Gay Myers, with the support of Lance Mayer, presented research on American artists gathered from primary sources including artists’ interviews, notebooks, letters, manuals, and suppliers’ catalogues, periodicals, and advertisements. Their presentation focused on a period when more Americans began traveling to Europe.
The influence of instruction from French academics like Thomas Couture (1815-1879) was particularly strong. The American painter Elizabeth Boott (1846-1888) wrote manuscripts about European techniques that delineated Couture’s studio instruction in Paris, William Morris Hunt’s (1824-1879) classes in Boston, and Frank Duveneck’s (1848-1919) practice in Munich. Couture advocated the method of painting thinly over brown underlayers (these paint layers become more transparent over time, and so, this method has sometimes led to problems). He influenced several nineteenth century American painters including Eastman Johnson (1824-1906), Winslow Homer (1836-1910), and Thomas Eakins (1844-1916). Hunt and his pupil Helen Knowlton (1832-1918) believed that caring too much about one’s technique was stifling. Duveneck employed large amounts of oil media in his paintings to achieve a “buttery” application and sealed his works with extremely glossy varnishes. Duveneck’s varnishes were so thick that the American painter John Singer Sargent (1856-1925), who preferred light varnishes, advised others not to let “D” or any of his boys varnish their paintings.
The Art Amateur (1879–1903), an American magazine edited by Montague Marks (1847-1905), used the artists’ advice columns to document Thomas Dewing’s (1851-1938) use of matte varnishes, the growing popularity of the shellac-based Soehnée’s varnish as both a retouching and final varnish, and the early beginnings of the tempera revival in America. The American author Albert Abendschein (1860-1914) was among those in opposition to the tempura revival and has been quoted stating “the egg is more useful taken internally and kept out of the studio.” Abendschein instead advocated for indirect painting in which glazes are layered onto a monochromatic underpainting. In his 1906 book, The Secret of the Old Masters, Abendschein documented the growing tempura revival, commercially-produced paints containing wax, as well as other art trends.
J.G. Vibert (1840-1902), Edward Dufner (1872-1957), Mary Louise McLoughlin (1847-1939), and other significant members of the art community discussed varnishing practices, pigments, added media, and supplementary topics in a series of interviews conducted by DeWitt McClellan Lockman (1870-1957). The French author Vibert advocated a preference for petroleum solvents, and similarly, the American artist Dufner began using kerosene oil instead of turpentine because it dries without a glossy sheen. Dufner considered glossy surfaces so undesirable that he wrote on the verso of one of his paintings: “This picture being in a light key is meant to be matte surface and should never be varnished.” Vibert was also a staunch believer that lead white was not compatible with vermillion or cadmium and offered zinc white as an alternative. Concern about the toxicity of lead white also lead many artists, including McLoughlin, to start using zinc white. Since that time, technical analysis has confirmed zinc white is more prone to cracking than lead white.
This presentation effectively demonstrated the extent to which American painters experimented during the late nineteenth and early twentieth centuries. If you would like to learn more about the materials and techniques of American painters, Mayer and Myers have authored multiple publications including American Painters on Technique: The Colonial Period to 1860 (2011) and American Painters on Technique: 1860-1945 (2013).
About the Speakers
Lance Mayer and Gay Myers graduated from the Oberlin College conservation program (1977 and 1978) and work as independent conservators to private collectors and public institutions including the Lyman Allyn Art Museum. The authors are fellows of the American Institute for Conservation of Historic and Artistic Works (AIC) and have each served as chair of the AIC Paintings Specialty Group. They have collaborated on conservation and research projects for over thirty years, were awarded the Winterthur Advanced Research Fellowship (1999), Museum Scholars at the Getty Research Institute (2003), and College Art Association/Heritage Preservation Award for Distinction and Scholarship in Conservation (2013).
Category: Paintings Conservation
42nd Annual Meeting, Paintings & Wooden Artifacts Joint Session, May 31, "The Analysis and Reduction of an Intractable Coating for the Panel Painting by Lluis Borrassa, Christ Before Pilate," by William P. Brown & Dr. Adele De Cruz
The presentation by William P. Brown and Dr. Adele De Cruz was an awe inspiring glimpse at the future of conservation. Through the collaboration of the North Carolina Museum of Art and conservation scientists from the University of Pisa and Duke University, an intractable layer of cross-linked drying oil, animal glues, and pigmented varnish was removed from the surface of Spanish painter Lluis Borrassa’s panel painting, Christ Before Pilate, 1420-25.
The painting, which had not been exhibited for over 40 years, was the victim of previous cleaning and coating campaigns, and several layers of consolidation materials and paints and glazes had been applied to the blue passages of Christ’s robe. As a result of the cross-linking of these consolidants and the dark pigmentation of a conealing varnish layer, Christs’s robe appeared almost black.
