OK so while I am still no expert on these impossible films I have become over time pretty good about obtaining useable exposures and figuring out what setting the camera needs to be at. For the PX600 UV film you pretty much need to set the exposure wheel to maximum dark and the image needs to be protected from from light and for the most B&W tones you need to develop the film at or below about 68 deg F. So while on vacation I was in Boulder, CO which you may or may not know is about 1 mile up in altitude. I took a few images in Boulder (none shown here, I promise to post them in the near future) and encountered nothing unexpected. Basically the film behaved just how I figured it would. The problems came when I traveled up the mountains. Once I got above about 8,000 ft all of my images started to look like they were either over exposed or had been subjected to light during developing. Since I knew I was shielding the images after exposure I figured that for the first few images I had just neglected to set the exposure wheel to all dark. Turns out that wasn't the issue. So the best I can guess is that the extra UV light that is present the higher up you go was responsible. The Impossible films either don't have a UV filter built in or the filter isn't strong enough at the altitudes I was at.
Anyway here is an example. One that I actually like. I did use Photoshop to increase the contrast a bit to bring out the details. The actual image is even lighter overall than you see here.
"Fear the trees..."
Polaroid SX-70 Sonar, Impossible PX600 UV+
