I want to address the technique of digital under-painting, which is a workflow borrowed from traditional oil painting that produces specific results in digital work.

In traditional oil painting, an under-painting establishes the value structure of the image before color is applied. The technique produces paintings where values are independent of color — the underlying structure is always sound.

Digitally: I paint the full composition in a warm brown or grey monochrome on a lower layer. I establish all the value relationships — lights, darks, halftones, shadows — completely before adding any color.

The color application: I use a Multiply mode layer above the under-painting for shadows (the under-painting shows through darker) and an Overlay or Soft Light layer for lights. The color modifies the under-painting rather than replacing it.

The advantage: I can change color direction completely without redoing the value structure. The under-painting layer can be re-used with different color approaches to explore multiple color directions from the same structural foundation.