

References:
The Constitution of Greece
Law and the Politics of the Past: Legal Protection of Cultural Heritage in Greece by Daphne Voudouri
Great Moments in Greek Archaeology Edited by Panos Valavanis

Further Reading:
FAIC-NHR (formerly AIC-CERT)
Disaster Response Plan (RAS) in museums and libraries
Purchase Maria’s disaster book HERE
Purchase Maria’s children’s books (really!) HERE

44th Annual Meeting & 42nd Annual Conference—Book and Paper Session, 15 May 2016: "Careful Consideration: Learning to Conserve a Kashmiri Birch-bark Manuscript," by Crystal Maitland

Waxing philosophical (in her own words) about the nature of treatment, her musings inspired by a unique Kashmiri birch bark manuscript, Crystal Maitland provided a holistic look at the considerations for and process of treating an object outside the normal range of paper conservation expertise.
In sharing her experiences treating this manuscript, Maitland observed that unusual projects provide opportunities to reflect on our everyday treatments as well—those which are well within our skill sets and comfort zone of interventions. Both the AIC and CAC ethics statements require conservators to recognize and work within their limits [AIC: “limits of personal competence and education”; CAC: “limits of his/her professional competence and facilities”]. So when presented with a treatment that requires us to move outside of that range of interventions, how do we ethically expand the limits of our skill sets?
Maitland suggested that we turn first to the expertise of others, via published literature and the knowledge of colleagues; in the case of the Kashmiri manuscript, while treatment information was scarce, she was able to draw on information about the materials and cultural context to begin to first understand the manuscript and then shape a plan. This amassing of information included both material and intangible aspects of the manuscript and consideration of potential audiences for the manuscript.
A primary question she posed in this stage was, why was this text written on birch bark? Common substrates of the period were inappropriate (parchment, made from animal skin, would be antithetical to the Hindu sacred text it would support) or unavailable (papyrus, for example, is not found in the region). The isolated location, however, has copious quantities of Himalayan birch, making it a logical choice. The composition of the bark also proved relevant. The early annual growth, light in color, contains botulin, an antifungal agent that may have contributed to its survival; the later annual growth, dark-colored, is rich in tannins. The characteristic striping of birch bark is due to the presence of transpiration nodes called lenticels.
Clues to the manufacture of the manuscript were also carefully observed and informed the eventual treatment. The individual leaves were laminated together, some naturally (i.e., the layers were harvested together, giving a matched pattern of lenticels) and others artificially (i.e., the layers were grouped after the harvest, with distinct, mismatched lenticel patterns). These manuscript pages were delaminating, the bark layers separating and sometimes torn, and also exhibited a waxy efflorescence, in addition to heavy soiling, curling, and tears along the edges.
Having established a baseline for the composition, manufacture, and condition of the manuscript, Maitland felt comfortable formulating and pursuing a course of treatment. The intervention ultimately drew on her research and careful consideration of the manuscript to make treatment decisions. Surface cleaning with a smoke sponge and cold deionized water was followed by relaxing the curling edges of the leaves with methanol vapor chambers. Mending utilized wheat starch paste of a lining consistency and Japanese paper for tears, placing the repair tissue between the layers of the birch bark where possible. Damaged lenticels were mended with toned tissue for additional structural support to the leaves where necessary. With access being a driving force behind the treatment, the entire manuscript was digitized; the manuscript was then interleaved with polyester film sleeves for safe handling in consultation, and stored in custom boxes.
Returning to the questions she posed at the beginning, Maitland suggested that conservators can expand their limits, ethically, by learning from colleagues, including published professional literature; by testing treatment options, carefully observing the results, and proceeding accordingly; by engaging in holistic thinking about cultural heritage and considering the intangible aspects alongside the materiality; and by playing to our strengths, or making the most use out of the techniques and skills that we already know and possess.
Maitland’s treatment and her process for developing it certainly provided food for thought. The intimate look at an unusual intervention combined with an exploration of how to expand our skill sets while respecting ethical limits encouraged reflection on our treatment processes for more routine treatments. Ultimately, I came away from this talk with the conviction that the way I approach treatment should not depend on the uniqueness or visual appeal of an item, but rather that each object deserves a respectful and appropriate treatment.

