A pentimento is a visible trace of a changed composition beneath a painting's surface. Learn how X-ray and infrared imaging reveal artists' revisions from Rubens to Ensor.
X-ray a painting by Rubens and you will find a second painting hiding beneath the surface. Figures have moved. Arms have been repositioned. Entire elements have been painted over and replaced. Rubens was a relentless reviser, and his canvases are full of what art historians call pentimenti, from the Italian word for "repentance." A pentimento is evidence that the painter changed their mind. The surface you see is not the first version. It is the final version, and beneath it lies a record of decisions made, rejected, and painted over.
A pentimento is a visible or detectable trace of a changed composition beneath the surface of a finished painting. The word comes from the Italian "pentirsi," meaning to repent or to change one's mind. Some pentimenti are visible to the naked eye, either because the overlying paint has become more transparent with age or because the original position of a figure or object shows through as a ghostly displacement. Others are invisible without technical imaging, revealed only by X-ray, infrared reflectography, or other conservation tools.
This entry covers what pentimenti are, how they are detected, what they tell us about an artist's process, and how to spot them in museums.
A pentimento forms when a painter alters the composition during the painting process. The painter covers the original element with new paint and continues working. If the overlying paint is thick and opaque, the change is invisible on the surface. But oil paint becomes more transparent over time as the oil binder ages and increases in refractive index. Over centuries, elements that were completely covered can begin to show through, appearing as ghostly shapes displaced from the visible composition.
Not all pentimenti become visible on the surface. Many are detected only through technical imaging. X-radiography reveals pentimenti because different pigments absorb X-rays to different degrees. Lead white, the most common white pigment in oil painting before the 20th century, is highly absorbent and shows up clearly in X-ray images. If a painter moved a hand that was originally painted in lead white, the X-ray will show both the original and final positions, creating a double image. Infrared reflectography detects carbon-based underdrawing and dark paint layers beneath lighter surfaces, revealing compositional changes at the drawing stage.
A 2025 study published in npj Heritage Science introduced a classification system for painters' reworking practices, using the oeuvre of Belgian Modernist James Ensor (1860-1949) as a case study. The research identified five types of reworking: (1) pentimenti, changes made throughout the painting process; (2) post-factum revisions, minor changes on already dry paint; (3) recycled works; (4) metamorphoses, modifications that fundamentally change the meaning; and (5) appropriations. Using macro X-ray fluorescence imaging and other techniques, the study documented numerous pentimenti and overpaints across Ensor's oeuvre. Read the study at Nature.
Pentimenti are as old as painting itself. Any painter who changes their mind during the working process produces them. But the systematic study of pentimenti as evidence of artistic process is a 20th-century development, enabled by the invention of X-radiography in the early 1900s and infrared reflectography in the 1960s. Before these tools, pentimenti were either visible on the surface or unknown.
The presence of pentimenti is significant for two reasons. First, it provides evidence of an artist's working method and creative process. We can see where a painter struggled with a composition, where they changed their mind, and how the work evolved from its initial conception to its final state. Second, pentimenti are used in authentication. A painting with pentimenti is more likely to be an original work than a copy, because copyists reproduce the final composition without the trial-and-error revisions of the original painter.
A study published by the Royal Society of Chemistry examined the role of pentimenti in authentication, using the de Brecy Tondo, a painting of a Madonna and Child attributed to Raphael, as a case study. The research argues that the presence of pentimenti, combined with historical provenancing and scientific analysis of pigments, provides the strongest evidence for originality. The study is available at the Royal Society of Chemistry.
Rubens is perhaps the most famous reviser in art history. The National Gallery in London published a technical bulletin on The Judgement of Paris (c. 1630s, NG194), documenting how the composition passed through three separate phases of development. X-ray and infrared imaging, combined with paint cross-sections and pigment analysis, revealed that the painting was extensively reworked. A smaller copy on panel in Dresden appears to show the composition at an early stage before later modifications. The final changes may have been made in France after about 1676 and before 1727, probably to make the painting more saleable on the French market. Read the research at the National Gallery.
