David Nimrod ~

[CharlesHarris]

In the bad old days the best high-res B&W sheet film was Kodak TechPan. For night use the wierd science boys would arrange the sheet film under glass in the dark room and briefly "flash" it about 6 fstops below its normal exposure tolerance, to pre-sensitize the emulsion, and then repack it into cut film holders for the mission. We would shoot a normal daylight exposure in full moonlight, and when we got back to the ship a nonstandard, heated developer was used for a longer duration to bring out the image. This permitted shooting a photo mission dual sets of cameras in both IR and B&W without dropping illum flares.

Old school technology...

Best sheet film these days come from Russia, since Great Yellow Father (aka Kodak) for out of that business.
Understand Agfa and Fuji still make 4x5 too, but I haven't used it in years. I keep in touch with a few retired recce techs and former combat cameramen who teach the old methods to law enforcement at the Federal Law Enforcement Training Center in Glynco, Georgia, because every once in a while they may need to work with a recovered batch of film under secure conditions. The spook agencies also send new techs to that school.