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 or acrylic gel medium sizing to reduce absorbency while retaining the color; acrylic gesso may be used to create a white surface. Very lightweight and compact, good for use while traveling.