Custom White Balance in a Pinch

The dome of a Gary Fong “Puffer” flash diffuser makes an excellent custom white balance filter.

If you need to do a custom white balance, but find yourself without a neutral surface to meter off, try using a flash diffuser such as the Gary Fong puffer.

You can hold the dome over your lens while taking a reading, and it will give you good results.

Like a light meter, you can read the light reflected from your subject, or take an incident reading by placing the camera in the direct path of the light source.