Fault Finding lines on negs - bronica SQAi

[hoffy]

Greetings,

I have had a bit of an intermittent issue with my Bronica SQAi where I have been getting some lines on my negatives.

Initially, I thought it was scratches, but I am not sure. The lines are dark on the negative, where's if they were scratches, they would be clear. (obviously, they print as white on paper). The other thing is they tend to not be in the same place, but appear to be similar shape.

Below is one specific example, scanned in as negatives, accompanied with a zoom into the spot.

Anyone got any clues?

Cheers

 

[DWThomas]

Well, it's in the direction the film moves (unless you've been holding the camera sideways! ) and the back, non-emulsion side should be protected by the backing paper (unless you had some 220 sandbagged). There are two very small rollers on the back portion, one above and one below the film gate. They are pushed toward the film by little leaf springs at the end. My guess would be one of those has some bits of ?? on it, or maybe for some reason isn't turning -- or there is a loose piece of grit wobbling around that area.

I think scratches can appear lighter or darker, depending on how deep and even the shape of the groove.

 

[pbromaghin]

Oh, man. That's really ugly. Good luck figuring it out.

 

[hoffy]

Well, it's in the direction the film moves (unless you've been holding the camera sideways! ) and the back, non-emulsion side should be protected by the backing paper (unless you had some 220 sandbagged). There are two very small rollers on the back portion, one above and one below the film gate. They are pushed toward the film by little leaf springs at the end. My guess would be one of those has some bits of ?? on it, or maybe for some reason isn't turning -- or there is a loose piece of grit wobbling around that area.

I think scratches can appear lighter or darker, depending on how deep and even the shape of the groove.

That's what I was originally thinking, but don't those rollers go down the middle of the film? Also, wouldn't they roll (& rub if they weren't turning) against the backing paper?

It also doesn't effect each and every frame.

 

[johnielvis]

What kind of film? perhaps quality control is not up to snuff--that can happen too. If it happens on every roll at random places with only one kind of film, then just try developing an unexposed one and see if they appear.

If this is with any type of film you've run through it, then this needs more investigation.

 

[Mick Fagan]

Are you developing the film yourself, or is it sent out and going through a roller transport film processor?

Mick.

 

[hoffy]

OK, it has happened with C-41 film (kodak more then likely, about 12 months ago), HP5 back then and with Fp4+ on this occasion. I would tend to suggest that its not the film.

The C-41 was processed by a lab, but the Fp4 was processed by me on a reel.

I will use the camera again tomorrow (there is a film still in it) and see what happens. Interesting to note that it tends to happen towards the end of the roll. I think that if people think that its scratches, there must be something in the gate that is slightly touching the bigger the roll gets on the take up spool.

 

[paul_c5x4]

The marks have all the characteristics of being scratches - Are they on the emulsion side ?

If they appear on the back of the film, then processing/handling are the most likely source.

 

[DWThomas]

I'm speaking of the rollers pointed to here (and in fact this unused for several years example might could use some attention!) And indeed, this would only apply if the scratches are on the emulsion side.




It looks as though the rollers span the entire width of the film. I suppose they are to reduce any effects of reverse curl coming off the big rollers to help keep things against the pressure plate. At any rate, they appear to be one of the only things (other than light!) that may contact the emulsion in-camera.

(Durn, something else on my do list!)

 

[Truzi]

Those rollers do look like they need some attention. Perhaps they do not roll as easily when there is less pressure on them (nearing the end of the roll).

 

[elekm]

I also was thinking that those rollers look rather cruddy. You might want to try a little bit of rubbing alcohol (or lighter fluid) on a cloth to clean them. Maybe it picked up a tiny piece of debris, which is causing the scratch.

 

[DWThomas]

I also was thinking that those rollers look rather cruddy. You might want to try a little bit of rubbing alcohol (or lighter fluid) on a cloth to clean them. Maybe it picked up a tiny piece of debris, which is causing the scratch.

Yes the one on the left in particular is embarrassingly cruddy, however I'm not the guy with the problem! As another Bronica owner I've just been speculating on possible causes. That back has been sitting on a shelf unused for several years when it obviously should have been enclosed somewhere, there's a bunch of dust on the exterior. I agree some sort of swab and alcohol or naptha ought to do it.

I posted the shot as it appeared there might be some confusion about what rollers I was talking about in my first response. There are two much larger ones that are part of the insert which the film reverse bends over to stretch out over the pressure plate. Those only contact the backing paper (unless you're shooting 220, a less and less likely scenario).

We can hope that over the next decade APUG can become a treasure trove of info for dealing with the quirks of some of these cameras.

 

[hoffy]

Ahhh, now I understand. Yes, they indeed may be the issue.

I'll check the out once I empty the camera.

 

[hoffy]

Digging this one up again.......

It appears my problem is intermittent. I can go many rolls of dim with out a scratch, but then they come back. I have checked the rollers again and again and they appear nice and smooth. I am wondering, though, if there is a slight flat spot on one of them, which occasionally prevents it from turning.

So the next question is, does anyone know where I can obtain SQA spares? If the price is not too bad, I'd give a new set of rollers a try.

Cheers.