Backing paper visible through negative?

[piu58]

I had a similar issue with another film. It seems, that some of the photographic layer react with the black color of the paper or even the paper itself. This takes some time: Don't store 120 film too long.

I never had such issues with "normal", classical film which I stored about 10 years (huge amounts of old APX 100). But I had it with an aerial film.

 

[AgX]

These cases have been described by manufacturers in the past but only referring to circumstancers that, as far as we no know, do not apply in the OP's case.
Though it would be interesting to know about your case, even if it applies on a case of non-intended conversion.

 

[miha]

What would be a case of non-intended conversion? Aerial film offered to the masses?

 

[AgX]

In this case aerial film converted to type 120. Though to me that is rather an academic issue, as I do not expect those films to react differently to backing paper than other camera films. But originally they never have been tested with backing paper.

 

[miha]

You've got a point there.