Can you explain how to paint strong light sources in a dark environment?
For this illustration I’ve made the two torches the only light source affecting the main figure, mostly to avoid any confusion about what light is coming from where. If the scene were in a city at night, for instance, then the ambient light from the buildings would illuminate the figure more.
When there’s just one light, though, any area on the figure that isn’t close to the flame and unobstructed will be so dark it becomes one with the background. If the edges of unlit sections were visible it wouldn’t make sense; the feeling of mystery created by only letting the viewer see a few key parts of the scene builds drama.
To figure out where the light would hit, imagine little arrows shooting off in perfectly straight lines in every direction from the flame. Each place the arrows touch (near the flame) will be lit up, and every spot that the arrows can’t reach will blend into the background. As for how lit a given object will be, it’s important to know that illumination from fire has a high drop-off rate.
The concept of lost edges is useful in all kinds of paintings, but absolutely crucial in torch-lit scenes.
Anything more than a few feet from a torch won’t be very illuminated by it, although you can increase the intensity of the light for dramatic purposes.