There used to be a very informative (and free!) technical booklet on IR Photography by Kodak. Might still be around, through a local rep. I MAY still have one copy, if I can locate it. But, I don't know if it would be okay to scan and post anything from it, w/o formal copyright permission.
The emissivity of a surface normally affects the inference of temperature on the film (or camera) in a very significant way. Accurate temp measurements require a std. of known temp made of similar material. So-called black body radiators, have a known peak energy vs wavength relationship (Planck BB Law). Emissivity numbers derive from the ratio of actual energy to BB theoretical energy at a particular wavelength.
I have heard that gold flashed sandpaper, works quite well as a nearly black body surface, but have never verified it experimentally.
For the B&W video camera, a sandblasted surface (or equivalently uniformly rough) heated to a known temperature would provide a near black body brightness-to-temperature calibration. Elimination of all IR in background lighting is critical, since that IR will illuminate the surface, making it appear hotter than it truly is. An IR blocking filter (in front of the light) helps here.
Dave Cooper
Created on Wednesday, June 13, 2001 3:13 AM EDT by David Cooper