AIC’s 44th Annual Meeting – Page 7 – AIC Blog Archives: Conservators Converse

44th Annual Meeting: Photographic Materials Session, May 16, "When Inkjet Prints Get Wet: First Contact to Weeklong Submersion," by Daniel Burge

As an emerging paper conservator, I was eager to attend Daniel Burge’s talk, “When Inkjet Prints Get Wet: First Contact to Weeklong Submersion.” I wanted to expand my understanding of this type of print that seems to be so fragile and difficult to preserve. Is there any hope for these objects after a water emergency?
The aim of Burge’s research was to critically assess the damaging effects of water on modern inkjet prints to develop disaster response protocols that maximize emergency response and recovery efforts of a damaged collection. Many types of inkjet prints were immersed in water for increasing increments of time: 1 second, 10 minutes, 1 hour, 8 hours, 24 hours, 48 hours, and 7 days. Damage to the colorants, paper coatings, and paper supports were recorded. The majority of inkjet prints proved to be damaged after one second of immersion. Some inkjet prints remained fairly stable during extended periods of immersion. This allows an emergency response timeline to be made focusing rescue efforts on saving prints that have some stability when exposed to water.

IMG_20160516_103650 — Title slide of Burge’s presentation showing examples of damage to inkjet prints after submersion in water.

Burge’s research also revealed that pigment colorants were generally more stable than dye colorants; and prints made on polymer or uncoated fine art papers were the most susceptible to damage. However, some anomalies of the statement above were observed. Burge explained that stability is not only related to the materials incorporated in the inkjet prints but that it is also linked to the relationship between the colorant and the coating as well as the relationship between the coating and the support.
In conclusion, Burge stressed the following points:

Priorities may be assigned to a collection based on a thorough understanding of the colorants, coatings, and supports of inkjet prints coupled with the results of this research guiding emergency response efforts during a water incident.
Good housing and storage methods may help to reduce potential water damage.

Slide from Burge's presentation: Anatomy of a Water Damaged Print. — Slide from Burge’s presentation: Anatomy of a Water Damaged Print.

Several people added to the presentation through their questions and comments. All agreed that IRIS prints are incredibly sensitive to moisture. A question was asked, raising the ethics of printing a new inkjet print from a file to replace a damaged print. Burge replied that even though this is possible, there is a unique relationship between the artist and the original, damaged print. We should be considerate of the significance of the original before making a reprinted version. I felt that I had gained a better understanding of the issues surrounding the inkjet print’s sensitivities to water that would allow me to better care for a collection. I greatly admired Burge’s enthusiasm and authority in this subject matter as well as his poise as a speaker.
An overview of Burge’s project and helpful information may be found on the home page of the Image Permanence Institute’s DP3 Digital Print Preservation Portal under the ‘Flood’ tab: http://www.dp3project.org/

44th Annual Meeting, Objects Session, May 17th, “The Use of Gums and Resins in Archaeology and Microchemical Tests for their Identification,” by Christina Bisulca

Christina Bisulca presented a fascinating paper that not only described the source of and uses for pine resins and insect lacs but also detailed various methods of testing for these substances in the lab. The Arizona State Museum is home to a collection of 35,000 objects representing every major cultural group in the southwest from Paleo-Indian to the historic period. As part of a conservation and rehousing project made possible by a Save America’s Treasures grant, conservators hoped to analyze and identify adhesive resins present within the collection.

Map showing regions mentioned in the talk

Certain plants and insects are found only within particular regions of Arizona due to the huge range of elevation and environmental biomes within the state. Since three of the most prolific cultures, the Hohokam, Mogollan, and Ancestral Puebloan occupied very different biomes, it was assumed their use of natural adhesives would vary according to location.

