I was thinking about Casagemas's death that started me painting in blue.
Notes from Wikiquote
Quoted in Pierre Daix, La Vie de Peintre de Pablo Picasso, Paris: Editions du Seuil, 1977. | Picasso explained his friend Pierre Daix (around 1965), why he started painting in blue early around 1905. Picasso had made a portrait of Carles Casagemas in 1899.