What materials did Robert Delaunay use for his artwork?

Robert Delaunay primarily used oil paints on canvas for his artwork. However, he also experimented with other materials such as:

- Gouache: Gouache is a type of water-based paint that is similar to watercolor but is more opaque. Delaunay used gouache for his early works and for quick sketches.

- Watercolor: Delaunay also used watercolor for his early works and for quick sketches.

- Ink: Delaunay used ink for his drawings and for preparatory sketches for his paintings.

- Graphite: Delaunay used graphite for his drawings and for preparatory sketches for his paintings.

- Collage: Delaunay used collage in some of his later works, incorporating various materials such as paper, fabric, and metal into his paintings.