Elise Effmann Clifford, Head of Paintings Conservation at the Fine Arts Museums of San Francisco (FAMSF), presented a case study dealing with the complex topic of evaluating a painting’s attribution, drawing on the research of psychologists to consider the biases at play when conservators and scholars approach such investigations. The artwork in question was a portrait of Pierre-Edouard Baranowski, which entered the collection of the FAMSF as a painting by Amedeo Modigliani from 1918. After a demotion in attribution in the 1990s, the painting was subsequently reattributed to the artist in recent years. Effmann traced the research trails of both investigations in her talk, evaluating the reasoning of each that led to their opposing conclusions.
Photo: art.famsf.org
The first of these investigations began soon after the painting entered the FAMSF collection in the early 1980s, when scholars and dealers first raised doubts over the authenticity of the work. These were based on the existence of another portrait of Baranowski by Modigliani in the collection of Robert and Lisa Sainsbury from 1937-1999, and referred to as the ex-Sainsbury painting in this talk. This work has airtight provenance and little doubt over authorship. It is painted in a style typical of the artist. Two portraits of Baranowski were mentioned in the earliest catalog of Modigliani’s work, but this states both were on canvas, where the FAMSF painting is on hardboard. Only the ex-Sainsbury painting is mentioned in subsequent catalogs. The provenance of the FAMSF painting was unknown prior to 1953, the year the donor purchased the work. A report from the FAMSF conservation department notes an underlying composition of what appeared to by a figure similar to those in an early series by Modigliani. Early restoration treatments to address flaking paint were noted, as was an early campaign of overpaint in the face. Expert opinions were sought, and at least 7 records from dealers and scholars exist in the curatorial file stating they did not consider the painting to be by the artist, that something was not quite right. The FAMSF painting’s lack of technical similarities to the ex-Sainsbury painting, incomplete provenance, its absence in early catalogs of Modigliani, including the irrefutable Ambrogio Ceroni catalogue raisonne, and the frequency of Modigliani forgeries all contributed to a decision to deattribute the painting. This was made official after the painting was taken to England to compare to the ex-Sainsbury painting in 1994.
Prompted by questions raised by the family of the donor, a technical investigation of the painting began in 2011. Effmann found more information on the unusual underlying painting, finding other similar compositions by the artist, also on hardboard. She found other examples of similar paint application, and discussions with conservators and scholars revealed that the artist showed a great deal of variety in his technique. There were several fingerprints found in the paint, ignored in the earlier investigation. Effmann also traced the provenance almost back to the artist. Current experts were consulted in light of the new information, and the attribution to Modigliani was reinstated.
Effmann notes that in hindsight, the authenticity of the painting seemed obvious. She found herself reflecting on the trajectory of research and reasoning that led to the initial conclusion that the painting was a poor-quality copy, and the role that bias may have played. The idea that such research outcomes may be influenced by cognitive biases has never been examined in the context of conservation, so Effmann turned to psychology, where the topic has been a significant area of research since the 1970s. She discussed the implications of heuristics, or cognitive shortcuts, we make constantly in order to quickly and efficiently process the vast amount of information we encounter. These heuristics usually serve us well, but cognitive psychologists have studied numerous ways in which they can lead to predictable errors or biases. Effmann identified several biases at play, including Attribute Substitution, when a difficult question is unconsciously replaced by a simpler one. Here, the question of ‘is this painting genuine?’ was replaced with ‘does this painting look like the other painting?’ Confirmation Bias (the tendency to favour information that agrees with preconceived hypotheses), Overconfidence Bias (overestimating the accuracy of one’s conclusion), and even Hindsight Bias (feeling as though one ‘knew it all along’) were all at play in the course of these events. (A good introduction into this topic is Daniel Kahneman’s ‘Thinking Fast and Slow’, Farrar, Straus and Giroux, 2011).
When we sit down at our microscopes, don our UV goggles, take endless notes, measurements, and photographs for documentation, it is easy to think we are looking at these artworks objectively. But the reality is: we’re not. Whether we’re embarking on a large-scale research project, or writing a condition report, we are drawing on previous experience and opinion which is necessary to guide us and make sense of the world around us efficiently, but can also lead us astray. Effmann says she’ll continue to research the topic of bias in the future, and I look forward to seeing what she finds. I know that I’ll be considering the reasons behind my reasoning much more carefully from now on.
Category: Paintings Conservation
42nd Annual Meeting – Paintings Specialty Group Tips Session, May 29
The PSG tips session at the 42nd annual meeting took place prior to the afternoon session on Thursday, May 29th. The following recaps the twelve tips that were presented. I’ve done my best to give you the most complete information possible, but please feel free to contact each tipper for more information or for clarifications. You can also always enter your questions into the comment section below!
Tip 1: “Texas Strappo” varnish removal, presented by Helen Houp
Helen began with a case study of a damaged painting with a thick varnish that needed to be removed. The thickness of the varnish combined with the severity of the damage to the painting precluded the use of traditional methods of varnish removal. A search for treatment alternatives led to the use of pressure sensitive tape for varnish removal. The tape was applied to the top layer of varnish and then pulled away gently to remove a thin layer of material without risking the paint underneath. It was also possible to use the tape to remove overpaint. The method allowed for a controlled removal of the varnish and overpaint in layers without leaving behind significant residues. I was unable to determine the type of tape that was used, but I’m sure Helen would be willing to provide details to those who may be interested.