Job Posting: Paper Conservator – Midwest Art Conservation Center (Minneapolis, MN)

Paper Conservator
The Midwest Art Conservation Center is seeking a Paper Conservator. This is a full-time position with occasional travel. Applicants must have an advanced degree in art conservation with a specialization in paper conservation. The position calls for treatments on a wide-range of works from all periods, including Asian art. A minimum of 5 years post graduate experience is preferred. The title and responsibilities will be commensurate with experience. MACC provides excellent salaries along with outstanding benefits including medical, dental, 403b contributions, vacations, AIC membership, and professional development.
MACC is a growing, independent, nonprofit, regional center providing comprehensive conservation services in Paintings, Objects, Paper and Textiles. The staff is collaborative, very collegial and works innovatively with the curatorial and collection professionals of hundreds of Midwest institutions – including the largest art museums, historical societies, universities, libraries and archives, as well as small and mid-sized institutions with unique and varied collections. MACC laboratories are located within the Minneapolis Institute of Art.
Please send your confidential curriculum vitae, cover letter and references to:
Colin D. Turner
Executive Director
Midwest Art Conservation Center
2400 – 3^rd Avenue South
Minneapolis, MN 55404
cturner@preserveart.org
612-870-3148

Job Posting: Objects Conservator – Midwest Art Conservation Center (Minneapolis, MN)

Objects Conservator
The Midwest Art Conservation Center is seeking an Objects Conservator. This is a full-time position with occasional travel. Applicants must have an advanced degree in art conservation with a specialization in objects conservation. The position calls for treatments on a wide-range of works from all periods. A minimum of 5 years post graduate experience is preferred. The title and responsibilities will be commensurate with experience. MACC provides excellent salaries along with outstanding benefits including medical, dental, 403b contributions, vacations, AIC membership, and professional development.
MACC is a growing, independent, nonprofit, regional center providing comprehensive conservation services in Paintings, Objects, Paper and Textiles. The staff is collaborative, very collegial and works innovatively with the curatorial and collection professionals of hundreds of Midwest institutions – including the largest art museums, historical societies, universities, libraries and archives, as well as small and mid-sized institutions with unique and varied collections. MACC laboratories are located within the Minneapolis Institute of Art.
Please send your confidential curriculum vitae, cover letter and references to:
Colin D. Turner
Executive Director
Midwest Art Conservation Center
2400 – 3^rd Avenue South
Minneapolis, MN 55404
cturner@preserveart.org
612-870-3148

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!

Job Posting: Assistant Conservator – Corning Museum of Glass (Corning, NY)

Corning Museum of Glass
Position Summary
Title:                           Assistant Conservator
Status:                       M&P, Full-Time
Reports to:               Chief Conservator
Summary:
Assists the Chief Conservator and Associate Conservator in all aspects of the physical care of the collection of glass and glass-related objects. Specializes in the care, cleaning and conservation of glass objects and sculptures, with a focus on modern and contemporary collections. Other primary duties include examination and conditioning of objects for acquisition and loan approval.
Responsibilities:

Assists the Chief Conservator and Associate Conservator in all aspects of the care of glass and glass-related objects in the collection and on loan.
Examines Museum objects requested for loan to other institutions, writes condition reports and recommends the appropriate response.
With the Chief and Associate Conservators, ensures that the handling and storage of conservation materials and the use of equipment in the conservation laboratory are in compliance with relevant federal and state regulations.
Maintains currency on the latest developments in the field of glass conservation and restoration, with special focus on Modern and Contemporary objects and sculptures.
Documents treatments and contributes to conservation website information.
Assists with the supervision and guidance of interns in the Conservation Department.
Observes and follows all safety regulations of The Corning Museum of Glass.
Is familiar with and observes the requirements of all Museum standards and the Code of Ethics and Statement of Practice of the American Institute for Conservation.
Represents The Corning Museum of Glass at domestic and international conferences and professional meetings through active participation and engagement.

Qualifications:
Master’s degree in Art History or a similar field, with a graduate diploma in conservation.

Minimum two years’ experience as an object conservator, or equivalent training and experience.
Experience handling contemporary glass desired.
Ability to complete high quality treatments in a timely manner.
Excellent organizational skills.
Ability to work independently and as a member of a team.
Excellent interpersonal skills.
Excellent research and writing skill. Knowledge of Excel, Media-Bin, and other record-keeping programs.
Ability to travel domestically and internationally.

Applicants can apply by emailing their resume and cover letter to employment@cmog.org.

