Marks on negs camera or handling?

[p. rex]

Hello all,

I’ve developed a few reels from my Rolleicord IV, my only medium format camera. The results look fine, except that there are dark vertical marks at intervals along the film. Initially, I thought these were light leaks. However, the more I look at them, the more I wonder if instead they are pressure indentation marks. I am using an off-brand Paterson-style tank with plastic reels. The reels seem to work well, but the marks on the negs are about where the insertion guides for the reel would go. I clip the corners of the negs before inserting them into the reel, and try to proceed as gently as I can, but even with perfectly dry reels, they don’t always go without resistance.

What say you all? I do think it’s peculiar that the marks are mainly toward the end of the roll. Perhaps there is something about loading the end of the roll that is causing pressure/scratching? It does occur to me that for most of the roll, I am unwinding a rolled-up negative, which might keep the film flat as it enters the roll, but at the end, the last bit of “roll” unwinds and may place tension or flexing at points on the film where it’s not helpful to loading.

Recent rolls of lab-developed film don’t show this effect, but those rolls were Pan F and Kodak E100 — since those are slower than the HP5 I’m seeing these effects on, they might not show a camera light leak so much.

Thanks!

 

[Kino]

Those look suspiciously like static discharge marks, the way they trail off in a fuzzy manner.

Is your darkroom very cold and dry? I don't recall ever seeing static discharge marks on a roll of 120, but there's a first for everything.

 

[p. rex]

It’s really not extremely cold and dry, but we use forced air heat here in the US, and static is something that’s always along for the ride. I actually own a zerostat static discharge gun to keep it off my vinyl records! But maybe I need to think more about static in my rudimentary bathroom darkroom.

How do you manage static electricity in the darkroom? Just find something to ground yourself on and touch it occasionally?

One point against the static theory: there are near-identical vertical marks further down the film, which suggests something related to the film’s vertical travel, in either the camera or the reel (I would think)

 

[Kino]

For static, I just try to keep the humidity in the room above 30% with 40% being about optimal (for me). I have a dehumidifier tuned-in to my basement darkroom environment, so there's always ambient humidity anyway.

It could be handling or pressure fog marks, but they are in a very strange place for either.

If you can borrow a different style tank from someone or purchase another one, you might try that to see if they persist.

Meanwhile check your film rollers inside the camera to be sure they do not have any build-up on them and blow out the interior to eliminate any possible particles that might be floating around to bind on the film as it passes over the rollers.

 

[snusmumriken]

One point against the static theory: there are near-identical vertical marks further down the film, which suggests something related to the film’s vertical travel, in either the camera or the reel (I would think)

If the static occurred while the film was spooled/curled up/on the reel, that would fit - although obviously not if the backing paper was present. The adhesive on sticky tape is one of the worst offenders for static, in my experience. Always peel tape slowly, is what I’ve learned. May not be your issue, but something to consider.

 

[Michael Howard]

Looks more like something digging into the film, starting out light and the pressure increasing as it goes. Are these scratches on the emulsion side or base side? If emulsion, your thumb pressure on the film as you ratchet it into the spiral could be gouging the film on a tiny sharp part on the film guide.

 

[MattKing]

Can you show us your reels?
If they are the AP/Arista Premium reels with the wider flanges, I've been using them successfully with both 120 and 135 for years. Perhaps it is how you are using them?
FWIW, I remove the 120 film first from the backing paper, then fold the tape over what will become the leading edge and insert that edge into the reels. Then, with the film hanging loosely below the reel and between me and the reel, I hold the reel gently and lightly between the fingers of my two hands - think like holding a balloon - and advance the fim into the reel. When it clears the opening, use my fingernail to push it a couple of inches further.

 

[p. rex]

Thanks to all y’all for the thoughtful and well-considered responses.

