Underdrawings.

Pieter Jansz Saenredam, Dutch, 1597-1665, The Choir of the Saint Bavo in Haarlem, 1636, oil on panel

New imaging technologies are allowing discovery of the processes used in painting of Dutch masterpieces.

I've seen some earlier work on using underdrawings, and this exhibit encourages me to explore this further. It seems to be an important missing link in my understanding of how these works came to be so powerful. Layers make sense to me.

A show at the National Gallery of Art in Washington DC displays some brilliant examples, and the online catalog provides a means of direct comparison of the underpaintings and the finished works.