Paintings Conservation – Page 2 – AIC Blog Archives: Conservators Converse

45th Annual Meeting – Paintings Specialty Session, June 1, “The Conservation of Alexander Calder’s Last Work Mexico #3: The cross-disciplinary treatment supported by SEM and TEM paint cross section analysis using focus ion beam (FIB) sample preparation,” by Sara Wohler and Ralph Weigandt

Author Sara Wohler discussed the fascinating history of Alexander Calder’s airplane model, Mexico #3, the last work he completed before his death, and then presented the conservation treatment of the model. Author Ralph Weigandt then discussed the technical analysis of the paint film on the airplane. This presentation served as a fun continuation of the painted airplane theme, following Lauren Horelick’s May 30th talk “When an Airplane Acts like a Painting: Applying Established Conservation Methodologies to Ephemeral Aircraft Materials.”

Background

Wohler described the beginning of Alexander Calder’s airplane-making career: In 1972, New York advertiser George Gordon approached Calder with the idea of painting an full-scale airplane. Calder loved the idea, as it would combined his experience in kinetic art and his background in engineering. Gordon paired Calder with Braniff International Airways, and Calder created the designs for two airplanes: Flying Colors of South America and Flying Colors of the United States. These were both tremendous public successes.

^Braniff International Airways employee ceremony, 1975, with Flying Colors of the United States.

The author then described the process in which Calder painted the planes: He began by experimenting with designs on several 1/25-scale Westway Aircraft Models. The chosen design from the model was then scaled up using graph paper that was attached to the full-size airplane. Calder and his team then used pounce wheels to poke holes through the design on the graph paper, and black spray paint was applied through the pounce holes. The graph paper was removed, and the paint colors were spray applied by a Braniff team. Calder supervised the entire process, and hand-painted the engine necelles during the spray process.

Then the author described the artistic process for the model Mexico #3. In 1976, Braniff commissioned a third plane from Calder, this one to celebrate the great relationship between the U.S. and Mexico. The author provided amazing historic film footage of Calder painting the Mexico #3 model plane. She noted that the plane itself was made of fiberglass, and Calder created his design using gouache. On November 11, 1976, Calder completed and signed the work, and tragically, passed away later that evening. Although the design was completed, Mexico #3 was not transferred to an airplane, as Calder was no longer alive to approve of the final result.

^Calder painting the Mexico #3 model.

Treatment

The model airplane was brought to Kuneij Berry Associates, Chicago, for conservation treatment. Through examination, the author found that the fiberglass model airplane had two priming layers, blue and grey, and a final, even, white coating. Calder painted onto the proprietary white surface using gouache, possibly that he made himself. While the airplane was quite dirty and structurally had sustained a few losses, the treatment was relatively straightforward.

The plane was in poor aesthetic condition; it had previously been displayed in a planter with dirt and plants around it, exposing it to both dirt and moisture. Fortunately, the gouache paint layer was generally in good condition and intact, aside from a few abrasions. The synthetic varnish layer, which had protected the gouache layer, was covered in surface dirt and grime. The plane was first surface cleaned with deionized water and PVOH sponges, but a lot of the dirt remained embedded in the varnish. The synthetic varnish was removed with aromatic solvents. Care was taken to only thin the varnish on top of the gouache paints, as the paints were sensitive to aromatic solvents.

^Detail of the varnish removal, cleaned (left) and with remaining varnish (right).

Structurally, the plane had suffered a few chips to its wings and there were a few areas of flaking paint. The flaking paint was consolidated with Paraloid B72. To recreate the tips of the wings that had been chipped away, molds were made of Elastosil M4600 A/B and cast using Milliputti. The cast pieces were sanded and adhered to the wings using Paraloid B72.

Shallow losses in the white priming layer were filled and inpainted simultaneously with Golden MSA colors. Losses in the gouache colors were then inpainted with QoR watercolors. The model was then sprayed with a few, light, protective layers of RegalRez 1094. After the successful treatment, it was recommended that the painting be displayed in a new, more environmentally stable location.

^Sara Wohler inpainting Mexico #3.

Technical Analysis

The technical analysis of Calder’s gouache paint was carried out by Ralph Weigandt, who is currently the primary researcher on the collaborative National Science Foundation (NSF-SCIART) grant with the University of Rochester’s Integrated Nanotechnology Center to advance the scientific understanding and preservation of daguerreotypes. The authors carried out technical analysis of the gouache paint in order to better understand Calder’s materials and techniques, potentially inform the conservation treatment, and to pioneer the use of Focus Ion Beam (FIB) milling for SEM-EDX analysis and PLM examination on paint films. Through Transmission Electron Microscopy, SEM-FIB allows for the elemental analysis of paint layers at the nanometer scale!

Weigandt explained in depth about the sample preparation process, the Focus Ion Beam milling of the larger sample into the much smaller (~12 um x 0.5 um) cross-section, the comparison between traditional SEM-EDX spectroscopic elemental analysis and mapping vs. the Transmission Electron Microscopy and associated SEM-EDX elemental analysis and mapping capabilities. In essence, the FIB milling and TEM allows for highly precise, high resolution elemental analysis and mapping, allowing scientists and conservators to see the inorganic composition of individual pigment particles. A poster from University of Rochester graduate student So Youn Kim outlines the project with excellent photographs and illustrations.

