Spill

What it is

Spill refers to unwanted light that falls onto areas of the scene you didn’t intend to illuminate, like the background, lens, or a subject’s face. It often happens when lights aren’t properly controlled or flagged.

Why it's important

Spills can ruin contrast, wash out shadows, create distracting highlights, or contaminate colors (especially on green screens). Controlling spill keeps the scene visually clean and intentional.

When/how to use

Spill is easy to miss but hard to fix in post production. Use flags, barn doors, grids, or black wrap to shape and control light. Monitor spill during setup and adjust angles or modifiers to direct light precisely.

Best Practices

Control with flags/barndoors – Block stray light from hitting unwanted areas.
Separate subject and background – Increase distance to minimize spill, especially with green screens.
Check for reflections – Watch out for shiny surfaces that may bounce spill back into the frame.