Blue

A few days ago I finished this harbor scene.
While I was painting it, I remember thinking what a pleasure it was, being able to mix these precious blues, not having to worry where the pigment came from nor how much of it I could use.
A few centuries ago artists were dependent upon shipments of Lapizlázuli from Afghanistan, or Cobalt from Iran. If they could afford them. Lapizlázuli was rather expensive especially if you wanted the really deep tone. Cobalt, which is found in the presence of arsenic, had the disadvantage of being poisonous. The third option for old masters was a blue found in copper mines: azurite. It was less expensive, but also less permanent and less beautiful.
By the way, today´s most basic tube color "Ultramarine Blue" got its name from the fact that the pigment had to be brought from "beyond the sea" (ultra mare), not from the comparison with the deep blue color of the ocean.