During treatment at the North Carolina Museum of Art, solvents were successful in removing the toned varnish from the painting. However, the reduction of the complex layer of intractable material covering Christ’s robe (the abstract describes this as a composite of old consolidant, cross-linked drying oil, and restoration materials) was not so straighforward. Conservation scientists (from the aforementioned institutions) used FTIR, SEM, and GC-MS analysis to identify the components of the intractable layer and to discern them from original material, which consistsed of lapis, indigo, and orpiment pigments in egg tempera and glue or bee pollen.
Dr. De Cruz took the podium at this point in the talk to describe the methods used to reduce the intractable composite material. Essentially, laser ablation was employed, which before this talk I was only familiar with in the context of dentistry. I have to admit that my intitial reaction to hearing the terms ‘laser’ and ‘art conservation’ used together might have been a wary one, but a refamiliarzing with the techniques involved with laser ablation (and recalling the established use of this technique on the delicate enamel surfaces of our teeth) was an encouraging and exciting reminder of the vast potential of interdisiplanary approaches to art conservation.
Dr. De Cruz explained that the 2940 nm Er:YAG (erbium) operates using an intense monochromatic wave of light (2.94 microwatts) at 15 pulses per second to vaporize the intractable material. The depth of penetration is very controllable, maintaining a shallow depth of penetration between 3-5 microns. This light pulse is highly absorbed by water, and produced a near instantaneous steam distillation. A glass cover slip is placed over the dirt, varnish, and paint layer. The laser is used to break up the intractable surface, which is ejected and contained by the glass cover slip. The debris is then swabbed from the surface of the painting and can be used for analysis.
There are several immediately obvious benefits to this method. It eliminates the need for toxic solvents, it allows for a highly controllable and low shallow depth of penetration. There is also no risk of chemical change to the substrate, and the reaction is low temperature.
Dr. De Cruz went in to incredible depth during this talk, and I realize that my summary only touches on the ammount of information she provided. I was furiously scribbling notes the entire time, and certainly wished I had a camera to take photos of her slides. I certainly look forward to hearing more about this topic in the future, and am excited for the future and ongoing collaboration of conservation and science.
42nd Annual Meeting – Painting Session, May 30, "A Hangover, Part III: Thomas Couture's Supper After the Masked Ball"
Conservators are often faced with objects that have had extensive past treatments. While undertaken with the best intentions, some treatments have resulted in aesthetically jarring effects and loss of original information embedded in the construction of the work. Fiona Beckett explored these challenges of decision-making within the treatment of Thomas Couture’s Supper After the Masked Ball (1855).
The large painting is a depiction of a scene in the Maison d’Or in Paris following a party in the infamous hangout for artists and writers. The hungover revelers acted as vehicles for Couture’s commentary about the degradation of society’s morals. Although the composition was originally intended for use as a wall paper design, Couture seemed to have a soft-spot for this scene and the finished painted version was kept in his studio as illustrated by its numerous appearances in drawings and depictions of the studio space.
Courtesy of the National Gallery of Canada
Supper After the Masked Ball had undergone two linings and at least two cleaning treatments in the past. It had been relegated to storage for the last 90 years because of its problems. While one lining was done with glue paste the second used wax resin resulting in an uneven combination of the two residues on the verso of the canvas. Ms. Beckett described the factors that had to be considered before removal of the lining. Some of the effects from the lining treatments included wax residue stains, shrinkage of the canvas and compression tenting from the glue paste, and flattening caused by the irons. Additionally, Couture’s habit of testing tints of colors on the verso of his paintings was obscured by the lining’s presence. The condition of the lining was such that it had already began to separate fairly easily from the original canvas and it was decided, after determining that it was not appreciably stabilizing the painting, to remove it. After removal, the color tints were indeed visible on the verso of the canvas. Another interesting aspect of Ms. Beckett’s treatment was her use of Gellan Gum to locally moisten and soften the glue residues on the verso prior to mechanical removal with a spatula.
The decision to not re-line Supper After the Masked Ball followed the trend to refrain from re-lining, but was also informed by other factors specific to the painting. The original canvas was in good condition after the lining removal and the previous linings appeared to not have been necessary. The residual glue and wax residues seemed to have added strength to the canvas as well. Lastly, the absence of the lining allowed easy viewing of the brush marks on the verso.
Final steps in the treatment included a spray application of B-72 to the verso, strip lining with Lascaux P110 fabric and BEVA, and building up the face of the stretchers to an even surface with the addition of mat board and a felt-like non-woven polyester.
