Video: How to balance background exposure

Lighting a seamless background with a single strobe sounds easy until you notice a distracting gradient creeping from one side to the other.

For portraits or product shoots, getting that backdrop clean and even will also save retouching time and keeps your images consistent.

But where do you start? Well, in new video for Adorama, the great David Bergman explains why uneven backgrounds happen and how to fix them.

The first thing to note is that every point on the backdrop is lit based on distance and beam strength.

The inverse square law means the near edge of a background lit from one side is always brighter, while the far edge is darker. That distance difference alone creates a gradient.

Your reflector makes things worse or better. A standard metal reflector is brightest in the centre and weaker at the edges. Instead of aiming that hot centre at the middle of the backdrop, Bergman suggests pointing it toward the far edge that is losing light.

The near edge then gets only the softer outer part of the beam, which evens everything out. When reflector falloff and distance falloff balance, the background appears smooth from side to side.

This is the same principle behind feathering a softbox. Angling the modifier so the backdrop sees only the softer part of the beam avoids hotspots. Backing the light up helps too because greater distance reduces the brightness difference across the background.

Once you know how to make a background perfectly even, you can also create gradients or hotspots deliberately.

To see how subtle angle changes affect exposure, the full video is worth a watch.