This talk was a good example of collaborative art historical and material science research. Two of the three authors, Kaslyne O’Connor and Ariel Pate, discussed a study that revolved around two gum-platinum prints by Edward Steichen from his 1904 “Moonrise” series in the collection of the Art Institute of Chicago that had titles and dates under question. Each print had been referred to by different names (“Midnight Lake George” and “Moonlight Lake George“), and varied in tonality and surface sheen (you will notice that the prints have the same titles and dates on the Art Institute of Chicago website). Furthermore, the image in one of the prints is flipped horizontally.
A letter from Steichen to Stieglitz talks about “Midnight Lake George” being a platinum print followed by blue print, then greenish gum varnish. This letter is a valuable piece of information, along with X-Ray Fluorescence and Fourier Transform Infrared Spectroscopy that gave characteristic signals for Prussian blue, platinum (“Midnight…” had more), palladium, mercury (traces in “Midnight…” only), chromium, iron (“Moonlight…” had more), and lead for both prints. Still to be determined is the distribution of Prussian blue throughout the print, which would suggest the cyanotype process vs. a Prussian blue watercolor wash over the entire surface of the print. Clip marks at the print edges did displace the gum layer, thus revealing a blue layer below, which could be a hint that the cyanotype process was used. Examination of “Midnight…” under ultraviolet light exhibited a green fluorescents characteristic of linseed oil.
A Camera Works supplement from 1906 refers to “Moonlight…”. A 1910 Albright Art Gallery catalog for the “International Exhibition of Pictorial Photography” refers to “Moonlight…” having been made using a platinum gum process “peculiarly [Steichen’s] own”. Ultimately, a timeline was proposed by the authors using the information gathered from this research, which supports the 1904 (“Midnight…”) and 1909 (“Moonlight…”) printing dates for each. More apt titles were also proposed–”Road to the Valley, Moonrise” for “Midnight…” and “Road to the Valley, Moonrise Lake George” for “Moonlight”. Something that was noted that I found to be particularly interesting was that Steichen became less “poetic” in his later years, and retitled many of his prints.
Also to note, this project was born out of a previous project to create the website The Alfred Stieglitz Collection, a rich resource recommended to visit.
Nathália Vieira Serrano’s talk focussed on the “incorporation” and “disincorporation” (accessioning/deaccessioning) of archival documents in the Department of Archives and Documentation at Casa de Oswaldo Cruz, in Fundação Oswaldo Cruz, in Rio de Janeiro. She discussed the overarching framework that was developed to help guide decisions of accessioning and deaccessioning collection materials, and then as a case study, the application of this framework to a specific collection–a collection of history of science of public health. This collection consists of glass plate negatives, roll and sheet film, all by various photographers and on different themes including, history, health education, scientific divulgation, and life sciences. A survey determined that the images were still in good shape, as were their supports.
The talk was a nice example of the challenges staff in the world of preservation face when needing to determine what can stay and what needs to go, the many factors to consider, and the criteria and prioritization to establish when making such important decisions. Serrano mentioned the mission of Casa de Oswaldo Cruz, the difference between multidisciplinary vs transdisciplinary, and the different stakeholders (researchers, collection managers, and potential current and future interested parties) that are taken into account. She also referred to Salvador Muñoz Viñas writings on contemporary theory of conservation and his statement that conservation is not a neutral act.
I appreciate how it is difficult to convey fully in a 20-25 minute talk the complexity of these types of projects. There are so many interesting points to think about, large and small, and people from different points of interest that are part of the decision making process. If there is one area I would have been interested in learning more about, it was some similarities and differences in their approach when compared to other national and international institutions. The presentation also gave insight to a large collection in Rio de Janeiro, how it is stored, and the building and environment that surrounds it.
Two questions that were asked after the talk were:
Is cost considered when deciding whether or not to deaccession? Answer: The survey is still underway, but cost will likely be considered.
What is the size of the collection? Answer: Still to be determined. (But an image was shown of the storage area the collection takes up)
Despite describing himself throughout his presentation as a 20th century dinosaur, Jonathan Ashley-Smith gave a very humorous and thought-provoking presentation on a topic that is very relevant to conservators of this and any other century. It overlapped and contrasted in a very interesting way with Elena Torok and Meg Loew Craft’s paper, presented shortly afterwards, “In Support of the Bigger Picture: Preventive Conservation as a Recognized Specialty”.
There was a lot of depth to the presentation – too much to be clearly conveyed in this post – and I hope that a paper is published so that I and others can take the time to digest and debate the issues raised. To cut to the chase, Ashley-Smith’s presentation lamented the loss of in-depth treatment knowledge and well-developed hand skills in the ‘modern’ conservator. He attributed this partly to the increase in preventive conservation activities in institutions, partly to the shift away from a craftsman model towards a more intellectual or scientific focus, and partly to a decline in the teaching and maintenance (including professional development) of interventive treatment skills.
