Fine Line on some negatives

Shaggysk8 · Sep 20, 2009

Hello again, I feel like all I am doing at the moment is asking for help.

Ok I have developed my second film and I seem to be getting a thin black line appear on some of the negs, its not consistent with each roll, the line either just starts or there is a few small thin lines then a lone one. it does appear in the same place across the film just not along it.

I am using Bronica ETRS with a 120 back, Ilford Pan F+, developed in a Paterson tank that holds one roll.

Its confusing me as at first I thought it could be grit scratching the neg but it seems as its in the same place across the film this seems unlikely, then I thought light leak, but I would think this would fog the film or just be along the whole film in the same place.

I have a Polaroid back and this line has never come out before.

So really over to you guys.

Paul

PS (sorry for all the questions)

trexx · Sep 20, 2009

First off keep asking question, it is what drives this forum.
Is the line in the same direction as the length of the film or across the short way of the film? As it is dark then that says extra light is hitting the film. It has not happened with the Polaroid back then a leak in the film holder may be suspect.

Can you get a scan of the neg. to post here?

Shaggysk8 · Sep 20, 2009

The line is the same direction as the length, does not go all the way along lets say it starts at frame 4 then off at 6 then one half way through 7 then off at 9 and the other roll is on at 9 and off half way through ten.

I can not get a scan sadly I could try and take a picture of it.

trexx · Sep 20, 2009

Is the line there between frames?

jeffreyg · Sep 20, 2009

Just a wild guess but check for a bur on the pressure plate that may not affect the entire roll because as the film is advanced there is less film and it doesn't rub.

Shaggysk8 · Sep 20, 2009

Yes there is a line between frames but not every frame. Will check for a bur!

Shaggysk8 · Sep 20, 2009

The line on the left hand side, I hope this helps

Shaggysk8 · Sep 20, 2009

no bur or anything like that where the film runs :S I am sure someone has an answer but I am very confused

Ian Grant · Sep 20, 2009

It looks like a grit stress mark, I've seen them on 35mm film where dirt has got into the light trap. You need to check the film back and make sure it's clean.

Ian

erikg · Sep 20, 2009

Do you have another back to compare against? I would look in the direction of something in the back, but with 120 you have the paper backing, so this is unusual. A scratch on the emulsion side would be clear on the film, so I don't think it is on that side. I've seen scratches caused by plastic film reels too, but not this far towards the center of the film.

Shaggysk8 · Sep 20, 2009

I don't have another back sadly, I would of thought any scratch would come out clear and not a black line, I will give it a good clean.

Ian Grant · Sep 20, 2009

erikg said:
A scratch on the emulsion side would be clear on the film, so I don't think it is on that side. I've seen scratches caused by plastic film reels too, but not this far towards the center of the film.

It is on the emulsion side a pressure scratch doesn't necessarily remove emulsion but like a kink in the film during loading causes a stress fogging.

A tiny bit of grit between the film and a roller can cause this, then drop away again, later getting trapped somewhere else.

Ian

MattKing · Sep 20, 2009

Shaggysk8 said:
The line is the same direction as the length, does not go all the way along lets say it starts at frame 4 then off at 6 then one half way through 7 then off at 9 and the other roll is on at 9 and off half way through ten.

Is the line as evenly spaced as this would indicate? Is it always the same length, or does the length vary?

If you were to lay one negative strip over another, would the images of the line coincide?

Matt

Shaggysk8 · Sep 20, 2009

It is always in the same place across the film but never the same length or in the same place around the film.

Paul

MattKing · Sep 20, 2009

Does the length increase or decrease sequentially as you move through the film, or does the length vary randomly as you move through the film?

I'm asking, because this might give an indication whether it is something like a pinhole light leak vs. grit in the back.

Matt

Shaggysk8 · Sep 20, 2009

It is very random. Which makes me think grit. I will have to get my cleaning head on I think.

Sirius Glass · Sep 20, 2009

Shaggysk8 said:
It is always in the same place across the film but never the same length or in the same place around the film.

Paul

It looks like a scratch or mark from the rollers or pressure plate on the film back. If it only occurres on one back it is the back. If it happens with more than one back, then look at processing causes.

[Paul, you do not have to agree with me here. ]

Steve

Shaggysk8 · Sep 20, 2009

My first step is to clean the back and shoot another film but I think the back is the best place to start

erikg · Sep 21, 2009

Ian Grant said:
It is on the emulsion side a pressure scratch doesn't necessarily remove emulsion but like a kink in the film during loading causes a stress fogging.

A tiny bit of grit between the film and a roller can cause this, then drop away again, later getting trapped somewhere else.

Ian

Wouldn't a bit of grit between the film and the roller cause a mark on the base side? Marks on the base side often show as dark lines, like this, despite the backing paper. We are probably saying the same thing. In any case I would look at those rollers very carefully, the offending particle can be extremely small and not at all obvious.

Ian Grant · Sep 21, 2009

It could be either it might be something sticking to the pressure plate, only needs to be small LD

Ian

Shaggysk8 · Sep 21, 2009

What would anyone suggest cleaning it with?

Ian Grant · Sep 21, 2009

Kitchen towelling dampened, a camel hair paint brush . . . . depends on how dirty it is.

Ian

Shaggysk8 · Sep 26, 2009

Ok cleaning the back, ran a film through and still the line, its in the same place across the film but random around. I was wondering is it worth putting the back of the camera in a light tight bag and only letting the lens show out of the end and shoot a roll again, that should eliminate light leaks, what do you think?

DWThomas · Sep 26, 2009

The following comment assumes the ET series back handles film like the SQ series. As such, only the paper backing contacts the large rollers on the insert and the pressure plate. The most likely spot for the culprit would be on the very small diameter rollers above and below the dark slide in the back frame. Those are so small my bleary eyes thought at first they were just rounded bars! Since they should be turning, I would expect a burr on one of them to produce an intermittent mark, but perhaps one is not turning -- mayhaps there's a "bit of something" stuck between a roller and the frame. The ends are held by little flat silvery spring clips.

I'm being purely analytical here, looking at an SQ-xx back, yours is one of the few problems I haven't had -- so far.

(Anyway, thanks for encouraging me to become more intimately acquainted with my film backs! )

DaveT

Shaggysk8 · Sep 26, 2009

I have just had a look at those rollers under an eye glass and nothing I can not see a thing on them, although it is nice to know what rollers to touch the film, I am also glad I could make you more intimately acquainted, I might be filling for divorce!!!!

Paul

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