Read parts one and two of this series.

Results of Treatment

Treatment resulted in a subtle but significant improvement to the picture’s appearance. Greater contrast between the dark colors in the background and the pastel “petals” in the foreground returns a sense of vibrancy and movement to the composition. In addition, although they remain inherently fragile, consolidation left the paint layers more stable–improving the overall condition of the picture.

No. 8 seen Before Treatment, left, and After Treatment, right

Left: The back of the painting showing the canvas and stretcher. Right: The back of the painting with a protective foam-core backing, attached to the stretcher to add support and protect the back of the canvas from dust and blows.

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.

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.