Tip 2: Reverse of Paintings Database, presented by Elise Effmann Clifford
Elise previewed a database for “Information on the Reverse of Paintings” that she has been developing in cooperation with the Fine Arts Museums of San Francisco, which will host the final site. The goal for the completed database is to provide a searchable and expandable archive of shared information specific to the reverse of paintings with international access and contributions. In the interest of security and permissions, a login will be required and it will be possible to make entries available to the general public or adjust privacy settings to limit viewing. Members will be able to upload images with file size allowances up to 30MB. Transcriptions and key terms will allow searches for details like canvas stamps, stencils, labels, and seals. The project is destined for beta testing beginning some time in July 0f 2014. People interested in taking part in the testing or submitting future contributions should email Elise.
The presentation of the database was followed by a brief question and answer period.
Q: Will any of the information contained in the database be found through a general internet search?
A: That will depend on the privacy settings. There will also be terms and condition sections on the site as well.
Q: Will uploaded images become property of the Fine Arts Museums of San Francisco once they are uploaded?
A: No.
Q: Will the database accept video? What kind of images are accepted?
A: It will not take video. Right now it cannot take RAW images but will handle things like jpg, tif, etc.
Tip 3: Filling cracks at the edges of canvas, presented by Kristin Robinson
Fine cracks along the turnover edges of a canvas can be very difficult and tedious to fill. Kristen suggested using dried modostuc, which can be held in the fingers and gently rubbed over the cracks to fill them quickly and safely. The dried material leaves very little residue and what remains can be gently wiped way.
Tip 4: Edge lining iron support, presented by Kristin Robinson
Kristin followed her first tip with a suggestion for edge-lining. A backing board or mat board can be folded into thirds to form a triangle, which can act as a rigid support for the iron to press against when applying an edge lining on folded margins.
Tip 5: IMAT developments, presented by Nina Olsson
This tip focused on recent advancements of the IMAT project, which is the natural progression of an earlier project Nina introduced to the Paintings Specialty Group in a talk presented at AIC’s 38th annual meeting in Milwaukee. IMAT refers to “Intelligent Mobile Accurate Thermoelectrical” mild heating devices. The aim of the project is to provide conservators with a controlled and mobile tool for the structural treatment of materials. It is worth noting that Nina is a paintings conservator but the IMAT was developed with a broad audience in mind, including but not limited to conservators of works on paper and textiles. The details of the IMAT project are significant and advanced so this is merely a summary of what was presented at this tips session. Links to more detailed information about the IMAT are included at the end of this summary.
The current IMAT team has developed working prototypes that should be ready for production within a few years. The current focus is on low temperature applications that can be sustained for many hours at a time with a low voltage requirements (I wrote 70-150 degrees Fahrenheit and 36 volts, though these should be confirmed through additional resources). The carbon nanotube heat source is galvanically insulated and has a thermosensor connected through bluetooth technology with a touch screen control for heating over time within a 0.5 degree Celcius fluctuation. The mats will be flexible and come in various sizes, though any customizable size will be possible.
There are 3 IMAT forms at present. The first is a standard mat that is opaque and does not offer any breathability. The second is a black mesh mat with a gray polyurethane coating and thin silicone coating. The third, which is still in development, is a transparent mat with silver nanotube technology. A fourth incarnation–a textile-type mat of silk organza with silver nanowire–is next in line.
All questions regarding the history and current developments of the IMAT project can be directed to Nina Olsson. Additional information can also be found via the following links:
PSG 2010 Postprints
imatproject.edu
H. Meyer, K. Saborowski, T. Markevicius, N. Olsson, R. Furferi, M. Carfagni. “Carbon Nanotubes in Art Conservation.” International Journal of Conservation Science. 4 (2013): 633-646.
Tip 6: PSG Wiki, presented by Gabriel Dunn and Erin Stephenson
In May of 2013 a core team of paintings conservators formed the Paintings Specialty Group Wiki Committee under the guidance of Chief Wiki Editor Erica James. The group worked to bring organization to the PSG wiki page. Gabriel and Erin presented the improvements that were made to the page and announced that the group is seeking contributions. They encouraged the PSG membership to visit the site and consider submitting material or reaching out to be paired with a liaison who can submit material on their behalf. Any questions or concerns about the PSG wiki can be directed to Erica James or any member of the current Wiki Committee listed on the main PSG wiki page.
Tip 7: Fume extraction, presented by Robert Proctor
Rob presented a design for a fome-cor “cabinet” that he built to enclose a painting during varnishing. The structure can fit around a painting to contain fumes, and hoses attached to the structure will remove the fumes before they escape into the studio space.
Another fume extraction tip involved the wheels on portable fume extractors. Rob mentioned that the ones sold with the portable extractors are expensive and mark floors. He suggested making a mobile base using wheels purchased at a home improvement store that will not mark the floors. As a side note, he added that it is not necessary to purchase the proprietary prefilters for the portable units because those used for home air conditioning units work just as well.
I’m certain Rob would be happy to provide details for anyone who wants more information on his designs!
Tip 8: Building your own microscope, presented by Ria German-Carter
Microscopes are expensive and can be an especially significant cost for conservators in private practice. When faced with the task of acquiring a new microscope, Ria decided to put together her own. She was able to find some good quality used components on eBay and save on additional parts by purchasing through amscope.com. She built an inspection microscope with the following specifications for under $1000:
- 8 inch working distance
- articulated arm
- different camera mounting tubes
- LED lighting
- fiberoptics
Unfortunately, I missed the specification regarding the microscope’s magnification. Please contact Ria if you would like more details!
Tip 9: Laser line for cutting batting and what to do with the scraps, presented by Chris Stavroudis
Chris gave a simple but effective tip to assist in cutting a straight line in batting material. He placed the line across the batting and was able to cut a smooth line without needing the assitance of a physical straight edge. He suggested using scraps of batting for cleaning dishes, lab tools, or as a less abrasive material for surface cleaning.
Tip 10: More fume extraction, presented by….
