On April 27, 2027, a study day organized by Claire Boisseau, Mathilde Carrive, and Amaëlle Marzais brought together scholars to examine the technical methods used in ancient and medieval paintings. The event aimed to challenge a long-standing historiographical view that medieval paintings are technically inferior to ancient frescoes, a belief rooted in an idealized perception of ancient art. This perspective has often led to the assumption that the medieval period marked a decline in artistic skill, based on an evolutionary reading of art history and an uncritical use of ancient treatises to evaluate medieval works, without considering how techniques were actually practiced in antiquity. Recent research has shown that the Renaissance redefined the concept of art and the role of the artist, placing technical mastery at the center of appreciation. However, the study of ancient and medieval paintings is often influenced by modern terminology and concerns that emerged after the 16th century, which may not always apply to earlier periods. Advances in scientific analysis, including physicochemical studies, archaeometry, toychography, and archaeography, have provided new insights into the materials and techniques used in painting, from the origins of pigments to their application on walls. Discussions at the study day focused on the terminology used to describe medieval monumental paintings in France, particularly the term "fresco." There has been debate about whether this term accurately reflects the techniques used, especially since some steps in the process were applied dry, not wet. A growing consensus supports the use of the term "mixed technique derived from fresco," which acknowledges the combination of wet and dry methods used during the Romanesque period and in some later Italian-influenced works. Similar semantic questions arise when examining ancient Roman painting, particularly regarding the technique used to apply pigments. While the archaeological community generally agrees that fresco was the primary technique in Roman painting, recent analyses have revealed a variety of methods used, supporting the term "mixed technique." The study day encouraged comparisons between the approaches of antiquarians, medievalists, art historians, and archaeologists, with a focus on how experimentation can serve as a scientific method to test hypotheses and better understand the material aspects of historical artworks. Participants were encouraged to present methodological reflections, comparative case studies, and analyses of preserved in situ ensembles, as well as files linking paintings to other decorative arts like architectural polychromies and stucco work.