I would appreciate some help with a problem I have when using plastic spirals. On a roll of ten 6x7 film I have a dark band on the eighth negative, always within a little in the same place. I have considered all sorts of possibilities, and have come to the conclusion that the end of the film is curling in and touching another part of the film (ie where the 8th negative appears).
None of my personal contacts have encountered this, and I've so far been unable to find anything on the internet. Does anyone have experience of how to overcome this? I am unable to post a scan.
It could be the way you load your spiral: the emulsion should face the centre of the spiral;
the film should be competely in the spiral;
when agitating turn the spiral both clock AND ani-clock-wise.
Hope this helps,
The natural curl of 120 film (when loaded with the curl towards the centre) would have the end touching the back of frame 8.
This wouldn't affect the emulsion side, only the back and anti-halation layers. Even then it'd be very small area. When you remove the spiral from the tank with the film still loaded, do you see the curl touching the back?
Are you sure you don't have a light-leak or fogging from somewhere?
A couple of things to consider or try.
When loading the film try giving the reeel 3 more turns to feed the film into the reel further.
Load the film into the reel from the end rather than the begining (last frame) , I find that this can be a bit easier to load on some tightly curled films.
Have you tried other reels ?
Do you cut the corners of the film off prior to loading ? - if so try a roll without doing this
I have never heard of this problem or no anyone who has had it either
But - do you load the film onto the spriral so that the end of the film is a couple of grooves into the spiral
If you don't get the film fully on the spiral is can flop about and contact the film on the next groove in
With a little light pressure from your thumbs as you ratchet the spiral back and forth you can "walk" the film further onto the spiral
I assume you are loading the spiral emulsion side inwards - with the natural curl of the film
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Thanks for the replies Peter, Mike and David. My first thought was that it was caused by a light leak, but this was happening with two different Mamiya cameras, so couldn't be in camera, and given the shape - a vertical band that doesn't extend into the rebate - it was difficult to see how it could be a leak during processing. Initally it was happening in about 90% of processed film. Having tried a number of things, I by chance noticed that the film was touching when I undid a spiral. I tried loading the film from the other end, only for the band to appear on the 3rd frame. Finally I tried cutting the corners off the leading edge, which has vastly improved the situation. The number of affected films has probably now reversed - down to 10% - 15%, and the marks are more faint. However this hasn't eliminated the problem, and interestingly, where a mark is visible it's now in the shape of the cut end!!
I am trying to load the film very slowly and carefully. I've tried to identify a problem with particular reels, but there doesn't appear to be any correlation. I haven't tried loading the film further into the reel, as suggested by David, and will give this a try.
In the meantime thank you for your suggestions. I am running out of ideas.
Originally Posted by Martin Aislabie
Martin - thanks for this. I was typing my first reply as you were posting.
I insert the film so that I push it just beyond the ball bearings. I have tied pushing it a bit in, but usually I then ratchet the reel back and forth as normal, with my thumbs helping where necessary and acting as a guide. Yes, I'm loading with the natural curl of the film. Someone suggested I try it upside down, but I found this to impossible.
Dumb question maybe, but do you cut off the paper sticker that holds the film to the paperbacking ?
I allways did en never had this problemm.
A question, do you remove the tape from the end of the film? There may be a minimal light leak in the tank, raising the base fog uniformly, except where it also reflects off the tape.
I remove the tape normally because it can absorb fixer more so then the film and I am concerned with contamination after drying.
D-76 is a standard developer, although not one I use.
Ansel Adams - The Negative
If I understand what you said, it seems to me you have just pinpointed the problem to be the reel, nothing else. If you have a different reel/tank system, like Stainless Steel, and in using it the band disappears, this would confirm the finding.
Originally Posted by formPhotography