Images in transformation: The color and its change in a group of Portuguese paintings from the second half of the 16th century

Abstract Four panel paintings depicting episodes related to the birth of Christ and attributed Portuguese mannerist painter Francisco João (doc. 1558–1585) were found exhibit a muted palette that had no correspondence with traditionally vivid colors used in sixteenth century represent joyful biblical events. Complementing previous research on disruption loss red glazes these paintings, investigation focused analysis materials, painting technique degradation issues further affected original changing viewer's perception understanding artworks. The combined visual examination surface microscopic spectroscopic binder pigments. A conventional made lead white, lead‐tin yellow, ochres, vermilion, verdigris, smalt, azurite, carbon black lake brazilwood cochineal was identified. pigments bound an oil‐based medium. Chemical physical alterations detected paints rich smalt verdigris be responsible for color changes affecting significant areas compositions. presence moisture reaction between pigment leading, among other products, soap oxalate formation, played central role long‐term behavior paint film. Understanding main processes involved their consequences is crucial when interpreting artists' designing best approach preserve paintings.