I apologize to this tipster for missing their identity! Please comment below if this is your tip. It described the use of a dryer tube/trunk for fume extraction rather than buying a specialized trunk. White mesh can be put ver the tube to make it less like a dryer tube and a PVC cap can be added to the end for finish and for weight. An angled piece, such as those used for water heater tubes, can be used to create a swivel at the end of the tube.
Tip 11: Proper ventilation, presented by Daisy Craddock
This wasn’t a traditional tip, but is still important information. Daisy pointed out that exhaust systems, such as elephant trunks, need to exhaust to the outside of a studio because they don’t remove all vapors and may produce precipitants. She also reminded us that microemulsions do not get extracted at all.
Tip 12: Storage rack solutions, presented by Kate Smith for Gordon Lewis
Gordon was not in attendance at the tips session so Kate presented his images of a storage system that involved the use of foam board. It appeared that the foam was used as an inexpensive alternative material to create slots in his storage racks. Gordon may be able to provide more details about his tip if interested people wish to contact him.
Thanks for the tips, everyone!
42 Annual Meeting-Joint Session: Paintings and Wooden Artifacts, May 31st, "Modern Materials and Practice in Gilding Conservation", Hubert Baija
Hubert Baija, Senior Conservator of Frames and Gilding, has been responsible for overseeing the conservation of the frame collection at the Rijksmuseum Amsterdam since 1990. Numbering over 7000 frames that are now accessioned and inventoried as works of art in their own right, Baija has had the opportunity to treat frames of different styles and condition issues. During his presentation, he discussed three treatments. He emphasized the need for close study and observation of the original materials, understanding the appearance and intended effect created by the frames in their original lighting situations, and choosing reversible materials in a creative way. He noted that a treatment need not be overly involved to successfully reintegrate the gilding.
His first case study was the treatment of a Louis XVI oval frame (1777-89) that was original to the portrait it framed. The discussion addressed the past practice of covering worn gilding with bronze paint, that later had been retoned with a dark glue/pigment layer to match the discolored bronze. These layers significantly altered the intended appearance of the frame, by negating the play of dark, light, and reflectance across the complex surface. Baija demonstrated that by removing the glue and bronze paint layers (using simple solvent mixtures), only a minimal amount of inpainting was necessary to reintegrate the gilded surface. While the improvement to the frame was impressive, the appearance of the painting when displayed in the frame was also significantly improved by the intervention.
Baija’s second example demonstrated his skill as an artisan, his keen observation, and his determined investigation of a little know technique that had previously been overlooked. He stylistically identified a pair of auricular frames carved from lindenwood to c.1660-1665. Both frames had significant worm damage, had lost smaller portions of carved decoration, and were overpainted and overgilded. Only small areas of the original gilding remained intact–between 5 and 30%.
The original gilding was done using a type of mordant gilding that is not known from historical texts and has not been identified before. Using SEM-EDX imaging of cross sections, the technique was characterized: the bare wood was prepared for gilding using a thick glue layer (1 mm Th), followed by a pigmented emulsion layer, to which the gilding was applied.
Noting that the tradition of gilding in the Netherlands had been lost since the 1580s, and that more traditional (and stable) gilding techniques would not be reintroduced to the Netherlands until later in the 17th century by French Huguenots, Baija surmised that this unusual technique was in use—only in the Netherlands–for a relatively short period of time. After his initial characterization of the technique on these frames, he has since identified other examples on Dutch frames and furniture that are stylistically dated to 1650-1680. Because the technique was inherently unstable given the response of the thick glue layer to changes in humidity, many pieces gilded using this technique have subsequently been overgilded.
After cleaning the frames of non-original layers, the carved losses to the wood were reconstructed using paper mâché /methyl cellulose mixture, mixed with water. The material can be handled like clay to buildup the appropriate forms. The paper mâché shrinks slightly, allowing for application of Modostuc finishing layer. Because an isolating layer of Paraloid B-72 had been applied to the original wood surface, the paper mâché fill remains easily reversible. Shallower losses were also filled with Modostuc.
Most creative was Baija’s approach to inpainting to create the illusion of distressed gilding. Noting that the original thick glue layer would only be very slowly soluble in water, gouache was chosen to provide a brown base tone over areas of lost gilding and structural reconstruction. Islands of worn gilding were recreated using mica pigments mixed with Schminke watercolors, masterfully creating the illusion of a worn gilded surface. Final toning was done using ethanol soluble dyes in Mowilith 20. Toning could also be done using Gamblin Conservation Colors, PVA, etc. Coincidently, the dating of the frames was confirmed and the paintings and frames temporarily reunited, when an early 20thC. photograph of the frames paired with their original paintings was identified. The paintings are signed and dated 1661.
In his final example, Baija described an approach to reintegrating an area of loss in the gilding on a panel painting by Lorenzo Monaco, Stigmata of St Francis, c.1420. The area of damage was on a stepped join that was filled using Modostuc and prepared for gilding with acrylic bole from the Kolner system. Baija emphasized the importance of selecting a gold that was the correct color, but lighter in tone than the final appearance needed. He noted that any toning layers/coatings would take away from the intended appearance of the gilding—imitation of solid gold. By simply inscribing the cracks in the newly gilded loss, using horizontal lines to disrupt the vertical disruption of the loss, the gilding was effectively knocked back to the correct tone. Minor glazes to create the effect of dirt in the cracks were then applied.
Each of these treatments demonstrated issues that are common to conservation of gilded objects. Gilded surfaces are often overgilded or painted with bronze paint to recreate the impression of gold. Alternatively, gilded surfaces tend to be toned dark, either to reintegrate corroded bronze paint or to tone back gold that may seem too garish or is disrupted in other ways.
