WW2 era 120 medium format film

When WW2 era 120 medium formal film gets too hot in the sun, can it melt, or become soft and sticky, and clump together?

 

It might seem like an odd question, but there is some background to it. My granddad on my father's side got drafted into the Wehrmacht, and took a camera with him when he served on the western front in France. When he came back, there were no photos. The reason that was always passed along in my family was that he left his backpack with all the film in the sun, the film clumped together, and he had to toss out the entire mess.

 

Of course as a kid I believed this, but now I am a chemist with some experience in polymer chemistry, and I know that some polymers can do that, but most won't. It's also awfully convenient for all the pictures from a war to disappear, that the photographer would rather not want to have been in.

 

As a side, note, my granddad later became a prisoner of war in Russia. At that stage he had left his camera at home, which is why I now have it. When he came home, people in the village did not recognize him, and the doctor gave him weeks to live. Thanks to the tender loving care of my grandma, he pulled through, and happily lived well into his 80s. My grandparents lived in the same house with us. I knew my granddad well, and we had a very good relationship. In all my life, I never heard him say one bad word about the Russians. He nearly starved to death, but so did the Russians after the war, and my granddad said they shared whatever little they had with the prisoners. Whenever questions came up about what the Germans had done, my granddad ended the discussion with one short sentence: "Germans are bad!"

 

But be that all as it may, at this stage I am really only interested in the material properties of vintage film. Will it melt in the sun or not? Does anybody have experience with this, and does my granddad's story check out?

 

AFAIK, by WWII Kodak was only coating on acetate(cellulose tri-acetate) for still photography(I think that was before polyester became common, but that's mostly been limited to sheet film and cinema applications).

 

I've had enough acetate based film sit in a hot car in the summer to not see that happen. BTW, acetate is still used for all the common roll films from the big three

 

With that said, I can think of a couple of possibilities:

 

1. If he was using a cellulose nitrate film(not sure if anyone was making it in 1940s still, again at least for still applications) it's POSSIBLE that it degraded enough to be ruined in the heat. Cellulose film that had degraded enough to cause problems, though, probably wouldn't leave the camera intact either.

 

2. I haven't examined WWII era backing paper, but I could see heat causing the waxy coating on it to melt. I can see this making a big mess that would make the film not worth trying to salvage. This is not an issue with modern backing paper, but I have no idea how it was made in that era. The backing paper from the 60s I've handled didn't seem appreciably different from modern paper, but that was also 20+ years later. If anything, this SEEMS the most likely explanation.

I thought Kodak, at least, switched to a thinner, polyester film base some time in the 80's.

I thought Kodak, at least, switched to a thinner, polyester film base some time in the 80's.

 

AFAIK, the only films Kodak coats on polyester are sheet film. I seem to also recall that MP print film was polyester, as was Tech Pan. In fact, I came across an unmarked bulk roll a while back that I suspected of being tech pan, and as a quick check before I clipped and developed some I took an IR spectrum of the backing. It corresponded to polyester, while the Tri-X to which I compared it was definitely on a different base(I didn't bother to confirm whether or not the spectrum was consistent with cellulose acetate, but it was definitely not polyester).

 

And, straight from the horse's mouth, Kodak calls out sheet TXP 320 as being on ESTAR(their name for polyester) while does not mention anything of the sort for TX 35mm or 120

 

http://imaging.kodakalaris.com/sites/prod/files/files/resources/f4017_TriX.pdf

I don't know whether it would have melted from modest heat, but the film was probably Agfa from Wolfen, although after May, 1940,there could have been other sources from the occupied countries. At least some of the Agfa films used Cellulose(link) as a base

The film base shouldn't melt, but older films had a gelatin with a lower melting point when wet.

 

The usual developer temperature has been 68F/20C for many years, but films from the 1940's and earlier need lower temperatures.

 

If the gelatin softens due to warm temperatures, the silver halide grains might clump, which could be what you were told.

 

High temperatures, such as inside a car in the sun, can easily ruin the image on film, though the film base is fine.