Rediscovering the Brilliance: Unveiling the Mystery Behind Miró’s Fading Yellows

From Van Gogh’s sunflowers to Edvard Munch’s “The Scream,” there’s an abundance of renowned artwork that features a vibrant color called cadmium yellow. However, the brilliance of this color often diminishes over time as the paint fades and becomes chalky.

Not only does this deterioration affect centuries-old artworks, but it also impacts more recent pieces. A team of art conservators and scientists recently studied degraded cadmium yellow paint from works by Spanish artist Joan Miró in the 1970s. Their research, published in July in the journal Heritage Science, identified a particular brand of paint that was likely responsible for the degradation observed in Miró’s pieces.

Cadmium yellow paint is primarily composed of cadmium and sulfur. It was first introduced in the 1840s and quickly gained popularity among artists. Miró praised the color as “splendid” and utilized tubes of cadmium yellow paint, including the Cadmium Yellow Lemon No.1 produced by Lucien Lefebvre-Foinet, in his studios in Mallorca, Spain.

In 2020, art conservator Mar Gómez Lobón began investigating the paints used by Miró during his time in Mallorca. She discovered that over 25 pieces in the Pilar and Joan Miro Foundation’s collection, painted in the 1970s, exhibited signs of degraded yellow paint.

To determine the cause of the deterioration and its connection to a specific brand of paint, Ms. Gómez Lobón and her colleagues collected tiny flecks of cadmium yellow paint from three of Miró’s untitled paintings from 1973 to 1978. They also obtained samples from paint tubes and studios. By analyzing how the paint interacted with light, the team examined the chemical composition and structure of each sample.

Analyzing a microscopic sample of paint offers significant advantages for scientific analysis. It eliminates the need to transport valuable artworks to a laboratory, which can be logistically complicated and risky. David Muller, a physicist at Cornell University, highlighted the benefits of working with such small samples when studying the degradation of cadmium yellow in “The Scream.”

Ms. Gómez Lobón and her collaborators found that the degraded paint samples from Miró’s paintings contained primarily cadmium, sulfur, and traces of zinc, as expected. The same composition was observed in the palette and one of the paint tubes. Additionally, all six samples exhibited poor crystallinity, indicating a lack of ordered arrangement between the cadmium and sulfur atoms.

The poor crystallinity of cadmium yellow has also been linked to the degradation of older artworks by Picasso, Matisse, and other artists. These new findings reveal that the issue persisted well into the 20th century, which surprised the researchers. Despite being a respected brand, Lucien Lefebvre-Foinet’s Cadmium Yellow Lemon No.1 also exhibited these degradation characteristics.

In the future, Ms. Gómez Lobón plans to catalog the remaining tubes of paint in Miró’s studios and further study their age and production processes. She believes that Miró’s studios hold valuable resources that warrant exploration. “These studios are like a gold mine,” she said.