Baija’s approach is one that brings back the appreciation of frames as works of art, rather than as just accessories to paintings. It emphasizes the need to understand the original and aged appearance of the gilding, and to recover what is left of the original. His approach is one that acknowledges the frames—like objects and paintings–should be treated in reversible ways, using conservation materials distinguishable from the original materials. It thereby breaks from the traditional approach of regilding frames using traditional materials and techniques. He encourages the exploration of new materials, the use of reversible layering systems, and acknowledging the patina of time and use. An overall theme of the talk was one of reintegrating the gilding only to the level of the best-preserved area of original gilding.
For those interested in furthering their understanding of gilding and approaches to gilding restoration, Baija teaches two workshops at the Campbell Center in Mt Carroll, Illinois. “Traditional Gilding” and “Gilding Restoration” combine lecture and practical work in the studio. I attended both workshops over the last two summers, and as a result have improved my treatment approach for gilded frames. I highly recommend them.
42nd Annual Meeting – Paintings Session, May 29 “Illumination For Inpainting: Selecting an Appropriate Color Temperature” by Steven Weintraub
So why do conservators prefer northern daylight for inpainting? In Steven Weintraub’s talk titled “Illumination For Inpainting: Selecting an Appropriate Color Temperature” which he presented in the Paintings Session at the 42nd Annual Meeting in San Francisco, he answered this question, as well as a few others about light sources and selecting an appropriate color temperature.
Steven explained how, in his opinion, it is the distribution pattern of skylight that helps make it so ideal. When diffuse skylight from a north-facing window enters a room, there is a “soft” directionality. This type of light distribution avoids the problem of harsh shadows typically associated with point sources of light. It also avoids the opposite problem of flatness due to the absence of shadows, a condition associated with diffuse sources such as over-head fluorescent lamps.
Using only skylight or daylight for inpainting, however, sets the conservator up for two problems: The first, as Steven mentioned in his abstract, is that the availability and control of northern daylight limits the amount of time, and the location in which it can be used. This becomes a real problem if you happen to be facing a tight deadline during the short winter days in the northeast, or like myself, have constantly changing lighting conditions, such as those during the bout of thunderstorms that we often have here during Houston summers. The second problem, which Steven explained in more detail during his talk, is that the spectral power distribution of typical sources of gallery lighting is pretty much the opposite to that of daylight. The result is that if inpainting is done only with daylight, it increases the risk of metamerism when exhibiting the artwork in an electric lighting situation utilizing a warm color temperature source.
It is for both these reasons that many conservators opt for a mix of electric light and daylight for inpainting, and when possible, test the matching of inpainting in the lighting conditions for which it will be displayed.
But, how does one choose an appropriate electric light source? Steven explained his research and suggested that selecting an appropriate color temperature with adequate color rendering properties was a key.
Apparently, color temperature in the range of 3800° Kelvin is the magic number. From Steven’s talk, I learned that color temperature within the 3800°K range is the transition point between warm to cool on the color temperature scale. Within this color temperature range, Steven theorizes that one gets the best balance of saturation with warm and cool colors.
Steven concluded his talk by illuminating a pair of reproductions of a very well known painting by René Magritte, demonstrating the difference in appearance of the image in various color temperature lighting conditions. This showed how the moderate (3800°K) range really did look the best.
42nd Annual Meeting – Paintings (Joint with Wooden Artifacts), May 31, “Painted Totem Poles at the American Museum of Natural History: Treatment Challenges and Solutions” by Samantha Alderson, Judith Levinson, Gabrielle Tieu, and Karl Knauer
Those who have beheld the Hall of Northwest Coast Indians at the American Museum of Natural History and its extraordinary “totem poles” will instantly recognize the potential scope of any study or treatment of such massive artifacts.
These objects are housed in the earliest wing of the museum, curated at its inception by Franz Boas, “the father of American Anthropology”, who organized the early acquisitions of the museum according to a revolutionary argument: that of “cultural relativism” in opposition to a chauvinistic, social-Darwinist organization that put “primitive” peoples at the bottom of an evolutionary tree, the pinnacle of which was white America. Today, this hall holds a landmarked status and remains relatively unchanged, as the poles are very hard to move.
Ten years ago, a renovation of the hall was proposed. Although the recession thwarted plans, the objects were still in need of stabilization and aesthetic improvements. Because this project—from its inception, through the research, testing, and execution stage, was so expansive—Samantha Alderson reminded her audience that her talk could only represent an overview of a four-year process. Those interested in a specific aspect of the project can look forward to in-depth, forthcoming publications.
One of the more important aspects of the research phase, and a professional obligation that is indispensable to the curation and conservation of native materials, was the consideration of ethical issues and provenance information. Most of these pieces entered the collection between the 1880s and the 1920s, and the majority has been on continual, open display since their arrival. Their presence in AMNH’s collection is widely acknowledged to be ethically complicated in itself, representing an era of unscrupulous dealing in Northwest Coast artifacts. (To read more about “Indians and about their procurable culture,” consult Douglas Cole’s, “Captured Heritage: The Scramble for Northwest Coast Artifacts,” about the coincidence of a taste for these native artifacts and the establishment of many of the country’s foremost natural history collections. (p.xi)]
The carvings, including the carved columns most commonly described as ”totem poles,” would have had numerous functions within their originating cultures: house frontal poles holding entry portals to buildings, interior house posts, welcome figures, memorial poles, and mortuary posts [For a technical study on these types of carvings, please consult “Melissa H. Carr. “A Conservation Perspective on Wooden Carvings of the Pacific Northwest Coast.” Wooden Artifacts Group Postprints. 1993.].