The Hohokam, for example used creosote lac, a polyester resin derived from an insect on the creosote bush found in desert lowlands. On the more northerly Colorado Plateau, where the Ancestral Puebloans lived, piñon pine was a plentiful source of diterpenoid resin. In general, Bisulca and her team assumed insect lac was used in the south and pine resin in the north.
Initial analysis was done with Fourier Transform Infrared Spectroscopy (FTIR) but researchers had trouble gathering reference plant material. They also realized these high tech, expensive tests are not readily available to many archaeologists, so they used microchemical tests in addition. Since no reliable microchemical test existed for shellac the team developed one based on the pH dependency of color in anthraquinone dyes, which are extracted from lac insects in Asia. In alkaline conditions the dyes turn from orange to purple. The test worked 80% of the time even in their archaeological collection. Where it did not work the resin had likely been charred or highly heated. The results of the tests challenged their assumptions about pine resin being used primarily by the north. In fact the team found more insect lac in the Ancestral Puebloan collection than pine resin. The lac would only have been available to these regions through trade. The researchers also investigated the use of each material. Bisulca used arrows, common to all three cultures, to highlight the different uses for each adhesive. Insect lac is stronger and less brittle so was used by each culture, regardless of location, for hafting the arrowheads to the shaft.

Overall, Dr. Bisulca’s talk was extremely informative and used excellent images to portray her ideas. The images she used of the lacs and resins as they are found in nature and on ethnographic objects helped to clarify the differences between the source and use of each. I have to admit I had not considered the significance of these resins in terms of their use in tracing trade routes and cultural practices. I am curious to know what similar substances would have been used by Eastern and Plains area cultures and how well such resins would be preserved in damp archaeological environments. This will certainly change the way I approach native material at my own site.
All images are from a poster on insect lac by Christina Biscula available here.
Information about the authors is available from The Arizona State Museum’s website.

44th Annual Meeting, May 17, Objects, Conservation and investigation of ancient bodies at Abydos– Challenging work in post-revolutionary Egypt. Lucy-Anne Skinner and Mohamed Ahmed Ibrahim.

Lucy-Anne Skinner spoke about the conservation of human remains at the site of Abydos, Egypt. Working for the Institute of Fine Arts, New York University project, Lucy had to engineer some novel solutions when two unusual burials needed to be block lifted. Lucy explained that block lifting an entire burial is not common at Abydos, as most graves are fully excavated in the field. Two graves excavated in the 2012 season in the North Cemetery presented unusually complete assemblages of grave goods, with one wearing a beaded headdress over well-preserved hair, and these factors prompted the conservators to block lift rather than to try to treat the components in situ.

The team of workmen working with the conservator helped build a wooden frame and slide metal sheets underneath, so that the entire burial could be lifted. Foil was used as a barrier layer, and expandable spray foam was used to lock components into place so that the burial could be transported back to the lab and eventually (in another field season) flipped over to work from the bottom to stabilize the lower portion of the coffin before addressing the human remains and other components. Lucy showed many details of the extraordinary finds including beautiful hippo ivory clappers. Though this project began in 2012, conservation of the burials was only completed a few days before this talk was presented (really!). Political instability in Egypt and the extraordinary logistical challenges surrounding excavating in a country undergoing political and social upheaval complicated the timeline and created extra challenges for the conservators.

Transporting a block-lifted burial to the depot at Abydos, Egypt (image courtesy Abydos excavations, Institute of Fine Arts, New York University)

For me, the big takeaways were that conservation in the field requires a great deal of planning and then a lot of on-the-fly creativity. Many digs lack a field conservator, but clearly the planning and execution of this complicated project really benefited from having Lucy on site over the course of multiple seasons. The project took several years to complete, so communication and planning in the off-season was needed for a successful outcome. Particularly challenging issues of working within Egypt while in the middle of a period of crisis were dealt with admirably by Lucy and her colleagues.

44th Annual Meeting – Research and Technical Studies Session, May 16, "Looking Closer, Seeing More: Recent Developments in the Technical Documentation of Paintings", by Ron Spronk

In the morning session on May 16th, Ron Spronk, Professor of Art History in the Art Conservation Program at Queen’s University, shared his experiences with several recent endeavors to standardize the technical documentation of paintings and to make the resulting information both accessible and user-friendly.

Followers of the Rembrandt Research Project will be familiar with the missions of the projects Spronk describes in that they each generally aim to comprehensively study the oeuvre of a single artist. However, the crucial difference is that the more recent ventures are web-based, open-access, and shareable, and they are highly reliant on the compilation and comparison of images obtained using consistent methods across institutional boundaries.

