Ilford Selochrome exp. 1956

Hi everyone,
I have been purchasing expired fims for a long while, often just picking them up as I come across them. I have been quite lucky having found various amounts and some I have had excellent results from, my favourite being some 1977 expired Tri-x Pan that I bought 2x 5 packs of. I recently found some old ilford stuff, never really had the intentions of using it as it was 60 years out of date and I know that the selochrome emulsion doesn't like to stand around especially for that amount of time.

Anyway, after some time I became more curious to see if I could get anything from it, especially as I had two rolls so I can have a little play around to get some results. I loaded up the first roll which wasn't in the best shape, no band around the film and it looked like someone had messed around with it at some point, but I thought I'd give it a go still.

I played about rating this one at around 12-25 iso just to get an idea of how dead it was. Turns out it was very dead! I sent it off to be developed and it was done in ID11. Some parts of the photos developed very well (more in the corners) but it had a large streak running through the middle of the entire film that looks to have ultimately ruined the photographs.

I have one roll left, stored the same way, same emulsion number and expiry date except it is still sealed! Having seen where the sun is on the photos it looks to have come out very well, with the darker subjects being barely visible. I was thinking I will rate the next roll at around 6iso or even lower. There is the benefit of it being ortho film so it could be developed under a safety light so that helps with the development stage. I was also curious to know what has caused the streak in the middle of the film? Is this just likely to be aging of the emulsion or is it likely to be from development? Obviously with it being a film of this age I've heard that processing them can cause all sorts of problems for the emulsion if it is not done very carefully.

I also shot a roll the tri-x during the same time, the results were lovely, if anyone is interested in seeing those too I'll be happy to make a scan of the contacts.

Possibly a rubber band or something wrapped around the roll for an extended period?

I suppose it may have been. I have no idea what was done to it throughout the years! I should have photographed it prior to using it, the paper edges were frayed, the leader was torn and battered too so I am not too bothered that it didn't turn out better. I have 4 rolls of 1940s selochrome (which I doubt I will ever use), 1970s selochrome, a few rolls of HP3, some 50s gevaert. If I purchase them to use I normally go for sealed boxes in good shape, this one I suppose was an exception!