To further hone their understanding of provenance, the 2009 CCI “Caring for Totem Poles” workshop in Alert, Canada, allowed the authors to travel through British Columbia with curatorial consultants, native carvers, and native caretakers, in order to study the techniques of manufacture. It was also important to keep abreast of the expectations of the native communities that might be borne out over the course of any treatment intervention or re-installation campaign.
The original aim of this project was to provide structural stability to those carvings which exhibited highly deteriorated surfaces caused by the weathering and biodeterioration in their original environment. These instabilities were often exacerbated by inappropriate environmental conditions and restoration interventions in the museum. The most significant issue requiring treatment was the presence of wood rot, insects, and biological growth, present in the original environment and continuing to run their course.
Although climate control was installed in 1995, soot from the age of coal heaters and lamps still blanketed the inaccessible areas of the objects. Dust from visitor traffic also dulled them, as the hall is adjacent to the entrance to the IMAX theatre. Routine and well-intentioned cleaning was ineffective against a century of accumulated grime and dust and was causing surface loss.
As there is no barrier between the objects and the visitor, touching has caused burnishing and scratching. The unfinished wood readily absorbs skin oils; and graffiti and adhered chewing gum had also become a most-unfortunate problem.
Early interventions after acquisition had caused condition problems of their own, as old fills had a hardness or density that is inappropriate for soft, weathered wood. These fill materials were only becoming more ugly, unstable, crumbly, and cracked with age.
All of these factors, taken together, provided a huge impetus for treatment.
To begin the treatment-planning stage, the conservators at AMNH performed examinations under visible and UV radiation and mapped the observed conditions and materials using a streamlined iPad-based documentation protocol. In some cases the restoration materials observed provided evidence of institutional and condition history. Although there were almost no previous treatment records of these objects, comparison with archival photographs of many of the objects showed the rate of deterioration since acquisition and provided clues as to dates of interventions and installation history.
In summary of the object-treatment stage, vacuums and sponges were first used in an attempt to reduce some of the dinginess of the surface and to increase the legibility of the painted designs. The many resinous and waxy coatings had trapped so much dust, however, that this treatment did not always have a satisfactory result.
The question of solvent toxicity held sway in all aspects of treatment, as operations were completed in makeshift spaces outside of the lab, due to the size of the objects; these areas had no fume-extraction infrastructure. Luckily, plaster fills could be softened with a warm-water-and-ethanol mixture and carved out.
Butvar B-98 and Paraloid B-72 were selected as potential consolidants and adhesives. A 5-10% Butvar B-98 solution in ethanol (i.e. without the toluene component for safety concerns) was used for surface stabilization, and Paraloid B-72 in acetone was used for adhesion of splinters and detached fragments.
Fills were designed using different materials depending on the location on the object. These were intended to reduce damage during installation, display, and regular maintenance. If the fill was not visible, shapes were cut from Volara, beveled, and adhered in place with Paraloid B-72 along the edges. These were often necessary on the tops of the poles to cover the deep voids of deteriorated wood. Some losses were back-filled with tinted glass micro-balloon mixtures of different grades and different resin-to-balloon ratios where appropriate. As some paints were solvent-sensitive, certain fills required the use of Paraloid B-67. The final fill type was a removable epoxy-bulked fill to compensate for deep losses in visible areas. These areas were first filled with polyethylene foam to prevent the fill from locking in. The edges of the fill area to be cast were protected by tamping down teflon (plumber’s) tape which conforms nicely to the wooden surface. West System 105 Epoxy Resin—with “fast” 205, “slow” 206, or “extra-slow” 209 hardeners—was used in different proportions to 3M glass microspheres and pigments to give fill material with various hardness, curing-times, textures, and colors (See Knauer’s upcoming publication in ICOM-CC Warsaw 2013 for more details). This method is notable for its invisibility, its reversibility, and its rejection of phenolic micro-balloons, which are an unstable and unsuitable and were historically used for such a wood fill merely for their brown color. Once cured, the bulked-epoxy (and the plumber’s tape) were removed and the fills were then tacked into place with B-72 to produce an aesthetically pleasing and protective cap.
Many losses which were previously filled were left unfilled, as would have been the case it they had been collected and treated today. Crack fills were incised so as to retain the appearance of a (smaller) crack.
Once the surface and structure was stabilized with the consolidation and filling operations, the team turned their attention to the various paint films to be cleaned. Many of these were proteinaceous but some were more similar to house paints. This data was consistent with the ethnographic findings and with current native practice. No preparatory layers were used, and the pigment layers were often very lean.
PLM, XRF, and SEM-EDS, as well as UV-FL imaging, thin sections, and analysis with FTIR was undertaken. Some binder analysis was also possible, but this was complicated by historical treatments. Interpretation of epi-fluorescence microscopy results was also thwarted by the presence of multiple coatings, the inter-penetration, -dissolution, and bleed-through of layers. As many as four different types of coatings were identified, and understanding and addressing the condition issues caused by these coatings became a primary concern. Cellulose Nitrate was often applied to carvings in the early 20th century. Whether this was to refurbish or protect, it has developed into a dark-brown layer which is alternately hazy and glossy and which obscured the original surface appearance. Lower regions evidenced PVA or PVAc on top of the Cellulose Nitrate. Shellac and dammar are present in isolated locations, as is an orange resin which eluded identification (even when analyzed with GCMS).
Although identification of these coatings was attempted, removal was not originally planned due to the difficulties designing a solvent system for its reduction, considering the variation in sensitivities, the interpenetration of the layers, and the unknown condition of the original paint films beneath. This plan changed when the poles were deinstalled for construction.
The treatment design was largely aided by the isolation of four house posts in the collection made by Kwakwaka’wakw artist Arthur Shaughnessy.
