Which technique involves painting on already wet paper and allows colors to blend and bleed?

The technique that involves painting on already wet paper, allowing colors to blend and bleed into each other, is known as Wet-On-Wet. This method is particularly popular among watercolor artists, as it creates soft, diffused edges and allows for seamless transitions between colors, enhancing the fluidity and vibrancy of the artwork. By applying paint to a surface that is still wet, the pigments merge naturally, enabling effects that are often sought after in expressive and abstract styles.

In contrast, a wash is a technique that typically refers to applying a diluted layer of color over a dry surface, which does not allow for blending in the same fluid manner. Sgraffito is a method that involves scratching through a surface layer to reveal a different color underneath, which fundamentally differs from the blending process of wet-on-wet. Alla Prima is a technique of painting directly onto a canvas in one session without allowing layers to dry, emphasizing immediacy and bold brush strokes rather than the soft blending achieved in wet-on-wet.