A follow up to - http://www.pbase.com/ed_k/image/96504105 - a recent PAD which was a painting with light experiment result that I fell in love with. Today's PAD is far from a love affair - just documenting a stop along the way to something better, I hope.
My goal for the next step in the evolution of this technique was to do a image similar to the previous success - except with star trails instead of more or less fixed stars. Today's PAD is the first attempt - a double exposure of #1 - a 15-20 minutes long exposure to capture star trails (I really want them to be much longer but didn't want to waste the time on this first try when I was pretty sure the ambient urban light pollution was going to kill me - which it did) and #2 a roughly 60 second exposure to paint the tree with a 3,000,000 candlepower light. I opted for a double exposure since the light painting success isn't a given - any more than the star trails. I didn't want to press my luck and try to get both right in the same image - and so shot several back to back without moving the tripod. You can see that it's a double exposure by the break that's visible at the top of each trail (or maybe you can't on this low res web version).
Issues - light pollution, aircraft (the planes taking off from a nearby airport are clearly visible), and *sensor capture noise*. The noise is going to be a tough one to experiment with because of the long exposure times needed to get a single image. I have long exposure noise reduction enabled which does help. Issues in this area will probably force me to keep trying the double exposure method. Because of the noise reduction enabled this one image took the better part of an hour - equal parts for the actual exposure and the noise reduction. It makes experimentation difficult because you don't get many samples in an evening. Stay tuned.