Sprocket/edge marks on Kodak 500T Developed in cinestill CS2 chemistry

Cinebellum · Jul 16, 2023

Hi everyone,
I've been developing Kodak 5219 in Cinestill CS2 chemistry (simplified ECN-2), generally with good results.
However, on some photos I'm noticing the presence of sprocket/edge marks. I know the usual culprits would be light leaks or surge marks, but I don't believe these to be the cause since only outlines are visible. I suspect it might have something to do with the rem-jet layer (I soak the film in bicarbonate of soda before developing, then remove any residue by hand during the final washes). The marks are vaguely the same colour as rem-jet, but appear to be permanent or extremely stubborn, even after re-washing and drying.
Any advice would be greatly appreciated.

Cinebellum · Jul 16, 2023

It looks like my photos didn't attach properly - the image can be seen here

koraks · Jul 16, 2023

Yeah, I know that problem.

What happens is that you have some remjet still on the film during processing and at some stage, the film curls up on itself, during handling. In my case, this is usually towards the end of the process when I unspool the film and it tends to curl up again.

Along the edges of the film and around the sprocket holes, the remjet is a little more persistent; it collects along these edges, and then it imprints on the emulsion of another part of the roll as soon as the film curls up.

The solution to this is two-fold:

1: Prevent it from happening. So prevent the film from curling up until all the remjet has been thoroughly removed. One way of doing this is at the end of processing, unspool the film while holding it underwater while rubbing the remaining remjet off with your fingers.

2: On affected areas, soak the film briefly (not time critical; 30 seconds is already enough) in a weak sodium carbonate solution (e.g. around 1%; again it's not critical). Now rub the remjet off of the emulsion layer with your finger, a (very!!!) soft cloth or brush. Evidently, this brings the risk of emulsion damage, so be careful, but at the same time you'll have to be quite persistent as the remjet stuff binds very well with the gelatin emulsion. Fortunately, the emulsion on these films is hardened very well, so it can take some abuse. After rubbing off all of the remjet, rinse the film, and briefly soak it in a weak acetic acid solution. This prevents stains from forming as the film dries. Now wash it thoroughly, and treat with a stabilizer bath if you're so inclined.

Prevention really is the best cure, evidently. Sadly, there appears to be no way of removing the remjet completely without any mechanical action, so you'll just have to be careful with the film until you've got all the remjet off.

PS: Welcome to Photrio, do stick around

Cinebellum · Jul 16, 2023

koraks said:
Yeah, I know that problem.

What happens is that you have some remjet still on the film during processing and at some stage, the film curls up on itself, during handling. In my case, this is usually towards the end of the process when I unspool the film and it tends to curl up again.

Along the edges of the film and around the sprocket holes, the remjet is a little more persistent; it collects along these edges, and then it imprints on the emulsion of another part of the roll as soon as the film curls up.

The solution to this is two-fold:

1: Prevent it from happening. So prevent the film from curling up until all the remjet has been thoroughly removed. One way of doing this is at the end of processing, unspool the film while holding it underwater while rubbing the remaining remjet off with your fingers.

2: On affected areas, soak the film briefly (not time critical; 30 seconds is already enough) in a weak sodium carbonate solution (e.g. around 1%; again it's not critical). Now rub the remjet off of the emulsion layer with your finger, a (very!!!) soft cloth or brush. Evidently, this brings the risk of emulsion damage, so be careful, but at the same time you'll have to be quite persistent as the remjet stuff binds very well with the gelatin emulsion. Fortunately, the emulsion on these films is hardened very well, so it can take some abuse. After rubbing off all of the remjet, rinse the film, and briefly soak it in a weak acetic acid solution. This prevents stains from forming as the film dries. Now wash it thoroughly, and treat with a stabilizer bath if you're so inclined.

Prevention really is the best cure, evidently. Sadly, there appears to be no way of removing the remjet completely without any mechanical action, so you'll just have to be careful with the film until you've got all the remjet off.

PS: Welcome to Photrio, do stick around

Thanks so much for this - felt like I was going insane because I couldn't find the issue anywhere online!
I suspected something like this to be the case. It makes sense that this occured when handling the film after development, firstly because the sprocket holes are going diagonally over the image despite the reels being loaded correctly, and secondly because it occurred extremely sporadically. I also noticed some fingerprints on the film, and I'm assuming this could also be from handling (pressing rem jet into the emulsion).
It's a little big scary knowing how sensitive the emulsion side of film is to staining, but I'm glad that the issue has been identified! At £3.5 per roll, motion picture film really is the way to go for the budget conscious...

cmacd123 · Jul 16, 2023

yes, It is rumoured to be MUH harder to get the rem jet off the emuslion if it transfers. been decades sonce I experimented, But I used two Photo sponges to try to get the rem jet off, so that the emmusion side sponge would keep the "Gunk" from getting a chance to to touch the emulsion.

Sprocket/edge marks on Kodak 500T Developed in cinestill CS2 chemistry

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