In presenting this thesis, Ashley-Smith did not deny the need for preventive conservation. He sees the increase in preventive activities as a response to budgetary pressures, where arguments of economies of scale and the risks associated with interventive treatment are encouraging institutions to favour “doing nothing”. He does remind us, however, that preventive conservation does not do nothing – you can alter the dimensions or rate of degradation of artifacts through altering their storage climate – with obvious potential benefit as well as risk. Furthermore, objects are not held in suspended animation in storage, they are just in a waiting room until they are “displayed, mended, rehoused, thrown out, studied or mauled”. In storage risk can be controlled but not eliminated.
With regards to his second point, Ashley-Smith argues that the decline in practical skills has occurred due to an increased focus on the intellectual, brains over hands. He cites the example of a skilled conservator with 40 years experience who was asked to leave his university teaching position because he did not have a doctorate. This is causing a decline in standards where conservators no longer have the required knowledge and hand skills to undertake complex treatments. In such a case it is unethical to undertake treatments where you do not have the required skills and experience, but it is not because the treatment in itself is unethical.
In addition, Ashley-Smith contends that there has also been a move by professional conservation associations to reduce risk, which is being achieved through increasingly narrow interpretations of what constitutes ethical treatment. In their turn, codes of ethics reference greater enforcement of ethical standards, with associated exclusion of those who do not meet the standards. This can be exacerbated by
social media where conservators can be shamed away from actions that others believe are wrong, and leads both to conformity and hiding skills, also preventing the development and celebration of treatment skills.
As a solution to these issues, Ashley-Smith has several propositions for conservation professional associations: to embrace diversity and inclusion, and reject conformity, through stimulating consistent reasoning and active discussion, and encouraging individual accountability; and to create more fellowships and internships for further study and practice of interventive treatment in individual conservation specialisations. If institutions are unable to accommodate this then it could be achieved by supporting the private conservation sector to offer training in hands on skills.
In finishing with a quote from Joni Mitchell, “that you don’t know what you’ve got ’til it’s gone”, Ashley-Smith left the audience to think about and debate this important topic.
As a library conservator, I enjoy breaking out of my niche by attending art-related talks, because it gets me back in touch with my roots as an artist once upon a time. I knew Samantha’s talk was not to be missed. She has shown through previous research that the conservation of modern and contemporary art on paper is exciting, as you often have a more direct link to the artists when treating their work. While the Hungarian-born artist Sari Dienes (1898-1992) is no longer living, I was confident Samantha would still get to know the intricacies of this unique artist thoroughly. There has never been a better, more urgent time to focus on the influence and mastery of women artists as it is now, in our current political climate, where suppression of the female voice rises as a concern once again. Samantha’s timely and engaging talk grabbed my attention not only for its focus on an unsung 20th century female artist but for the way Samantha, paper conservator at the Virginia Museum of Fine Arts (VMFA), throws herself into her projects wholeheartedly.
By now many colleagues have heard about Samantha’s research and treatment of original artwork by the tattoo artist “Sailor Jerry” during her time as paper conservator at CCAHA. I admired how much her work on this project became a part of her, literally and professionally. The tattoos she took away as a permanent “souvenir” of this work, on her own skin, really left an impact on me. Having overlapped with her in grad school at Buffalo, I remember how much Samantha loves her work and shows a special curiosity. Samantha’s project on Sari Dienes’ large-scale rubbings was no exception.
While Dienes worked in many mediums and styles throughout her lifetime, Samantha presented Dienes’ rubbings of manhole covers, which she created using brayer-applied ink on Webril – a material used in the medical field as padding between skin and cast. While Webril today is commonly 100% cotton, it was not in the past, and the fiber composition of the Webril Dienes used was not recorded. True to her immersive spirit, Samantha travelled to the Sari Dienes Foundation in Pomona, NY, where she was able to collect historic samples of materials from the artist’s collection to use for testing and analysis. She explained that identification is not resolved as she seeks colleagues with fiber samples she might use for comparison, since her reference library did not provide a match to her FTIR analysis.
Samantha Sheesley creates a rubbing of a manhole cover in the style of Dienes
In her presentation, Samantha led the audience on a manhole scavenger hunt through the streets of NYC, where she traced Dienes’ steps at the artist’s preferred working time, Sundays at 5am. Samantha wondered how Dienes navigated the city streets with all her required bulky supplies, and explained that Jasper Johns sometimes served as her assistant. Dienes would talk to people passing by on the street as she worked, which is inevitable in the extroverted city of New York. To get a sense of the physical work required, Samantha produced rubbings in the same manner as the artist.
It’s impressive how well-connected Dienes was to artists of the time, but because she was a woman, she was not well-liked or accepted by the many of her male contemporaries. Jackson Pollock spoke poorly of her, but she collaborated with Jasper Johns and Robert Rauschenberg for an exhibit in the Bonwit Teller department store in 1955. The VMFA acquired two of the manhole rubbings that were at Bonwit Teller, which were in poor condition. One of the pieces Samantha focused on is titled “Marcy.” It was stapled to an acidic cardboard backing, which subsequently discolored the Webril, along with displaying many other condition problems.