Spronk spoke first about Closer to Van Eyck: Rediscovering the Ghent Altarpiece, an initiative made possible through the partnership of many organizations, including the Royal Institute for Cultural Heritage (KIK/IRPA), the Getty Foundation, and the Netherlands Organisation for Scientific Research. During the presentation, Spronk briefly toured the audience through the website, which is beautifully user-friendly and self-explanatory. Definitions are available for each of the analytical techniques used, and it is also possible to download condition, materials research, and dendrochronology reports.

The follow-up website, Even Closer to Van Eyck, is set to launch shortly and will focus more on the treatment of the altarpiece. As the Getty Foundation website pronounces, “This second phase of the Van Eyck project will incorporate high-resolution images produced during and after the full conservation of the altarpiece, which is currently underway. The web application is expected to set new standards for digital projects related to art history and conservation by providing access to the decision-making process for the treatment of the altarpiece and by disseminating the open-source technology behind the website to the museum community.” Another extension of the Closer to Van Eyck website is VERONA, or Van Eyck Research in OpeN Access, which has aimed to study and document all paintings securely attributed to Van Eyck in a standardized manner. The resulting scholarship will be published online.

The Bosch Research and Conservation Project similarly attempts to consistently document the entire oeuvre of Hieronymus Bosch and includes restoration of nine works. Several structural treatments were supported by the Getty Panel Painting Initiative. The Bosch website shows three works represented by high-resolution photographs in normal light, infrared images, and X-radiographs, with a three-pane slider moving between them. Spronk described the method by which all of the images were obtained using a window frame, which lets the camera remain completely parallel, and showed a video demonstrating the documentation process. A larger website application is set to be launched at an indeterminate date.

Although not covered during the presentation, the abstract also lists the “Hand of the Master on panels by Pieter Bruegel the Elder,” a comprehensive workshop on Bruegel that took place at the Kunsthistorisches Museum in Vienna from November 24-25, 2015. The workshop program and a presentation by Angela Cerasuolo on The Parable of the Blind and The Misanthrope in the Museo Nazionale di Capodimonte, Naples may be found on Academia.edu.

In searching for these websites after Spronk’s presentation, it became clear that these projects are all very much in progress, and only partial information is, as of yet, available. However, these endeavors appear to be extremely promising. The Even Closer to Van Eyck website in particular is eagerly anticipated because it will share the methodology used to treat the altarpiece. Much as the altarpiece during treatment is itself on display, this website should set a new precedent for transparency and should further raise public awareness of conservation activities. The founding concept of comprehensive, standardized, and open-access documentation on which these projects are based presents an encouraging model that will hopefully one day become more common practice, providing greater opportunities for interdisciplinary research and collaboration.

