Photos shot on a white background are easy for buyers to use. White provides a consistent color (or non-color, if you will). So, as a result many of us spend time perfecting setups that will allow for people or objects to be isolated on these pure white backgrounds — “floating in space.” Built in camera meters are, unfortunately, not designed to help you achieve that look. Nobody, however well intentioned, can give you a “secret formula” for creating this white background look, but here are some guidelines:
- Your camera will try to make a scene’s exposure average out to 18% gray. That means a scene that is mostly white will wind up looking gray because the in-camera meter is working at cross purposes to your intent.
- To be white (and that means 255, 255, 255 in RGB), the background must be 1.5 to 2 stops brighter than the main subject.
- Lights tend to produce “hot” spots that could be 2 stops brighter at the center, but falling off at the edges.
These effects look, to read many of the blog posts on the net, easy to achieve by taping a couple of little strobes in strategic positions. This turns out not to be the case for reliable results. Besides the +2 exposure for the background, there are a couple of other questions:
- How do you get a background that bright?
- And how do you make sure that light doesn’t pollute your subject?
How to Get a Really Bright Background
There is only one way to do this, with a few variants: Shine a really bright light at it. The variants are that you can shine a light off a white background, shine several lights off that background to reduce falloff at the edges of the frame, or shine bright lights through a translucent background. So that’s at least one light in addition to your keylight.
How Not to Get Light Pollution on the Subject
The short answer to this is distance. The further from the background the more distinct the separation between the subject an the background and the less background light will spill around the edges of the subject. The longer answer is that whatever light you have pointing at the background needs to be modified so all of its output is toward the background and none up off the ceiling, or back at the subject. Barn doors, black cards, cereal boxes, anything that doesn’t let light shine through is fine.
The Other Option: Photoshop
The words I hate to hear in conjunction with a planned photograph is “and we can Photoshop this later.” If you know about the problem beforehand, it’s always easier to solve the problem with cropping and lighting. Ok, say that doesn’t work. No way do you get your 255, 255, 255 background that you so dearly desire. The temptation is to grab the eraser tool and start hacking. And everything is fine until you get near the object you wanted isolated, at which point, everything begins to look quite artificial.