Samantha Sheesley treats “Marcy” at the VMFA
The goal was to repair Dienes’ work in order to restore her legacy and display all the manhole rubbings together again. After much testing on samples, Samantha decided to wash the delicate Webril supports using wet Tech Wipe, and created over 70 inserts using acrylic-toned Hanji adhered with methyl cellulose. Pastel pencils were used for visual integration. The work was logistically challenging and time consuming, to say the least, but the audience was able to see clearly how much care was taken with excellent results depicted in Samantha’s treatment photos.
I was thrilled to be exposed to an artist I never heard of, but who was in fact so very influential. Samantha explained that Dienes’ work not only influenced Rauschenberg and Johns, but was associated with Fluxus artists such as a personal favorite, Naim June Paik. Dienes believed any material could be used to create a work of art and to end her presentation, Samantha shared an inspiring Dienes quote that deserves to be passed along: “Spirit lives in everything. It has no age, no color, no sex.” Samantha should feel proud of sharing the life and work of a woman who influenced many, while standing in the shadows of history. One of our greatest responsibilities and joys as conservators is to repair artifacts so that silenced voices can be heard once again. Samantha continues this charge with admirable determination.
Having a new conservation space built is the greatest hope and fear of many conservators – such an opportunity to take advantage of, and also to potentially go wrong! Justin Johnson’s presentation about their experiences at the University of Washington Libraries in Seattle, WA was a great insight into the process, and, given they seem to largely be pleased with the outcome, demonstrates that you sometimes can get what you want, as well as what you need.
The previous conservation space was located in a basement, cramped at only 2000 sq ft, and had last been updated in 1963. A new conservation position, partly funded by the Andrew W. Mellon foundation, was the impetus to create a new conservation space with more up-to-date equipment and space for the now four full time conservators, plus up to three part-time students and interns.
One of the early things the conservation team did was to create future goals for their space. Some of these included:
increasing the ability to undertake major treatments on collection items, while maintaining general collection work
incorporate book, paper and photograph treatments in the same space
have the ability to teach and train student conservators and interns
have a flexible and open space that could be used for workshops and research as well as treatment
The team also consulted widely with conservation scientists and treatment conservators of many disciplines.
A new space on the rooftop was identified, double the size of the previous space at 4000 sq ft, with natural light from five skylights. However, there were limitations on HVAC and ducting placement for a fume hood. Services with restrictions were placed in the design first, with other equipment fitted in around them. The fume hood location was determined first, followed by the rest of the wet lab: sinks, exhaust trunks, microscopy, suction and humidification, light bleaching and materials storage.
A multi-purpose documentation room was designed, where curtains could screen off an area to allow for photography or artefact examination and low-tech analysis, but still allow the space to be open to the rest of the lab area.
At one end of the main space a storage, office and reception area was located, with the rest of the space being fitted out for the main treatment work, including space for 10 work benches and more storage. This space had an open focus to encourage communication and collaboration as well as reconfiguration, when required.
While an architectural team was engaged to create the space, the conservation team were heavily involved, thinking through the design of furniture (especially for storage purposes) and thoroughly investigating the departmental work flows and how they would work in the space.
The conservation team drew their workflow movements on paper and overlaid them on the design drawings and also used computer tools, such as Live Home 3D Pro, to visualise the space and move furniture around to try out new orientations. This software was very useful to ‘walk through’ the space, make adjustments to the design and then send them via pdf to the architects. It also facilitated communication between the conservators and architects and saved a lot of money in lengthy redesigns which would have occurred in a later phase of the project.
15 months after the initial bid phase, the team moved into their new space in February 2016.
Questions:
Q1) What is the climate and do you know the air exchange rate? A1) Aiming for 70F/50% but are still in the process of balancing the AHUs. They are finding that the fume hood competes with the HVAC.
Q2) Who did the lighting design? A2) It was done by a UWA group at the end of the project; the Live Home 3D Pro software has a large database of furniture and lighting which can be added to the design.
Q3) What was the total budget? A3) Got support from the Mellon grant, UWA donors and campus funding. A lot of money was saved in design fees by the proactive work of the conservation team.
Q4) What was the size of the benches and the area around them? A4) The benches both fixed and moveable are all the same height and measure 60” x 38” with 3.5’ between benches.
Q5) Detail on the skylights: specification and R values? A5) The lighting system has an automated system to take the daylight into account; the lights reduce on a bright day (which is rare in Seattle!).
This year ECPN rolled out a new program during a pre-meeting session that allowed poster presenters another venue to share their projects and research. I was very excited for this session because I have felt overwhelmed by the number of posters and limited free time to view them. A similar sentiment was later echoed at the AIC Business Meeting. I hope that ECPN (or AIC generally) considers organizing a similar session next meeting and I would encourage anyone looking for more engagement with poster authors to attend.
