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.
Tag: Painting Specialty Group
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 – Paintings Session, May 29, 2014, "Oil Paintings on Metal Support: Study, Intervention, and Challenges" by Mónica Pérez
Mónica’s talk focused on the treatment of five oil paintings on meta at the National Center for Conservation and Restoration (Centro Nacional de Conservación y Restauración, or CNCR) in Santiago, Chile.
In 2012 five paintings from the Bernardo O’Higgins House Museum in Talca, Chile were brought to the CNCR in serious need of treatment. The paintings represented an exciting moment for the CNCR, since paintings on metal had not been treated there previously. One of the paintings was signed by Willem Van Herp, 1655, making it the oldest painting to be treated at the CNCR. All five of the paintings were bought in Europe in the 19th century by Eusebio Lillo (who also happens to have been the author of the Chilean national anthem) who donated his large collection of art to the museum upon his death in 1911.
Of the five paintings treated by the center, three were 21 x 29 inches, and two were much smaller, measuring 9 x 7 inches. Two had been previously cradled, and the rest were otherwise unrestrained. Four of the paintings were on copper, and one was painted on tin-plated iron. Various condition issues, all common with paintings on metal, were present; the most serious issues were corrosion (which consisted of brown stains and corrosion products protruding from the paint layer), distortion of the support, flaking paint, discolored varnish, and puncture holes where the paintings had been nailed to walls or altars. In addition, large areas of overpaint were present.
Treatment of the paintings began with documentation and an initial analysis of the imagery depicted. All of them appeared to be allegorical or religious, and a few were clearly similar in composition and subject to other, more famous paintings, such as the painting referred to as “Disciples of Emmaus” by the center, which featured two parrots that were exact matches to those in a Jan Breughel painting from c. 1620.
Cross sections of the paintings were taken in order to help conservators to distinguish between original and later paint. The four paintings on copper were found to have a lead white ground, and the painting on tin-plated iron had a ground consisting of Prussian blue and lead white. Varnishes were found to be mastic or dammar, but were clearly not original for several of the paintings. UV examination revealed aggressive cleaning and intervention in the past.
In order to determine the best methods for treatment, copper prototypes were created and used to test adhesion of various adhesives. The CNCR used Isabel Horovitz’s research into paintings on copper as the primary resource for their work. Following testing on the prototypes, corrosion was mechanically removed, and a solution of 15% B-72 in toluene was used to isolate the corroded areas and to consolidate flaking paint.
Distortions in the support were significant on a few of the paintings, and conservators hoped to be able to reduce it. Flattening was attempted on prototypes using a book press, and the result was considered to be less distracting. A few of the paintings were flattened in this manner. An acrylic plate was applied to the reverse to provide support and to allow the reverse of the metal plates to be seen.
15% B-72 in toluene was used as a base for filling losses in the paint surface, and a tacking iron was used to level the edges of the fills. Fills were isolated with a varnish and inpainted to a full visual reintegration. After cleaning and inpainting, the subjects of the paintings were revealed to be religious and not allegorical. The center has suggested re-naming the paintings accordingly, and has sent their proposed titles to the O’Higgins museum. The treatments and the revealed subjects will be summarized in an upcoming book.
AIC’s 39th Annual Meeting – Joint Paintings/Research and Technical Studies Session, June 3, “Developing Cleaning Systems for Water Sensitive Paints by Adjusting pH and Conductivity” by Tiarna Doherty
As a fitting end to a conference full of great talks, Tiarna Doherty, from the J. Paul Getty Museum, wrapped up the final session of the joint PSG/RATS session at the annual meeting on Friday evening with an incredible talk about new developments in cleaning water-sensitive paintings. The project was a collaboration between herself and two others, Chris Stavroudis, conservator in private practice, and Jennifer Hickey, Graduate Intern at the Metropolitan Museum of Art, that aims to develop a methodological approach to cleaning water sensitive works by measuring the pH and conductivity levels of the surface of the artwork and cleaning solutions in use.
Doherty began her presentation by introducing us to the Modular Cleaning Program (MCP), a database system that has been developed to assist conservators in their approach to cleaning artworks. The MCP performs valuable computations which assist the conservator in creating cleaning solutions that take into consideration, pH, ionic strength, HLB, and the functions of surfactants, buffers, and chelating agents, within aqueous cleaning solutions. Using MCP workshops given by herself and Stavroudis as an example, Doherty highlighted how practical experience with the MCP has helped them to understand how paints interact with cleaning systems, and thus aided in their current research.
