Green fog/stain on antique Mimosa film

[RauschenOderKorn]

I have some old pre-war Mimosa film which was processed around 1935-1938. Some of the film has a GREEN base fog - like oxidised bronze. I have tried washing, with no effect, but Moersch alkaline fixer resolved the problem removing the whatever-it-was within a few seconds. So I assume the film was not fixed or properly when originally processed, but why has it turned green? Can this be caused by silver, or am I looking at some fixer residuals which became “funny” over time?

Does anybody have an idea what might have happened?

 

[AgX]

Dye attached to the halide.

With retained halide the dye remained too.

 

[Ian Grant]

Could be Dicchoic fogging that's its colour and appearance, happens with stale materials.

Ian

 

[AgX]

Interesting thought!
But I never saw a greenish shine.

I guess now a photographic eveidence would be good to have. The OP seems to have "spoiled" his sample ...

 

[RauschenOderKorn]

I have about a dozen affected films (and another 30 unaffected) , besides, what are leaders for?

In reflective light, it looks like this:

The leader with the "4" on it has been refixed and does not show the stain any more. The affected films have an overall greenish cast, with darker green spots.

If put on a light box, it looks like this:

The green is a little less prominent, but still there.

 

[RauschenOderKorn]

I guess now a photographic eveidence would be good to have.

If it is of particular interest for you, I can send you the green leader from the pics . Just send me a PM.

 

[AgX]

Fine that nothing has been "spoiled", but still strips are left as evidence.

If the cause would have been dye attached to retained halide, due to underfixing, the effect should be strongest at the rebates, as there 100% halides would have remained before fixing, of course based on homagenous processing.

 

[AgX]

Meanwhile I found in my archive a photograph of an artefact with somewhat similarity.
Yes, I think Ian is right with the dichroitic fog (caused by bad processing).