Fig. 6From: Discovering the evolution of Jacques-Louis David’s portrait of Antoine-Laurent and Marie-Anne Pierrette Paulze LavoisierDetails of elemental distribution maps for two selected areas. A Hg (red), Ca (green), and Fe (orange) maps of the objects and scientific instruments on the desk. B Ca distribution map acquired in the upper right of the painting where red arrows indicate what appears as a relatively large scientific instrument with globular glass containers. The location of this detail of the Ca distribution map in the overall painting is indicated in Additional file 1: Figure S9ABack to article page