My dad said in New Guinea, the temps were often well over 100F. He's shoot 10 rolls of film. The "dark room" was a couple layers of tents. The chemicals would get so hot that he said he'd quickly dip them in the developer and immediately dip them in the fixer and about 95% of them would be overdeveloped. There was no way to slow down the process in the jungle. They didn't have ice baths. He had a lot of pictures of the local native people, as they were allies agains the Japanese. He didn't have any classified stuff. Some trucks and planes and his buddies. He said he'd blow stuff up (not pictures, explosives, as he was also a demolitions officer) and have to take pictures of it afterwards, go through the remains of things, and people, and send the intelligence back to the higher ups. As a boy, he got into telescopes and cameras, ran a local observatory for Notre Dame with his sister, built his own telescopes, etc. Optics was interesting. We'd build periscopes, pin-hole cameras, telescopes, etc. Fun guy. I miss him.
On a related note, while I worked at the newspaper for 30 years, one of my duties was taking care of all the film processors in the photo department and the plate making department. That film was 14" wide by 24" deep. The camera was 8' tall and had a lens about 5" across.