Banding on negative

[Don'tknowmuch]

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Well... I have good and bad news.

The bad news is that the fault was mine, and that I've rather wasted your respective times by asking you for help. The good news is that I know what the problem was. The bad news is that I can't help but look like a twerp now, but I'm big enough to own up and let on in what way I have let the side down. The good news is that I have been able to not only learn how to avoid the same thing happening again, but that I have been able to treat all the negatives that showed the banding and now have good negs!

As I said I would do in the above post I developed a piece of unexposed FP4+ in the same way as I had the Tri-X, and took the film out of the fixer after about 3 minutes to see what was going on (no actual images to spoil if I did this too early) and it hadn't fixed much at all. So I put it into a measuring jug with fixer in to watch it finish clearing in daylight, and noticed that it cleared from the edges first. I thought sprocket holes might act as an edge as far as a migrating reaction was concerned (because the clearing did travel from the edges in), and watched as a faint stripe of film in line with the sprocket holes cleared fractionally before the whole film cleared out. Was this it?

So I put a less critical strip of the latest problem stripey film, now dried, into the fixer and sure enough, after I'd dashed in a few ml of fresh concentrated fixer into the mix the stripes cleared off! I have since mixed up a complete fresh batch of fixer and have also cleared the stripes off the strips of film from the first time and... well, I'm sure you can imagine that it's a relief to know. I'm sure you also must realise that I now feel a bit foolish having asked you all for help and received support for something that was, as I'm sure many of you thought but were too polite to mention, always going to be some sort of a basic mistake. In my defense, it was quite weird.

The problem was that the old fix mix was weak - it was clearing, but took about 10 mins to fully work as opposed to the normal 4 or 5 that a new mix takes, and the striping was the fog of un-cleared film... How do I feel? Both elated and stupid... I hope you'll allow me to put this down as another step along the path. Progress, even, perhaps?

Thanks for all your help, and James, thanks for your offer of direct developing help.

Jim.

[Vieri]

Jim,

 

glad you worked it out - don't feel bad or anything, in fact I must add that your experience adds to the collective wisdom, and as such is very very welcome. One more reason to check our fixer and its working times more often - too many times we do take things for granted when we do them for such a long time, and it's good to have a reminder from time to time that care and attention to all the steps of the developing process should never be abandoned.

[rob_x2004]

Well, that was a head scratcher. Remind me to send you my next unsolvable problem to sort out.

Good to hear you are now investing in stop bath to look after your fixer:p.

 

Ps ... Now you know the fix, will you be working out why it follows that particular pattern?

[Don'tknowmuch]

Ho ho... Hopefully I won't need to conduct any further experiments! But I do know why it led to stripes, yes. The clearing happened from the edge of the emulsion inwards. If the film had been, say, 120 rollfilm with no sprocket-holes, it would have migrated in from the edges, leaving a band of uncleared film running along the middle of the length of the film. I guess fresh chemical meets the edge of the emulsion more absolutely than it does the face of it; on the face any reaction has to happen on one side only, whereas on the edge it has the edge that is no longer using up chemicals and the face to work on. With the 35mm film and its sprocket-holes the edge now becomes more complicated, and it, rather amazingly, but nontheless definitely because I saw it happen in open light, clears from the edge of the film as a whole and also from the edge of the sprocket-holes and this clear patch joins up with its opposing clear patch before the section clears between them. With weaker fixer (and it was still working, but over a longer time than I was giving it) this window of differential-clearing would have been extended, thus giving the manifestation of bands a longer window of opportunity to screw things up for me.

Back to real life - altogether less complicated. Thanks again all.

Jim.

[stunsworth]

If it is the fixer then you should be able to re-fix to 'fix' the problem.