Supper After the Masked Ball was an excellent case study to illustrate the decision-making processes conservators must use when approaching prior extensive treatments. Ms. Beckett made an astute observation that it is quite easy for us to criticize these past treatments, but we must acknowledge that they were carried out with the intentions to preserve and stabilize using the most advanced technology available at the time. Often it’s the case that these linings and such really did have a positive effect on the preservation of the pictorial surface, although these measures need to sometimes be undone in the present day when we have less invasive and more effective processes available.
42nd Annual Meeting – Paintings Session, May 30, "Aspects of Painting Techniques in 'The Virgin and Child with Saint Anne' Attributed to Andrea Salai" – Sue Ann Chui and Alan Phenix.
This paper, presented by Sue Ann Chui, intrigued and enticed us to want more. She noted at the beginning that the title had changed to “Leonardo’s Obsession: A Workshop Variant of his ‘Virgin and Child with Saint Anne’ from the Hammer Museum, UCLA.” This is a pertinent point to keep in mind in the broader scope of the day’s PSG talks.
Leonardo da Vinci spent fifteen years working on the painting of “Virgin and Child with Saint Anne” (now at the Louvre), keeping it in his possession, leaving it unfinished at the time of his death. While continuing to work in his studio, other variants were being created in the workshop. It was noted that the Hammer painting is in remarkable condition (both structurally and aesthetically) and that the panel is virtually unaltered.
The oil on wood panel painting, in storage for many years and thought to be an early copy, was attributed to Salai (Gian Giacomo Caprotti da Oreno 1480-1524). The panel support, estimated to be poplar with coniferous wood battens, tangential cut and not thinned, is remarkably close to Leonardo’s original panel (the “Louvre” panel) with similar tool marks and dowels. In addition to these similarities, the panel’s thickness (2-2.8cm) would suggest that both wood panels came from the same workshop in northern Italy.
Analysis revealed the ground to be calcium sulfate and glue with an imprimatura of lead white. Compositional changes can be seen in the under drawing (infrared imaging) of Saint Anne’s left foot and several other areas. Walnut oil was characterized as the binding medium in other samples. Pigments were characterized as lead white, carbon black, vermillion, lead tin yellow, red iron oxides, natural ultramarine, azurite, orpiment, transparent glazes of copper green and red lake.
The Virgin’s mantle, with a complex stratigraphy, presents some interesting questions. Does the stratigraphy represent an original sequence or changes by the artist? Analysis of the blue mantle reveals three applications of grey, along with ultramarine, and two applications of red lake glazes on top of the imprimatura and below the grey layers. Is a thinly applied transparent glaze as a preliminary layer, similar to Leonardo’s technique, intentional? The purple toned sleeve of Saint Anne, comprised of reds, red lake and layers of what appear to be retouching varnish is changed from a red-brown to a purple color similar to color found in the Louvre painting.
Two interesting finds in the Hammer Museum’s panel were imprints from fabric and fingerprints. Historical references mention the use of a textile to even out a glaze, as seen in an area of blue on the panel and using the palm of the hand to uniformly spread a glaze (leaving fingerprints in the paint – who might those fingerprints belong to?). Differing paint application in the scene’s plant foliage hint the passages may be by two different hands. Fine brushstroke’s in the face of Saint Anne suggest a very accomplished artist, leaving us to wonder if perhaps the master provided some assistance to workshop apprentices. It would seem the Hammer panel was almost certainly created in da Vinci’s studio.
The change in the title of the presentation tied in nicely with Elise Effmann Clifford’s presentation “The Reconsideration of a Reattribution: Pierre-Edourd Baranowski by Amedeo Modigliani.” In her talk Elise pointed out the biases and prejudices we all carry and need to be aware of. The need to look at each work afresh, consider all the findings of technical analysis, provenance, along with curatorial knowledge and instinct must inform how we approach artworks, while being mindful of our own biases.
As for my personal bias regarding the analysis of the Hammer panel I must admit that, like many in the attentive audience, I was hoping for a surprise ending that announced the Hammer painting would, in fact, be declared to be by the hand of the master. The session was packed full of high quality technical analysis (including a peek into workshop practices) suggesting deeper questions and the paint geek’s favorite, paint cross-sections!
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Additional articles you may be interested in being cognizant of biases, the writer’s and your own!
