Amelia Soth at JSTOR Daily:
There’s something odd about the sky in Giuseppe Cesari’s rendition of Perseus and Andromeda. The blue is too bright, too saturated; it has a hyperreal quality that feels appropriate for a myth. This luminous sky and its fuzzy wisps of cloud were not picked out by an artist’s brush, but rather, formed by geological forces. The painting is worked on a chunk of polished lapis lazuli. It’s a visual pun: in the myth, Andromeda was chained to a rock, just as her image is secured to a stone in this painting. Cesari returned to this story over and over, producing versions on wood panels, on limestone, and on slate. Each substrate contributes to the painting in its own way: wood gives the scene an underlying warmth; slate lends the image a dark, silky luminosity; unpainted limestone becomes the rugged rock to which Andromeda is chained. But none match the lapis for its dreamy, jewel-like brilliance.
more here.