She continued by concisely explaining why they focused on pH and conductivity. First, recognizing that the pH of something as simple as water may vary widely, Doherty notes that even exposing de-ionized to air over a long period of time eventually causes the pH to lower. Likewise, carbonated water also has a low pH, but since an acrylic paint film swells at a pH of 7 and higher, the use of carbonated water has been shown to successfully clean some water sensitive acrylic artworks. Doherty finished her introduction on pH with a brief explanation of buffers and the use of acetic acid and ammonium hydroxide to adjust the pH of water for cleaning, noting that both of these components of the solution will evaporate over time without leaving a residue on the surface of the artwork.
Next, Doherty continued her talk by segueing into an introduction on conductivity. Conductivity, the ability of a solution to transfer (conduct) electric current, was recently explored as a means to evaluate the surface of an artwork during cleaning and to create/develop useful cleaning systems. In a simple manner, the conductivity of a painting’s surface can be measured by placing a small drop of water on the surface of the painting, and then transferring it to a conductivity meter after a short period of time. Doherty reported that recent research in the field has concluded that there is less swelling of a water sensitive paint surface when it is cleaned with a solution that has a of pH of 6 or lower and a conductivity of 6000 micro-Siemens.
The talk continued with two in-depth cleaning case studies on an oil painting and an acrylic painting, which were both painted in the 1960’s, and had proven to be sensitive to water. Using solutions with adjusted pH, various conductivity levels, and the addition of materials such as chelators, surfactants, and even an emulsion system containing a proprietary material called Velvasil®, Doherty’s team tested and successfully developed systems for cleaning each of the two artworks (which, to ensure accuracy of content, I will point you in the direction of the post-prints for the details of).
As Doherty concluded her talk, I couldn’t help but be a little excited about possible implications of this and future research on these topics. This talk not only raised many interesting considerations about the cleaning of paintings, but, it also revealed the practical application of a new a tool set for conservators who face the challenge of water-sensitive paintings.
Bravo Tiarna (and team), I look forward to hearing more as this project progresses.
39th Annual Meeting – Joint Paintings/Research and Technical Studies Session, June 3, “Potential Cleaning Applications of Poly(vinyl alcohol-co-acetate)/Borate gels on Painted Surfaces” by Lora Angelova & Kristin deGhetaldi
Where to begin? First let me start by saying, if you missed this presentation during the joint PSG/RATS session, then you should be sure to check out the paper in post-prints once available. The details and future potential of this research cannot likely be given its due justice in a short blog post, but I will do my best to give you the major highlights.
On the final day of the annual conference Lora Angelova and Kristin deGhetaldi presented their findings regarding recent research on Borate gels, a new aqueous co-solvent gel system for use on painted materials. This collaborative project between Angelova, a Ph.D candidate in the department of chemistry department at Georgetown University and deGhetaldi, the Andrew W. Mellon Painting Conservation Fellow at the National Gallery of Art, along with Senior Conservation Scientist Dr. Barbara Berrie and Professor of Chemistry Richard Weiss at the NGA and Georgetown, respectively, resulted in the development of a new aqueous based gel system with great potential for use by conservators in the cleaning of paintings and painted surfaces.
The presentation was first introduced by Kristin deGhetadi, who immediately hooked the audience with the highly successful results of a case study, which utilized the cleaning gels in question.
The case study involved the cleaning of a painting titled Multiple Views, a 1918 work by Stuart Davis in the collection of the National Gallery of Art. After a brief history of the work, including an antidotal account about how Davis painted the work during a three-day contest in an “atmosphere of drinking and conviviality”, deGhetaldi described in detail the before treatment condition of the work. The painting, which suffered from extensive previous restoration, was waxed lined and covered with an extremely yellowed and degraded dammar coating that analysis revealed contained not only wax, which likely migrated to the surface from the lining, but protein, polysaacharides, drying oil, and, even nicotine.
Needless to say, deGhetaldi realized that this particular coating would prove to be challenging to remove. She described her methodical approach to the treatment using the Modular Cleaning Program developed by Chris Stavroudis. After exhausting the options of traditional free solvents, various aqueous cleaning solutions, and solvent based gels, she turned to the use of an aqueous emulsion that contained Pemulen TR-2 with 5% Benzyl Alcohol. While the latter worked very well to remove the coating over much of the painting there were still areas where a particularly tenacious dark coating remained. For these local areas the Borate gels being developed by Lora Angelova were tested and used for treatment.