44th Annual Meeting – Paintings Specialty Group Tips Session, May 17

This year’s Paintings Tips session focused predominantly on a range of commercial products that can be adapted for specific uses in paintings conservation.
Gordon A. Lewis, Jr. recommended powerful LED and UV flashlights for examination of paintings in-situ, which are available from Amazon.com. In addition to other uses, he demonstrated the suitability of these lights for transmitting a strong light through the back of a canvas to reveal tears and other structural issues.
Dina Anchin introduced the audience to the ProScope Micro Mobile, a hand-held, high-resolution microscope that attaches to one’s phone and allows the capture of photomicrographs. This is particularly useful when examining paintings in-situ or on research visits.
Alexa Beller presented on behalf of herself and Joyce Hill Stoner on miniature “Humidification Chambers,” using a moistened blotter placed within the lid of a pigment capsule (such as used for a palette of dry pigments) and positioned over the area of the painting requiring humidification.
Josh Summer recommended miniature hand mixers or milk frothers as a helpful and inexpensive tool for preparing emulsions and gels.
Erin Stephenson presented on behalf of Sarah Gowen, who has researched and tested a number of materials potentially suitable for filling cradled panel paintings prior to obtaining an X-radiograph. These fillers include Elvacite 2045, Elavacite 2044, Elvacite 2046, Poly(vinyl alcohol), Butvar B-76, Paraloid B-72, and wood flour. Of this list, Sarah recommends Elvacite 2045, as other materials tend to clump, are too visible in the X-radiograph, or produce slippery residues.
Claire Winfield described the recipe for a “milkshake” paintable fill (1 part Modostuc or spackle, 1 part acrylic gesso, dry pigment and water to taste), so-named because it is mixed to the consistency of a milkshake. This fill material can then be brush-applied within areas of loss and is particularly useful in retaining some canvas texture.
Gwen Manthey pointed out that many websites including Pinterest show helpful flat-lay pack methods when packing tools for on-site conservation work. She also mentioned that shaving brushes are often made of badger hair, and shaving product companies can be a useful source for these brushes.
Judy Dion presented a number of product recommendations, including washer head screws for attaching backing boards (such as Teks Lath Screws), a muffin cooling fan for low solvent extraction from studio spaces, and small LED spotlights with flexible necks for microscope work . Judy also demonstrated the use of a T-track for clamping, easel construction, or a height-adjustable armrest for working on large paintings.
Rustin Levinson spoke about the recent construction at ArtCare Inc. of a mobile paintings storage rack consisting of marine ply and PVC with clear vinyl flooring. The entire rack can be covered and moved around the studio.
Rob Proctor recommended a number of tools, including 1 mL calibrated glass droppers and vacuum nozzles adapted as handles for burnishers. To minimize shock to a painting during structural treatments, he also demonstrated using a nail pusher to insert tacks and using a clamp to gently push in keys.
A few attendees volunteered last-minute tips, including a portable Miroir projector for on-the-go presentations, and the brand Muji for black Q-tips, useful for testing sensitivity of light-colored paint passages.
The session ended with an update from Elise Clifford about the Reverse of Paintings Database being developed at the Fine Arts Museums of San Francisco. The completed database will allow users with a login to upload and search information related to the reverse of painting such as labels, canvas stamps, and stencils. If you are interested in participating in beta-testing of the website, you are invited to email Elise.
Thank you to all of the presenters for such valuable tips!

44th Annual Meeting – Photographic Materials Session, May 16, “Photochromatic Images of Edmond Becquerel: Where do the colours come from? Tracks in the understanding of the origin of their colours.” by Dr. Marie-Angélique Languille, Edouard de Saint-Ours, Jean-Marc Frigerio, and Christine Andraud

Edouard de Saint-Ours clearly described the fascinating work he and his colleagues have done to identify the source of the colors in one of the earliest color photographic processes. In 1848 Edmond Becquerel successfully produced a color photographic image, but himself was unable to identify the cause of the colors. The discovery of several of his early plates in the archives at the National Museum of Natural History in Paris sparked Edouard and his colleagues’ interest in Becquerel’s process and the source of his colors.
Edouard began by explaining the two known ways in which color can be produced in photography: through the use of colorants, or through the production of interference colors. It was assumed that Becquerel had been relying on one of these two types of color, and the research team focused on methods of analysis that would identify either of these two methods of producing color.
Becquerel’s photochromatic images were made by dispersing sunlight through a prism for several hours, exposing the plate in camera to form a direct positive. The images were not fixed, and will fade if exposed to light. In order to understand the physical and chemical composition of the Becquerel plate, Edouard and his colleagues replicated the technique themselves. To make a photochromatic image a silver plate was polished and cleaned, and sensitized by immersion in copper chloride, or by hydrolysis in a bath of hydrochloric acid. The latter is referred to as an electrochemically sensitized plate. Once sensitized, the plate takes on a red-brown hue. In the replication of the process the plates were exposed to a Xenon lamp with colored filters, and the colors produced on the plate corresponded to the color of the light.
Once they had replicated the technique, they set about studying their sample plates in order to identify the cause of the colors they had produced. SEM analysis and cross-sectional analysis showed that there were no surface or structural differences between the different colors. Although this suggested against interferential colors, it did not rule out the possibility entirely.
SEM-EDX offered the researchers more information about the chemical composition of the different colors, but also indicated no difference between the green and red colors on the sample plate. Both were almost entirely comprised of silver chloride. However, Edouard mentioned the very interesting possibility that very small variations in the proportion of silver could cause different sizes of silver nanoparticles to form on the plates. In this scenario, a different size of nanoparticle would form from each color of light, and the color of the silver nanoparticles would vary depending on their size.
From this hypothesis, the researchers performed spectroscopic analysis of the colored surfaces, a technique which can detect the chemical state of an element. However, this analysis showed only oxidized silver on all colors, with no indication of difference between colors, or the presence of metallic silver. Again, this suggests against the presence of silver nanoparticles, but does not definitively rule out that possibility.
Although the project has not returned any definitive results, the research is ongoing. In the meantime, the work has cast light on the complexity of Becquerel’s early process, and the intriguing questions still presented by early color photography.

