Toulouse-Lautrec and Vuillard used tan card stock for oil painting. This thin resin-sized card stock is far more permanent than that used by the famous painters of past centuries. Great undercolor for oil, acrylic or pastel paintings. Many artists paint directly on them, but for most oil techniques, we recommend a coat of Golden GAC-100 Multi-Purpose Acrylic Polymer, acrylic gel medium or acrylic gesso as a sizing to reduce absorbency while retaining the color. Very lightweight and compact, good for use while traveling.