In the end, the elemental analysis did not contribute greatly to the decision-making process of the treatment, but did provide excellent information about Calder’s painting techniques and materials for Mexico #3, which can inform a discussion about his art-making process for this piece and his art in general. It is clear that this Focus Ion Beam technique coupled with Transmission Electron Microscopy and SEM-EDX elemental analysis is an exciting analytical technique that will be extremely useful in the precise identification of inorganic pigments, fillers, etc., in paint films. Furthermore, it is great to see yet another example of private conservators working with scientific departments at universities (or elsewhere) to investigate materials of cultural heritage objects!

45th Annual Meeting – Paintings + Research & Technical Studies, May 30, “Pioneering Solutions for Treating Water Stains on Acrylic Paintings: Case Study of Composition, 1963, by Justin Knowles” by Maggie Barkovic and Olympia Diamond

Maggie Barkovic and Olympia Diamond presented a case study that outlined the decision-making process that lead to the successful treatment of darkened, dirt-infused water stains on the bare canvas portion of a large-scale acrylic dispersion painting: Composition, 1963, by Justin Knowles. The authors attributed the treatment’s success to the combination of extensive evaluation of Knowles’ materials and aesthetic aims and the understanding of new, innovative cleaning techniques designed for acrylic dispersion paintings (with the help of Brownyn Ormsby, TATE, and Maureen Cross, Courtauld Institute of Art). This presentation served an excellent compliment to Jay Kruger’s presentation Color Field Paintings and Sun-Bleaching: An approach for removing stains in unprimed canvas, which discussed the treatment of acrylic solution and oil paintings on bare canvas.

Composition is a privately-owned work that was brought to the Conservation and Technology Department at the Courtauld Institute of Art for treatment in 2013. The large-format work is a two-dimensional acrylic painting with brightly colored geometric forms juxtaposed against an unpigmented acrylic sized canvas. The painting had sustained disfiguring water stains along the top and bottom edges which disrupted the aesthetic reading of the image, rendering it unexhibitable.

Context

In the first step of the conservation process, Barkovic and Diamond assessed how the water stain affected the aesthetic interpretation of the painting. They explored where this painting fit into the artist’s oeuvre: it was part of a series of early, pivotal works where Knowles explored his initial ideas of spatial tension using non-illusionistic geometric compositions that incorporate negative space in the form of unpainted canvas. The authors carried out technical examinations of four other paintings from this early stage in his career, finding that Composition was painted in a comparable manner to his other early works: a fine linen canvas was stretched on a wooden stretcher and then sized with an unpigmented (pEA/MMA) acrylic dispersion coating. Then, Knowles used pencil and pressure-sensitive tape to demarcate where he would paint the geometric forms with acrylic dispersion paints. Though he applied a transparent acrylic “size” layer over the linen/negative space, he still considered the visible canvas “raw” and unprimed. Through the examinations and research on Justin Knowles’ personal notes, the authors assessed that the characteristics and color of the linen canvas were equally important to the interpretation of the work as the paint colors. As such, the canvas should be treated and the water stains removed if at all possible.

Replicas

Second, the authors explained that they needed to identify the components of the water stain (with no prior knowledge of water-staining incident) in order to test cleaning methods. Replicas were made using linen and the same unpigmented acrylic polymer that Knowles most likely used. The replicas were then stained with dirty water. Using XRF spectroscopy and empirical testing as a guide, a visually accurate and equally tenacious water stain was made with iron, calcium, and organic “dirt” components from aged linen. The test replicas were aged in a light box for two years to allow the stain to photo-oxidize and bond with the fabric and size layers.

Testing

Third, the authors needed to determine how to treat the water stain with the presence of the unpigmented acrylic dispersion size layer, which swelled in water and was affected using polar solvents. Their goal was to remove the stain or reduce the appearance of the stain to make successful inpainting possible. The authors looked to successful textile and paper conservation treatments for possible methods. The initial cleaning and/or retouching tests included the use of solutions with various pH values, conductivities, chelating agents, surfactants, bleach (sodium borohydride), the application of toasted cellulose powder, and pastel retouching.

The authors thoroughly explained the various test groups, but a recapitulation of all of these various solutions is outside of the scope of this blog post. In general, higher pH values (around 8) and higher conductivity values (above 2.5 uS) allowed for better cleaning efficacy. Perhaps more notably, the chelating agent DTPA (diethylene triamine pentaacetic acid) greatly outperformed TAC in cleaning efficacy. This is likely because DPTA is a much stronger chelator that is much more suitable for sequestering iron and calcium (which XRF showed to be present in the stain). DPTA could be used safely because the acrylic size layer was unpigmented. Finally, the use of agar (rather than free solution) was found to be useful in the reduction of the stain. The agar gel allowed for greater control of the solution distribution onto the stain and dirt absorption into the gel. The most effective cleaning agent, which was eventually used to clean the painting, was made from a higher concentration of agar gel at 5% (w/v), using Boric Acid 0.5% (w/v), DTPA 0.5% (w/v), TEA, at pH 8, 2.4 mS.

Evaluation of Successful Treatment

While a successful treatment methodology was developed through empirical testing, an investigation into the effects on the surface morphology of an unpigmented acrylic dispersion size layer was thought necessary due to the different absorbencies among the test canvases, observed differences in retention times for the agar gel, and concerns about the higher pH required to reduce the stain. The lack of pigmentation and hard surface features made changes caused by cleaning more difficult to perceive, measure and contextualize, so changes in surface gloss and stain reduction were evaluated with a spectrophotometer and subjective observations by conservators. The impact of the cleaning methodology on the surface of the size layer and canvas fibers were examined with dynamic Atomic Force Microscopy (AFM) and high resolution digital microscopy. A preliminary investigation into possible residues from cleaning was also investigated using FTIR-ATR spectroscopy.

