Bought a bulk loader which had really ancient Pan F in it. Myself and a friend downrated this to 25 and it was stand developed in Rodinal for 90 minutes. Images came out grainy and lacking in contrast and definition - they looked ‘pushed’. The best of them was a picture of an aircraft in the sky.
This got me thinking. What if I pre-flash the remaining rolls. IE make a mark on the film leader and then expose the film to a bland sky at 1/2000 at F22. I them rewind the film and start over from the mark on the film leader to take the real images.
Is it really Pan F, or Pan F+? (Can you tell? If it's old, the edge markings may have vanished.) Why not just de-rate it by a stop and develop it like normal, with agitation and a typical, shorter, developing time? I don't understand what the stand development is supposed to improve here, if there is a compensating effect it would tend to decrease contrast. I've developed 20+ year old film per typical manufacturer's recommendation and it came out fine.
To be honest I wouldn't stand develop. I'd expose at 25 as you have but process in something more standard like ID-11/D96.
Are you able to guestimate the age of the film? Is it Pan-F or Pan-F + ? Harman will be able to estimate age if you send them the numbers in the rebate, or at least give you a ballpark timeframe. I had some FP4 that was clearly "ancient" and after contacting them they weren't able to give me a date but said likely 1970-77
No - regular agitation. I wouldn't suggest stand for anything, for the most part. I suggested Rodinal at 1:25 because you obviously have Rodinal - and I consider it a good developer at 1:25.
I have a bulk roll of Pan F (not Pan F+) and it develops fine exposed at 25 or 50 - but the edge numbers are almost invisible, when fully developed.
Many people like Pan F+ at iso25, even when it's fresh.
Take a short strip, expose it on the same normal-constrast scene at iso 6, 12, 25, 50, then develop according to Ilford's instructions for Pan F+. That will give you an idea how good it is for any of those speeds.
As far as I know, stand development further reduces contrast. At least that's what I've been observing with stand development using Rodinal. Perhaps OP could develop it without a stand procedure and with normal agitation? Like, with 1+25 Rodinal or 1+1 ID-11/D76 as others have already suggested?
Take a short strip, expose it on the same normal-contrast scene at iso 6, 12, 25, 50, then develop according to Ilford's instructions for Pan F+. That will give you an idea how good it is for any of those speeds.
I had also bought a loader loaded with PanF from the 90's. Surprisingly - this film is practically like new. Absolutely clean base, the sensitivity has down to about 25 ASA. But in my opinion, the new one also does not have 50 ASA. Responds very well to Pyrocat-HD. Good results with Kodak D-96 as well.
Came around two rolls of expired panf once (70's or 80's, can't remember, black box), it came out fine shot at box speed and developed in rodinal following the time printed inside the cardboard box, normal ilford agitation. Yours are older, but I don't think it's necessary to go below EI 25.