This session was in no way comprehensive of all the poster submissions. ECPN members received a notification about the session about a year before the meeting. However, ECPN contacted all poster authors once they were accepted to the general AIC poster session. The email solicitation encouraged “emerging conservation professionals” and “topics relevant to ECPs (not necessarily authored by ECPs)” according to Rebecca Gridley, ECPN Vice Chair and one of the organizers of the session. There were 14 presenters total this year, which were chosen from email responses of poster authors indicating an interest in participating. The final selection was chosen to offer a range of talks across specialties and include speakers spanning the ECPN demographic, according to Gridley. Unfortunately not every author interested was able to be included due to time restraints of the session, but ECPN is considering how this could be improved in the future.
This year’s inaugural Lightning Round did seem to have mostly young presenters including pre-program, graduate students, and recent graduates. It does seem that ECPN is trying to be more inclusive and the demographic of “ECP” is only loosely defined. Certainly the audience this year was more diverse than the presenters and included AIC Fellows and other more established professionals in the field. At the same time, the environment of the Lightning Round felt very safe and welcoming. We were seated at round tables, which was more casual than auditorium seating. This was a great opportunity for first-time presenters to get their feet wet. One of the speakers was a first-time attendee and presented on her first conservation treatment ever as a pre-program. This session promoted information sharing and dialogue—activities that I personally feel will only help strengthen our field.
Alex Nichols reflecting on the benefit of the Lightning Round said, “I was approached by several conservators and researchers in specialties other than my own [modern and contemporary objects] who said that they were introduced to my research through the lightning round presentations.” In comparison to the last time Nichols presented a poster (at the 43rd Annual Meeting in Miami), she had more people ask about her research, which she attributes to the exposure from the ECPN Lightning Round.
Cathie Magee presenting alongside Michiko Adachi at ECPN Poster Lighting Round. The moderators are seated at the table.
The 14 poster topics were divided into two rounds, which allowed for a necessary intermission/bathroom break. The rounds were moderated by Michelle Sullivan, ECPN Chair, and Rebecca Gridley, ECPN Vice Chair.
In the spirit of the “Lightning Round” each presenter was given two minutes and three content slides to summarize their poster at the podium. This seemed like a daunting task and like I might not receive much more information than the title of the poster. I was really impressed with how clear and concise all the speakers were (I think the tambourine—symbolizing time’s up—only had to be used once). I learned a lot from the brief presentations and there was even time for one or two questions for every speaker. Having the visual component of the slides I felt took this beyond what a written abstract can offer. The Q & A was also very lively and I think emphasized how valued the poster presentations are to the conservation community.
I found this Lightning Round useful not only for the direct information, but also in helping me be more efficient with my time in the exhibition hall with the posters. Each PowerPoint included the poster number for easy reference to the location in the exhibit hall. Feeling similarly, Claire Curran, Assistant Objects Conservator at the ICA, also in attendance, and reacted, “definitely visiting this one—sounds really cool” in response to a treatment of a Hopi Katsina doll. The room was filled and there seemed to be a strong positive response to the session.
To keep things light and encourage additional networking during the ECPN Happy Hour (which immediately followed the Lightning Round) a fun fact about each presenter was announced in addition to his/her professional bio. For example, Sarah Giffin was introduced as the “meat whisperer” because of her delicious slow cooking brisket recipe.
I am embarrassed to say that I did not know that the posters are published on the AIC website after each Annual Meeting. You can access them here.
To help your exploration of the .pdf files online, here are some of the highlights each presenter chose to emphasize during the ECPN Lightning Round.
#30 Conservation in Miniature: The merger of museum object and historic interior in the treatment of a Victorian era dollhouse
Sarah Giffin
Applied in situ treatment methodology used for full-scale interiors to miniature interior of Horniman dollhouse
Mist consolidation with nebulizer using Klucel G in acetone (tests in water solubilized tannins in wooden walls creating issues with tidelines)
Condensation in the small tube was a challenge and had to tap out liquid droplets at times
#60 Conservation and Art Historical Data goes Digital at the Art Institute of Chicago
Kaslyne O’Connor
Interactive website for conservation treatment of a collection of Alfred Stieglitz photographs and some contemporaries
artic.edu/Stieglitz
Used WordPress platform because easy interface and allowed for frequent updates to content
Provides links to art historical information as well conservation/ technical information and research
#44 Applying Fills to Losses in a Flexible Polyurethane Foam Chair at the Museum of Modern Art
Alex Nichols
Research and analysis to confirm type of foam composition of the chair
Bulked methylcellulose and grated polyurethane foam for consolidation and filling of losses; liquid nitrogen helped harden foam enough to easily grate and shape
Inpranil DLV/1 is a traditionally favored consolidant for polyurethane foam but has been challenging to acquire
#92 Chemical Cleaning and Intervention Criteria in a Brass Dial Clock from the XIX Century