The number of samples for AFM was too small to draw concrete conclusions without more testing and utilizing additional analysis such as FTIR-ATR; however, a general trend was observed that an increase in the gel concentration from 2.5% (w/v) to 5% (w/v) appeared to reduce the time in which fiber flattening occurred. In addition, FTIR-ATR showed a decrease or complete removal of migrated surfactant from the acrylic size layer surface in all treated samples regardless of the agar concentration in the gel, and along with the swelling of the acrylic layer, was considered by the authors an acceptable risk with this treatment. IR bands corresponding to agar or the additives in the cleaning solutions were not detected.

Final Treatment

As mentioned previously, the cleaning agent that was eventually used to clean the painting was made from a higher concentration of agar gel at 5% (w/v), using Boric Acid 0.5% (w/v), DTPA 0.5% (w/v), TEA, at pH 8, 2.4 mS. The agar was hand-cut to perfectly align with the stain patterns on the canvas and weighted with sandbags to increase the gel-canvas contact. Using this method, stains were greatly reduced. However, a few, minor discolorations remained after the cleaning. Further tests were carried out to determine the best inpainting method for these residual discolorations. Dry pigment with Lascaux Jun Funori, Aquazol 50, Aquazol 200, watercolour and gum arabic and Paraloid B72 were all tested for optical effects, handling properties, and reversibility. The Aquazol 50 series was found to be the most effective overall and was used to inpaint the remaining discolorations.

Conclusion

The authors concluded by restating that the success of the treatment would not have been possible without the combination of art historical and material understanding of Knowles’ work and research into new cleaning methodologies for acrylic dispersion paint films. They thanked their project advisors Maureen Cross, Courtauld Institute, and Bronwyn Ormsby, Tate, and many others for their generous support and guidance throughout the project.

45th Annual Meeting – Pre-session, May 29, 2017, “ECPN Poster Lighting Round,” moderated by Rebecca Gridley and Michelle Sullivan

This year ECPN rolled out a new program during a pre-meeting session that allowed poster presenters another venue to share their projects and research. I was very excited for this session because I have felt overwhelmed by the number of posters and limited free time to view them. A similar sentiment was later echoed at the AIC Business Meeting. I hope that ECPN (or AIC generally) considers organizing a similar session next meeting and I would encourage anyone looking for more engagement with poster authors to attend.

This session was in no way comprehensive of all the poster submissions. ECPN members received a notification about the session about a year before the meeting. However, ECPN contacted all poster authors once they were accepted to the general AIC poster session. The email solicitation encouraged “emerging conservation professionals” and “topics relevant to ECPs (not necessarily authored by ECPs)” according to Rebecca Gridley, ECPN Vice Chair and one of the organizers of the session. There were 14 presenters total this year, which were chosen from email responses of poster authors indicating an interest in participating. The final selection was chosen to offer a range of talks across specialties and include speakers spanning the ECPN demographic, according to Gridley. Unfortunately not every author interested was able to be included due to time restraints of the session, but ECPN is considering how this could be improved in the future.

This year’s inaugural Lightning Round did seem to have mostly young presenters including pre-program, graduate students, and recent graduates. It does seem that ECPN is trying to be more inclusive and the demographic of “ECP” is only loosely defined. Certainly the audience this year was more diverse than the presenters and included AIC Fellows and other more established professionals in the field. At the same time, the environment of the Lightning Round felt very safe and welcoming. We were seated at round tables, which was more casual than auditorium seating. This was a great opportunity for first-time presenters to get their feet wet. One of the speakers was a first-time attendee and presented on her first conservation treatment ever as a pre-program. This session promoted information sharing and dialogue—activities that I personally feel will only help strengthen our field.

Alex Nichols reflecting on the benefit of the Lightning Round said, “I was approached by several conservators and researchers in specialties other than my own [modern and contemporary objects] who said that they were introduced to my research through the lightning round presentations.” In comparison to the last time Nichols presented a poster (at the 43^rd Annual Meeting in Miami), she had more people ask about her research, which she attributes to the exposure from the ECPN Lightning Round.

Cathie Magee presenting alongside Michiko Adachi at ECPN Poster Lighting Round. The moderators are seated at the table.

The 14 poster topics were divided into two rounds, which allowed for a necessary intermission/bathroom break. The rounds were moderated by Michelle Sullivan, ECPN Chair, and Rebecca Gridley, ECPN Vice Chair.

In the spirit of the “Lightning Round” each presenter was given two minutes and three content slides to summarize their poster at the podium. This seemed like a daunting task and like I might not receive much more information than the title of the poster. I was really impressed with how clear and concise all the speakers were (I think the tambourine—symbolizing time’s up—only had to be used once). I learned a lot from the brief presentations and there was even time for one or two questions for every speaker. Having the visual component of the slides I felt took this beyond what a written abstract can offer. The Q & A was also very lively and I think emphasized how valued the poster presentations are to the conservation community.

I found this Lightning Round useful not only for the direct information, but also in helping me be more efficient with my time in the exhibition hall with the posters. Each PowerPoint included the poster number for easy reference to the location in the exhibit hall. Feeling similarly, Claire Curran, Assistant Objects Conservator at the ICA, also in attendance, and reacted, “definitely visiting this one—sounds really cool” in response to a treatment of a Hopi Katsina doll. The room was filled and there seemed to be a strong positive response to the session.

