I'm bumping Chris's comment to the front of the line with an example of how effective the older (cheaper and available) sensitizers can be. I'm using erythrosin in my current favorite emulsion. The ASA (old term for old emulsion ) is hitting around 125 at high summer, sea level, on the 45th. Higher in the mountains. The red food dye is what makes this possible. Right now, I have the first of my attempts with pinacyanol chloride and pinaflavol drying in the darkroom. It would take the wildest of luck to make the first experiment successful, but I'm sure it will get there --- because it got there before. That's the beauty of this. Pan (or even near-pan) emulsions open up a world of possibilities, most notably color -- my Holy Grail. But, also hopefully, these kinds of film speeds even in the winter.
Anyway, all this was mostly an excuse to share a video from my part of planet. http://video.msnbc.msn.com/rock-cent...7076/#48007076 and my take on the event: http://www.thelightfarm.com/cgi-bin/...tent=27Jun2012.
Best of weekends with lots of photography -- whatever your camera.