44th Annual Meeting – Photographic Materials Session, May 16, “Understanding Temperature and Moisture Equilibration: A Path towards Sustainable Strategies for Museum, Library and Archives Collections,” by Jean-Louis Bigourdan

Preventive conservation is becoming an increasingly important part of our work as conservators, but it often seems that many important questions about environmental control have yet to be answered. Questions such as to what degree are fluctuations of temperature and RH humidity damaging to collections, and are they more or less damaging than strictly maintained but not ideal conditions?
Jean-Louis Bigourdan addressed some of these uncertainties in his talk on temperature and moisture equilibration in storage spaces containing significant quantities of hygroscopic materials. He focused on reconciling the need for climate-controlled storage with the quest for sustainability and the pressure of budgetary limitations. His introduction was reassuring: the current thinking on storage climate is that relatively stable low temperatures are desirable (“cool storage”), but there is little benefit to maintaining a perfectly stable climate (i.e. without fluctuations). Rather, a certain degree of cycling is acceptable, so long as the shifts are not extreme.
Following from this fact, Jean-Louis presented the concept of “dynamic management” of HVAC systems. Dynamic management entails shutting down the HVAC for short periods, such as overnight, and adjusting climate set points seasonally. This would save on energy, and thus reduce the environmental impact and cost of operating such systems. Of course, we as conservators are immediately concerned with the effect on collections materials during such shutdowns: How extreme are the fluctuations in temperature and RH resulting from periodic shutdowns of the HVAC?
This is the questions Jean-Louis attempted to answer through two phases of testing. He was particularly focused on the possibility that collections containing large quantities of cellulosic and/or hygroscopic materials might buffer against large or sudden shifts in temperature and RH. Jean-Louis undertook two phases of testing to understand the extent of the self-buffering capabilities of such materials. The first round of testing was conducted in the laboratory, and the second in library and archive collections storage rooms.
In his laboratory tests he exposed different types of materials to large fluctuations in temperature and RH. The materials included things like closed books, matted photographs and drawings in stacks, and stacks of unmatted photographs. He also tested the effects on these materials when they were placed inside cellulosic microenvironments, such as archive storage boxes, measuring the temperature and RH at the surface of objects, and at their cores. His results indicated that the RH at the core of books or stacks of cellulosic material does not change as rapidly as the exterior environment. Temperature equilibration occurred over a period of hours, and moisture equilibration occurred over the course of weeks or even months. Microenvironments increased the time to equilibration, mostly by controlling diffusion of air.
Another useful result of this laboratory experimentation was that it demonstrated that the moisture content of paper-based and film collections was more affected by environmental temperature than by environmental RH. In other words, at the same exterior RH, the moisture content of the collections object was lower at higher exterior temperatures. The laboratory testing therefore suggested that storage spaces with significant quantitates of hygroscopic materials will be buffered against large changes in RH and temperature due to moisture exchange with the collections materials.
Jean-Louis found that field testing in collections storage spaces returned many of the same results as his laboratory tests. 6-8 hour shutdowns of HVAC systems had little impact on environmental RH, and many of the systems they examined were already following seasonal climate cycles without causing dramatic shifts in the temperature or RH of storage environments. He encouraged conservators to take their collections materials into account when evaluating the buffering capacity of their storage environments.
I was very encouraged by these findings, although I have some remaining questions about the potential effects on collections materials. How much moisture is being exchanged with collections items in such a scenario? Is it enough to cause dimensional change in hygroscopic materials, especially on exterior surfaces, and will that contribute to more rapid deterioration in the long term? Regardless, I was happy to be prompted to remember that collections materials are an active part of the storage environment, not an unreactive occupant of it.
The talk wrapped up with Jean-Louis raising a few areas of further research. He hypothesized that changes in storage climate which are achieved through a series of small but sharp changes would result in slower moisture equilibration between environment and collections than would a change made on a continuous gradient. He also raised the possibility of predicting the internal moisture fluctuations of collections materials using their known hygroscopic half-lives. Both of these areas of research could be extremely helpful to conservators attempting any dynamic management of their climate control systems.
A particularly thoughtful question by an audience member provided the opportunity for more climate control wisdom. A Boston-area conservator of library and archive collections wondered whether it made sense to use dew point as the set point on HVAC systems in the winter to save money on heating costs, but during the summer to use RH as the set point to insure against mold growth. Jean-Louis felt this would be an unnecessarily complicated method of control, but offered a general rule for the storage of hygroscopic collections. He suggested thinking of lower temperatures as the primary goal, and of RH as important to maintain within a broader range. Lower temperature slow degradation reactions inherent to such materials, and so generally lower is better. However, RH need only be high enough so as not to embrittle material, but low enough to prevent mold growth. Essentially he suggested that if your RH and temperature are too high, you are better off reducing temperature slightly, which will slow degradation reactions, and as a side-effect your collections may absorb a small amount of moisture, thereby lowering the RH in the building environment.
Jean-Louis’s talk left me intrigued and excited about the possibility of taking advantage of hygroscopic collections materials to provide a more stable and sustainable storage environment.

