They may not be quite as famous as his sunflowers or self-portraits, but Vincent van Gogh’s olive-tree paintings still represent an important entry in his sprawling oeuvre of more than 2,000 works. The series was completed during the penultimate year of the Dutch post-impressionist’s life, in 1889. Van Gogh was staying at a psychiatric hospital in Saint-Rémy-de-Provence, having admitted himself after suffering numerous breakdowns in nearby Arles. He was given a spare room for painting and, after some time, was allowed to venture outside, which is when—in June—he came across the local olive trees.
It was not van Gogh’s first encounter with the species. While in Arles, he had written to his younger brother and longtime pen pal, Theo, that he wouldn’t dare paint the trees because they were too beautiful. He overcame that trepidation while at Saint-Rémy and completed 15 landscapes. One has been in the permanent collection of the Museum of Modern Art (MoMA) in New York since 1998. Theirs is perhaps one of the most recognizable of the bunch, as van Gogh made it as a companion to his famous Starry Night (1889), with the former presenting the scene during the day and the latter in the evening.
Now, for the first time, the series will be reunited. An October exhibition at the Dallas Museum of Art will give viewers greater insight into the techniques and palette that van Gogh used as the works will be witnessed as a collection. But first, a few touch-ups are required. At MoMA, conservator Michael Duffy was tasked with restoring The Olive Trees (1889), a meticulous process that he began in summer of 2019.
1. Ideal Image
Duffy observes an X-ray image of the painting. X-rays and photographs under different lighting conditions are taken before restoration begins so that damage invisible to the naked eye, such as microscopic tears, as well as places where the paint is less dense or missing entirely can be observed.
2. Perfect Chemistry
The painting has a varnish on it that wasn’t applied by van Gogh but was added later in an attempt to preserve the artwork. Now the varnish has discolored, so Duffy has to remove it. He uses an organic solvent that will safely dissolve the varnish without harming the oil layers beneath and refers back to MoMA’s reports from when the piece was last restored as a guide.
3. Clean Slate
Duffy painstakingly applies the solvent with a brush through a soft tissue, which absorbs the varnish from the painting’s surface.
4. Zoom In
Van Gogh’s works famously feature impastos where he applied paint in very thick layers. Some of the varnish can get stuck in the crevices and loops of the paint in these areas, so Duffy uses a microscope and a small brush to ensure that it’s all removed. This is the most challenging and time-consuming part of the entire process.
5. Wax Off
Conservation wasn’t always as high-tech as it is now. To help reinforce a painting, restorers in the Netherlands in the ’30s and ’40s would often attach another canvas to the back of the original via an adhesive made of beeswax and resin. Here, some of that material, which has now turned orange with age, has come to the front of the impasto areas. Duffy uses a small hot-air tool to soften the wax and then gently scrapes it off the edges.
6. Color Theory
Some areas where the paint has flaked off have to be refilled, but first Duffy must determine what pigments are appropriate for the task. The special conservation paints are water-based colors that imitate the original hues and can be reversed if necessary—if the color match is not perfect, for example.
7. By the Numbers
Duffy applies these pigments to the areas where the original oil paint has come off. A few of the most obvious losses are in the left corner of the foreground.
8. Wear and Tear
The canvas has been stretched and folded many times throughout the years, causing small tears and losses to emerge along the edges. Unfortunately, they’ll always be present, but Duffy applies a minimal amount of gesso putty on the small flaws to stabilize the borders.
Now that the restoration process is complete, the viewer can appreciate The Olive Trees on a much deeper level. “You can clearly see [van Gogh] used four different blues in the mountains, whereas before, because of the varnish, it looked like one,” says Duffy. “So that’s super gratifying.”