Acros Marks - Backing Paper?

[bvy]

Hello. Let me dazzle you with my latest film developing problem. I'm sure it won't be the last time! Two different rolls of Acros 100 (120) developed at different time in HC-110, dilution E, 68F for 8 minutes (no prewash). Both rolls were exposed in a Yashica Mat 124G. Both frames below (third frame on each roll) show slightly underdeveloped marks that run parallel to the long edge of the film. I've enhanced the contrast to show them off. This doesn't look like a development or drying error to me.

I will tell you that both rolls sat for about 18 months from the time of exposure to the time of development. (Yeah, I know.) The film was stored in a cool dry area, though, in the dark. I'm wondering if it could be the backing paper. What's interesting about the left frame is that the flaw is dead center in the middle of the film. There are numbers and circles printed on the backing paper, although an inspection of the backing paper of each roll (where the flaw would have sat) doesn't show anything unusual.

Thoughts?

My next question would be about ideas for obfuscating them in the darkroom as I'd like to make enlargements of each.

Thanks for taking a look.

 

[winger]

Looks like a pressure-type mark? Like something slightly scraped the emulsion. Since those are positives, then the marks would be clear-ish spots on the film, hence my guess.
And I emphasize it's a guess.
To cover them, maybe some dabbing with diluted spot-tone?

I do have a microscope here, btw. It's low-ish power (dissecting 'scope, basically), but it might let us see if there's anything physical in/on (or not on) the film.

 

[Photo Engineer]

IDK what the marks are, but the scene looks familiar!

PE

 

[AgX]

Pressure marks from something wound with or onto the film, likely before exposure.

 

[bvy]

Thank you, Bethe! Don't know if it's worth that level of investigation, but I'll keep it in mind -- especially if it keeps happening.

PE, you must recognize a certain bridge!

AgX (and Bethe), interesting idea. I wonder if it could be something inside that camera.

 

[Sirius Glass]

It looks like the marks that come from having a rubber band around the film.

 

[bvy]

It looks like the marks that come from having a rubber band around the film.

It does, but I've never done that.

 

[Anon Ymous]

Any stress - kink marks I've ever seen look darker than the surrounding area of the negative, so they would have been brighter at the positive image. IMHO, it's not pressure related.

 

[AgX]

Pressure marks of both kind exist.

 

[jeffreythree]

I had marks like that(much worse) in a Ciroflex TLR that had some rust spots/debris on the film rollers and the rollers also did not turn smoothly under pressure. Cleaned and lubed rollers, and it went away.

 

[JW PHOTO]

IDK what the marks are, but the scene looks familiar!

PE

PE I believe that's the famous Half Dome!

 

[Photo Engineer]

Nope, either of the two rivers in Pittsburgh.

PE

 

[bvy]

Hello again. Processed another roll, and I have more marks -- though these might carry a little more insight into the problem. This time the defects manifest themselves as two marks, both along a line parallel to the long edge of the film. In one case, there's a dark and a bright spot. It almost looks like emulsion flaking off or some such. Again, this is Acros 100 exposed in a Yashica Mat 124G and processed in HC-110. This roll was exposed in Aug. 2014.