Here's some great advice from my light painting guru, Harold Ross, on the importance of getting your backgrounds to complement rather than compete with (and distract from) your subject.
"In many ways, photography is about getting the viewer to see what we want them to see. This is true of any kind of photography, not just light painting. For instance, in landscape photography, we must distill the world down, simplifying it in order to make our point visually.
Still life work is no different. We hope to get the viewer to connect with our subject matter. In my opinion, a background that does not recede can interfere with this. In my own work, I try to keep the background where it should be… In the background.
There are three basic ways to make the background recede. I tend to use all three of them together, or sometimes I may just use two of these methods, but I think it's worth considering their use.
1. Brightness.
This is the most obvious and important one. Subconsciously, we tend to see lighter things as coming toward us (or toward the light, if you will) and dark things as receding. If we make a background darker, it is going to feel like it is further back than if it were lighter. By the way, I use this concept every time I make an image!
2. Softness.
As humans, we know that blurry things tend to be on a different plane, or at a different distance from, things that are in sharp focus. Of course, this relates very much to the depth-of-field in a photographic image. The tilt-shift craze of a few years ago really took off because of this very principle. We couldn't perceive the tilt-shift scene in any other way except to think it was a small miniature set with limited depth-of-field… something we were used to seeing as humans in a photograph of a very tiny subject. Then focus stacking came along! We cannot use focus stacking in light painting, but I do use a small aperture to get enough depth-of-field for my subject, and I generally don't want my background to be tack sharp.
3. Color.
This one is not so obvious; we tend to perceive warm colors as being closer to us, and cool colors as being further away. This is just another aspect of our vision that we can use to make a background recede, creating more depth in the image. This is one reason I often use cool colors in my backgrounds.
One can juggle these three concepts around… You can make a background recede by making it dark and soft, but it may not have to be cool. Or, you could make it soft and cool, and maybe it doesn't have to be as dark. It is the balancing of these three concepts that requires a little time to implement, but I think it is worth the time to make sure that our background is not fighting with the foreground!"
