“Big Set” Lighting
by William Lulow
Readers of these blogs have already learned how important it is to think of the background as a separate subject. So, when you have a lot of people to photograph, you should always light the background as if it were a subject. You may need to “carry background tone” throughout the picture. Or, you may need to make sure that the same tone goes from the front of the image all the way to the back. You can vary the tone of almost any background by lighting it separately.
The way I usually go about this is as follows: I always begin by lighting the subject. Once I’ve got the light and exposure the way I want it, I then go about lighting the background. Sometimes a white wall or no-seam paper will reproduce as a shade of gray if it’s not lit properly. Usually, if you want a white wall to appear white (so you won’t have to retouch it in Photoshop) you need to have it two stops brighter than the main light. In other words, if the reading on the subject is f/8 then the background should register f/16. Whenever I need to do this, I set up one light stand on either side of the background and place two strobe heads on each stand, that’s four lights on the background. One head is placed on the top of the stand and the other is placed closer to the floor. This ensures that the background will be covered from top to bottom. I make sure that the settings on those heads read two stops brighter than what I’m getting on my main light. The increase in exposure on the background will make it appear bright white.
With the main light set up producing the correct exposure on the subject, I then have to check if the foreground is registering f/16, same as the background. If it isn’t, I need to add light to the floor as well. I sometimes have two lights just lighting the foreground as well. One is sometimes mounted on the same stand as the main light while the other one is on its own stand on the other side of the camera and aimed at the floor. Again, in order to have the background and floor register as “white” the exposures need to be the same front and rear.
It may be easier for some to just shoot the background as is and edit it later in Photoshop, but I have always believed that it’s best to get it right in the camera.