Kim Jones, associate curator of French paintings, and Barbara Berrie, head of scientific research, explain how Titian used oil glazes to tone and deepen color. “Trenta, quaranta velatura” (Thirty, forty glazes), he once boasted. This is an exaggeration, surely, but one that emphasizes the importance of these thin veils of translucent paint applied layer on layer. The effects made possible with these glazes offered the greatest advantage of oil paints over the older tempera paints. This clip is from Making Art: Seeing Color, produced by the National Gallery of Art, Washington.