B&W negatives deteriorating after storage in hot/humid climate

[Mateus Castilha]

Hello everyone,

I’m hoping you can help identify what might be happening to these negatives (see attached photos). They belong to a friend and were developed about twelve years ago using chemicals prepared in a university lab. He no longer remembers exactly which chemicals were used, but they were probably locally mixed D-76, a citric acid stop bath, and a fixer of unknown formulation.

The negatives were stored in PrintFile sleeves, archived inside polypropylene binders, and kept in a common room in a fairly hot and humid city (Mauá, Brazil).

Does anyone have an idea what could be causing this kind of deterioration? Are there any recommended ways to mitigate it or prevent further damage?

Thanks

 

[Mateus Castilha]

Since the denser areas were not as severely affected, my guess is that the fixing process was inadequate — possibly the fixer was exhausted and failed to fully dissolve the unexposed emulsion. Any other thoughts?

 

[RalphLambrecht]

Since the denser areas were not as severely affected, my guess is that the fixing process was inadequate — possibly the fixer was exhausted and failed to fully dissolve the unexposed emulsion. Any other thoughts?

That's likely what happened; there's no hope of rescuing or stopping the decay! Good reason to use the 2-fix method.

 

[koraks]

This looks like bacterial growth or mold to me. The fact that it is less severe in the denser areas can be due to the antiseptic qualities of silver.
The reason why I'm leaning towards this is the apparent formation of conglomerates that seem to grow outwards from a central spot. Furthermore, it almost looks like there are several competing colonies that are separated from each other by barriers.

Are there any recommended ways to mitigate it or prevent further damage?

The negatives could be washed and (if desired) re-fixed (although I doubt that this has much to do with it). Then they might be treated with a stabilizer of some sort; e.g. a weak formalin solution. They should then be dried and stored in a reasonably dry place.

Hot & humid climates are problematic for gelatin.

 

[joho]

I think a root problem is the polypropylene it self--- --- just an idea ---see the att pdf.

 

[koraks]

I think a root problem is the polypropylene it self

That's all the way down at the list of probabilities. This looks in no way, shape or form like deterioration of the film base as such - which, btw, is acetate on this film, not PP.
Sorry, but the suggestion is about as random as proposing aliens landed and started painting the negatives.