Matt, I believe I have the Arista premium tank set. At least the tank and reels look identical to the pictures I’m pulling up for that online. Why do you consider it important to push the film in another couple of inches after it clears the guides? Is it possible I have contact between the film and the guides? Seems unlikely, since those areas would then be lighter rather than darker, but I’m not sure.

Michael, I am out and about right now but will have another look at the negs when I get home. How do you tell whether the marks are on the film or emulsion side? The emulsion side doesn’t really look *scratched*, not as such. Nothing’s gouged. But I’m told that pressure marks that would otherwise be invisible to sight and touch will react strongly to the developer and appear as black. I can’t shake the suspicion that this is what’s happening.

Maybe I just need to do another roll and be very fussy about loading and unloading.

Also, I’m badly tempted to get a bigger tank anyway, for time efficiency reasons. Maybe this is a good pretext.

 

[Michael Howard]

Hold the negatives emulsion side up at an angle to the light, "wiggling" the negs at an angle to the light, you should be able to see the marks, even if they are just pressure marks and not scratches. It's kind of hard to describe. Otherwise, if you have a good magnifying glass or loupe you should be able to see the marks, if that's what they are.

 

[MattKing]

Matt, I believe I have the Arista premium tank set. At least the tank and reels look identical to the pictures I’m pulling up for that online. Why do you consider it important to push the film in another couple of inches after it clears the guides? Is it possible I have contact between the film and the guides? Seems unlikely, since those areas would then be lighter rather than darker, but I’m not sure.

I push the film in a bit farther because the film can move in the guides, and if it is close to the opening to start, it can end up moving part of its length right out of the reel. Also, the wider flanges could contact the emulsion during the development and affect the results, so it is best to move the film away from them.
If you have mechanical contact with the emulsion, the pressure on the emulsion can cause a similar result as exposing the emulsion to light. This is most often seen with those crescent shaped marks one can get from rough handling of the film.

Also, I’m badly tempted to get a bigger tank anyway, for time efficiency reasons. Maybe this is a good pretext.

The reels are designed to fit in Paterson tanks. I've standardized on the tanks that hold 1 litre of fluid, and either two reels set to 120 size or 3 reels set to 135 size. I frequently put two 120 films on the same reel, so those Paterson tanks can process four 120 rolls at a time.
And yes, there is a particular technique involved in loading two 120 rolls on an AP/Arista Premium reel and developing them successfully.

 

[p. rex]

Michael, I hate to say this, but I looked very closely and can see no creasing, scratching, or other sign of mechanical injury. The grains are darkened as if exposed to light, but I can’t see anything abnormal in either the base or emulsion. I looked closely under a work lamp, and up against a light source with a loupe.

It really doesn’t look like a light leak, right? If it is, maybe it’s the product of some strange internal refection. I did find a tiny scrap of white paper stuck near the upped edge of the back, near where the take-up spool goes. Maybe that was causing some sort of unwanted internal reflection?

Maybe the static hypothesis is the winner.

And Matt, I do intend to try the two-rolls-on-one-reel trick eventually.

 

[snusmumriken]

Michael, I hate to say this, but I looked very closely and can see no creasing, scratching, or other sign of mechanical injury. The grains are darkened as if exposed to light, but I can’t see anything abnormal in either the base or emulsion. I looked closely under a work lamp, and up against a light source with a loupe.

It really doesn’t look like a light leak, right? If it is, maybe it’s the product of some strange internal refection. I did find a tiny scrap of white paper stuck near the upped edge of the back, near where the take-up spool goes. Maybe that was causing some sort of unwanted internal reflection?

Maybe the static hypothesis is the winner.

And Matt, I do intend to try the two-rolls-on-one-reel trick eventually.

Do you wear a watch with luminous points/hands? Just trying to eliminate some alternative ideas.

 

[koraks]

The grains are darkened as if exposed to light, but I can’t see anything abnormal in either the base or emulsion.

'Exposure' by force doesn't always leave otherwise visible traces. This still looks like mechanical activation to me.