(Old) Rollei Infrared 400: Green Tint after Processing

[four-by-five]

Hi everyone,

I hope this topic is not redundant! I've been reading through quite a few threads and tried to find one that addresses this very issue here but I came back empty-handed. Please forgive me if I overlooked something!

I have recently acquired a sizable lot of Rollei Infrared 400 in 120 format. All of it is the same batch#, all expired over a decade ago. The film works excellently, a slightly elevated base density compared to fresh film but that's something I can live with, that's nothing that would affect my prints noticeably.
However, there is one thing that has really stood out to me: all the film retains a certain green color tint after processing is finished. Said tint is somewhat obvious to the naked eye. Again, I can print from those negatives just fine but this phenomenon is new to me. I've read that a certain, pretty slight "blue-purple-ish" tint is normal with some film stocks and that there's the dreaded issue of pink stains as well but this appears to be different to me.

My typical film processing routine involves a citric stop bath, film-strength alkaline fixer (two baths with ca. 2x clearing time in both), a wash using the Ilford method, then another 10-15 minutes under running water and finally a brief wash with a few drops of Adostab. My film always comes out with a perfectly gray ("clear") or perhaps for some stocks (namely Ilford/Kentmere films) with that super slight "blue-purple-ish" tint I had mentioned above. But this old lot of Rollei IR always comes out so green! I've tried giving it more (fresh) fixing, more washing but neither helped.

This is concerning to me as I care a lot about image permanence and fear that this might be a hint at a processing issue. The following questions arise:

1. Is this a simple age-related defect of the film? Other old and even more expired film I've shot in the past did not exhibit such issues which is why I have my doubts but it's expired so you can never really know
2. Is this perhaps dangerous for image stability? Does this hint at bad fixing or washing?
   1. If so, can I change anything about my processing to help it? And what can I do to already processed films to "save" them?
3. Am I just paranoid about nothing? Or is this phenomenon perhaps even to be expected with Rollei IR, even fresh stock? I doubt it, the Rollei website claims it's coated on a base as clear as glass...

Thank you very much for reading about my newest darkroom insecurities...

Greetings and the best wishes!

Edit: I forgot to add: it's been quite a few months since I bought that film lot, it has been in my freezer ever since arriving here. Back in spring, I took a few rolls out for a spin and that's where I first noticed the green tint but I didn't think so much about it then. It was only this weekend that I shot and processed another roll of it that I started to question whether that tint is "fine". Even though I have not used my densitometer to measure base density on the spring negatives back when I processed them, I'd wager they haven't changed in any visible way at least. To the naked eye, they look like the day they came out of the tank and the base tint looks exactly like on the roll I shot/processed this weekend.

 

[Sirius Glass]

Two things to try:

1. Prewash the film to remove some of the dyes, if any.
2. Wash the film longer that you are to reduce any residual dyes.

 

[four-by-five]

Two things to try:

1. Prewash the film to remove some of the dyes, if any.
2. Wash the film longer that you are to reduce any residual dyes.

Thanks for your quick reply!

I'm pre-washing all my film for a few minutes in clean water at processing temperature with some agitation, I should have stated that in the original post.

About the increased washing later on: that's a sound idea, I'll try and see with my next roll. For what it's worth: both the pre-wash water and the developer always come out in a hue between dark blue and total black. Apart from that, no chemistry seems to change their color/hue (incl. the fixer and later rinses). I'll try washing for half an hour or more with my next roll.