Artificial intelligence (AI) can be trained to detect details in images that elude the human eye, and an AI neural network has identified something unusual about a face in a Raphael painting: it was not actually painted by Raphael himself. The face in question is that of St Joseph, located in the top left corner of the artwork known as the Madonna della Rosa (or Madonna of the Rose). Art scholars have long debated whether the painting is an original by Raphael. Determining an artwork's provenance requires diverse evidence, and a newer analytical method using an AI algorithm has supported the view that at least some strokes were made by another artist. Researchers from the UK and US developed a custom analysis algorithm based on works confirmed to be by the Italian master’s hand. “Using deep feature analysis, we trained the computer on authenticated Raphael paintings to recognize his style in great detail—examining brushstrokes, color palette, shading, and every facet of the work, ” explained mathematician and computer scientist Hassan Ugail from the University of Bradford, UK, in 2023, when the findings were published. “The computer can perceive far more deeply than the human eye, down to the microscopic level. ” Machine learning models typically require a large number of training examples, which can be scarce when dealing with a single artist’s oeuvre. To address this, the team adapted a pre-trained architecture developed by Microsoft called ResNet50, combined with a traditional machine learning method known as a Support Vector Machine. This approach has previously demonstrated 98 percent accuracy in identifying Raphael paintings. Usually, the AI is trained on entire images, but in this study, the researchers also instructed it to analyze individual faces. While the Madonna, the Child, and St John were all identified as creations of Raphael, this was not the case for St Joseph. Prior debates about the painting’s authenticity noted that St Joseph’s face appeared less skillfully rendered than the others. “When we tested the Madonna della Rosa as a whole, results were inconclusive, ” Ugail said. “So we examined individual sections, and although most of the painting was confirmed as Raphael’s work, Joseph’s face emerged as most likely not painted by him. ” Giulio Romano, one of Raphael’s pupils, may have painted the fourth face, though this is not certain.

This example highlights how modern technology, particularly AI, is uncovering new insights into classic artworks. Experts estimate the Madonna della Rosa was painted on canvas between 1518 and 1520. By the mid-1800s, some art critics had begun suspecting that Raphael may not have painted every part of the piece. Now, those suspicions appear to have been largely confirmed. Nevertheless, the research team stresses that AI is intended to assist art experts rather than replace them. “This is not about AI taking people’s jobs, ” Ugail emphasized. “Authenticating artwork involves many factors—provenance, pigments, condition, and more. This kind of software is simply another tool to aid that process. ” The study was published in the journal Heritage Science. An earlier version of this article appeared in December 2023.