João Henrique Ribeiro Barbosa
Clock face (only surviving element of the clock) composed of three different metals joined together with rivets
Previous cleaning by polishing left white residues and new corrosion products developed underneath
Ammonium citrate solution addressed polish residues with “DTCNa” or sodium diethyldithiocarbamate solution addressed corrosion products
#24 History, Treatment, and Preparation for Digitization of 14th-century Estate Rolls
Annabel Pinkney
Surface cleaning, humidification, repair with Japanese tissue
Rehousing to handle during treatment, digitization, and future research
#42 Treatment and Reconstruction of a Badly Damaged Hopi Katsina Doll Made of Gourd
Hayley Monroe
Gourds painted in acrylic
Treatment included surface cleaning, consolidating cracks, introducing new internal armature to help with reassembly and stabilization
Used silicone self-adhering bands to secure while mends were setting
Armature was set in place before doll head was reattached; tensioned wire extending to wings before head was placed back on
#10 Towards Nondestructive Characterization of Black Drawing Media
Nathan Daly
Redon drawings were used for case study
Redon working period overlapped with commercial materials available in 20th century
Macro XRF scanning used to map elements combined with micro Raman spectroscopy
Characterization relied on peaks in fingerprint region and peaks indicative of known additives to distinguish between different carbon-based media
785nm laser for Raman because of heavy use of fixatives on the drawings
#27 (I Can’t Get No) Documenation: Preservation reporting in the Archives
Marissa Vassari
Established a template “Preservation Report” for standardized documentation and condition reporting
Focus on up-to-date condition and documentation of current status of projects and personnel involved; address realities of institution with changing/temporary staff and disruptions project workflow
Format based on feedback from other institutions and existing condition reports in the archive
#80 Bedbugs: A pesky problem
Meredith Wilcox-Levine
Addressing infestation of a Lakota teepee in private hands installed behind owner’s bed
Freezing unsuccessful likely not able to achieve low enough temperatures throughout
“Solarization” using hatchback car appeared to work (i.e. no live bugs remained)
For domestic infestation chemical treatment often necessary for bed bugs; they are night feeders and hide during the day
#32 Treatment of a Shattered Bark Basket from Australia
Marci Jefcoat Burton
Basket likely eucalyptus bark sealed with natural resin
Consolidated with B-72; bridged with tissue and blend of Lascaux adhesives
Removable internal support for storage constructed of backer rod (trapezoidal shaped Ethafoam strips) shaped to the contour of the basket and padded with Volara
#84 Lifting the Microfiber Veil: Utilizing Evolon fabric at the Mauritshuis to remove aged varnish from Hendrick Heerschop’s A Visit to the Doctor
Julie Ribits
Evolon is 70:30 polyester: polyamide spun-bond fabric
Evolon originally developed as anti-bug fabric
Used to lift and remove aged varnish; gentle and appropriate for surfaces with extensive lead soap networks
Polyamide fibers are hydrophilic and contribute to aqueous cleaning
#22 Captain America Encounters Klucel M
Michiko Adachi and Cathie Magee
Captain America pages had been stapled together in case binding
Mending utilized solvent reactivated tissue to avoid solubility issues and tidelines from acidic migration of newsprint substrate
Klucel M used as adhesive because of strength and transparency
Klucel M artificially aged by Library of Congress and seems to have similar properties/behavior to Klucel G
#67 Initial Treatment Techniques for Japanese Lacquer-based Metallic Thread and Cut Paper Applique
Elinor Dei Tos Pironti
Solubility testing was used to characterize original adhesive for metallic paper threads on a Japanese garment
Urushi was used to consolidate metallic threads
#31 Under Close Observation: A pilot study monitoring change in objects’ conditions
Ashley Freeman
Summarizing current research and findings of the Managing Collections Environment Initiative at the Getty
Comparing different methods of monitoring conditions of objects including photographic documentation (DSLR, point and shoot camera, iPhone), caliper measurements to monitor cracks, acoustic emissions
14 objects representative of materials found in institutional collections used for case study; exposed to humidity cycling
Remy Dreyfuss-Deseigne described research related to mending methods for transparent materials using nanocellulose films. His research has been carried out with several institutional partners, at the National Library of France (BnF, Paris, France), Research Center for Conservation (CRC, Paris, France), French Museum of Cinema, and during his 2015-2016 NEA fellowship in paper conservation at the Conservation Center for Art & Historic Artifacts (CCAHA, Philadelphia, PA).
Remy opened with some images of difficult structural problems: torn gelatin windows, animation cells, and architectural drawings on tracing paper. He then introduced nanocellulose, explaining how it is made, what its properties are, and its potential for use in conservation.
His work focuses on one kind of nanocellulose, microfibrillated cellulose (abbreviated MFC). Nanocellulose materials are produced for a variety of uses in electronics and biotech, and are being researched and manufactured by several universities including in Grenoble, France and at the University of Maine.
Nanocellulose is produced by mechanically shearing wood to rip apart the fibers until they are nano in scale. Cotton, spruce and birch can all be used as sources for nanocellulose. The amorphous parts of the remaining cellulose structure are treated with acid in order to dissolve them, leaving highly crystalline fibrils. There is a lot of ongoing research into the production of nanocellulose in the nanotechnology, renewable materials, and sustainable engineering fields.
