As you are well aware I shoot a lot of action photography, particularly cheer leading. Now this is largely to do with the fact that my two kids are in that sport but at any rate I started upping my game this year and I also wanted to make an effort to learn flash. Now here is the problem I was facing. I'm in an arena, typically tungsten or sodium lights, and I realize I need a touch of flash to make the image right. I flip on the flash I set it up. I readjust my white balance and I make the image. When I get it back I note that my subject is in the right color range while the background is of a slightly different color. While this does not bug me to much I realize I made a mistake. That mistake floats around in my brain and then wham! I realize why.
It's elementary my dear Watson. The flash was one color temp while the room lighting was another. In the foreground my subject is lit with the flash and as the camera white balance is set to the flash color temp they look great. The background on the other hand is lit by the normal lights which are far warmer than the flash. The solution is simple, warm the flash. How do you warm a flash...with gels!
The video above is my way of checking my logic. I jumped to YouTube and found this explanation. I was right. Solution in hand I go to my camera gear, dig out my gel pack. Which I bought a number of years ago and I proceed to make a set of gels to throw in my bag for the next event. Isn't the internet wonderful!