Issue with reversal processing

Hi,

I did quite a bit of B&W reversal a couple of years ago, using the Ilford method, but have had a lapse until recently.

I've just processed a roll of HP5+ which I found I had exposed but not developed. It was of some night shots of an oil refinery.

They've turned out quite nicely but there is an issue with a few of the frames where there are dark vertical streaks (the gaps between the streaks corresponding with the perforations in the film). Could any of you experts shed any light on which part of the process I am making an error in which might have caused this?

I use distilled water for all solutions, for the first washes after first development, and for the final rinse, but tap water for the other washes.

I'd be most grateful if someone could shed some light on this. There are also a couple of frames where there are what look like other bits of emulsion swirling but not in the above pattern, although as they're long exposures and there was steam etc coming out of the refinery equipment it's quite hard to distinguish steam from development problems!!

Dark marks on the neg that line up with the sprocket holes are usually surge marks - over-agitation has forced more developer through the sprocket holes, so there's more development in those streaks, because more fresh developer is hitting the emulsion as it rushes through the sprocket holes.

I've gotten this when using 35mm to try out new film and dev combos and using shorts strips of film (like 4-6 frames) in a reel. Realized (reel-ized?) that agitation is much more efficient with short strips, since there's not all those coils of film blocking the flow. Surge marks like mad.

That's my assumption anyway, it's kinda dicey to post a question like this without including a scan or even a phone shot of the negs on a light box or at least with a diffused light source behind them - leaves us all guessing a bit, y'know?

How accurate is your metering? In poor lighting situations it's best to bracket.This is particularly true when making slides.

It sounds like surge marks. See post #2.

Thanks for the replies. I have since processed a few more rolls and I think the problem was indeed with my agitation method. I think in fact I was not doing enough initial agitation. Apologies for posting the question without pictorial examples - I was going to upload some but I think I've found the cause (thanks partly to the above replies) so there's not really any need now!