to make the invisible visible

There is a watercolour so magical in The Age of Enchantment that you really cannot see how it is done. By the great Edmund Dulac, it is a vision of Circe on a balcony overlooking a moonlit sea upon which Odysseus approaches in his boat. Circe's pet leopards have already fallen glassy-eyed under the spell that will soon overwhelm the sailors and all is dangerously becalmed. Nothing moves except for the powdery smoke rising from an incense burner. This burner gleams gold, and yet no gold is used in the picture. The silver stars are not made with paint, so one guesses they must be invisibly tiny pinpricks of bare paper. Though everything has its own colour, from the leopards' yellow to the lilac of Circe's gown, the entire painting is somehow a deep misty blue and the smoke seems to flow right out of the image. How these effects were produced is a mystery to the eye; if the scene is enchanted, then so is the picture.

more from The Guardian here.