The Pushkin State Museum’s collection of French Impressionists and Post-Impressionists’ paintings is rightly considered one of the best outside of France and has always been interesting both to specialists and the general public. The greatest masters of the genre are represented here by true masterpieces, and the collection as a whole gives a comprehensive idea of how this, perhaps, the most popular and valued art movement developed​.

The word impressionism comes from the French word "impression", as French artists painted their landscapes, portraits and whole compositions directly from nature and in nature, and not in the workshops, like their predecessors in the 17th and 18th centuries. It is also connected to the concept of painting "en plaine air" (in the open air). For a long time, it was believed that the Impressionists painted their pieces in one or two sessions, so much their works convey a sense of a fleeting impression, but the study of their paintings using X-ray completely debunks this persistent myth.

The first studies of the Impressionists’ paintings using X-ray were conducted in the museum already in the 1960s. Here we present the results of the recent studies.

Pierre Auguste Renoir. Young women in black

French Impressionists mostly used ready-made canvases for their paintings, primed and stretched, they were sold together with other art materials in specialized shops for artists. Therefore, since the middle of the 19th century onward, the sizes of the canvases had been more or less standardized. For paintings, the manufacturers mostly used fine-grained canvases, often to save money, because their thin material required a much thinner layer of primer, which, with large volumes of production, resulted in significant savings of lead white, which was the main component of the primer. The distinctive structure of the French fine-grained canvas is clearly visible in the X-ray images of Auguste Renoir’s paintings.

Young women in black’s x-ray image demonstrates the expressive nature of Renoir's picturesque manner. The paint layer is not homogenous on the surface of the painting, it is thick in some places and thin in the others. Despite his belonging to the new art movement, Renoir perfectly understood the optical principles of the "classical" painting technique of the 17th and 18th centuries masters, therefore, when building the volume, he used underpaintings with a large amount of white, which would be the optical basis of the painting. Therefore, a thick layer of white underpainting is visible in the x-rays even under the visually darker details of the painting (black dresses, for example).

Like most artists, in the process of creation Renoir could make more and less significant changes in the composition. In the lower right corner of the painting, a change in the position of a girl’s hand, originally painted at a greater distance, is clearly visible.

Pierre Auguste Renoir. Portrait of Jeanne Samary

The portrait of the "Comedie Française" actress Jeanne Samary gives the impression that it was painted from nature in one session. The portrait has always attracted attention with its ease of execution and the freshness of the image of a young woman. The x-ray image of the picture, on the contrary, demonstrates the intensity of posing for the portrait that took a long time. The image clearly shows that the artist changed the position of the hand under the chin of the woman several times. In the original version, the hand would have slightly covered the lower part of the face, which probably gave her image some tension.

From comparing the painting to its X-ray image and studying the small brush strokes creating the forms, it is clearly visible that at first the artist used a broad brush with quite thick paint, using a significant amount of white. The final artistic effect, somewhat reminiscent of quick studies, was made in pastel technique in the upper layers of the painting.

Claude Monet. White Water Lilies

Claude Monet painted his landscapes in one or two sessions, so his paintings demonstrate the fleetingness of a moment seen in the nature. Usually, the artist would start his work on the painting with a colour layout of the composition, placing large colour spots on the canvas plane, and then  he would accentuate the effects of the light with thick brushstrokes of whitewashed colours, and sometimes with pure whites.

Unlike Renoir, who often made changes both to the entire composition, and to its individual parts, Monet wrote "in one breath." The x-rays of the White Water Lilies clearly demonstrate the absence of any changes to the original composition, showing the diverse lively manner of his quick brushstrokes, sometimes rounded, and sometimes made with rapid jerky movements.

Jean-Louis Forain. Race.

Jean-Louis Forain (1852-1931) received a classical art education in the School of Fine Arts in Paris, studying painting from one of the most significant representatives of the French academicism, Jean-Leon Jerome (1824-1904). Later, the artist joined the Impressionists, he was friends with E. Degas, E. Manet and K. Monet. Under the direct influence of Degas, he painted Race in which all the features of Impressionism are shown: attention to sunlight, the immediacy of perception and the general study-like of the composition.

