As an aside, but related, when the Americans started using very high flying aeroplanes for looking at the enemy, they started to have problems with their film's ability to cut through the atmospheric haze.
Kodak's Infrared film had grain the size of golf balls, so, although it cut through to the chase, so to speak, you couldn't really see what you were looking at.
To this end, either before or during WWII Kodak Technical Pan film was invented. As it was going to be enlarged enormously the first criteria was to make it incredibly fine grained, this they achieved admirably.
The second requirement was to cut through atmospheric haze so the emulsion sensitivity was extended further into the red than normal to achieve this, which apparently it did. I don't know how successful the haze filtering worked, but I believe that when Gary Powers in the U2 (?) was shot down the people who saw it's film and just what it could do, were amazed.
I had a lengthy discussion in 1994 in Jena (East Germany) at the Jena Optik Werke Museum. My Father in-law was a photographer for the German Army during the war and he knew a lot about high resolution photography from the cameras in the Zeppelins. They used to photograph stuff on the horizon with great clarity, especially if it wasn't a windy day.
He gave me the name of an old colleague who was stuck in the East when the wall went up, when I met him he noted that I was using Tech Pan film. This started him off on a technical discussion that I could hardly keep up with, about the relative merits of what they were sent to analyse after getting their hands on some film and what they were manufacturing for their own aeroplanes and sputniks during the cold war era.
Fascinating stuff!
Mick.