LA Times article on Hammer St. Anne:
http://articles.latimes.com/2013/feb/05/entertainment/la-et-cm-leonardo-getty-20130206
Recent article in The Art Tribune mentions the Armand Hammer, UCLA panel:
http://www.thearttribune.com/Saint-Anne-Leonardo-Da-Vinci-s.html
Guardian article on over cleaning of panel:
http://www.theguardian.com/artanddesign/2011/dec/28/louvre-leonardo-overcleaned-art-experts
ArtWatch article:
http://artwatchuk.wordpress.com/tag/leonardos-virgin-and-child-with-st-anne/
Credit: via Tumblr from WTF Art History
42nd Annual Meeting, Paintings & Wooden Artifacts Joint Session, May 31, "Long Term Hygromechanical Monitoring of Panel Paintings," by Paolo Dionisi Vici
As a conservation student entering my first year of graduate study this fall, I was at first intimidated by the topic at hand and the thought of relaying this information to the conservation community, potentially including research scientists, techs, and seasoned conservators who may have a jump-start on understanding these concepts, their implementation, and design execution. However, Paolo Dionisi Vici’s presentation not only made the material pertinent and compelling, but also accessible to a layman like myself. I only hope I can do justice to the complexities of the issue.
The talk abstract provides a great summary as to the ‘why’ of hygromechanical monitoring of panel paintings. Mathematical models and theoretical systems regarding the short and long term effects of environmental conditions on objects need to be substantiated by real life data sets in order to move forward with our understanding of the impact of microclimates (and their fluctuations) on objects. This topic is in direct diologue with the conference theme, Conscientious Conservation: Sustainable Choices in Collection Care, and harkens back to the opening session talks broadly titled Exploring Sustainable Preservation Environments, in which the generally accepted environmental paramaters of the museum were discussed, questioned, and even at times directly challenged. Data-logging by experimental measures, as exemplified by Vici’s talk, is paramount to the future of this conversation.
Vici posed an excellent question at the beginning of his talk by asking “What does stability really mean?” As an example of the potential complexity of this issue, he refered to the localized monitoring of one of the viking ships in Oslo, in which different data responses were logged based on the instrumentations’ location on the ship. The abstract aptly states, “Due to the specificity of each artwork… the analysis of an artifact’s response… can supply useful information about its “individual” sensitivity to the exhibition microclimate….” As the viking ship demonstrates, the complexity of individual responses can even vary within a single (albeit enormous in this case) object.
Now to get to the nitty gritty of the talk, and the part where I formally apologize for my unavoidable oversimplication (of what I suspect Vici already drastically simplified) of the sophisticated instrumentation used to monitor panel paintings. I should mention that while this instrumentation can be used to monitor a variety of wooden objects (such as the viking ship), the abstract notes that “panel paintings are useful in representing the complexity of possible reactions.”
The system of monitoring, the Deformometric Kit (DK), employs two displacement transducers, attached perpendicularly to the grain of the wooden panel. Linear deformations in the panel can be measured based on the proportional change of length of the transducers and subsequent trigonometric calculations. The transducers can be mounted on the back of a panel in different configurations and are not visible while the object is on exhibition.
The DK has undergone several design modifications to improve the specificity of the data being collected and its practicality in a museum context. In earlier models, the transducers were screwed directly into the panels. This complicated the data, because the specifics of what was being measured (surface vs. interior deformations and fluctations) could not be determined. Improvements at the Metroplitan Museum of Art were tested, and the transducers were eventually glued to the surface of the panel. According to Vici, minor shifts in the mounting glue would not negatively reflect the recorded data, because the information being gathered between the two vertical elements reflects general, averaged fluctuations. A further improvement was made when the base of the system was split, with ‘clips’ being glued to the surface of the panel and the transducers then being attached to these clips, making the transducers removable for transportation of the panel.
Vici provided several examples of the DK in action. Simulations of the potential asymmetry of a panel’s surfaces were conducted by connecting transducers to both sides of test panels. The effects of the movement of moisture as it reached equilibrium within the panel could then be monitored. The data Vici shared with us from these trials spanned hundreds of days, and the applicability of this system’s monitoring to both short and long term condition fluctuations should not go unmentioned. The DK also assisted in inform conservators regarding the appropriate crosspieces needed to provide auxiliary support for a long crack running through The Annunciation, oil on wood, Peter Candid, 1585. The DK was able to assist in determining how rigid the cross pieces needed to be and what kind of connection to the panel would be most appropriate.
I would like to reiterate that Vici did an incredible job engaging the audience with what could have been a very esoteric topic. And, yes, while it could be said that this is AIC, and perhaps only we could be ‘enthusiastic about dust’ (a group of people of which I am proud to be among), I felt the room earnestly abuzz after his talk. One of the most important thoughts that I took away from this talk was the importance of empirical validation of theoretical modeling. It is this sort of empirical validation that will inform our decisions as conservators and museum specialists moving forward with the care of our collections.
