Identifying film coating faults vs. handling / process problems.

[Tim V]

Hi all,

I'm wondering if there is any online resource here or elsewhere with pictures on how to determine if a fault seen in a processed sheet of film is a coating vs. a processing fault.

I ask this because I've been trialling a new brand of film and am seeing things I've never seen with Ilford or Kodak. Some things like pinholes, but also things that look like scratches in the emulsion – I'm fastidious and in over 1000 sheets of 8x10" film I've never seen it quite like this before – and things I might describe as pitting, plus subtle – but visible at certain print densities – banding in the skies.

I process in a Jobo using an expert drum, if that makes a difference.

Thanks,

Tim

[Bob Salomon]

Have you contacted the film maker? If there is a problem they can’t fix it without hearing about it. But if film coating was a problem there would be hundreds, if not thousands, of users contacting them.

[Sal Santamaura]

My late grandfather once shared the wisdom with me that "you're not wealthy enough to afford cheap stuff."

Why struggle with such issues when Kodak and HARMAN still offer top quality products?

[Pere Casals]

Hi all,

I'm wondering if there is any online resource here or elsewhere with pictures on how to determine if a fault seen in a processed sheet of film is a coating vs. a processing fault.

I ask this because I've been trialling a new brand of film and am seeing things I've never seen with Ilford or Kodak. Some things like pinholes, but also things that look like scratches in the emulsion – I'm fastidious and in over 1000 sheets of 8x10" film I've never seen it quite like this before – and things I might describe as pitting, plus subtle – but visible at certain print densities – banding in the skies.

I process in a Jobo using an expert drum, if that makes a difference.

Thanks,

Tim

You may provide detailed information: film, developer, stop bath type and high res crops of the pitfall.

¿do you make a final rinse with distilled water? ¿filter? ¿have water borne particles?


One possible cause for pins are carbonic bubbles generated when some films soaked with some developers are placed into an acid stop bath... carbonate reacts making carbonic bubbles inside emulsion.

Try distilled water for final rinse, and try plain water stop bath, if problem continues post hires crops of the pins.


It can also be air bubbles in developer/film, See here (http://www.afterness.com/darkroom/fi..._problems.html) the "pinholes" link. Tap water may contain air that is released when water losses pressure...

[jp]

You may need to sacrifice a few sheets to examine in daylight fresh out of the box.
Once I had had some scratched up 8x10 fresh out the box, not from one of the major two manufacturers. I stopped using it.

Other people have had great film but processing decisions cause pinholes, etc...
Subtle banding could very likely be developing choices.

[Sal Santamaura]

...Subtle banding could very likely be developing choices.

Or, more likely, standing waves in the emulsion during coating by the manufacturer.

[Drew Wiley]

It's extremely unlikely that either of these two major manufacturers would have the same problem. It's probably related to your drum technique.

[Bob Salomon]

It's extremely unlikely that either of these two major manufacturers would have the same problem. It's probably related to your drum technique.

He hasn’t specified which manufacturer’s film he used.

[Drew Wiley]

Thanks Bob. I re-read it, and it seems you're right. I have had the problem he describes with Forte/Arista 200 sheets, even tray developed. But that's the only case.

[Tim V]

I purposely didn’t name the manufacturer because I want to know what I’m seeing first on my negatives before pointing the finger. I will say that it’s not from one of the big two though. As I said also, I’ve never seen these things with Ilford but that’s not to say it’s not my developer or something.

Any resources to reference? I’ll post samples soon...