Lighting The Background
by William Lulow
Most people, when they take pictures, aim their cameras at the scene they want to capture and snap away. You will begin to get better images when you start to think of lighting the background as well as the subject!
There are lighting situations in which the background must be lit separately from the subject in order to give the photograph some depth. You must think of the background in order to: (1) separate your subject from it, (2) make the background register a specific tone or (3) lighten up the overall mood of the photograph.
If you place your subject in front of a white no-seam background, even if you are using studio strobe units (which are normally fairly powerful), you will still not have enough light to make the background come out white. The reason is that light from a flash unit only travels to the subject. Especially if you are using an automated speedlight, it will automatically measure the distance from the light to the subject and put out exactly the right amount of light.
When I want the background to register as pure white, I light it with two separate, small umbrellas, one from each side of the background so that the light is distributed evenly. In addition, I make sure that the light from these background lights is at least one stop brighter than the main light. If you keep all the lights the same brightness, they will all just add to the overall light level of the scene. If you want the background to appear white, the light levels on it have to be brighter than all the rest. Here’s an example:
Since this image was just a head shot, I placed my background light on the floor behind the subject and turned up the power until my light meter read one stop brighter than my main light. (You do this by taking a reading from your main light, say, it reads f/11. You then set your background light until your reading is f/16. That would be one stop brighter!) That’s how you assure that the background will reproduce as white, not a shade of gray.
Here’s another use for a background light:
In this case, I set up a background light behind the group and bounced it off the ceiling of this store. If I didn’t have a background light here, the whole rest of the store would have been dark because the lamp-to-subject distance here was only about four feet, and I wanted to be sure that the people stood out from the background.
Here is yet another use of background light:
This is a shot from a backyard party. I couldn’t set up studio lights here, so I had to use my speedlights. I set one up just to the left of the front group and another just to the left of the rear group. In this case, everyone in the image is receiving some light. If I had simply used my speedlight on the camera, it would have only lit the front group and since it was nighttime, the rest of the image would have been black.
So, the takeaway from this is that you must think of the background separately from your main subject and light it according to what you want to show.