AIC's 52nd Annual Meeting

Over the past decades, the conservation field has explored new methodologies to replace traditional approaches to cleaning cultural heritage. Atmospheric oxygen, lasers, hyper-absorbent tissue, and gels are a few additional “tools” to safely control the removal of surface deposits or oxidized materials.

The Museum of Fine Arts Houston (MFAH) has partnered with the GREen Endeavor in Art ResToration (GREENART) consortium (G.A. 101060941, www.greenart-project.eu) to test greener alternatives for the cleaning, coating, consolidation, and packaging of selected artworks within its extensive collection. Among these artworks, this contribution focuses on Morris Louis’ Slide (1962) and presents preliminary considerations related to its analytical investigation and cleaning treatment.

In his last years, American Color Field painter, Morris Louis (1912 – 1962) perfected his technique based on thinned washes of acrylic pigments used to “stain” unprimed cotton duck canvases. During the Stripe period, which lasted ten months before his untimely death in 1962, Louis created fewer than 75 paintings. These Stripe works are characterized by adjacent tall bands of vibrant colors obtained by pouring highly diluted Leonard Bocour Magna acrylic formulations to saturate the canvas weave. Louis' unique use of large canvases allowed him to control the flow and stain of the acrylic paints, resulting in some of the most iconic works of Color Field Painting.

Slide, an example of Louis’ Stripe paintings in the MFAH collection, has several conservation issues despite its generally stable condition. An overall yellowing is present, along with significant areas of staining that disrupt its intended appearance. The central area of blank canvas with uneven stains appears to have resulted from a cleaning attempt. Liquid staining in a drip pattern heavily affects the painting, especially at the lower edge, making it unsuitable for displaying in the museum galleries. The tacking edges were covered with black electrical tape, leaving a gray residue when removed. In 2013, some unsatisfactory cleaning tests ranged from agarose gel with citrate, DTPA, and benzyl alcohol to buffered solutions thickened with xanthan gum and free solvents.

For this conservation campaign, the painting was first documented using technical photography, colorimetry, and digital microscopy. Then, MA-XRF investigation of the painting was carried out to characterize the materials used and identify areas with diagnostic or uneven elemental composition that could help us understand the appearance of the painting to its conservation history. The canvas' overall discoloration could, in fact, have been caused by oxidation, a coating, or a past treatment involving a surfactant that has since oxidized as the covered areas of the canvas do not present discoloration. MA-XRF investigation revealed the unexpected presence of titanium-rich areas, uncovering the image of a human hand in the center of the canvas, whose origins are still under study.

In a second step, cleaning tests using greener alternatives were performed, which are discussed within this contribution. These preliminary attempts were tailored to the characteristics of the painting and designed within the GREENART project with the aim to remove both staining and electrical tape residues and revive the appearance of the painting.