Painting dramatic backlit scenes is a specific lighting setup I've studied in depth because the visual impact is high but the execution is tricky.

The principle: when the primary light source is behind the subject, the subject is mostly in shadow as seen from the camera's viewpoint. But the edges of the subject — the rim — are lit by the background light.

The visual result: a glowing outline (rim light) around a mostly-dark silhouette. The contrast is extreme. The subject reads as a shape rather than a detailed form. This is visually powerful for dramatic or mysterious subjects.

The common mistakes: making the shadow too flat (it should have ambient light variation even without direct light), making the rim light the wrong color (it should match the color temperature of the background light source), and not committing to the extreme contrast (trying to show too much detail in the shadow loses the effect).