Is this due to light leak?

Wow - I have never seen a fault like that! It is very regular and even across the entire strips of film that you show. I would imagine that, if it were a light leak, it would show much more variation, as you would stop and start the film transport, and you were most likely changing the lighting conditions. So for now, let's rule out a camera borne light leak.

Did you do anything with this film prior to shooting, like re-roll it? No? I didn't think so, but needed to eliminate that possibility.

A light leak through the 'lips' of the cassette also does not make sense. The only place that I can imagine a light leak that would make this kind of pattern is when rewinding. Maybe something slips and a tiny pinhole opens up during that step?

After that it is on to the processing. What kind of reel do you use, is there any mechanical touching of the central part of the film during spooling? Anything odd during development?

The mark has a slight, periodic undulation. Try to determine if the period of that waviness coincides with the film wound inside the cassette, with the film on the take-up spool (the tulip) or on the development reel. This will help pinpoint when the marking occurred. Perhaps you have a bad batch of film!

eta: the period corresponds to a diameter of 0.7 inches, which is compatible with being on the take-up spool or inside the cassette, but not on the development reel. Look at the period near the beginning of the roll. If the spacing is tighter then it's associated with the take-up spool, wider then it's happening in, or near the cassette.
 
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My first thought was something or other on one of the rollers. I wouldn't have thought that a light leak could be so uniform, and effect the none-exposed areas equally as much as the exposed. Also, light leaks tend to vary in intensity from edge to edge.
 
It's not a light leak. Some sort of processing problem, seems to be.
Light leaks in bodies are expensive to fix. Could it be a light leak in your developing tank?
 
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I develop with patterson tank and plastic reels. I have 4 and i am pretty sure i used different reels this time around.
In terms of developing technique..... nothings changed for the past 30 rolls.
Both films were Tri-X in their original cassette as bought.

.....?????
 
Back door creaking is quite common, I believe. My M4 did it a bit and so did the M2. On M2, I ever so slightly corrected it by wiggling the door very very carefully. Either way, that shouldn't give a leak like this unless the light trap part of the door or boddy is actually yanked off or something...

Maybe you can try different film from different batch to eliminate the possibility of film/cassette issues?
 
I am going to shoot a roll of C41 today as a test.
Will see what happens.......

What else could cause the band other than light????? A deep scratch or something??? Improper film loading???
 
I can't think of a way to produce this "scratch" in camera. It's wavy so the film had to be extremely loose to get this if this was in camera. Even if it was a light leak, why is it so wavy? Hmmm. I'm leaning towards darkroom problem (or small chance of defect in film cassette) more and more.
 
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I'd try another brand of film as a further test. It's unlikely, but maybe there was a coating problem at Kodak and a bad batch of film got through QC. Maybe it was the beginning or end of a coating run.
 
Shooting a roll of Ilford XP2 now.
Will try a roll of Ilford FP4+ after......

Took me awhile to source for this particular M4 so...... really would like to sort it out rather than return it. Bought it from a dealer and they offer a 6 months guarantee.

Sent them an email with the pictures too..... see what they malke of it......
 
why don't you have some one else (like a photo lab) process a role of film exposed like you did in the shots above in an attempt to narrow down where in the process this arises?
 
I have experienced issues with Kodak film lately. But it has been limited to short rolls (24 exposures in a cassette marked 36.) I have never seen a 'pre-marked roll. Because of the period of the wave, I think it is something that has gotten into your film transport mechanism that is rubbing on the film, leaving a mark. Do you see the mark on the film? Does it look at all physical rather than optical?
 
Chris: I don't remember seeing any physical scratch or mark on the film. I did think if it could be due to improper film loading....maybe missed the sprocket or something.......
 
I know...what a mystery.

Thinking about it though..... how can processing error give such an artifact????
If there was light leak during the developing/film loading stage....surely it'll go everywhere rather than be confined into such well demarcated regular pattern.......
 
The streaks on the first roll were rather straight, but wavy on the last. Is there a clue here?
 
I think Martin may well be right here. Ferraby - are you sure this roll hasn't been near the X-Ray department? :)
 
Is there any chance at all that you've worn a wristwatch with a luminous dial whilst loading the developing tank in the darkroom or bag?
 
This looks nothing like x-rayed film, unless the film has been deliberately x-rayed using a filter to produce the line artifact. The luminous watch idea might have some merit though.

I am leaning toward something touching the film during rewinding, or reel loading though.
 
Loaded film with my bare hands. No luminous watch.

With regards to X-ray, the only X-ray that could have zapped the film would be during transit from US to Australia.
Bought this batch of film during the recent order from B & H that I co-ordinated
 
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