What's causing these patterns?

[Roundabout]

Hi

I send my colour film to a lab to develop. Recently I've been getting uneven areas of development, or horizontal 'streaks' - I'm not sure what to call them. I've attached an enlarged detail, as examples. (I've upped the contrast to exaggerate the effect).

(I don't know whether it's connected, but on a previous roll of film, some of the negatives a tiny areas of hard congealed shiny almost 'varnish' type of substance on the edge of the film.)

At first I thought this was camera scratches, but this doesn't happen with every roll of film. At the same time, could this be caused by something in the camera?

 

[markbarendt]

Chemical problems typically don't create sharp parallel lines. Sharp parallel lines are more likely caused by mechanical or electronic issues, scratches or dirt on the scanner's lens.

Are these defects visible on the film with a loupe or just in the scans?

 

[Roundabout]

I can't see this on the negs, but I'm just using a 50mm lens as a loupe. It doesn't seem as 'deep' as film scratches, which I can see one or two on the negs.

It's a Plustek 8100 scanner, so it would be hard to check of that's causing anything. There's no problems with other films, as far as I can see.

 

[Ian Grant]

I'd complain to the lab it's probably caused by their processing machinery. Poor maintenance is usually the problem.

Ian

 

[Roundabout]

Just scanned another frame, from a different roll, and it seems fine.

Edit: Although that was developed by a different lab.

This is a new (for me) camera (Nikon FM2n), so perhaps I ought to put it in for a CLA. But it seemed so well preserved, that I thought I'd get away with it. Even the light seals seem pretty good.

 

[markbarendt]

I'd complain to the lab it's probably caused by their processing machinery. Poor maintenance is usually the problem.

Ian

Yep, I'd definitely ask the lab for a redo.

One wild card here is the quality level of scan that you paid for, not all lab scans are created equal. If you only paid enough to get the basic "big enough" for email or web use scan that would explain the issue too.

 

[markbarendt]

Just scanned another frame, from a different roll, and it seems fine.

Edit: Although that was developed by a different lab.

This is a new (for me) camera (Nikon FM2n), so perhaps I ought to put it in for a CLA. But it seemed so well preserved, that I thought I'd get away with it. Even the light seals seem pretty good.

If both rolls went through this same camera then the camera probably isn't the variable causing the problem.

 

[bernard_L]

On the first image (1.jpg) the lines are not parallel to the frame edge. Unless it was rotated after scanning, this excludes he camera or processing machine. Taking a clue from: "on a previous roll of film, some of the negatives a tiny areas of hard congealed shiny almost 'varnish' type of substance on the edge of the film" I'd guess the lab had some processing issue and clumsily tried to wipe the film clean. Go to another lab if you have the choice; if you have no choice, try to politely educate them.

 

[AgX]

To me the structure looks like brushed. Not to explain with a camera defect and hard to explain with a processor fault.

 

[Roundabout]

Thanks.

Just to confirm, I've made the scans myself and it's not an electronic issue. Scanning the same frames produces the same results and frames developed elsewhere scan fine.

I tend to agree that it's the lab and not the camera. But, like the first reply from markbarendt, I wondered about the straight lines. I thought that it might be something to do with the film rubbing against something.

 

[markbarendt]

Yep sounds like the lab in question.