A Subtle But Significant Improvement: Conserving A “Petal Painting” (Part II)

Read part one of this series here.

Consolidating Flaking Paint

Before the picture could be cleaned safely, flaking paint throughout the canvas needed to be stabilized, or consolidated, to prevent losing original material. A water-based glue made from fish bladders was selected for consolidation–the adhesive is relatively strong at low concentrations and, because it is used warm, it helps to relax lifted paint to allow it to be set flat again.

This detail shows an area of cracked and flaking paint. To consolidate the paint, the water-based adhesive was fed into cracks using a small brush.  Adhesive was applied through a layer of tissue to protect the paint surface.

This detail shows an area of cracked and flaking paint. To consolidate the paint, the water-based adhesive was fed into cracks using a small brush. Adhesive was applied through a layer of tissue to protect the paint surface.

For consolidation, the 66 x 48-inch painting was placed flat and elevated on blocks.  A flat suction platen was placed underneath, against the back of the canvas (The grey hose that attaches the adjustable platen to a vacuum can be seen in the picture above).

For consolidation, the 66 x 48-inch painting was placed flat and elevated on blocks. A flat suction platen was placed underneath, against the back of the canvas (The grey hose that attaches the adjustable platen to a vacuum can be seen in the picture above).

Gentle suction was used to draw adhesive through cracks in the paint and beneath the paint layers. The adhesive was kept warm in a beaker with an electric mug warmer. The warmth and moisture of the adhesive relaxed areas of lifted paint so they could be carefully set down. The suction held the consolidated paint in place while the glue dried. Any glue residue was removed using warm distilled water, which was applied through tissue to protect the paint surface and prevent paint loss.

Cleaning a Delicate Paint Surface

In order to clean the painting without altering the surface, the conventional methods needed to be modified. In the end, a fairly simple solution of cleaning through a layer of tissue was found to work very well to release the grime layer while protecting the delicate paint. The type of tissue that worked best, “wet-strength” tissue, is the same as that used for making tea bags. Careful testing found distilled water adjusted to a custom pH to be a safe and effective cleaning solution for the picture. Applied through tissue using a cotton swab, it released a fine, yellowish grime from the paint, which soaked into the tissue. Tissue squares and swabs were carefully monitored for hints of other color, but even the dry media–the white chalk and black charcoal–were protected by the tissue interleaf.   …Read part three tomorrow.

Conservator Patricia Favero holds a square of tissue against the paint surface with her left hand while, with her right hand, applying the pH-adjusted cleaning solution through the tissue using a cotton swab.

Conservator Patricia Favero holds a square of tissue against the paint surface with her left hand while, with her right hand, applying the pH-adjusted cleaning solution through the tissue using a cotton swab.

A subtle but significant improvement: Conserving a “petal painting” (part I)

This is part one in a three-part series.

Bradley Walker Tomlin, No. 8, 1952, Oil and charcoal on canvas; 65 7/8 x 47 7/8 in.; 167.3225 x 121.6025 cm.. Acquired 1955. Phillips Collection, Washington D.C.

No. 8 (1952) was the first of two late abstract expressionist works by Bradley Walker Tomlin to enter The Phillips Collection in the 1950s. Purchased in 1955 from Tomlin’s dealer, the Betty Parsons Gallery in New York, Duncan Phillips called this painting “Blossoms” and referred to pictures with its particular style of short, thick brushstrokes as Tomlin’s “petal paintings” for their resemblance to falling flower petals.

Painted in 1952, No. 8 was 60 years old when it came into the Conservation Studio at the Phillips last year, and the painting was showing its age. Paint around fine cracks in various “petals” of color was beginning to lift and flake off, and over the years a layer of fine, yellowish grime had also accumulated on the unvarnished paint surface. The overall appearance was dull with diminished color contrasts. No evidence of previous restoration was observed on the painting or found in files, suggesting this was the picture’s first comprehensive conservation treatment since it was painted.

The goal of treatment was to improve the painting’s overall condition and appearance with as little intervention or alteration of original material as possible.

A Delicate Paint Surface

The media line of No. 8‘s label reads “oil on canvas,” but Tomlin’s is not a typical oil paint film. In some places, the paint surface is glossy and cohesive, and in others it is matte with a slightly rough texture. In a few areas, the paint has a soft, velvet finish–here, it is thought Tomlin may have mixed wax with his oil paint to get that effect. Tomlin also sketched in chalk and charcoal over dry paint, and some of this dry media remains visible in the final composition.

Cleaning this painting in a conventional manner–either by gently rolling a wet cotton swab over the paint surface or using dry techniques–would be impossible to do without removing or otherwise altering original material. The chalk and charcoal would be easily wiped away, and any friction on the surface would burnish the matte areas, especially where Tomlin mixed wax into the paint.  …Read part two tomorrow.

Detail of the matte, unvarnished paint surface with lines dry media -- white chalk and black charcoal

Detail of the matte, unvarnished paint surface with lines dry media–white chalk and black charcoal.

Rehousing a Diego Rivera Watercolor

In the summer of 2012, The Phillips Collection received the generous gift of an original Diego Rivera watercolor from Kerry H. Stowell. The watercolor is executed on delicate Japanese paper and depicts a poignant child labor scene. The artwork had become wrinkled in its old matting and frame over time. Whenever a new artwork enters the museum’s collection, the conservator examines its condition. The picture receives treatment when necessary and is rehoused in museum quality materials. In this case, the Rivera picture required removal from an acidic, poor quality backing board and flattening before being hinged into a new mat.

After removing the old paper hinges and flattening the paper, new hinges of Japanese paper are prepared. Since the artwork will be floated in its new mat, the Japanese paper is toned with acrylic paints in order to be less visible. The following photos illustrate eleven steps that were taken to prepare the newly acquired artwork for exhibition at the museum.

Step 1: Hinges are toned to match the original color of the artwork so they will be invisible. Photos: Patricia Favero

Step 1: Hinges are toned to match the original color of the artwork so they will be invisible. Photos: Sylvia Albro

Step 2: Conservation technician, Caroline Hoover, prepares the hinges and wheat starch paste for the new mount

Step 2: Conservation technician, Caroline Hoover, prepares the hinges and wheat starch paste for the new mount

Step 3: Pasting out the Japanese paper hinges with wheat starch paste

Step 3: Pasting out the Japanese paper hinges with wheat starch paste

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