Author: Stephanie Auffret

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.

42nd Annual Meeting – Wooden Artifacts Group Session, May 29, 2014, “Review and interpretation of X-Rays of construction details of American seating Furniture”, by Gordon Hanlon

In his talk, Gordon Hanlon discussed a project that started at the Museum of Art Boston (MFA) in 2005 around a controversy regarding the date of manufacture of a side chair by Philadelphia furniture maker and carver Benjamin Randolph (1721-1791). In his 1972 book American Chairs, Queen Anne and Chippendale, John Kirk argued that a chair bearing a Randolph label and its mate – both in the Karolik Collection at the Museum of Fine Arts, Boston – were out of period. Consequently, both objects were removed from exhibition. Kirk’s analysis was refuted twenty six years later by Philip Zimmerman in an article published in American Furniture, entitled “Labeled Randolph Chairs Rediscovered”, available online at: http://www.chipstone.org/html/publications/1998AF/Zim/1998ZimIndex.html. While the Museum of Fine Arts was preparing for the opening of its new American wing, the Randolph chair was X-rayed to study its joinery. This examination confirmed Philip Zimmerman’s judgment that the chair’s construction was consistent with period manufacture techniques, most likely around 1765-75. This investigation was the start of a much larger campaign of study of chairs’ construction through X-Ray examination.
The MFA collection counts 278 American chairs, from early 17th c. to 1950, allowing for thorough comparison of construction techniques and tool marks associated with joinery. The Furniture laboratory started x-raying chairs as they came into the lab, which worked well in conjunction with the American wing project. One type of chairs did not lend itself well to that type of analysis: painted seats with lead based ground.
When film was used in the initial phase of this project, it was scanned at 300 dpi. The file was then enhanced in photoshop, using for instance the “unsharp mask” tool, then brightness and contrast adjustments. Many other options are of course available to reveal various levels of information on the image. The MFA recently switched to digital X-Ray, which seems to surpass film from Gordon’s point of view.
In order to compare information revealed by the X-Ray images, Gordon made mock-ups of joints and looked at a selection of bits. 36 chairs have been x-rayed so far. A few examples were illustrated in the talk, showing tenon and mortise joints as well as dowels.
To record the data gathered, TMS database showed some limitations, leading the lab to use Filemaker pro. The lab already had experience with this database as they used it for two previous projects: in 2005 for a study of historic fasteners (Chris White), and in 2008 for an investigation of painted furniture (Carola Schuller and Michelle Derrick). Currently Christine Schaette, who also gave a talk during this WAG session, is also using Filemaker pro to record her findings on inscriptions found on furniture. Gordon concluded his talk by inviting his colleagues to share results of their own examination of seats. This is something to investigate for WAG, to hopefully find a way to create a platform for everyone to share X-Rays of chairs.