Archive for November 2010

The importance of IR “white balance”   Leave a comment

Here’s a primer on the importance of using a custom white balance in your digital IR photography. As you might imagine, “white balance” takes on a different meaning in infrared. In regular, visible light photography, white balance is a relatively simple concept: If you have equal amounts of all the colors in the spectrum, you get white (or gray, which is a luminosity, not a color, value.) So, the theory goes, if you can render a perfect white in the conditions you are shooting in, all the colors should fall into perfect balance. Pretty simple. In IR, however, we are not trying to balance color, because there is no color, except for the small amount of red at the end of the visible light spectrum. IR exposures depend on the reflectivity of light, so we want to set our white balance not on a white object, but on a highly reflective object. And the object of choice is brightly lit green grass or foliage, as these are among the most reflective objects for IR photography. An auto white balance gives an image with a heavy red cast that may require substantial post processing. An IR image with a custom white balance – I use a custom white balance set off bright grass – yields an out-of-camera image that is almost ready to go that needs minimal post processing. Here are some examples, shot with a Panasonic Lumix DMC-ZS6 converted to standard 715nm infrared:

Here are the same images after a standard processing in which simple white and black points were selected in levels:

Here are a few additional samples of a tree line in my hometown of Bakersfield. This one is with an auto white balance and a white and black point set in levels:

This one is with a custom white balance set off green grass, and the same white and black point selected in levels. I should point out that I set this white balance off my front lawn several days before taking these shots, and do not think it is necessary to set a custom white balance for every shoot.

Needless to say, my opinion is that digital IR photography must be done with a custom white balance and auto white balance should be avoided. If your camera does not allow you to set a custom white balance, the current thinking is to set your camera to the tungsten light preset, which will bring you much closer to a standard IR look than an auto white balance will.