... 67 poets take on 'indigo'
"The term “indigomania” was coined for the Impressionists’ “unhealthy” passion for blues."
from 'The essence of blue' by Belinda Recio and Catherine Kouts
"... “One year one paints violet and people scream, and the following year every one paints a great deal of violet,” Manet remarked on a different occasion."
from 'Color in the Age of Impressionism: Commerce, Technology, and Art' by Laura Anne Kalba