In oil painting, underpainting refers to which practice?

• A. A final glaze
• B. A preliminary tonal sketch painted underneath the final layers
• C. A wax-based medium
• D. The final varnish coating

Answer: (B)

Underpainting is the practice of laying down a preliminary tonal sketch underneath the final layers. In oil painting, this establishes the value structure—the light, middle tones, and darks—before color is added. By painting in a neutral or limited palette (often a single color like burnt sienna or ochre), you can model forms, plan the composition, and check how light reads across the subject. Later color glazes and opaque layers are built on top of this map, which helps create depth and cohesion that would be harder to achieve if you started with color. This step is not a final glaze, a wax-based technique, or the varnish coating. It’s a foundational stage that guides how light, shadow, and form will read in the finished painting.