To keep things light and encourage additional networking during the ECPN Happy Hour (which immediately followed the Lightning Round) a fun fact about each presenter was announced in addition to his/her professional bio. For example, Sarah Giffin was introduced as the “meat whisperer” because of her delicious slow cooking brisket recipe.

I am embarrassed to say that I did not know that the posters are published on the AIC website after each Annual Meeting. You can access them here.

To help your exploration of the .pdf files online, here are some of the highlights each presenter chose to emphasize during the ECPN Lightning Round.

#30 Conservation in Miniature: The merger of museum object and historic interior in the treatment of a Victorian era dollhouse

Sarah Giffin

Applied in situ treatment methodology used for full-scale interiors to miniature interior of Horniman dollhouse
Mist consolidation with nebulizer using Klucel G in acetone (tests in water solubilized tannins in wooden walls creating issues with tidelines)
Condensation in the small tube was a challenge and had to tap out liquid droplets at times

#60 Conservation and Art Historical Data goes Digital at the Art Institute of Chicago

Kaslyne O’Connor

Interactive website for conservation treatment of a collection of Alfred Stieglitz photographs and some contemporaries
artic.edu/Stieglitz
Used WordPress platform because easy interface and allowed for frequent updates to content
Provides links to art historical information as well conservation/ technical information and research

#44 Applying Fills to Losses in a Flexible Polyurethane Foam Chair at the Museum of Modern Art

Alex Nichols

Research and analysis to confirm type of foam composition of the chair
Bulked methylcellulose and grated polyurethane foam for consolidation and filling of losses; liquid nitrogen helped harden foam enough to easily grate and shape
Inpranil DLV/1 is a traditionally favored consolidant for polyurethane foam but has been challenging to acquire

#92 Chemical Cleaning and Intervention Criteria in a Brass Dial Clock from the XIX Century

João Henrique Ribeiro Barbosa

Clock face (only surviving element of the clock) composed of three different metals joined together with rivets
Previous cleaning by polishing left white residues and new corrosion products developed underneath
Ammonium citrate solution addressed polish residues with “DTCNa” or sodium diethyldithiocarbamate solution addressed corrosion products

#24 History, Treatment, and Preparation for Digitization of 14^th-century Estate Rolls

Annabel Pinkney

Surface cleaning, humidification, repair with Japanese tissue
Rehousing to handle during treatment, digitization, and future research

#42 Treatment and Reconstruction of a Badly Damaged Hopi Katsina Doll Made of Gourd

Hayley Monroe

Gourds painted in acrylic
Treatment included surface cleaning, consolidating cracks, introducing new internal armature to help with reassembly and stabilization
Used silicone self-adhering bands to secure while mends were setting
Armature was set in place before doll head was reattached; tensioned wire extending to wings before head was placed back on

#10 Towards Nondestructive Characterization of Black Drawing Media

Nathan Daly

Redon drawings were used for case study
Redon working period overlapped with commercial materials available in 20^th century
Macro XRF scanning used to map elements combined with micro Raman spectroscopy
Characterization relied on peaks in fingerprint region and peaks indicative of known additives to distinguish between different carbon-based media
785nm laser for Raman because of heavy use of fixatives on the drawings

#27 (I Can’t Get No) Documenation: Preservation reporting in the Archives

Marissa Vassari

Established a template “Preservation Report” for standardized documentation and condition reporting
Focus on up-to-date condition and documentation of current status of projects and personnel involved; address realities of institution with changing/temporary staff and disruptions project workflow
Format based on feedback from other institutions and existing condition reports in the archive

#80 Bedbugs: A pesky problem

Meredith Wilcox-Levine

Addressing infestation of a Lakota teepee in private hands installed behind owner’s bed
Freezing unsuccessful likely not able to achieve low enough temperatures throughout
“Solarization” using hatchback car appeared to work (i.e. no live bugs remained)
For domestic infestation chemical treatment often necessary for bed bugs; they are night feeders and hide during the day

#32 Treatment of a Shattered Bark Basket from Australia

Marci Jefcoat Burton

Basket likely eucalyptus bark sealed with natural resin
Consolidated with B-72; bridged with tissue and blend of Lascaux adhesives
Removable internal support for storage constructed of backer rod (trapezoidal shaped Ethafoam strips) shaped to the contour of the basket and padded with Volara

#84 Lifting the Microfiber Veil: Utilizing Evolon fabric at the Mauritshuis to remove aged varnish from Hendrick Heerschop’s A Visit to the Doctor

Julie Ribits

Evolon is 70:30 polyester: polyamide spun-bond fabric
Evolon originally developed as anti-bug fabric
Used to lift and remove aged varnish; gentle and appropriate for surfaces with extensive lead soap networks
Polyamide fibers are hydrophilic and contribute to aqueous cleaning

#22 Captain America Encounters Klucel M

Michiko Adachi and Cathie Magee

Captain America pages had been stapled together in case binding
Mending utilized solvent reactivated tissue to avoid solubility issues and tidelines from acidic migration of newsprint substrate
Klucel M used as adhesive because of strength and transparency
Klucel M artificially aged by Library of Congress and seems to have similar properties/behavior to Klucel G

#67 Initial Treatment Techniques for Japanese Lacquer-based Metallic Thread and Cut Paper Applique

Elinor Dei Tos Pironti

Solubility testing was used to characterize original adhesive for metallic paper threads on a Japanese garment
Urushi was used to consolidate metallic threads

#31 Under Close Observation: A pilot study monitoring change in objects’ conditions

Ashley Freeman

Summarizing current research and findings of the Managing Collections Environment Initiative at the Getty
Comparing different methods of monitoring conditions of objects including photographic documentation (DSLR, point and shoot camera, iPhone), caliper measurements to monitor cracks, acoustic emissions
14 objects representative of materials found in institutional collections used for case study; exposed to humidity cycling

45th Annual Meeting – Paintings Session, June 1, “A Colonial Portrait and a Mystery,” by Rustin Levinson.