42nd Annual Meeting – Paintings Session, May 29, 2014, "Oil Paintings on Metal Support: Study, Intervention, and Challenges" by Mónica Pérez
Mónica’s talk focused on the treatment of five oil paintings on meta at the National Center for Conservation and Restoration (Centro Nacional de Conservación y Restauración, or CNCR) in Santiago, Chile.
In 2012 five paintings from the Bernardo O’Higgins House Museum in Talca, Chile were brought to the CNCR in serious need of treatment. The paintings represented an exciting moment for the CNCR, since paintings on metal had not been treated there previously. One of the paintings was signed by Willem Van Herp, 1655, making it the oldest painting to be treated at the CNCR. All five of the paintings were bought in Europe in the 19th century by Eusebio Lillo (who also happens to have been the author of the Chilean national anthem) who donated his large collection of art to the museum upon his death in 1911.
Of the five paintings treated by the center, three were 21 x 29 inches, and two were much smaller, measuring 9 x 7 inches. Two had been previously cradled, and the rest were otherwise unrestrained. Four of the paintings were on copper, and one was painted on tin-plated iron. Various condition issues, all common with paintings on metal, were present; the most serious issues were corrosion (which consisted of brown stains and corrosion products protruding from the paint layer), distortion of the support, flaking paint, discolored varnish, and puncture holes where the paintings had been nailed to walls or altars. In addition, large areas of overpaint were present.
Treatment of the paintings began with documentation and an initial analysis of the imagery depicted. All of them appeared to be allegorical or religious, and a few were clearly similar in composition and subject to other, more famous paintings, such as the painting referred to as “Disciples of Emmaus” by the center, which featured two parrots that were exact matches to those in a Jan Breughel painting from c. 1620.
Cross sections of the paintings were taken in order to help conservators to distinguish between original and later paint. The four paintings on copper were found to have a lead white ground, and the painting on tin-plated iron had a ground consisting of Prussian blue and lead white. Varnishes were found to be mastic or dammar, but were clearly not original for several of the paintings. UV examination revealed aggressive cleaning and intervention in the past.
In order to determine the best methods for treatment, copper prototypes were created and used to test adhesion of various adhesives. The CNCR used Isabel Horovitz’s research into paintings on copper as the primary resource for their work. Following testing on the prototypes, corrosion was mechanically removed, and a solution of 15% B-72 in toluene was used to isolate the corroded areas and to consolidate flaking paint.
Distortions in the support were significant on a few of the paintings, and conservators hoped to be able to reduce it. Flattening was attempted on prototypes using a book press, and the result was considered to be less distracting. A few of the paintings were flattened in this manner. An acrylic plate was applied to the reverse to provide support and to allow the reverse of the metal plates to be seen.
15% B-72 in toluene was used as a base for filling losses in the paint surface, and a tacking iron was used to level the edges of the fills. Fills were isolated with a varnish and inpainted to a full visual reintegration. After cleaning and inpainting, the subjects of the paintings were revealed to be religious and not allegorical. The center has suggested re-naming the paintings accordingly, and has sent their proposed titles to the O’Higgins museum. The treatments and the revealed subjects will be summarized in an upcoming book.
Two Mellon Postgraduate Fellowships: Paintings and Objects Conservation
The Brooklyn Museum is offering two Andrew W. Mellon Postgraduate Fellowships, one in paintings and one in objects conservation. Each position will be two years with the option of a third, each commencing in September 2014. The Fellow will carry out examinations, research, and treatments, produce and maintain technical documentation, and participate in preservation activities within the Museum. The applicant should be a graduate of a recognized conservation training program.
Each Fellowship includes an annual stipend of $34,000.00, full benefits including health insurance, and $2,500.00 in travel funds. Applications should be sent electronically as pdf files containing: statement of interest, résumé, and three examination and treatment reports with photographic documentation. These documents should be sent to Ken.Moser [at] Brooklynmuseum.org. Please include in subject line: “Andrew W. Mellon Fellowships Conservation.” Confidential supporting letters from three conservation professionals familiar with the applicant’s work should be sent directly to: Ken Moser, Chief Conservation and Vice Director for Collection, 200 Eastern Parkway, Brooklyn, NY 11238, or at e-mail above.
All application materials must be received by January 1, 2014. Receipt of application will be confirmed by e-mail.