Commissioned by AMNH in 1923, these had never been installed outdoors but which had been coated in the same manner and exhibited in the same space. This allowed for the development of controlled methods for coating reduction.
A Teas table (or Teas chart) was used to identify potential solvents or solvent mixtures, which were tested over every color and monitored for any leaching or swelling. These initial tests were deemed unsuccessful.
In areas without paint, film reformation with acetone reduced haziness or glossiness. Where the coating was completely removed, the wood was often left with an over-cleaned appearance which necessitated some coating redistribution with MBK, MEK, and propylene glycol. Wherever possible, gels were used to reduce the exposure to toxic solvents. In painted areas, the large variation in solvent sensitivity, the inconsistency of media binders, the varying porosity of the wood, and the changing direction of the wood grain required that the conservators work inch-by-inch. DMSO, a component of “safe” stripper, and NMP were controllable over certain colors but caused considerable swelling.
February 2012, the museum saw the reinstallation of the Shaughnessy poles, marking the effective conclusion of the testing period and the successful management of a challenging triage situation by conservation staff.
It was Kwakwaka‘wakw artists like Arthur Shaughnessy who kept carving traditions active when the Canadian government prohibited the potlatch ceremony in 1885. The ban was lifted in 1951, after AMNH’s acquisition of the house posts.
The completion of treatment represents an important opportunity to educate the public: Although these monumental carvings are exhibited in a historic wing of the museum, we need to dust them off and remember that these carvings represent very, active traditional practices and communities.
There is still the need to develop more systematic solvent strategies, as well as to consult with a paintings conservator. But it is clear that these objects stand to look much improved after the grime and coatings are removed or reduced and the objects are thoughtfully reintegrated with a well-designed fill system. Thanks to the remarkable talents of the AMNH team, these stately creations are finally commanding the respect they deserve.
___
Resources:
Hall of Northwest Coast Indians :: AMNH
From the Bench: These Face Lifts Require Heavy Lifting :: IMLS
Arthur Shaughnessy house post carvings reinstalled following conservation treatment (February 2012) :: AMNH
Changing Approaches to the Conservation of Northwest Coast Totem Poles :: Reed College
Andrew Todd (1998). “Painted Memory, Painted Totems,” In Dorge, Valerie and F. Carey Howlett (eds.), Painted Wood: History and Conservation (pp. 400-411). Proceedings of a symposium organized by the Wooden Artifacts Group of the American Institute for Conservation of Historic and Artistic Works and the Foundation of the AIC, Colonial Williamsburg Foundation, 1994. Los Angeles: J. Paul Getty Trust.
A Brief History of the Jesup North Pacific Expedition :: AMNH
42nd Annual Meeting –Paintings Session, May 29, 2014, “Conserving Spanish Colonial Paintings – Finding the Divine in Conservation," by Cynthia Lawrence
In this Thursday afternoon talk, Cynthia Lawrence presented an in-depth look into the materials and condition problems frequently present in Spanish colonial paintings.
Dating from Columbus through the nineteenth century, Spanish colonial paintings have generally entered collections in remarkably poor condition. Because these paintings have not been widely studied or exhibited, conservators have infrequently encountered them for treatment.
Paintings from this period often did not receive an original application of varnish, and as a result, dirt and debris are found directly in contact with the paint layer. Interventions by early restorers included varnishing and consolidating with wax, resins, and synthetic materials overtop of dirt, resulting in painted surfaces with an obscured, uneven appearance.
The structures of the paintings were often complex. Wood, fabric, paper, and metal served as supports for the paintings. Compositions sometimes included shell inlays and fugitive cochineal reds painted over thin grounds. Some paintings were executed directly on a substrate without the use of a ground at all, and canvases were often affixed directly to the stretcher.
Cynthia showed slides and presented summaries for the treatment of several Spanish colonial paintings featuring divine narratives. She began by illustrating a treatment of a painting of St. Thomas on laid paper over wood that exhibited convex warping, vertical wood movement, planar deformations, paint loss, heavy grime, and a dark varnish. Cynthia’s treatment included consolidating with isinglass and attaching the paper to the panel with BEVA. She cleaned the surface with aqueous solutions and used a xylene mixture to remove the varnish. B-72 was applied to the break edges, which were clamped and weighted. The painting was varnished with MS2A prior to fills and inpainting, and Regalrez 1094 with a bit of wax was applied as a final varnish. After conservation, curators were able to positively attribute the painting to Gregorio Vásquez, a well-known Colombian painter of the Latin American Baroque period.
Cynthia also discussed several treatments in which she found a variety of materials layered over the divine subjects.
A collagen-based glue was found on the surface of one painting, while synthetic varnish, acrylic, PVA, wax, and natural resin varnishes were found overtop centuries of accumulated soot and grime on others. Due to the varied solubilities of these materials, Cynthia employed mechanical action, aqueous solutions, and solvent-based mixtures to remove dirt and incongruous materials.
For all of the paintings she treated, Cynthia discussed the importance of judicious inpainting. She inpainted the most noticeable areas of damage in order to maintain unity in the composition, but the paintings were not aesthetically compensated to appear new. Since many were used for devotional purposes, Cynthia stressed the appropriateness of preserving them in a way that was sympathetic to their original display.
Cynthia’s talk brings attention to the need for continued innovation in conservation treatment, and more research and scholarship on Spanish colonial paintings. Spanish colonial paintings are often in such poor condition as to be deemed “lost causes” or “problem children” by conservators, but she cautions that conservators will likely begin to see paintings like these more, as museums and collectors seek out lesser known works. As we work to understand these paintings better through treatment, analysis, and historical research, we will undoubtedly come to balance creative problem solving with the painting’s long life and history — it is here that we find the divine.
