Monet made significant changes to the three panels of Water Lilies over a period of eleven years (c. 1915–1926) as he developed and reworked the composition. X-radiography was used to see elements that were painted out as the composition progressed.

With this examination technique, x-rays pass through the painting and expose film placed behind the canvas. Dense pigments block x-rays from reaching the film and produce light areas on the processed x-radiograph.

The black and white x-radiograph (top left) shows a beautiful lily pad and bloom that Monet eventually covered with green paint.

Comparisons between the earlier water lilies and the final composition reveal a dramatic change in the way Monet painted; the lily pads shift from distinct oval masses to the loosely painted, abstracted forms that we appreciate today.

Looking closely at the surface of Water Lilies reveals a landscape of brushwork—each one chronicles Monet’s decisions through arrested patterns of movement and revelations of color.

Monet applied paint to Water Lilies in a variety of ways, including wet-over-dry and wet-into-wet brushwork.

Much of the paint is applied wet-over-dry, meaning that new paint was added on top of a dry lower layer.

When Monet applied the sweeping, white paint stroke (above left), his paint skipped across the bumpy textures of the dry paint below. The resulting paint stroke, applied wet-over-dry, has an energized, rough, tactile quality.

Conversely, wet-into-wet painting occurs when paint is added on top of a layer that is still wet.

The paint colors intermix on the canvas, producing a blended appearance.

When Monet applied bright red to the base of the water lily flower (above right), some red paint mixed into the white. In this same area, notice how the purple paint on the outer edge of the flower swirls and blends into the white.

A paint cross-section is a minute sample of a painting—roughly the size of a pinprick. The sample, embedded in resin, is sanded from the side to expose the layered structure and then viewed with a microscope. Cross-sections provide detailed information about Monet’s process by revealing initial color choices and paint application over time.

All cross-section samples show the earliest paint application on the bottom and each successive layer on top. In this example, the lowest layer is the white ground (a preparatory layer applied to the canvas prior to painting), followed by a thin layer of green painted over with thicker layers of purple, white and pink.

Mary Schafer, Associate Conservator at the The Nelson-Atkins Museum of Art
Simon Kelly, Curator of Modern and Contemporary Art at the Saint Louis Art Museum
Johanna Bernstein, project scientist, Rutgers University