AIC's 41st Annual Meeting, Paintings and Research and Technical Studies Joint Session, May 31, "Water in Oil Microemulsions: A Novel Cleaning System for Acrylic Paints" by Tom Learner, et al
This presentation summarized the collaborative research of the cleaning of acrylic paint films by the authors representing the DOW Chemical Company, the Tate Gallery and the Getty Conservation Institute. The aim of the research is to develop and educate professionals in the cleaning of complex, contemporary synthetic painting media. Early findings of this research have been presented at the AIC Annual Meetings in Los Angeles (2009) and Milwaukee (2010) and at the Cleaning 2010 Conference in Valencia. The components of these systems have varying effects on the medium: acrylic paint films are easily swollen in an aqueous environment, hydrocarbons have poor cleaning efficacy and on large colored surfaces there is a risk of tidelines. The surface character can be changed if extracts are removed.
Dynamic mechanical analysis of potential cleaning materials was conducted; the procedural process was described as “clamping” system that would provide uniform tension across the test film as it was dipped in solution. The displacement of the grips is measured as the paint film contracts upon drying. Acetone and water produced significant swelling, mineral spirits resulting in a flat line. Analysis was conducted using FTIR-ATR (Fourier transform infrared-attenuated total reflectance) spectroscopy on cleaning swabs indicating the level of surfactant material at the surface.
Trial microemulsion cleaning formulations were prepared by DOW and the Tate which were tested by conservators at workshops, including four CAP’s (Cleaning Acrylic Paintings) seminars presented in different cities by Chris Stravroudis. Resulting evaluations have contributed to further refinement of formulations for better compliance with performance criteria desired by conservators. Three classes of microemulsions were produced. All have an aliphatic hydrocarbon in a continuous phase. They incorporate different surfactants. The presence/level of an alcohol as a co-solvent is sometimes incorporated, as an alcohol is required in some systems to enable a stable microemulsion structure. One class of potentially useful formulations of water-in-oil microemulsion systems that are thermodynamically stable is being tested. They incorporate deionized water, a non-miscible hydrocarbon solvent (one being tested is hexanol/butanol (?)) and a surfactant in an attempt to remove grime without removing original material, namely surfactants used in the manufacture of these painting materials, which are known to migrate to the surface as they age. They offer the possibility of exploiting cleaning efficacy associated with aqueous systems but in a predominantly solvent environment where the micelles formed has the surfactant on the outside and the water on the inside. The pH in these systems can be varied using sodium chloride. The ionic strength of the solution should be compatible with the paint film; conductivity should be adjusted, as needed. A stable microemulsion will be clear, while an unstable one will be milky. Other components of the three series included a “green” surfactant, Ecosurf®, a promising new Triton material, Triton GR7, which is soluble in Shell Sol solvents, and the introduction by Richard Wolbers of silicon based cleaners. The latter material was reviewed by Chris Stravroudis in his article, “More from CAPS3: Surfactants, silicone-based solvents, and microemulsions”, WAAC Newsletter 34/3 (Sept 2012), pp 24-27.
The series of microemulsions are being extensively tested including the issue of clearance. A new publication on the progress of this research is expected in 2014.
41st Annual Meeting – Book and Paper Session, June 1, “Testing the Waters: Applying New Techniques to the Cleaning of Acrylic Paint Film by Amy Hughes and Daria Keynan”
New York-based paper conservator Daria Keynan and Amy Hughes, third-year graduate student at NYU Institute of Fine Arts, shared exciting new contemporary cleaning techniques that have the potential for more effective and efficient treatment of paper-based objects by custom-matching the pH and conductivity modular stock solutions to the original object. This presentation was a wonderful and inspiring cross-specialty exploration of how paintings conservation techniques can be applied to paper conservation – and who doesn’t want more tricks up their sleeve?
Keynan was first introduced to the concept at the 2011 CAPS (Cleaning of Acrylic Painted Surfaces) workshop at the Museum of Modern Art. (I am now kicking myself for thinking that these workshops wouldn’t necessarily apply to my work as a book and paper conservator, so jealous!) To date there have been four innovative series of CAPS workshops supported by the Getty Conservation Institute to further the dialogue between theory and practice among conservation scientists and conservators as well as to introduce the concept of modular cleaning systems. Struck by her experience at the 2011 CAPS workshop and impressed by their use for treating acrylic paint films on art on paper, Keynan has further explored the use of pH and conductivity customization for other areas of paper conservation.
The CAPS workshop introduced several different cleaning techniques to minimize removal of surfactants when cleaning acrylic film surfaces. Acrylic paint and modern materials are scary (my word, not theirs.) Emulsions are often complex with many proprietary and artist-introduced ingredients. Colors react differently after drying, in treatment, and as they age. Some colors may be more sensitive to chemical and mechanical cleaning than others. Surfactants and other soft solids may never solidify, creating a tacky surface that can attract dust and grime. Conservation treatment, particularly aqueous treatment or mechanical cleaning with damp cotton swabs, can introduce immediate disfiguration like abrasion or swelling. Readily soluble surfactants can leach to the paint film surface or verso of the paper substrate. Treatment can also jumpstart deterioration that is not apparent until the future due to unknown chemical and mechanical consequences.
