Below is a step by step of the Perseus painting. The breakdown shows each stage of the painting and how to focus on each area. These early stages clearly shows the Umber scrub which is very important to establish the structure of the forms and also stage 3 with the whiting impasto [calcium carbonate] this creates presence when viewing the painting in the flesh, so to speak, with a thicker more opaque application of paint in these areas and also for longevity because eventually the oil will slowly become more transparent so having the white impasto will help counteract the oil in these areas becoming more transparent thus revealing the layers underneath and if those layers are darker the lighter areas on top will become much duller and lose their brilliance. Caravaggio [and his followers] employed this method.