Rusty Levinson’s talk was perfectly fitting as the final Paintings Specialty Group presentation. The talk was informative and had some levity and humor to boot.

The portrait (see an auction photo before treatment at left), treated and researched by ArtCare Miami with technical analysis by Emily MacDonald Korth, has been believed to depict Button Gwinnett, one of the three Georgia signers of the Declaration of Independence. This identification was not certain, and the inscription on the reverse identifying the artist and sitter, was suspect. Moreover, it appeared to be written in two different hands. The inscription is visible through a cut-out window in the lining fabric left by an old restorer. Gwinnett had a short-lived political career before dying in a duel the year after signing the momentous document. Recently, a signature of his came to auction and fetched over $700,000 in its sale, reaching an all-time high price for a signatory of the Declaration of Independence. This event brought this historic figure some current-day notoriety, captured by Stephen Colbert on the Late Show last year, which coincidentally appeared during the treatment and research of the portrait. Colbert and Hamilton creator and star Lin-Manuel Miranda performed “Button!” on the Late Show after an interview with Miranda. The “Button!” rap-style performance in costume is a spoof off Hamilton, and it is hilarious. You can view it at https://www.youtube.com/watch?v=uhFeQSBZUSk. It is definitely worth a watch! I have never experienced such a hearty laugh during an AIC presentation.

One of the goals in the analysis, research, and treatment of this portrait was to help determine whether the picture likely did in fact depict Mr. Gwinnett. The painting was covered in old varnish and different campaigns of overpaint, making it difficult to compare the likeness with a known, earlier portrait of Gwinnett by British artist Nathaniel Hone (see image at left). The painting in ArtCare’s studio was attributed to Jeremiah Theus, a Swiss-born portrait painter who

worked primarily in and around Charleston, SC. Charleston was known as Charles Town until 1783. This fact creates one of the problems with the inscription, which identifies the city as Charleston, postdating the date of the portrait, which would have been before Theus’ death in 1774. Another issue with the inscription(s) was the presence of modern pigments, identified through analysis, that were part of a red layer on the canvas reverse that lies beneath the inscription(s). Zinc was identified in that layer, thus discrediting the coating as well as the overlying inscription as original to the piece. It is possible that the two inscriptions were written at some point(s) in the past, perhaps early in the life of the painting, but were later reinforced by a restorer.

Scientific analysis was conducted using a variety of techniques including cross-sectional analysis, XRF, PLM or polarized light microscopy, and optical microscopy. The results revealed typical pigments used by mid-18^th c. American painters along with modern pigments appearing in overpaint and coatings. Elemental analysis helped identify the pigments vermilion, a lead-based pigment, a chromium-based pigment, and zinc white on the painting, while on the verso, the presence of lead, calcium, and copper were detected, and vermilion and zinc white were identified. Part of the historical research involved looking at archival information about the Theus portrait. One such document was created when Sheldon Keck was asked to examine the portrait in the 1950s. At this time, Keck declared the portrait a “genuine eighteenth century painting.”

Once cleaned the painting was compared with the Hone portrait of Gwinnett and similarities in facial features were noted. Levinson toyed with an online program to attempt to visually age the face in the Hone picture. This rudimentary program, while somewhat amusing, was not revealing. A chance connection with someone from the Georgia Bureau of investigation led to a visual comparison by the Bureau whereby they did a much higher tech, digital rendering of the earlier Hone portrait to artifically age the figure’s face, and they made a comparison with the treated picture. They determined it was plausible that the sitters were the same man.

I wish there had been a bit more discussion on the artist attribution question. Even though the focus was not on the artist, I had hoped for a bit more information on the portrait’s attribution to Jeremiah Theus, particularly since I encounter Jeremiah Theus portraits in my private practice. I would have liked to know more about the connoisseurship used in the attribution, whether/which art historians may have looked at the portrait, and/or whether any of the technical analysis was compared to that of other known Theus portraits. Finally, I also would have enjoyed more discussion of the treatment, as it was somewhat glossed over. A few before and after shots side by side, including details of areas of heavy overpaint before and after with a little more discussion of the overpaint removal, would have been welcome additions to this presentation.

44th Annual Meeting – Research and Technical Studies, May 17, "Binders and pigments used in traditional Aboriginal bark paintings” by Narayan Khandekar

This was the last talk I saw at the meeting and was a perfect way to wrap things up, with a travelogue-slash-fascinating research project on the materials and techniques of Aboriginal paintings from the northern part of Australia. Narayan traveled to various art centers and museums to look at and sample pre-1960s paintings, talk to artists and gather local materials. He took about 200 samples from 50 paintings (including some from Harvard’s collection), the oldest from circa 1878. He also obtained materials from artists working today, some of whom took him around to gather materials from local sources, including the beaches of Bathurst Island (part of the Tiwi Islands off the coast of the Northern Territories – thanks Google Maps!). Back at Harvard, he and his colleagues (co authors were Katherine Eremin, Daniel P. Kirby & Georgina Rayner) gathered information on pigments, binders and other materials present that may indicate previous treatments. Narayan pointed out that only two samples of similar paintings had been analyzed and published before, such that this study presents entirely new information.

