MEXICO CITY.- One of the most recognizable images of Sor Juana Inés de la Cruz is now the focus of a major scientific and art historical study, as specialists from Mexico’s National Institute of Anthropology and History (INAH) and the National Autonomous University of Mexico (UNAM) join forces to closely examine the celebrated portrait painted by Miguel Cabrera.

The large oil on canvas, preserved in the collection of the National Museum of History at Chapultepec Castle, anchors the research and conservation project An image of breath and ashes: the portrait of Sor Juana between matter and memory. The initiative brings together experts in restoration, physics, art history, and museology to better understand the work’s materials, technique, and long-term preservation needs.

Between February 3 and 13, museum visitors were able to witness part of the process firsthand, as specialists carried out non-invasive imaging and spectroscopy analyses in public view. Using portable equipment, researchers recorded the painting in visible and ultraviolet light to study surface details such as brushstroke direction, glazing layers, later alterations, and the condition of pigments. In a second phase, X-ray fluorescence and fiber-optic reflectance spectroscopy were used to identify the elemental and molecular composition of the materials, including pigments, organic substances, binding media, and the preparation layer beneath the paint.

According to Salvador Rueda Smithers, director of the National Museum of History, Cabrera likely painted the portrait around 1750, possibly commissioned by the superior of the Jeronymite order. The artist is believed to have drawn inspiration from an earlier likeness by Spanish painter Juan de Miranda, both portraying Sor Juana in her thirties, after she had returned to convent life under the guidance of her confessor.

“Cabrera’s painting is the iconic portrait of Sor Juana,” Rueda Smithers notes. “He must have relied on descriptions from nuns who knew her personally. The way he depicts her—seated, with one hand resting on a book and the other holding a rosary—conveys both spirituality and intellectual strength.”

The study also sheds light on Cabrera’s artistic process. Preliminary X-ray images have revealed several pentimenti, or changes made by the artist while working. Among them are adjustments to the size of the inkwell, the repositioning of Sor Juana’s left-hand fingers to create what experts describe as a gesture “more gallant than devout,” modifications to the length of her habit, and even revisions to the titles of books in the painted library behind her.

For Nathael Cano Baca, coordinator of the MAPEoS research project, understanding the technical construction of the painting is key to appreciating Cabrera’s mastery. Unlike his large hagiographic series, commissioned portraits such as this one demonstrate a refined and highly controlled approach. Cano Baca notes that deeper knowledge of the materials and techniques used in this oil on canvas may also help scholars better understand the evolution of portrait painting in New Spain. He recalls that Cabrera himself undertook a famous technical examination in 1751 of the tilma bearing the image of the Virgin of Guadalupe, seeking to produce the most faithful painted version.

The portrait, measuring 2.10 by 1.50 meters, is being studied through the interdisciplinary framework of heritage science, which integrates art historical research, scientific analysis, conservation practice, and curatorial interpretation. The collaboration involves the museum’s Restoration Department, UNAM’s Institute of Physics and its National Laboratory for Research and Conservation of Cultural Heritage, as well as participation from the Mexican National Committee of the International Council of Museums.

The next phase of the project will involve approximately three months of data processing and collaborative study. Researchers plan to compile their findings, along with documentary research, into a scholarly publication and compare the results with technical studies of Cabrera’s works held in international collections, including the Museo del Prado in Madrid.

Beyond its scientific importance, the project reinforces the enduring cultural significance of Sor Juana—often called the “Phoenix of America”—and the powerful image that helped shape her legacy. As Octavio Paz once wrote, the portrait functions almost like a ritual space: Sor Juana appears, offers herself to the viewer, and then seems to withdraw. More than two centuries after Cabrera painted her, that presence continues to inspire both scholarship and public fascination.