44th Annual Meeting & 42nd Annual Conference – Objects Session, May 17, 'Using Heat and Cold in the Treatment of a Lakota Winter Count,' Madeleine Neiman and Nancy Odegaard

Madeleine and Nancy presented a very interesting talk that shared their experiences using cold temperatures to achieve a specific treatment goal. Nancy began by introducing the object, a Lakota Winter Count. The object is one of a type of pictorial calendars that depict the history of the community and serve as a counting device. A historian would have been in charge of the count, naming years for remarkable events related to astronomy, the environment, or culture. Tribal keepers knew the name of the years, helping them to recall the oral history of the community.
The Lakota Winter Count that inspired this talk is from the Heard Museum in Phoenix, Arizona. At some point in the past, it had been folded so that the pictograph surface faced out. The interior surface had become stuck to itself, preventing the unfolding of the object. As the Heard Museum does not currently have a permanent conservation staff, the object was brought to the Arizona State Museum for treatment.
The primary goal of treatment was to unfold the count, enabling the viewer to see all of the pictographs at the same time. Additionally, there is bleeding, mold, darkening, and tears on the support. There was no history of fabrication or provenance associated with the object so the Arizona conservation team undertook documentation and investigation.
There are 121 pictographs on the non-coated side of the support that documents the years 1799 to 1918. The outlines are drawn in graphite and the limited additional pallette is consistent with other winter counts. These include two browns, a bright pink pastel, and blue and orange colored pencils. Specifically, the Heard winter count is very similar to a Long Soldier Winter Count at the NMAI. Sometimes, duplicates of counts were made for use or for sale, which could explain the similarities of the two pieces that cover roughly the same period. The Heard count is likely from a similar region in North Dakota.
The object was analyzed and the support was determined to be a piece of commercial oilcloth. FTIR showed the oilcloth coating is linseed oil and shellac. Fiber samples taken indicate that the fabric is cotton. This is consistent with commercial oilcloth produced in the late 19th, early 20th century; during this time period, commercial products began to replace local materials. Maker’s marks on the oilcloth identify the manufacturing company and Nancy and Madeleine shared contemporary advertisements, which demonstrated the prevalence of the product in the average household. The mark gives a terminus post quem of after 1901.
The fusing of the oil cloth to itself was likely due to ambient heat. A 1-2 cm opening along the edge was the maximum access before treatment. Dave Smith, conservation scientist at Arizona, was able to determine the glass transition period of the oilcloth coating is approximately 31⁰C. The average temperature in Arizona exceeds this from April to October, so the environment could have caused the shifting in the structure of the materials that led to the current sticking.
Madeleine undertook testing to explore options for opening the count. Organic solvents were not effective as the coating is cross-linked and now impervious. At this point, it was clear that whatever treatment was applied would be time consuming and invasive. The conservators asked the curators how crucial the treatment was to the object; however, the curators said that the current condition was fundamentally comprising the interpretation of the object as the chronological reading of the object was disrupted.
Knowing this, the conservators went back to the drawing board. Dave suggested considering cold temperatures, because polymers are long chain molecules whose movements are highly linked to temperature. If the temperature is below the Tg, then the polymers can no longer stretch and instead cleave, allowing for the two sides to be separated. Conservators tried compressed cooled CO2 gas, which was not effective. Similarly, overall freezing works at first, but the object warmed up too quickly for this to be viable for treating the whole object. Next, they used a Peltier cooler to apply repeated cold in a smaller area. The team worked to retrofit a USB beverage chiller to be able to consistently apply a 5⁰C. This system was used by applying the cooling plate to oilcloth surface for three minutes, then lifting the device so that Madeleine could use a stainless steel spatula to cleave small sections of the cloth from the opposite surface. She continued in this way for three months, working on the project for portions of each day.
After the cloth was opened, treatment turned to the tears, some of which appear to be linked to earlier attempts to force open the oilcloth. Stitching the tears was not viable because there was no safe place to secure the tears given the nature of the oilcloth. Adhesive backings also were not expected to be successful, as they would likely curl away from the coated surface over time. Instead, Madeleine found that by applying granules of textile welding powder to individual warps and wefts, she could control her mends and allow for a degree of reversibility. This process required four steps: relax the creases using Gortex, Dartex, and weights; pull misaligned fibers back into place; reweave fibers where possible; and, apply the granules of adhesive. The granules were heated in situ to a temperature at which they began to soften but did not completely solubilize, so that individual granules could then be mechanically removed if necessary. In some places, a secondary support was added where there were not enough wefts or warps. Small pieces of Remay were torn to the right shape, toned with dilute acrylics, dusted with the welding powder, and heated between silicone release paper in place.
Thus, the treatment presented benefited from the use of both low heat and cold temperatures. It was highly time intensive; however, this was considered justifiable as the object was a special project. The speakers also encouraged conservators to consider the use of cold for other treatment applications, as it seems to be underexplored when compared to higher temperatures.
After the presentation, one question was asked:

Q: Why did they not just heat the oilcloth coating to past the glass transition temperature? A: Doing this would likely have caused the cloth to become more sticky, more bonder, and more flexible. When the polymers are cold, they want to break due to the brittleness. The weakest point of contact in this case was with the other side, so cleaving the polymers facilitated the treatment goal.