You can see pictures of some of the paintings Cynthia Lawrence treated in this article, and visit the New Mexico History Museum’s page featuring an exhibition of these works, on view until March 2015.
42nd Annual Meeting – Paintings, May 30, "Piet Mondrian: Technical Studies and Treatment" by Ana Martins, Associate Research Scientist, MoMA, and Cynthia Albertson, Assistant Conservator, MoMA
NYC’s Museum of Modern Art owns sixteen Piet Mondrian oil paintings, the most comprehensive collection in North America. From this starting point, conservator Cynthia Albertson and research scientist Ana Martins embarked on an impressive project, both in breadth and in consequence—an in-depth technical examination across all sixteen Mondrians. All examined paintings are fully documented, and the primary preservation goal is returning the artwork to the artist’s intended state. Paint instability in the artist’s later paintings will also be treated with insight from the technical examination.
The initial scope of the project focused on nondestructive analysis of MoMA’s sixteen oil paintings. As more questions arose, other collections and museum conservators were called upon to provide information on their Mondrians. Over 200 other paintings were consulted over the course of the project. Of special importance to the conservators were untreated Mondrians, as they could help answer questions about the artist’s original varnish choices and artist-modified frames. Mondrian’s technique of reworking areas of his own paintings was also under scrutiny, as it called into question whether newer paint on a canvas was his, or a restorer’s overpaint. Fortunately, the MoMA research team had a variety of technology at their disposal: X-Radiography, Reflectance Transformation Imaging, and X-ray Fluorescence (XRF) spectroscopy and XRF mapping were all tools referenced in the presentation.
The lecture discussed three paintings to provide an example of how preservation issues were addressed and how the research process revealed information on unstable paint layers in later Mondrian paintings. The paintings were Tableau no. 2 / Composition no. V (1914), Composition with Color Planes 5 (1917), and Composition C (1920), but for demonstration’s sake only the analysis of the earliest painting will be used as an example here.
Tableau no. 2 / Composition no. V (1914) was on a stretcher that was too thick, wax-lined, covered in a thick, glossy varnish, and had corrosion products along the tacking edges. Research identified the corrosion as accretions from a gold frame that the artist added for an exhibition. The painting has some obviously reworked areas, distinguished by dramatic variations in texture, and a painted-over signature; these changes are visible in the technical analysis. The same research that identified the source of the corrosion also explained that Mondrian reworked and resigned the painting for the exhibition. XRF mapping of the pigments, fillers, and additives provided an early baseline of materials to compare later works to, as the paint here did not exhibit the cracking of later examples. Ultimately, the restorer’s varnish was removed to return the paint surface to its intended matte appearance, and the wax lining was mechanically separated from the canvas with a specially produced Teflon spatula. Composition no. V (1914) was then strip-lined, and re-stretched to a more appropriate-width stretcher.
It is possible to create a timeline of Mondrian’s working methods with information gleaned from the technical examination of all three paintings. His technique had evolved from an overall matte surface, to variations in varnish glossiness between painted areas. XRF analysis demonstrated a shift in his palette, with the addition of vermillion, cobalt, and cadmium red in his later works. XRF also revealed that the artist used registration lines of zinc and lead whites mixed together and used on their own. Knowing the chemical composition of Mondrian’s paint is vital to understanding the nature of the cracking media and identifying techniques to preserve it.
The underpinning of all this research is documentation. This means both accounting for un-documented or poorly documented past restorations, as well as elaborating upon existing references. Many of the MoMA paintings had minimal photographic documentation, which hinders the ability of conservators to identify changes to the work over time. The wealth of information gathered by the conservation and research team remains within the museum’s internal database, but there are plans to expand access to the project’s data. Having already worked in collaboration with many Dutch museums for access to their Mondrian collections, it’s clear to the MoMA team how a compiled database of all their research and documentation would be groundbreaking for the conservation and art history fields.
42nd Annual Meeting – Paintings , May 30, “The Pied Piper of Hamlin: Color and Light in Maxfield Parrish in the Palace Hotel, San Francisco” by Harriet Irgang Alden, Director/Senior Paintings Conservator, ArtCareNYC/A Rustin Levenson Company
In the spring of 2013, San Franciscans were outraged to discover that a cherished Maxfield Parrish wall painting had been removed from its home in the Palace Hotel and sent to New York to be sold. Prior to auction, it was to be cleaned of the hundred-plus years of accumulated grime and accretions it had been subjected to while hanging in The Pied Piper Bar. Thus, even after the Palace Hotel had acquiesced to public sentiment and agreed to return it to San Francisco, the painting remained in New York to be treated.
Harriet Irgang Alden, of Rustin Levenson Art Conservation Associates, had experience with other Parrish wall paintings, and knew the treatment concerns that were inherent to his working methods. The artist alternated thin transparent glazes of brilliant, unmixed pigments with saturating layers of varnish. This made the removal of a restorer’s varnish on a Parrish painting a fraught process that is typically not undertaken, because of the likelihood of disrupting the original layers. The planned treatment outcome only focused on grime removal. The immediate uniqueness of this Parrish wall painting was in the details of its construction. Despite its substantial size at 5 feet by 16 feet, the Pied Piper was not painted in sections, as Parrish’s other wall paintings were. The painting appeared to have been shipped rolled from the artist’s studio to San Francisco, where a stretcher was constructed for it—possibly of redwood due to the incredible length of the members. Additionally, the back of the original canvas remained visible, and displayed a ticking pattern similar to the canvas used for an 1895 Old King Cole painting. The unlined canvas, as well as the unique stretcher, provides new material evidence of Parrish’s working methods.
