Rocketboy:
I use the peaks, because I've been told that if one adjusts the image so that the background sky is "black" (i.e. make it a dark shade of grey) then the overall image won't have a color cast to it. They say that the peaks have to line up. So, I've been trying to get a color balance where the average value across the background of my images will yield average R,G & B pixel values that are nearly equal. I don't know if this is a problem or a good thing. Gosh, there's a lot more for me to learn!
Richardo:
That's some impressive drainpipe imaging you've been doing!