Of particular interest was the investigation into possible binders. Oral histories and documentary evidence recorded various possible binders, including turtle eggs and orchid mucilage, but it was generally thought that paintings made before the arrival of missionaries in the 1920s didn’t have binders at all (a similar question has been on my mind regarding the paintings made in the Sepik River region of Papua New Guinea). Binders were present in 77% of the samples analyzed. No proteins, waxes, fats or blood were detected. The analysis of the oldest paintings did reveal the presence of orchid juice, confirming that binders were in use that early. The techniques of using orchid mucilage could vary; the sticky juice could be mixed with the pigment, or laid down first before applying the pigments mixed in water.
As expected the pigments were largely ochres, and Narayan noted that the trace elements present in the samples provide a fingerprint that can in theory be used to begin to trace the occurrence of different ochres in different areas, but that more study and sampling is necessary to pursue this.

Other interesting findings included the use of dry cell batteries as a source for black manganese and zinc pigments on paintings from Groote Eylandt (yes a very great big island off the east coast of the Northern Territories); this area also shows the use of natural manganese-rich ores and charcoal for black pigments. A curious silver oil-resin paint on two paintings from the 1920s turned out to correlate with the roof repainting of a nearby lighthouse at the same time. The presence of DMP (dimethyl phthalate) in some paintings prior to 1957 resulted from the liberal use of insect repellent (FYI this is the main ingredient in Avon’s Skin-so-Soft; it fell out of use when DEET was invented). The presence of nitrocellulose on Groote Eylandt paintings was connected to records from the 1948 expedition suggesting that they had been consolidated with Duco.
As always, research continues, and Narayan mentioned that they would be looking further into the use of gums and of bloodwood, though I didn’t get down any details on that (I hadn’t actually planned to blog the talk, so apologies for any lacunae!). Also, I’m pretty sure there was a crocodile sighting mentioned, but that too didn’t make it into my notes, so here’s one of my favorites for good measure…

44th Annual Meeting, Paintings Session, May 17, 2016, “Experimental study on merits of virtual cleaning of paintings with aged varnish” by Giorgio Trumpy and John K. Delaney

Giorgio Trumpy presented interesting work he has been conducting on the “virtual cleaning” of paintings at the National Gallery, Washington, D.C. as a post-doc with John Delaney. He described a mathematical/- computer model which is being developed to predict and represent what a painting would look like after the removal of a yellowed varnish. The idea is not to replace the conservator, but to provide a tool in helping conservators visualize the results of such a treatment.

GIF_VanHuysum_animated — Click on the animated .gif image to see the difference in before, virtual cleaning, and real cleaning (after).

The model makes use of the contribution of the scattering (diffuse reflectance) of light from the surface of a painting with and without an aged varnished, after application of a fresh varnish, and from the interface of the paint layer and the varnish surface itself. Measurements were made on two paintings to obtain values for use in the model, and the optics of the yellowed varnish itself was estimated by measuring the transmittance through a solvent containing the dissolved yellow varnish.
The results give a pretty good indication of what the painting might look like after removal of the vanish. Click on the image* to see the animated .gif (it worked on my computer). There are differences with the paintings however as can be seen comparing the virtual cleaning image and the after (real) cleaning image. Trumpy thinks that the differences are due, among others, to the fact that the model does not account for local variations in varnish thickness or aging, and the use of the transmittance values for the yellow varnish as measured through the solvent.
In a follow-up e-mail van John Delaney I understood that the goal of the work is to better understand which factors are important for this kind of modelling work, and also to determine the limits of what the model can do. Still, I found it fascinating to see how far they had gotten.
______________________
* Image courtesy of G. Trumpy and J. Delaney, Scientific Research Department, National Gallery of Art, Washington, D.C.; detail from “Flowers in an Urn” by Jan van Huysum, c. 1720/1722, oil on panel,
79.9 x 60 cm.

44th Annual Meeting – Paintings Session, May 15, 2016, “The History, Technical Study, and Treatment of Francis Bacon’s Painting 1946” by Ellen Davis, Michael Duffy, Chris McGlinchey, and Lauren Klein

I am interested in artists’ involvement with the conservation of their pieces, and I love Francis Bacon’s paintings so I was happy when I saw that this presentation needed a blogger.
Francis Bacon considered Painting 1946 to be a break-through work. It was purchased by MoMA in1948 two years after it was painted. Because Bacon used pastel ground in water as well as oil paint, the painting almost immediately had issues with the media flaking and fading.
In 1959 and again in 1971 Bacon proposed scraping down the pastel and repainting the background. In 1959 the museum was interested in this option, but for unclear reasons, Bacon did not end up reworking the piece. In 1971 before Bacon’s retrospective at the Grand Palais in Paris, Bacon again offered to repaint the background. This time MoMA did not want the artist to address the issues with his piece, but agreed that the painting needed conservation.
Before the Paris retrospective, conservator Jean Volker consolidated with gelatin and inpainted with crushed pastel. Francis Bacon was thrilled with the results and believed that the painting had been given a new life. He decided that he even liked the faded colors better.
Over the years, the pastel inpainting faded and no longer matched the original, gelatin consolidation residues turned gray, and there was continued flaking. The painting again needed treatment. Given Bacon’s satisfaction with the 1971 results, it was decided that the goal should be to return the piece to its post-1971 treatment state, but using more stable materials.
Ellen Davis’ treatment involved removing the gelatin aqueously through tissue followed by silicone solvent cyclomethicone D5 (to avoid tide lines). Lifting paint was consolidated with TRI-Funori. Where possible the faded inpainting was reduced mechanically. The new inpainting was carried out with more light-fast pastels.
As Davis noted at the end of her presentation, this painting can only be as stable as its original materials. It is fortunate that it is in a collection where it can be carefully monitored.

