Instead they applied bright colors directly to a smooth, hard layer of zinc-white or gesso.

WSJ: Victorian Avant-Garde | Pre-Raphaelites: Victorian Art and Design | National Gallery of Art | By Barrymore Laurence Scherer

The intellectual practices of doubting authority and trying out experiments happened on lutes and with tempera on gesso before they turned toward the stars.

NEWYORKER: Moon Man