44th Annual Meeting – Research and Technical Studies Session, May 16, 2016, “Combining RTI with Image Analysis for Quantitative Tarnish and Corrosion Studies” by Chandra Reedy

This talk focused on the combination of two technologies, Reflectance Transformation Imaging (RTI) and Image analysis. Much of the talk dealt with the application of these two technologies to evaluate accelerated aging or Oddy Test coupons in a quantitative manner. As the evaluation of Oddy tests has traditionally been subjective, making reproducibility problematic, I was particularly interested in the potential for quantitative analysis.
Reflectance Transformation Imaging (RTI) is a relatively inexpensive and simple tool that creates a mathematically synthesized image of an object’s surface from a series of image (typically ~36) lit from different angles and directions. The image produced by the RTI software can reveal visual information that is difficult to discern under normal conditions.
Image analysis software utilizes algorithms that enhance the visual separation of features and marks them for analysis, a process known as segmentation, thereby enabling those features to be quantified. The software used by the authors of this presentation was Image Pro Premier by Media Cybernetics, which has previously been used for thin section analysis of ceramics.
The authors used RTI and Image analysis in combination to evaluate Oddy test coupons. The process aided in visual assessment, improved the documentation of the results, and provided quantitative results. Adding RTI and Image analysis to the Oddy test protocol was not a cumbersome addition, requiring only ~ 20 minutes. It was noted that the type of coupon used made a big difference for this technique, as foil and bent coupons were not ideal since the added texture complicated interpretation of the results.
After exposure, the coupons were photographed and processed in batches by metal: silver, copper, and lead. A single image of the coupons was chosen from the RTI viewer and used for image analysis. A different protocol was used for each metal. The image of the lead coupons was converted to grayscale and the colors inverted, background, control, and corrosion areas were defined, and the “Smart Segmentation” tool used to separate and quantify them. The image of the copper coupons was not converted to grayscale and the variety of corrosion types were all treated the same by the segmentation process. The image of the silver coupons was converted to grayscale or pseudo-color to enhance differences before segmentation. The software allows for individual segmentation protocols to be saved and reused. The percentage of tarnished to untarnished surface could be calculated for each metal. Comparison with visual evaluation of test coupons yielded the following results:
Control or clear pass: 1-4% tarnish
Clear Fail: 45-100% tarnish
Pass for temporary use: 7 – 17% tarnish
The “temporary” category is particularly hard to judge when evaluating Oddy tests in the traditional manner, so this method seems to be especially useful in this case.
In addition to Oddy test results, RTI and image analysis were used by the authors to evaluate rapid corrosion tests and coating tests. In each case, like with the Oddy tests, the process provided good documentation as well as the possibility for quantitative results. The combination of these techniques seems to have great potential for a number of applications and their relative simplicity and inexpensiveness make them a great tool for institutions with limited analytical capabilities.