Unlike previous Parrish treatments, grime removal on the Pied Piper had revealed a broken varnish layer. Apart from thick brush drips and a pockmarked appearance, there were passages of flaking, which curiously did not reveal dull, unvarnished paint beneath. Instead, beneath the discolored upper varnish there appeared to be a clear, glossy layer of a different varnish, and beneath that were the brilliant blues typical to Parrish’s paintings. FTIR analysis at the Museum of Modern Art in New York verified that there were two distinct varnishes: the crumbling upper layer was an alkyd, and the lower a decolorized shellac. Alkyds like this alcohol-acid polymer were not produced prior to the 1920’s, so they could not have been original to Parrish’s 1909 Pied Piper. The decolorized shellac was stable and was still firmly adhered to the paint beneath. Both original layers had actually been protected from UV and bar patron damage by the alkyd addition.
After an aqueous cleaning removed the grime layer, the conservators were faced with an exciting prospect: could they remove the restorer’s varnish, and in doing so, reveal a pristine Maxfield Parrish painting? Solvents would penetrate through both layers and affect the pigment. A more complex process was tested: methyl cellulose in water was applied, and removed after five to ten minutes, to soften the alkyd layer. Though in initial attempts a scalpel was used, the conservators found that the softened alkyd varnish would lift easily and safely by being pulled up with tape using the ‘Texas Strappo’ method. This technique was successful, and revealed a brilliant and unharmed original varnish layer, but it was also incredibly time consuming.
The Palace Hotel declined to extend the treatment of the Pied Piper to include a months-long varnish removal. The alkyd removal test area was toned to blend back in, the painting was varnished with Regalrez, and the Pied Piper returned home. The non-original alkyd varnish remains, still degrading, but it continues to protect the pristine painting and original varnish beneath. In the future, it will be possible to remove the new Regalrez varnish with naphtha, which does not affect the original shellac varnish. It will also be possible to remove the alkyd layer with the solvent and mechanical methods outlined in the test, and revarnish with Regalrez, and possibly a UV stabilizer. Maxfield Parrish’s vibrant original may not be fully unveiled, but until then, the beloved painting is safely on display.
42nd Annual Meeting- WAG Session, May 31, “Lost for One Hundred Years: The Conservation of a Unique Polychrome Neoclassical Pulpit in Upstate New York” by Alexander M. Carlisle
Alex Carlisle presented a fascinating and detailed treatment of the pulpit in Fort Herkimer Church, German Flatts, New York (http://fortherkimerchurch.org/7.html). The church has a long history; the current structure dates to 1767, with many additions and expansion in war and peacetime. The pulpit was added in the early 19th century, and seems to be completely unique; it is made from white pine, but nothing is known about the workshop.
During a recent, major renovation of the church, white paint coating the pulpit was partially sanded off and discovered to be covering polychrome decoration. At this point, Carlisle was asked to work on the project, to remove the remaining white overpaint and preserve the original polychrome layer. At least one coat of white paint was lead-based, and very intractable; the majority of this was mechanically removed. Fortunately an older resin coating layer was present, and the lead white paint tended to cleave off at the interface.
Once the white overpaint was removed, the remaining original surfaces were consolidated and coated with a barrier layer. Losses in the polychrome ornament were inpainted to re-create the original decorative effect. So far the base and main section of the pulpit have successfully been treated; the canopy awaits funding to complete the project (keep an eye out for part 3!)
42nd Annual Meeting – Joint PSG/WAG Session, May 31, 2014, “Recent Developments in the Evolution of Spring-loaded Secondary Supports for Previously Thinned Panel Paintings”, by Alan Miller and George Bisacca
In his presentation, Alan Miller, Assistant Conservator in Paintings Conservation at the Metropolitan Museum of Art in New York, showcased recent developments of spring-loaded secondary supports attached to the back of panel paintings.
He began by reviewing how usual 19th and 20th century treatment of warped panel paintings involved severe thinning of panels along with the application of wood “cradles” on their backs to straighten them and provide “support”. This portion of the presentation wonderfully complimented Karen French’s earlier talk on the evolution of the structural treatment of panel paintings at the Walters.
As Karen did in the morning, Alan discussed the consequences of past treatments on the panel and its painted surface. New treatment approaches have evolved over the past two decades with the development of flexible supports attached to the back of panels, allowing for the natural curvature of the wood and its movement in response to changes in relative humidity. Specific consideration was given to previously thinned panels, very vulnerable once their cradle is removed. Alan provided a review of the development of the spring mechanisms they developed with George Bisacca these past years, referring to the Getty Conservation Institute’s panel paintings initiative (link: http://getty.edu/conservation/our_projects/education/panelpaintings/panelpaintings_component1.html)
The presentation was generously illustrated with images of the various spring mechanisms developed at both the Istituto Superiore per la Conservazione ed il Restauro (ISCR) and later by Bisacca and Miller, explaining the pros and cons of each. For instance, the earlier conical spring designed at the Istituto allowed for much movement but required thickness of the wooden strainer attached to the back of the panel painting, an issue in terms of flexibility of the strainer, not to mention weight and volume. On the Met’s most recent strainers, which are much thinner, grooves are cut cross grain and filled with a silicon based material for added flexibility. Miller emphasized the importance of the number and placement of the springs attached to the back of a previously thinned panel.
He listed the criteria established for the development of spring mechanisms specifically designed for previously thinned panels: springs should be as small (contained) as possible to allow for a thin strainer, easy to adjust, economical and re-usable. Most recently their work has focused on a thin laser cut disk spring, associated with a flexible threaded nylon screw, which allows light weight, flexibility and fine adjustment.
This talk provided very valuable information on recent developments in the treatment approach of wooden panels, applicable not only to paintings but possibly to furniture or architectural wooden panels.