Of the many cleaning techniques available within contemporary conservation, Hughes and Keynan limited their presentation to the customization of pH and conductivity as a more finely-tuned and safer aqueous cleaning technique. They shared their methods by highlighting the treatment of works of art on paper brought to the Daria Keynan Paper Conservation in Manhattan for treatment where adjusted water – tweaking the pH and conductivity of the deionized water – was a key factor of success.
In the Garden (1986) by Paula Rego was surface cleaned to reduce dust and embedded grime altering the surface sheen. After dry cleaning with cosmetic sponges, Hughes tested various acrylic paint colors for pH and conductivity testing. Cylindrical pellets of cast agarose gel (recipe and supply information to be published in their BPG Annual post-print) were uniformly shaped with a medical-grade biopsy punch. (Heed Hughes’ warning, online image searches for “biopsy punch” are not for the weak-stomached!) The agarose pellet, acting like a poultice, was placed in contact with the acrylic paint film for 45 seconds to absorb the surface pH and conductivity. Agarose was selected because it imbibes the surface readings without visibly swelling the paint with excess moisture as in more aggressive techniques like local, direct application of deionized water. Keynan explained that the contact time of the agarose pellet can be matched to the estimated treatment time so that testing parameters can meet real-world treatment situations, increasing the predictability and reproducibility of testing results.
The pellet was transferred from the paper surface to the well of a pocket-sized, hand-held pH meter (Horiba Laqua pH Tester from Cole-Parmer) to record the pH of the paint surface. A droplet of deionized water was then placed on the pellet and transferred to another pocket-sized, hand-held conductivity meter (Horiba B-171 Twin Conductivity/Salinity Pocket Tester from Cole-Parmer) to record the conductivity of the paint surface. (As someone who absolutely dreads calibrating our cumbersome pH meter I was overjoyed to hear how easy these were to use – my purchase order request is already submitted.)
The conservators used the recorded pH and conductivity for a given area of the painted surface to identify the optimal working solution for cleaning. They selected from among a variety of premixed stock solutions that were created according to the CAPS workshop directions using deionized water, glacial acetic acid, and ammonium hydroxide in a range of ph 5-8 and conductivity 1000-6000 µS (micro Siemens.) Once mixed, the stock solutions can be stored in the refrigerator for up to several months. Keynan also reported that they often add several drops of an antimicrobial preservative for a longer shelf life.
The embedded material and dust on In the Garden released easily with 3-4 passes of lightly damp, pre-blotted cotton swab rolled over the surface. Hughes warned that since acrylic film is susceptible to abrasion it is important to monitor the paint surface during treatment. Cotton might not be appropriate for all acrylic surfaces so additional experiments with different swab materials may be useful. Similar success was seen in the mold removal and stain reduction of Maquette for Smoking Cigarette Relief (1983) by Tom Wesselmann.
Since Superstorm Sandy hit New York City in October 2012, Keynan’s studio has seen many complex treatments because of the unusual and unknown composition of the storm water which was often contaminated by sewage (uh, gross.) Many of the paper-based objects were stained with tidelines that were difficult to remove and fluoresced brightly under UV. Standard paper conservation techniques often visibly removed the tidelines but were deemed unsuccessful since under UV they shifted along the paper fibers or sank but were not completely removed from the paper support. She related that altering the pH and conductivity of her treatment water dramatically improved treatment results. Removal of the fluorescing blue tidelines (both external and internal) was achieved by local application of the adjusted water and using fumed silica poultices to block the formation of new tidelines.
The last example Keynan shared was a sample of naturally aged 2-ply paper board. (This was exciting, anyone else ever stare blankly at a nasty tideline on an illustration board and just sigh?) Traditional and adjusted treatment waters were applied with cotton swabs in several passes to clean the surface with varying results. Traditional deionized water cleaned less and was uneven, leaving a soft and vulnerable surface. The solution set at pH 6.6 and 6,000 µS glided more easily and had more even results. It also felt more controllable when working. The third sample solution set to pH 5.5 and 14,000 µS gave the most effective cleaning but in real life would probably not need three passes. After drying, the surface readings for all three areas had almost identical conductivity and pH readings.
Keynan concluded that by matching a pH- and conductivity-adjusted solution to the surface of the object it is possible to create a near chemical equilibrium at the surface to eliminate leaching from or depositing into the paint film. In treatment, using adjusted solution equals maximized cleaning efficiency with less wetting out of substrates, less pigment transfer, less repeated action, less loss of surface texture, and reduced distortion of the working area. Conservators have always adjusted pH for various uses, but by measuring the conductivity we can tailor our treatments to the physical needs of the object material with more refinement and subject it to less invasive treatment. Adjusted waters are an incredibly useful tool for improving and refining treatments in our conservation practice.
