Master pastelist Alain Picard showcases many different underpainting techniques on UART Premium Sanded Pastel Paper.

Underpainting techniques on UART: Watercolor Wash. Part One: The Underpainting  

Underpainting techniques on UART: Watercolor Wash. Part Two: Applying Pastel

Underpainting Techniques on UART: Complementary Alcohol Wash Part One

Underpainting Techniques on UART: Complementary Alcohol Wash Part Two: Massing In

Underpainting Techniques on UART: Complementary Alcohol Wash Part Three: Refining The Painting

Underpainting Techniques on UART: Mineral Spirit Wash Part One: Local Color Underpainting

Underpainting Techniques on UART: Mineral Spirit Wash Part Two: Applying Pastel