Fig. 4
From: Portrait of an artist at work: exploring Max Ernst’s surrealist techniques
a Chroma DI (1050–650, 650–550, 550–450 nm) imaging of Zoomorphic Couple: in the upper part is clearly visible (in light green) a stain in the sky, due to a discoloration, whereas the different shades suggest an inhomogeneity of the background; b Chroma DI (1050–650, 650–550, 550–450 nm) detail of the Garden Airplane Trap. The floral detail was clearly done after painting the underside, as seen by the visible striped outlines. Some construction lines are also detectable, as highlighted by the different shades in the chroma DI details