44th Annual Meeting – Paintings Session, 16 May 2016, “Bocour paints and Barnett Newman paintings: context and correlations,” by Dr. Corina Rogge and Bradford Epley

Installation view of Barnett Newman: The Late Work, The Menil Collection, March 27-August 2, 2015. Image found here.

Barnett Newman was fairly private about his technique, and until recently, much less was known about his methods and materials than many other artists from the same era. Over the last few years, Dr. Corina Rogge and Bradford Epley have conducted an extensive study of Newman’s technique centered on the 2015 Menil Collection exhibit Barnett Newman: The Late Work, which included paintings drawn from the Menil and collections across the United States and Europe. By analyzing each of the paintings brought together for the show along with studio materials and Newman ephemera, the Menil team were able to learn a great deal about Newman’s working method, and Dr. Rogge’s presentation on the second day of the PSG sessions explored his loyal use of paints produced by Leonard Bocour.

Phillip Pearlstein, Leonard Bocour, 1966. Image from: http://philippearlstein.com/portrait-oil-1960s/wwtb3r20xfzsy40q37iajw3hz8wema — Phillip Pearlstein, *Leonard Bocour*, 1966. Image found here.

Bocour began producing paint in the early 1930s, opening a storefront in Manhattan which quickly became a hang-out spot for AbEx artists. In 1947, Bocour Artist Colors introduced the solvent-borne acrylic Magna, and in 1963, the water-borne acrylic Aqua-Tec, which was a favorite of Newman’s. In addition to these and other lines, Bocour often produced bespoke colors for his artists, and Newman himself often hand-mixed pigments and other additives into Bocour paints, complicating the issue when trying to understand which paints are present on Newman’s various works.
Dr. Rogge highlighted some of the idiosyncrasies of Bocour’s paints, such as the fact that the names of colors don’t necessarily correspond to the actual colorants in the paint. For instance, she found that Bocour Hand Ground Oil Ultramarine Red was colored with manganese violet pigment, while his Bellini Oil Colors Cobalt Blue was actually ultramarine. Generally, these misleading names aren’t too much of an issue, but in certain colors synthetic organic dyes – which Bocour referred to as “toners” – were added, and this is where things get dicey. His so-called cadmium colors like red and yellow contained a mixture of (not necessarily cadmium-based) inorganic pigments and organic dyes, which causes them to be light-sensitive and susceptible to fading or color shifts. She also found that the paint formulas went through changes in their colorants, binders, and additives over their years of production, and offered this handy tip: the address listed on the tube will indicate the period from which it originates – Bocour tubes initially listed simply “New York City,” and then, in 1943, there’s the addition of a two-letter postal zone, and the addition of the newly created five-digit zip code in 1963-64.

Hans Namuth, Barnett Newman in his studio, 1952. Image from: http://henrimag.com/blog1/?p=6402 — Hans Namuth, *Barnett Newman in his studio*, 1952. Image found here.

The Menil team collaborated with the National Gallery to analyze the historic Bocour materials in their Art Materials Research and Study Center, and with Harvard Art Museum’s Center for the Technical Study of Modern Art to analyze the Newman studio paints in their collection. They also received a timely gift: sculptor Robert Murray, a friend and sometimes studio assistant of Newman’s, was an invited lecturer and guest at the Menil symposium accompanying the exhibition of Newman’s late works. Murray then donated to the Menil paints from Newman’s studio, including many Bocour products. By analyzing the pigment ratios of Newman’s hand-mixed additions to the standard Bocour colors, Dr. Rogge was able to group certain paintings together as having been created at the same time.
Rogge and Epley’s broad study of Barnett Newman’s work has benefitted from some excellent collaboration and has highlighted the great value of our national study centers for historic artists’ materials. Their study is allowing scholars to understand the chronology and evolution of his late works, many of which were simply found in his studio after his passing. Her presentation emphasized the fact that the apparent aesthetic simplicity of Newman’s canvases belies not only the surprising complexity of his working method but also his fervent commitment to technical excellence and the physical longevity of his work.

44th Annual Meeting – Paintings Session, 15 May 2016, "The Mellow Pad in layers, colors, and time: investigating the materials and technique of Stuart Davis," by Jessica Ford

For the last talk of the first PSG session, Jessica Ford (Andrew W. Mellon Fellow in paintings conservation, Brooklyn Museum) presented an in-depth look at the technique and legacy of Stuart Davis (1892-1964). This talk is timely considering the renewed interest in Davis – the retrospective Stuart Davis: In Full Swing is currently on view at the Whitney Museum of Art through September 25. A loan request prompted Jessica’s study of The Mellow Pad (1945-51), and a subsequent grant from the Bank of America Conservation Fund supported not only the pre-exhibition treatment, but also a technical study of the painting and some envy-inducing technology upgrades for the BKM conservation department.

