August 2001, I used to shoot exclusively slide film. I was going back through slides and scanning them to get family pictures together. I came across some of my lightning photos and noticed the vibrant blue spots and scanned extra large and brightened to enhance them.
I took several others shots that same night, this is the only one that had them. This photo was taken outdoors on our front porch facing north east and camera was on a tripod. I had 3 others I had shot at same time within 2 minutes, of other lightning with no blue in them. The green light at the bottom left was from mercury vapor night light from the people that live about a quarter mile away.