Roger Dellar is a self-taught artist known for his dynamic approach to painting. Dellar's passion lies in the process of painting rather than the outcome, focusing on the discovery and emergence of the subject. He finds joy in the surface textures, brushwork, and the interplay between lean and fat paint. His goal is to create works that read as reality from a distance but reveal a series of marks up close.

Dellar’s compositions evolve through an exploration of spatial qualities, seeking balance by allowing shapes to create and resolve imbalances. He often works with a limited palette, adding a few bright colours for emphasis.

His methodology includes working both from life and in the studio, utilising oil, pastel, watercolour, or gouache. Dellar frequently uses a sketchbook to gather information when traveling light, as it helps him understand the subject. Many of his works begin as small oil paintings created on location, which he later develops into larger, more refined pieces in the studio. When preparing for an exhibition, he works on several pieces simultaneously to avoid becoming overly critical or precious about any single work. In the studio, he uses sketches and photographs as starting points, interpreting rather than copying the scenes.