Nanocellulose fibrils vs. crystals, image from: https://3dprint.com/69012/american-process-and-ornl-say-nanocellulose-will-rival-carbon-fiber-for-3d-printing/
For conservation applications, Remy compared the properties of nanocellulose films to lightweight Japanese papers like gampi and kozo used to mend tears on translucent artworks. Nanocellulose is supplied as a gel that can be cast out by pouring into a petri dish and evaporating out the water, creating films that vary proportionally in thickness related to concentration. Remy’s research investigates its properties in combination with different adhesives, and its response to artificial aging tests (light, temperature and humidity) as well as mechanical strength tests.
He found that the nanocellulose films were thinner than papers but quite strong (nearly as strong as Gampi), and mostly behaved like cellulose, a good thing for their use as a paper conservation material. Most importantly, mends made with the thin films are practically invisible in regular and transmitted light. These mends were demonstrated on translucent slides with tears from the collection of the French Museum of Cinema (impressive work!). Ongoing testing will include further analysis of the material, e.g. pH and mechanical strength measurements and fungal resistance tests.
While this was the first time I had heard about nanocellulose it has many potential uses, and not just for mending translucent materials. As a biomaterial derived from renewable forestry resources, nanocellulose has gotten a lot of attention over the past five years for its potential in industrial applications. Given its high ratio of strength to weight it has great potential for use in fill materials of all types, and has already found applications in industrial 3D printing as a substitute for carbon fibers in composites. Since it is compatible with many adhesives, it may find wide-ranging applications in conservation. I am looking forward to hearing more about Remy’s ongoing research and thank him for the excellent introduction to an interesting material. You can learn more about Remy’s work at his website.
Jan Cutajar is Research Assistant at the University College of London, and Hana Bristow is Assistant Conservator at the National Museum of the Royal Navy, Portsmouth. They jointly presented on their experiences making acrylic resin fills with Paraloid B-72, an acrylic co-polymer, for use with glass repair. They based their work on techniques previously established by Steve Koob from the Corning Museum of Glass and recently updated at the CCI Symposium in 2011 (See here for the last update: https://www.cci-icc.gc.ca/discovercci-decouvriricc/PDFs/Paper%2035%20-%20Koob%20et%20al.%20-%20English.pdf).
Cutajar and Bristow treated two archaeological glass vessels: one Sassanian glass from UCL, and one beaker from Exeter, as case studies. They had common goals of needing reconstruction, stabilization, and the ability to be studied. They also had similar physical characteristics of degraded but stable glass with relatively good contact between the extant shards, thin walls (as thin as 0.2 mm), and substantive loss around of 35%.
Detail of resin fill in place on the Exeter glass jug (300/1988/G155, Royal Albert Memorial Museum, 2015). Photo by Hana Bristow
In looking for a fill system, they wanted a material that could reinforce weak areas, aid in practical assembly, and be as minimally interventive as possible. Since working with epoxy would require considerable manipulations with the artifact for both direct and indirect casting methods, this was not chosen. Instead, acrylic resin fills were explored because they are lightweight, strong, flexible, thin, detachable for future retreatment, simple to produce and insert, and can be manipulated for color and opacity matching.
Detail of resin tab application on Sassanid glass vessel (6300, UCL Conservation Teaching Collection, 2015), highlighted on the left and blended against the glass on the right. Photo by Jan Cutajar.
Koob’s technique is based on 30% w/v Paraloid B-72, an acrylic co-polymer, in acetone, with ethanol added to slow the evaporation rate, thereby reducing the potential for bubble formation. For coloring, ground pigment can be added to the ethanol before adding it to the resin mixture. The pigmented ethanol should be first decanted to prevent larger pigment particles from being added. The solution is cast and stored in a partially sealed environment for slow evaporation. Bristow felt that B-72 alone was too flexible, so she explored resin mixtures and tested varied proportions using B-72, B-48N or B-44 either straight or mixed in 2:1 ratios but always 30% in acetone. She also tested these opacifiers: fumed silica, marble dust, titanium dioxide and whiting. She cast the test resin mixtures in boxes of the same size, also holding the volume and concentration of the solution and the volume of added ethanol constant. The tests were evaluated after 4-5 days of curing for hardness, plasticity, and appearance. She found that a 2: 1 solution of B-72: B-48N produces a strong film without brittleness. This film was stronger than the B-72 film and not brittle like the B-48N alone or B-44 films.
The resin films are set to cure in a partially sealed solvent atmosphere. Photo by Hana Bristow.
For the opacifiers, Bristow found that fumed silica worked well for adding translucency, and marble for opacity, but whiting and titanium dioxide produced speckled results and were difficult to homogenize with the mixture. She also notes that dry artist pigments are good for tinting but shouldn’t be relied on for opacity as well, because they easily over saturate the mixture, resulting in a cracked and weakened cast. She recommends a maximum of 1.5 micro-spatula scoops per 30 mL resin mix.
