Here is my problem, I've been shooting film for a long time, and stopped shooting Fuji like everybody since 2013. A friend of mine just sold to me a huge stock of Fuji Eterna 500, the pictures come out great, but the lab here in Paris is not happy at all because a part of the "dorsale" (that is how we call it in french) does not completely dissolve in the processing. If I understood well, it is the back of the film (the side that does not expose itself) that does not get totally dissolved in the process. The labs says that it is because the film stock is too old or has not been well stored.
The white stains disapear if I scratch them with alcohol frame by frame directly on the film, but you imagine it is not possible in long term to do that.
Anybody has any solutions or has never had this same problem ?