Working together, Angelova and deGhetaldi performed a variety of tests with the gels and adapted them to the particular problem of cleaning Multiple Views.
deGhetaldi finished her portion of the presentation describing this treatment with numerous beautiful before, during, and after treatment images and a full description of the practical use of the Borate gels, before handing the podium over to her co-presenter.
Lora Angelova began her half of the presentation by describing in detail the formation, characterization, and modulation properties of the borate gels (and the chemistry involved).
The gels are composed of a partially hydrolyzed poly-(vinyl alchohol-co-acetate) polymer that combines by cross-linking with a very small amount of borate ions. The formation of the gel is immediate and proved to be thermally stable with soft elastic properties found desirable for use in treatment. Additionally, due to the acetate groups present on the polymer, the gels allow for the use of large amounts of polar organic solvents to be incorporated into the system. Which was utilized in the case study discussed by deGhetaldi.
Angelova continued by describing several properties of the gels that may make them useful in conservation, including the fact that the gels are transparent, pliable, and as mentioned, have the ability to hold large amounts of commonly used solvents. She then went on to describe how the gels are easy to remove, leave no detectable residue, and have the ability to clean a precise area with little solvent penetration into the paint layers. Which of course grabbed the attention of the conservators in the audience.
Using the results of from a number cleaning tests and further analysis, Angelova further described testing of the prior mentioned traits. She used residue tests conducted by attaching a naturally fluorescing molecule to the polymer in the gel. This allowed for testing regarding the removability of the gel and demonstrated that no detectable residue of the gel was left behind after removal.
Finally, Angelova eloquently concluded her presentation with a brief discussion of future work and the testing that is necessary in order to fully understand and develop the use of Borate gels in conservation.
So, while these gels may not be quite ready for use in the wider world of conservation yet, as was made clear by both the author’s conclusions and some of the thought provoking questions posed by audience members, they are definitely showing great potential as a tool for conservators already and I know many, myself included, who look forward to hearing more about the results that this project produces.
39th Annual Meeting – Paintings Session, June 2, 2011, “Giovanni Antonio Boltraffio’s Madonna and Child in the context of Leonardo da Vinci’s Studio Practice” by Sue Ann Chui
Ms. Chui presented a truly gorgeous Renaissance painting that came from the Budapest Museum of Fine Arts to the J. Paul Getty Museum for a collaborative research and conservation project. Immediately it was clear that the style was recognizable as influenced by Leonardo da Vinci. This was probably the reason for the misattribution in the 18th century and earlier. With an array of beautiful photography comparing various paintings art historically, the very convincing case was made for the current attribution to Giovanni Antonio Boltraffio, a student of Leonardo in his workshop in Milan at the turn of the 16th century.
Extensively but not expertly previously restored, Ms. Chui unraveled the condition of the panel painting layer by layer with excellent documentation from the international team that worked on this project. Each layer of discovery added further proof to Boltraffio’s authorship.
In fact, it seemed to me that the research and documentation discovery process on this painting must add to the collective knowledge on Leonardo’s techniques and teachings. Adding to that body of knowledge is always an exciting prospect. It was wonderful to see the evidence that Ms. Chui presented of the master’s hand in the manufacturing process and the design work. Specifically, I found the discussion on original fingerprints left behind in the imprimatura layers interesting, though no conclusion was insinuated that they were definitely by Leonardo.
While none of the conservation treatments were innovative, they were most interesting, well photographed and pleasantly presented. As you might expect, the quality of the conservation work resulted in maximizing the original beauty of a truly unique and beautiful image of this holy mother and child. It made for excellent technical entertainment much the way I found myself eagerly awaiting, back in the day, the arrival of the latest National Gallery Bulletin. Detailed, colorful cross sections, exceptional and easy to understand diagrams to clarify, photographic references and ties to other works of art and the fluid manner of Ms. Chui made this a 1st class presentation.
If you missed this presentation, then I’m sorry but it is impossible to do the material presented justice in this blog post. We can only hope that Ms. Chui publishes her material accompanied by all of the slides of her powerpoint (doubtful). Visually, it’s a great presentation but, in addition, the info needs to be searchable and referenced by others.
Contact Ms. Sue Ann Chui at schui@getty.edu and (310) 440 7023
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Scott M. Haskins
Fine Art Conservation Laboratories (FACL, Inc.)
www.fineartconservationlab.com
(805) 564 3438