Cutajar and Bristow offer some practical notes and tips:
Achieving desired film thickness can require some trial and error. Expect about 70% volume shrinkage.
Trays should be non-absorbent and easily release the resin. Making or using solvent-resistant boxes lined with release papers or films works well.
Enclose the poured resin trays in an acetone rich environment to slow the rate of evaporation. This will help prevent bubble formation.
Films should set for at least 4-5 days before removing, otherwise the films are too flimsy for these applications.
Films are best to manipulate directly after demolding. Things that can be done are:
Texturing
Shaping
Cutting – determine the size by taking a tracing of the loss area
Shape can be adjusted using heat; about 20 seconds under a hair dryer works well. Once warm, hold the cast in the desired position until it cools enough to hold the new shape. This can be done through repeated heating and cooling cycles until desired shape is achieved.
Adapt a cast by creating a lip at the edges where joins are very thin. This creates a slight overlap with the adjacent glass. The lip can be created with a heated spatula away from the glass.
Bonding can be activated with acetone, but Cutajar and Bristow suggest using more adhesive (Paraloid B-72) to make the join since acetone can compromise a good fit.
The film can be cut into tabs and used as reinforcements across joins. Cut the tabs into shape, lay them across the join, and activate with solvent. The tabs are virtually invisible.
The film can be used to make recessed fills for backing thin, curved glass, providing local stabilization and weight redistribution.
Backing films are easier to apply when they are freshly removed from the solvent atmosphere and retain a slight tack.
Paula Artal-Isbrand, Objects Conservator at the Worcester Art Museum, presented the various ways in which she uses paper in her objects treatments. She shared some background on paper types. Asian papers typically come from the paper mulberry tree and produce long fibers (kozo) and strong paper or from the gampi tree, producing shorter fibers to make crisp and translucent papers. Mitsumata shrubs are a third source, but not part of this presentation. Western papers are more often made from cotton, linen, flax, or hemp. Paper in conservation is strong, inert, compatible with conservation materials, has excellent long-term stability, and does not pose health risks. It can also be manipulated to mimic a wide range of materials through inpainting and coating. By choosing the right coating materials, the translucency and texture can be adjusted to fit the application. These papers can also be inpainted with standard inpainting materials to match color and texture.
Beaker, Roman, 3-5th century CE, glass, 15.5 x 7.0 x 6.5 cm. Sardis archaeological site (Turkey), Inv. # AhT67.IV.130N3,before and during treatment using kozo paper saturated with B-72 acrylic consolidant (Courtesy of Sardis Archaeological Excavation, photo: Paula Artal-Isbrand)
Artal-Isbrand outlined two ways for thinking about how to use paper. First, it can be used as a restoration material. Artal-Isbrand offered several examples of how she’s used paper in this way. For example, she used acid-free matboard cut into shape for a loss repair in a fan. For archaeological glass, she toned paper kozo paper with watercolors (not with acrylics since they would create too much opacity) and impregnated the paper with Paraloid B-72, acrylic co-polymer. The toned and resin soaked fill was a perfect match for the glass and was attached with Paraloid B-72. She has made paper fills to reconstruct chain mail, for joining heavy elements of an iron helmet, for reinforcing failing solder joins for bronze armor, and for backing a Roman lead curse tablet that needed to be unrolled. These repairs were carried out using a combination of kozo paper with Paraloid B-72, and are a testament to the paper’s strength. Artal-Isbrand also described that paper can be an interlayer between an artifact and fill material to ensure reversibility and how cellulose powder can be a bulking additive for fills, and if toasted, can also impart pigment to fills.
Missyurka turban helmet, Ottoman Empire or Caucasus, 16th century, iron, 29 x 18 x 18 cm. Worcester Art Museum, 2014.102. Bequest of John A. Higgins, during and after treatment with kozo paper strips. (Courtesy of Paula Artal-Isbrand)Missyurka turban helmet, Ottoman Empire or Caucasus, 16th century, iron, 29 x 18 x 18 cm. Worcester Art Museum, 2014.102. Bequest of John A. Higgins, before, during (using kozo paper band-aids) and after treatment. (Courtesy of Paula Artal-Isbrand)
Second, paper can also be used as a tool. It can work well as a facing for an intermediate phase of treatment. It can also serve as a barrier layer. For example, thin papers are a great barrier film for gels. Here, Artal-Isbrand mentioned that thin gampi paper can be good for this. The paper is placed between the surface and the gel, allowing for easier clean up in gel removal. Paper can be a poultice material. Artal-Isbrand uses Whatman cellulose powder, which will cling well and hold the poultice solvent. For these same reasons, shredded filter paper soaked and blended in water can be used to create a mold of another artifact. The mold should be sealed with resin (for example, Paraloid B-72) to keep it from getting damaged by water applications. If using the mold for creating a plaster fill, this step is critical.
