45th Annual Meeting – Paintings Session, 1 June, “Color Field Paintings and Sun-Bleaching: An approach for removing stains in unprimed canvas” by Jay Krueger

Jay Krueger’s talk was a great synthesis of the most interesting and exciting ideas running through this year’s conference: interdisciplinary collaboration, a thoughtful and considered approach to complicated and seemingly radical (but necessary treatments), and recognition of the fact that well-intentioned traditional attempts to minimize or limit treatment can cause unintended secondary damage. The talk focused on the National Gallery of Art’s treatment of Morris Louis’ 133, painted in 1972.

Color field painting, as exemplified here in Louis’ work, focuses on areas of pure color, and its abstracted forms are freed from the constraints of representation, brushwork, etc. Unlike traditional paintings with distinct layers of canvas, ground, paint, etc. the direct application of (sometimes thinned) paint to unprimed canvas allowed the paint to soak into the canvas support, staining it rather than sitting on its surface.  The unprimed canvas is integral to the composition: its flat, unbroken expanse of color (i.e. the material itself) and relationship to the paint is essential, and any disruption of this is as detrimental to the work as damage to the paint layer would be.  The painting was already described as having a “smudge” on the canvas when it entered the Gallery’s collection in 1976, and its condition had not improved over time, despite attempts at locally treating damages and defects in the canvas.  By 2007 the stain was so pronounced, and other areas of staining had developed to such a degree, that the painting was suggested as a suitable candidate for more significant treatment.

It was at this point that the NGA felt comfortable enough to consider putting into practice a methodology they have now spent twenty years investigating and testing, and which I found to be the most inspiring part of the talk. Their proposed treatment embraced the rejection of three principles generally regarded as law in paintings conservation: don’t put your paintings in direct sunlight, don’t expose them to water, and limit your interventions to the minimum level of what is necessary to treat areas of damage.  The NGA quite rightly recognized that for these specific conservation concerns, paintings conservation could gain from consulting and borrowing from our colleagues in paper conservation by approaching the treatment of canvas supports in the same ways that paper conservators treat their cellulose-based supports.  They also brought the Getty onboard, since their history of using scientific research to inform and support treatment made them the ideal partner for investigating the material aspects of the painting, necessary vs. superfluous components of various treatment steps, and the longterm success and effects of the treatment itself.  The Getty’s spacious private terraces and steady supply of California sunshine also proved to be very beneficial!

I will leave the details of the treatment to be more rightly and thoroughly covered in Krueger’s contributions to the postprints, but the essential process is an adaptation of the aqueous sun-bleaching technique used in paper conservation. The painting (mounted to a working strainer) is positioned on an incline, completely dampened and held in a steady flow of water, in full sun.  By treating the canvas as the homogenous material it is, you avoid the problems of trying to control the movement and activity of water as applied locally, and instead appropriate and better exploit those same properties to our (and the painting’s) benefit.

Significantly, the extraordinarily successful treatment uncovered secondary damage caused by those previous localized attempts at canvas cleaning/stain reduction: after aqueous sun-bleaching (which in and of itself could not overclean the canvas), these were visible as noticeably lighter patches of canvas which then had to be toned back. Additionally, the project included investigation of whether the treatment had material as well as aesthetic benefits.  Paper conservators report that paper supports are stronger after washing, and there was some thought that washed canvases could show similar improvement.  Alan Phenix ran tensile strength and color change tests on canvas after washing and sun-bleaching.   The canvas did show some improvement in strength, and both washing and sun-bleaching helped prolong the life of the canvas by removing damaging degradation products.

Krueger’s talk forms a natural trio with two others given at this year’s conference: Maggie Barkovic and Olympia Diamond’s “Pioneering Solutions for Treating Water Stains on Acrylic Paintings: Case Study of Composition, 1963, by Justin Knowles” and Jonathan Ashley-Smith’s “What’s so ethical about doing nothing?”.  Barkovic and Diamond’s presentation highlighted their successful treatment of a similarly damaged painting using a modified agar gel, and their different approach emphasizes (as Krueger himself did) that aqueous sunbleaching is not suitable for all paintings (the Knowles’ canvas is sized, unlike Louis’ 133).  Ashley-Smith’s provoking contemplation of the future of conservation elegantly pointed out that an overemphasis on minimal intervention can, and has had, unintended consequences; one of these is unknowingly damaging the pieces themselves.  By being so risk averse as to avoid treatments that seem unnecessarily invasive, are we in fact contributing to the degradation of the works we are charged to care for?  Although the pendulum swing towards minimal intervention and preventive conservation is understandable, these talks serve as a valuable reminder to continue to explore new treatment methodologies supported by our increasing wealth of collaborative knowledge and technical advancement.