This post was written from my personal notes, which may contain errors or inaccurately represent the author’s original intentions.

44th Annual Meeting- Book and Paper, May 17th, 2016: "A Protocol to Conserve Glazed Paper after a Water Damage." by Celine Allain

This talk was given by Céline Allain of the Bibliothèque nationale de France (BnF), after the lead author, Lucille Dessennes, also of the BnF, was unable to attend the conference.
In 2014, a pipe burst in the BnF, causing damage to 12,000 books, mostly from the 18th and 19th centuries. 360 of these 12,000 items contained coated papers, and when the disaster salvage/freeze drying contractors arrived on the scene, they would not accept books with coated pages for treatment.
The emergency team at the BnF instead had to use 6 freezers at the BnF to freeze-dry the 360 books with coated pages, although 51 of the 360 were too dry to be freeze-dried. Allain spoke to how difficult it was for the emergency team to accurately identify which books had coated pages—whether because the feel and look of the papers can vary or there might only be a few coated papers in a volume— and encouraged the audience to train emergency response teams to recognize coated papers beforehand. The difference is rarely as easy to identify as in the graphic below:

A common theme through the talk was the importance of keeping coated papers wet until they can be frozen. Even in the 2-3 hours it took the emergency team to arrive and place books in freezers, a number of books with coated papers had to be frozen “half-dried,” which limited the recovery outcome for these books. Had the books been kept wet and then frozen wet, they would have fared better.
Allain addressed the makeup of coated papers in order to explain why the pages should be kept wet: the coating (a mixture of pigments, binders, and other elements to improve opacity or water resistance) swells in the presence of water, readily attaches to the wet coatings of facing pages, and congeals into a “block” of stuck pages upon drying that cannot be separated without delamination of the paper surface. When the coated papers are still in a wet state, however, the pages can still be separated without loss of content.
The standard treatment for drying coated papers is freeze-drying (see below Further information), as long as there it is not a vacuum-thermal drying procedure. This allows the frozen water to sublimate.
For the 51 books that had been frozen half-dry, however, there were some that had blocked pages that needed to be un-blocked. The authors adapted a number of treatments to the books, including using a Teflon spatula to separate pages while still frozen.
The authors knew from previous research into the paper industry that the main binding agent in the papers was styrene-butadien latex (LSB in French, SB latex in English), which is soluble in tetrahydrofuran. Because the tetrahydrofuran’s toxicity made it too dangerous for use, Allain and Dessennes consulted the solubility triangle to arrive at a less toxic solvent. Using a mixture of toluene and ethanol (50/50 vol/vol), the conservators were able to attain equivalent solubility parameters and un-stick blocked pages of the affected books. The conservators brushed on the mixture, softening the SB latex, and then used a stiff spatula to separate the pages. The work is done in a fume hood. The authors noted that a large drawback is that the solvent can only be applied to specific areas of blockage and cannot be used on a large area or an entire book because the inks are frequently soluble in the solvent mixture.
Dessennes experimented with using the solvent in a solvent chamber, but speculates that because of the thickness of the block, that the vapors could not penetrate the interstices of the paper. Because of the limitations of the solvent applied as a liquid and in vapor form, Allain and Dessennes have plans to experiment with the solvent used in a low pressure environment.

Further information:
“Effet de la lyophilisation sur le comportement mecanique et chimique du papier, du cuir et du parchemin” Flieder, Francoise; Leclerc, Françoise; Chahine, Claire
Carlsen, Soren. “Effects of Freeze drying on Paper,” IADA Preprints, 1999, p. 115-120.
David Tremain on Emergency Drying of Coated Papers http://cool.conservation-us.org/byauth/tremain/coated.html
NEDCC leaflet on Freeze-Drying: https://www.nedcc.org/free-resources/preservation-leaflets/3.-emergency-management/3.12-freezing-and-drying-wet-books-and-records
CCAHA on freeze-drying techniques: http://www.ccaha.org/uploads/media_items/ccaha-freezing-drying-techniques.original.pdf
NARA on efficacy drying techniques: http://www.archives.gov/preservation/conservation/drying-methods-02.html
LOC on drying techniques, what to do if collections get wet: http://www.loc.gov/preservation/emergprep/dry.html