Lesson Learned: Be Careful Mixing Flash and Ambient Sources

In one of my first posts, I asked the question, "If I want to mix incandescent light sources with diffused sunlight, will my white balance get thrown off?" A broader question is: Will mixing lights of different color temperatures cause problems? The answer is yes on both counts. In this picture, I forgot to gel my flash to match the color temperature of the tungsten torch lamp in the room. The torch lamp was at 5:00 camera right while the bare flash was positioned at 2:00 camera right (on the other side of the window blinds). The torch lamp illuminated Matt's face and Esther's arms while the flash lit up the ceiling and left wall. Using Adobe Lightroom I balanced for tungsten and Matt's face more or less appears correct, but the ceiling and wall look too blue. If I had gelled the flash with a 1/4 or 1/2 CTO, then the ceiling and wall would have looked more warm (more orange and less blue). David Hobby has a great Q & A post about this issue.