Hughes and Keynan’s presentation was an approachable and exciting take on the contemporary research going on in the field of conservation science and paintings conservation, especially as led by Chris Stavroudis (freelance paintings conservator in Los Angeles) and Richard Wolbers (Winterthur/University of Delaware Program in Art Conservation) in, well, all things related to cleaning painted surfaces and the Modular Cleaning Program.
Other presentations at the AIC meeting in Indianapolis such as “Mass Spectrometric Imaging of Acrylic Emulsion Paint Films: Engineering a Microemulsion-Based Cleaning Approach” (Paintings + Research and Technical Studies Thursday, May 30) show that the MCP and CAPS research continues. During the question-and-answer period Dr. Anthony Lagalante (Villanova University) shared that he and Stavroudis had recently recorded a video about using and calibrating the meters – it was on the cutting room floor, but will be posted to the CAPS website soon. Lagalante also sent me a link to their illuminating Studies in Conservation article that is currently available as a pre-print:
C.E. Dillon, A.F. Lagalante and R.C. Wolbers “ Aqueous cleaning of acrylic emulsion paint films. The effect of solution pH, conductivity and ionic strength on film swelling and surfactant removal” Studies in Conservation 57(1), (2014). http://www.ingentaconnect.com/content/maney/sic/pre-prints/2047058412Y.0000000076
The concept presented by Hughes and Keynan in “Testing the Waters” has the potential for wide application for all book and paper conservators. Working with stock solutions is a fast and economical lab practice. Customizing treatment solutions increases the workability and effectiveness of the treatment. Many of us in the room instantly coveted the easy-to-use digital meters as we thought of the hassle of calibrating traditional models. I’m intrigued by how this research can be applied to aqueous treatments meant to introduce alkaline reserves to acidic paper.
This was a welcome multi-disciplinary presentation that encouraged conservators from other specialty groups like PSG and RATS to attend the BPG program. I am not alone in hoping for more presentations like it at future meetings so we can all benefit from the exciting things happening in all areas of our conservation community.
41st Annual Meeting – Paintings Session, Thursday May 30, "Traditional Artist Materials in Early Paintings by Andy Warhol" by Christopher A. Maines
I was looking forward to hearing this talk by Christopher Maines, Conservation Scientist from the National Gallery of Art, on artist materials used by Andy Warhol in his earlier artworks, especially since it mentioned the possibility of traditional materials. Maines began his talk with a brief summary on Warhol’s early techniques as a commercial artist between 1949-1960, specifically the blotted-line technique. Warhol’s first pop paintings during 1960 and 1962 consisted of acrylic paints on primed, stretched canvas which he hand-painted, such as 1962’s A Boy for Meg. The end of the 1960s, Warhol moved into using hand-cut silk screens with synthetic polymer paints, such as 1962’s Green Marilyn. Warhol continued to use these silk screens and synthetic polymers into the 1980s, before dying in 1987. In summary, Warhol chose to use these particular materials because they were quick drying, offered a thrill or chancy nature, and Warhol was accepting of any imperfections which occurred during the creative process, such as drips.
Maines continued to discuss synthetic polymer paints and thoughts when they were originally introduced. The NGA began analysis of Warhol’s A Boy for Meg in preparation for an upcoming exhibition to determine it’s material composition. The artwork was sampled in four places and GC-MS analysis revealed Warhol was using drying oil and egg when he was transitioning from his commercial work into his pop paintings. It was likely that Warhol was using egg as a material because he was already familiar with its behavior. NGA was fortunate enough to be granted the opportunity to sample from two other artworks from this time period owned by museums in Germany: 129 DIE IN JET! and DAILY NEWS. Both revealed drying oil and egg in these samples, as acrylic paints over a ground layer consisting of drying oil and egg.
I found this talk very interesting, especially to know that Andy Warhol was using a mixture of traditional and modern materials in his artworks. Scientific analysis can provide such fantastic insight to the working materials and methods of artists and I am very glad NGA shared their findings for this time period of Warhol’s career at this year’s AIC Annual Meeting.
Any there any other Warhol fans out there? What are some of your favorites of Warhol works? If you could read the scientific analysis report for any famous artwork to find out exactly what the artist used, what would it be? Please share any thoughts or comments!
NOTE: Other authors on lecture are Suzanne Q. Lomax, Organic Chemist and Jay Krueger, Senior Conservator of Modern Paintings, both at the National Gallery of Art.