An X-ray image of the painting, however, demonstrates a brilliant mastery of the classical oil painting technique with a detailed lead white underpainting.

The x-ray shows the changes the author made in the process. Originally, there were no men in top hats or a lady with a white parasol in the foreground.

Initially, the artist was more interested in the movement of the horse: the x-ray shows numerous changes made to the position of its legs.

Vincent van Gogh. Portrait of Dr. Felix Ray.

Van Gogh’s portraits were usually painted in one session, afterwards, he would only correct the areas he was unhappy about. An x-ray of Dr. Rey's portrait clearly demonstrates the artist's creative method. The suit was made with broad brushstrokes, the face, however, was painted with short lines with a thin brush in one session. Thus, there is no characteristic whitish volume-building underpainting of the face visible in the x-ray.

The x-ray also shows that the artist used the canvas he primed himself, which was typical for Van Gogh. In the upper part of the x-ray, we can see the traces of the movement of a wide priming brush. In addition, we can also see a characteristic feature of canvases primed in haste: chaotically scattered white dots: the traces of the primer steeping through the holes in the canvas. Professionally primed canvases never have such defects.

Paul Gauguin. Self-portrait.

Post-impressionist artists, in contrast to their predecessors, have completely changed the classical technique of oil painting, refusing even to use whites for modelling the body. The main expressive means was now colour itself, volume modelling gradually became secondary.

Paul Gauguin began his artistic career as an amateur artist, so there is no underpainting in his paintings, which is clearly seen in the x-rays of his works.

The exact date of the painting is disputed. Some experts place it in the short Arles period, when he worked together with Vincent van Gogh in a studio that the artists rented together. The type of canvas used in the Self-portrait is identical to the canvas on which Van Gogh's Red Vineyards in Arles was painted; it is supported by Vincent's letters, from which it is known that he personally prepared canvases for himself and for Gauguin. However, some specialists think that the painting belongs to the beginning of the Tahitian period (1894), judging by certain stylistic features of the portrait.

Paul Cezanne. The Plain by Mont Sainte-Victoire

Paul Cezanne is an artist who directly influenced the art of the XX century and became a true reformer of painting and painting techniques, much like Van Gogh and Gauguin. Like the latter, he preferred to paint on canvases covered with white primer, mixing whitewashing his paints on the palette, and sometimes applying pure colours in separate geometric shapes or strokes: this was the basis of the easily recognizable style of Cezanne himself and his numerous followers.

The view of Mount St. Victoria (Sainte-Victoire) was one of the artist’s favourite, he never got tired of returning to it, praising the sunny landscapes of Provence. This view is one of the first versions of this theme in the landscapes of Cezanne. The X-ray image of the painting shows a dense, well-structured underpainting made with whitewashed paints. The middle plan of the picture and the mountain itself are painted with darker colours than the foreground. But in the x-ray, it is easy to see how thorough their whitewashed underpainting was.

Maurice Denis. Portrait of Martha Denis, the artist's wife.

The portrait is painted on unprimed canvas, lightly covered with glue. The brownish colour of the canvas in this case played the role of an intermediate tone, on which the artist "built" the form. Spots of almost unpainted canvas are visible around the head upon closer examination and in an x-ray image. One of the features of the artist's manner was the initial layout of colour spots, followed by a subtler modelling of volume and refinement of details.

Maurice Denis combined certain principles of classical volume modelling with the decorative painting techniques. The x-ray also shows some significant alterations of the landscape in the background.

Maurice Utrillo. Rue du Mont-Cenis in Montmartre

An x-ray clearly shows that, when painting, the artist used not only a brush, but a palette knife for depicting the rough white walls on the sides of the street. There is an opinion that one of the postcards sold to tourists in Montmartre was a reference for this painting.

A careful study of the X-ray image does not disprove this opinion. It can be clearly seen that the individual details in the painting were painted over the dried lower layer, for example, the rooftops of the houses are painted on top of an uninterrupted underpainting originally made for the sky. The windows of the houses are also painted in this technique. This is typical for landscapes made in the studio, where an artist can return to the painting again and again.