44th Annual Meeting – Photographic Materials Session, May 16, "Separation Anxieties: Freeing photos adhered to glazing or to each other" by Barbara Lemmen and Emma Lowe

This talk was split into two sections, beginning with a presentation by Emma Lowe examining the nature of the adhesive bond formed between blocked photographic prints (prints stuck together in a block) and glazing. This was then followed by Barbara Lemmen providing an overview of existing treatments used by photo conservators to tackle this issue.
The Experiment
Lowe’s research aimed to assess the nature of a blocked bond, and determine the factors that affect the bond e.g. surface finish, glass coatings, age of the bond.
She tested artificially aged samples of both glossy and matt prints adhered to three different types of glass including glass with no coating, glass with UV surface coating, and glass with integral optical coating. Half the samples were aged for 80 days, the others for 150 days at 30°C (86°F) and 50% RH.

Blocked glossy and matt DOP samples — Blocked glossy and matte DOP samples

Experiment Results
At 80 days, it was found that all the samples could be popped off the glass. At 150 days, 75% of the samples tore upon removal; glossy prints were even more likely to tear than matte samples.
XRF analysis of the gelatin layer pre and post-experiment showed that there was migration of the elements in and out of gelatin. At 80 days, there was a slight increase in Si in matte samples. At 150 days, there were changes in elemental composition. FTIR showed compositional changes in gelatin and glass pre and post experiment. SEM/EDS on cross sections of the artificially blocked samples showed the migration of elements across the blocked bond. Changes in elemental composition were seen within the gelatin colloid.
In short, Lowe’s experiment determined the following points:

The initial adhesion between matte finished prints to glass is stronger, but aging leads to a stronger bond between glossy finished prints and uncoated glass.
UV coating on glass acts as a barrier to adhesion
There is a migration of materials between 80 – 150 days; electrostatic attraction between the glass and print converts to a covalent bond, explaining the increased bond strength. At 80 days 100% of samples separated without damage, at 150 days 75% of samples tore from the glass.

Treatment Overview
Lemmen then presented a variety of techniques used for the separation of photographs from glazing or blocked prints. For prints on glass (depending on the sensitivities of the object), the introduction of heat or moisture allows the gelatin to swell; this can be done via local humidification, the targeted application of aqueous solutions, steam or immersion (less common). Mechanical methods include removing the object from glass with a blade, or breaking the glass using a glass cutter. Dry heat or freezing with dry ice can also be used as a form of separation.
Blocked prints can be peeled apart mechanically, or they can be swelled with moisture. While trying to peel the sections apart, the local application of aqueous solutions to the adhered areas can aid separation. Overall humidification can be done on fiber base only. Splitting the RC prior to immersion was also discussed.

what works reliably — Treatment options for fiber base and RC prints

In conclusion, it was recommended to prioritize treatment of prints adhered to glass. In the occasion where prints need to be framed without a window mat or spacer, use UV filtering glass face-in to reduce the possibility of adhesion.

AIC Quebec City Trip Travelog Part 3

On our final day we split up into two groups: one traveled to the archives of the Musse de l’Amerique Francophone part of the Musées de la Civilization and the other to the storage facilities of the same museum network. The tour of the storage facility was led by one of the museum’s curators, who wove several fascinating stories about items into our visit (including an especially intriguing and gruesome tale about the gibbet of Marie-Josephte Corriveau that recently made its way into the museum’s collection). The storage center organizes collections primarily by material and preventative conservations needs. Rooms are titled by their principal contents, such as large objects and furniture, small wooden objects, paper, metal, etc. Each room’s temperature and relative humidity vary according to the items in storage. The facility also includes large rooms for initial quarantine, cool and cold storage, a relatively small conservation lab for minor treatments, and an area for documentation. Despite the large scale of the storage spaces, barely a speck of dust could be found anywhere and it was clear that the collections are cared for very well. We only stayed for the morning, but we easily could have spent an entire day or weekend just to see the facility in its entirety.

Storage facility of the Musées de la Civilization

After our tour we headed back to the Chateau Frontenac on our bus, being sure to give Ruth Seyler a large round of applause for a productive meeting and a marvelously-planned tour of Quebec City. Old Quebec is sure to charm any visitor with its historic ramparts and European flair, although the opportunity to experience the city and its museums with historians and conservators was an especially wonderful treat.