As Fraser notes the main problem with thermal camera images is that they tend to be quite noisy, whether fixed or moving. The human eye is quite good at averaging out 'brightness' noise but colour noise drives it crazy.
So the main thing is to stay away from very harsh colour changes. That is what 'Iron' and several variations on blue->green->red achieve.
Simple palette design can be done in the likes of ImageJ, but only for still imagery.
Black hot is classic for military use, goes back to mono displays, and was supposed to be better with cold skies which made 'white hot' imagery get too bright in the interesting areas.
White hot is more sensible for commercial / technical use including firefighting, with limited colour for indicating temperatures of interest. A lot of palettes seem to be useless padding though.
Bill