During the question / answer period, there was a brief discussion on how shredded paper serves well for poulticing, and is better than cellulose powder or other very fine materials, because those become difficult to remove and can leave a hazy residue. So, it is important to distinguish between powder and pulp or shredded and/or ground paper. An interleaving layer can be helpful if powder is used. Also during the discussion, another example was mentioned that paper can be rolled into “worms,” impregnated with Paraloid B-72, and inserted it into losses to provide filling that is more easily removed than putties or other fillers.
Art from the Kizil Caves at the Smithsonian Freer Gallery of Art and Arthur M. Sackler Gallery
David Thomas and I could be career siblings. We both have technical backgrounds in materials and polymer science. We both spent time in industry. And this the first time for both of us at an annual AIC meeting. Add in my pre-conservation R&D work on adhesives and the photochemical reactions of polymers, and it’s not surprising that I was chomping at the bit to hear his talk “Stability of Polyvinyl Butyral Polymers with Light Exposure”.
David explained how he, Matthew Clarke, and Blythe McCarthy were looking at the possibility of using polyvinyl butyral (PVB) as an adhesive material for use in consolidating fragments of wall paintings from the Kizil Cave Complex in Xinjiang Province, China. These wall paintings are generally matte in appearance and are comprised of gypsum on mud plaster support. More specifically, sixteen fragile fragments had been leant to the Freer Gallery from the Smithsonian American Art Museum.
PVB was identified as a potential match to the consolidation needs of the wall painting fragments for a few reasons. It darkens to a matte surface comparable or better than similar materials, it is easily applied and removed using ethanol, and it has been shown to be an effective consolidant for wood and bone materials. This left the question: how does PVB age under light exposure?
Photo-aging of PVB might sound familiar. David pointed out that Robert Feller published results on the photodegradation of PVB materials in 2007 (http://www.sciencedirect.com/science/article/pii/S0141391005005057), digging into the chemical mechanisms of PVB degradation. The goal here, David emphasized, was not to look at the degradation mechanism itself but to investigate a more practical comparison of similar consolidation materials in actual use.
I found David at his most compelling when digging into the compositions and manufacturers of various grades of PVB. The types of PVB available vary primarily in their relative amounts of butyral, alcohol, and acetate content, a consequence of the polymer manufacturing process. He had a clear wealth of knowledge to offer here, and I wish he had presented even more (but that might just be the polymer scientist in me, your mileage may vary).
David and coworkers cast test films of a number of these grades of PVB, as well as control films of pure polyvinyl acetate (the industrial PVB precursor) and the ubiquitous Acryloid B-72 acrylic polymer, which were all then exposed to UVA (long wavelength UV) irradiation. At the same time, coworkers aged the same films by exposure to a weatherometer’s Xe lamp at the National Gallery of Art. They then tracked changes in color, mass loss, and IR spectra.
Trends in weight loss during aging of the films seemed to correspond with the polyvinyl alcohol content of the PVB: more alcohol led to more weight loss (ie, Mowital B30H degraded more quickly than Butvar B-98). The controls of B-72 and polyvinyl acetate showed no weight loss, and no appreciable discoloration. And by using a fiber optic-coupled FTIR to track the C=O carbonyl signal, an indicator of light-induced oxidative degradation, David showed that indeed the most rapidly degrading B30H showed increased C=O during aging compared to B-98, while the stable B-72 showed comparatively little C=O change and thus less degradation. In all cases, light-exposed PVB could be easily removed with ethanol, showing that no cross-linking reactions were occurring.
Comparison of chemistry induced by light sources as different as a weatherometer’s Xe arc lamp and comparatively narrow-band UVA lamp is a delicate affair. So I was disappointed that the talk did not include how the team evaluated light irradiance and dosage. It begs the question of how much photo-chemical energy was actually imparted to each sample. This also begged the question of heat. A Xe arc lamp in a small weatherometer chamber could reasonably be expected to induce a significant amount of heating compared to UVA bulbs. As David highlighted the comparatively high temperatures of Feller’s prior PVB work compared to the work presented here, it makes it difficult to determine how similar or different these varied results might be.
The data showing PVB applied and aged on Plaster of Paris mock-up materials looked promising. David offered some reasonable guesses as to why PVB might be more promising in real object application than on thin films. For example, more opaque materials would shield PVB from full light exposure by acting as a competitive absorber. And the color changes in PVB could be relatively minor compared to the colors of the treated object.
I still would have loved to have seen more about how closely the thin films and mock-ups behaved and had time to ask some of my more nagging questions about light and heat levels.
There are a few broader take-aways from David’s talk that I know I will be keeping in mind for myself:
It never hurts to take an extra look at the sourcing and composition of “trade name” products. As vague as they might be, a product’s MSDS/SDS could provide a useful starting point to sleuth out the components in new products or find changes in existing ones.
Mindfulness in equipment specs are crucial for useful comparisons of test cases. Perhaps even more crucial is carefully reporting those specs to simplify and aid others in their own comparisons.
Don’t take old studies at simple face value. David made a good case for trying them again closer to home and closer to your specific application of interest. You never know what you might find.
The team also consulted widely with conservation scientists and treatment conservators of many disciplines.
