Now supply-chain woes have come for the color blue

Pittsburgh Post-Gazette: It’s the color of the Virgin Mary’s robe, used in the Impressionists’ sumptuous seas and skies, favored by a depressed Picasso and a spendthrift Vermeer. Once more valuable than gold, ultramarine blue, now sold in its synthetic form, is so popular today it ranks just below whites and blacks in sales by top suppliers of paint for artists.