Rubens's The Fall of Phaeton (c. 1604-1605, National Gallery of Art, Washington) shows equally extensive pentimenti. Research published in the Journal of Historians of Netherlandish Art documented three distinct stages of the composition: the initial version from Rubens's early years in Italy, his first revisions, and the final composition after his return to Antwerp. X-radiography reveals the addition of a white horse in the upper right and the removal of a twelfth Hora from the lower right, where only the Hora's foot remains in the X-ray image. Read the study at JHNA.
Leonardo's The Virgin of the Rocks (1483-1486, National Gallery, London) shows pentimenti in the angel's hand, which was originally positioned differently. Infrared reflectography reveals changes in the composition of the rocks and the arrangement of the figures. These changes are part of what distinguishes Leonardo's original from the studio copy in the same gallery.
Rembrandt was a constant reviser. His The Night Watch (1642, Rijksmuseum) shows pentimenti in the arrangement of figures, documented through the Rijksmuseum's Operation Night Watch research program. The most notable change is the removal of a figure on the left edge, which was painted over but is visible in X-ray images.
Velazquez's Las Meninas (1656, Museo del Prado, Madrid) shows a pentimento in the position of the Infanta Margarita's arm, which was originally raised and then lowered. X-ray analysis also reveals changes in the positions of the other figures and in the mirror on the back wall.
Ensor reworked his paintings long after their initial completion, creating what the 2025 npj Heritage Science study calls "metamorphoses" and "post-factum revisions." Over 80 paintings were radiographed as part of the Ensor Research Project, revealing small pentimenti and numerous cases of complete overpaints. Ensor's reworking blended realism and irrealism in a way previously unseen in Western art history.
Some pentimenti are visible to the naked eye. Look for ghostly displaced elements: a hand that appears to have an extra thumb, a column that seems to continue beneath a figure, a face that shows a second outline. These appear because the overlying paint has become more transparent with age, allowing the original position to show through.
In the National Gallery in London, look at Rubens's The Judgement of Paris and you may see traces of the earlier composition beneath the surface. In the Museo del Prado, Velazquez's Las Meninas shows a faint pentimento in the Infanta's arm if you look closely. In the Rijksmuseum, Rembrandt's The Night Watch has been extensively analyzed, and the museum's displays include X-ray images that show the pentimenti alongside the painting.
A study published in the Journal of Mathematics and the Arts presented a method for visualizing pentimenti by comparing X-ray images with color photographs of paintings. The researchers developed tools that suppress clutter in X-ray images and highlight visually significant differences between the X-ray and the visible surface, allowing both experts and museum visitors to explore the artist's creative decisions. Read the study at Taylor and Francis.
Pentimenti are related to underpainting, the foundational layer beneath a painting's visible surface. While underpainting is a deliberate part of the painting process, pentimenti are the traces of changes made during that process. The study of pentimenti connects to the broader field of chiaroscuro research, as technical imaging of pentimenti often reveals how artists built up light and shadow in their compositions. Pentimenti also relate to impasto, since thick paint layers can hide or reveal underlying changes depending on their opacity.
For more context, read our blog post on how to read a painting, or explore our entry on sfumato to see how Leonardo's layered technique produced its own pentimenti.
Visible pentimenti are rare in reproductions, which flatten the surface and hide the subtle ghost images that show through. You need to stand in front of the actual painting and look carefully at the edges of figures and objects.
Start with Rubens at the National Gallery in London, where the technical bulletin on The Judgement of Paris is available alongside the painting. Then go to the Rijksmuseum in Amsterdam, where Operation Night Watch has produced extensive imaging of The Night Watch pentimenti, some of which are displayed alongside the painting. End at the Museo del Prado in Madrid, where Las Meninas shows visible pentimenti in the Infanta's arm and the museum's technical research is well documented. For more on how scientific analysis reveals the hidden history of paintings, read our entries on underpainting and chiaroscuro, or explore our post on chiaroscuro and dramatic contrast.
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