Stuart Davis (American, 1892-1964). The Mellow Pad, 1945-1951. Oil on canvas, 26 1/4 x 42 1/8 in. (66.7 x 107 cm). Brooklyn Museum, Bequest of Edith and Milton Lowenthal, 1992.11.6

Davis’s art centers on his interaction with color and space, and was heavily influenced by American jazz. He approached his compositions in the same way jazz musicians of the time approached theirs, often riffing on a past theme to arrive at a new result. The Mellow Pad is a riff on a work he began more than a decade before – 1931’s House and Street. In her talk, Jessica illustrated the work’s origin and evolution, even finding old studio photos that showed previous iterations of the work, manipulating and overlaying them to understand how the layers were built up over the long period that Davis worked on this painting.
Jessica took the non-destructive technical study to new heights with the help of the BoA grant, acquiring for the museum a multi-spectral imaging (MSI) setup, reflectance transformation imaging (RTI) equipment, and a fiber optic reflectance spectroscopy (FORS) system. She also collaborated with Nottingham Trent University to bring optical coherence tomography (OCT) to the museum to elucidate questions of layering in the paint without removing a sample. The graphics showing a moving optical cross-section and the feature where you can essentially fall into the paint layer were especially enthralling to this OCT newbie.
The wax-lined painting in its pre-treatment state had significant interlayer cleavage with resulting lifting, due to interlayer chalk from the artist’s technique, zinc-containing pigments, interlayer dirt from the long period of creation, or unstable binding media – or, more likely, some fearsome combination thereof. Jessica performed an admirable feat of BEVA consolidation, captured in this time-lapse video, which I highly recommend you watch because it’s weirdly satisfying to see an immense consolidation job vanquished in 43 seconds. Another condition concern was the discoloration that seemed to only affect paints that were layered in a certain way – a magenta stripe fading only where layered over a certain type of black. This problem is still under study and Jessica included a call-for-commiseration to anyone who might have seen this phenomenon on another Davis painting.
Davis’s work has gone through cycles of interest, and it’s nice to see it’s on the uptick, though there is still significantly less known about his working method than many other American artists of his era. Jessica’s presentation contributed to the aim of increasing our knowledge of Davis’s technique while simultaneously serving as a reminder that there is a lot left to be learned from this artist. I hope this fascinating study spurs more interesting collaborations among the author, the BKM, and other conservators and art historians studying his work.

Joint 44th AIC Annual Meeting and 42nd CAC-ACCR Annual Conference — Paintings Session, May 15th — "The Aftermath of Hurricane Sandy — Rescue and Treatment" by Carolyn Tomkiewicz and Caitlin Breare

Carolyn Tomkiewicz’s presentation began with a photo of a modest statue of Mary in the garden of a local church. It had been wrapped up against the oncoming storm—not by conservators, but by mindful parishioners. This protection had more in common with how you shield a plant from frost than how a museum usually guards against damage, but their effort and conscientiousness was rewarded when the statue survived the flood unscathed, a reveal that Tomkiewicz ended the talk with. These photos opened and closed the talk as a demonstration of how a community’s response, as much as a conservator’s response, is vital to the protection of the art in their midst.

Tomkiewicz begins at Westbeth Artists Residence, where studios and storage spaces in the basement were swiftly subsumed by the nearby and overflowing Hudson. When the artists were granted access ten days later, the salvage efforts began immediately. The rescue team—composed of the artists themselves, volunteers from AIC-CERT (Collection Emergency Response Team), and local conservation studios—took over the building’s courtyard and turned it into a makeshift triage center. Salvage operations rely on ingenuity: the team MacGyvered door screens into paper drying racks, applied toilet paper as facing for damaged paintings, used puppy training pads as blotters, and when faced with the unappealing prospect of leaving art unattended overnight, they stored as much as they could in a rental truck that they could lock up. Gaining access to indoor spaces at Westbeth improved the security of the artwork. However, as triage operations continued, more and more objects were brought to the team to be treated. The extent of the work to be done in those first few days never seemed to diminish, but the crew pressed on, even addressing the residents’ personal items as well as their art.

The Westbeth example typified an important part of the success of the Sandy response: educating artists on triage procedures to save their own artwork. This education came through including artists in the conservator-led salvage efforts as well as many informational sessions—specifically a well-attended public presentation at MoMA—and online support forums and resources. That AIC-CERT’s involvement was assisted by private conservators, public museums, and even conservation vendors who donated supplies, was what really propelled the Sandy response to be come an example of effective salvage outreach. Of course, few places worldwide rival the level of cultural saturation as Manhattan, but even cities and towns without MoMA should be able to construct a scaled-down version of this type of unified response within the local arts community.

The opening of the Cultural Recovery Center (CRC) in Brooklyn, run by FAIC to provide in-depth treatment at a secure facility, was the culmination of the volunteer effort to restore art after the devastation of Superstorm Sandy. Tomkiewicz discussed the treatment of three heavily deformed and flaking oil on canvas paintings at the CRC that required gradual-tensioning stretchers, humidity chambers, and a burnt-finger technique which utilized a lightbulb as the convex heat source. Given the type of damage Sandy left behind, she devoted special attention to the variety of ways to re-tension water distorted canvases, including Rigamonti stretchers and a “Gleitrahmen” (sliding frame) technique. Details of the treatments were published in the WAAC Newsletter Volume 35, Number 2 of May 2013, “A Tensioning Device for the Reduction of Severe Planar Distortions in Paintings,” by Carolyn Tomkiewicz.

She concluded her talk with the following advice: don’t store art in the basement in a flood zone!