Quote Originally Posted by BrianShaw View Post
The best resource I have found to help with this issue is the 1970's-era Kodak Master PhotoGuide (the blue cover book). There is a calculator that helps sort out the myriad of variables - bulb type, reflector type, shutter speed, distance, and aperture. I've found it to be "dead on" 99% of the time.
Is that a companion book to the Darkroom Dataguides? I have an old Master Darkroom Dataguide which I just love to no end.

I also use the GN charts on bulb boxes when they have the speeds that I use (if I'm lucky they will have ASA 400 !).