Suddenly a thin layer of residue appears on negs

[Elmarc]

Just wash them in a tray, retreat with Photo Flo (mixed to the proper dilution since not-dilute-enough Photo Flo may be your problem) and hang from a line with a wooden clothespin from a corner (just like you would sheet film). It is easy to position the clothespin so it just barely grabs a couple of mm of the corner.

The suggestion to soak them in an acetic-acid solution (acetic-acid stop bath will work just great) is a good one.

If you aren't 100% sure your negatives are not underfixed, then refix before the wash too.

Best,

Doremus

I have been using less than the specified 1:200 dilution for a long time with no problems.
Coincidentally I did perform a hypo test recently and the results were clear ie: no stain. So I don't think this is a case of under fixing but just to be sure I will perform the same test on this roll,
Can you suggest a time for both the stop and wash?
I will test one strip first to check the results.

Best

Mar

 

[Elmarc]

Is this film developed in a spiral?

Yes, and with constant agitation.
I was actually due to update this thread as I recently developed a roll of fomapan 400 and all is well again. This is following the exact same process as usual. So quite strange...

 

[Doremus Scudder]

Elmarc,

First, I misspoke (mistyped) in my previous post; I meant to say that a too-strong solution of Photo Flo may be the problem. Using it more dilute than recommended works fine providing that you get the required surfactant effect (i.e., no water droplets).

By "hypo test," I assume you're testing for residual hypo with the HT-2 test. Be aware that fixer that starts to sulfur out may contain very fine suspended particles that can coat the film, but still be active enough to completely fix the film. These are two different problems. If particulates are coating the film, they will need to be wiped off.

As far as time in the acetic acid bath (with the goal of dissolving the deposit if it's carbonate or the like), there aren't any hard and fast rules. A longer soak won't hurt the film. I'd toss it in for 15 minutes and see what it looked like after that. If no change, then soaking longer likely won't help any.

Glad your subsequent processing went well.

Doremus

 

[Elmarc]

Elmarc,

First, I misspoke (mistyped) in my previous post; I meant to say that a too-strong solution of Photo Flo may be the problem. Using it more dilute than recommended works fine providing that you get the required surfactant effect (i.e., no water droplets).

By "hypo test," I assume you're testing for residual hypo with the HT-2 test. Be aware that fixer that starts to sulfur out may contain very fine suspended particles that can coat the film, but still be active enough to completely fix the film. These are two different problems. If particulates are coating the film, they will need to be wiped off.

As far as time in the acetic acid bath (with the goal of dissolving the deposit if it's carbonate or the like), there aren't any hard and fast rules. A longer soak won't hurt the film. I'd toss it in for 15 minutes and see what it looked like after that. If no change, then soaking longer likely won't help any.

Glad your subsequent processing went well.

Doremus

Yes Doremus, I presumed that is what you meant regarding the amount of photoflo.
I use 0.7ml in 450/500ml of water. I arrived at this amount many years ago when I was experiencing some random photoflo marks at a slightly stronger dilution.
Yes, I did use the HT-2 test.
The fixer (Ilford rapid) was from a new bottle. Although, as we know, Ilford do not print manufacturing dates, they have recently started to use stickers on generic bottles here in the EU so I am fairly confident that this was fresh stock.
I was not aware of the phenomenon of the 'sulphuring out' and the ability for particles to coat the film. Thank you for that.
The thin coat will actually wipe off. I confirmed this on a non image part of the film, so I am hoping that a soak will be successful. I will keep you posted with the results as and when.
Thank you for your thoughts.

Marc

 

[Elmarc]

Hello all. A quick update...
I thought the problem had disappeared as my most recent rolls did not exhibit any traces of residue.
However, the latest roll shows 'streaking' once again.
I have managed to take a photo albeit not the best quality.
If the residue was from Photo Flo I would have thought the streaking would be less uniform. Plus, I hang my negs at a slight diagonal and the streaking is vertical.
Any ideas as to what could be causing this?

 

[BobUK]

I cannot puzzle out what is what on the photo.

A couple of times I didn't remove the sticky tape that holds the film and backing paper together.
The glue dissolved in the tank and left streaks down the film.
Now I always remove the sticky tape from the film before loading the spiral.

 

[Don_ih]

How did you develop? Like Bob, I can't tell much from that photo. What I see looks like it might not be completely fixed.

Also, if you get developer into your fix, you could end up redepositing dissolved silver back onto the film, if the fix is heavily used (it's pretty unlikely).

 

[Elmarc]

How did you develop? Like Bob, I can't tell much from that photo. What I see looks like it might not be completely fixed.

Also, if you get developer into your fix, you could end up redepositing dissolved silver back onto the film, if the fix is heavily used (it's pretty unlikely).

I have added some detail in the form of red lines. Hopefully you can see that there is a formation of clear film interspersed with lines formed by this residue.
Fix is always fresh and one shot.
Continuous agitation tank.

 

[Elmarc]

I should add that this streaking is only really visible when the film is held at a certain angle against a dark background. That is why it is quite difficult to get a good image of it. The streaking is not apparent when the film is held against the light. Nonetheless the artefacts exist.

 

[Elmarc]

I cannot puzzle out what is what on the photo.

A couple of times I didn't remove the sticky tape that holds the film and backing paper together.
The glue dissolved in the tank and left streaks down the film.
Now I always remove the sticky tape from the film before loading the spiral.

I normally do not remove the tape without any problems regarding migrating glue.

 

[pentaxuser]

Does the streaking affect the reproduction of the negs as prints. If this question has been asked then just ignore it but it struck me that everyone is trying to think of an answer to the streaking but if it doesn't affect printing/ scanning and now seems to be not there all the time then and we none of us have found the answer then as long as it doesn't affect the final product I wonder how much it matters as it is not the negative that anyone admires or wants to see. It's the posítive as a hard print or a scan that's important

pentaxuser

 

[Elmarc]

Does the streaking affect the reproduction of the negs as prints. If this question has been asked then just ignore it but it struck me that everyone is trying to think of an answer to the streaking but if it doesn't affect printing/ scanning and now seems to be not there all the time then and we none of us have found the answer then as long as it doesn't affect the final product I wonder how much it matters as it is not the negative that anyone admires or wants to see. It's the posítive as a hard print or a scan that's important

pentaxuser

I understand your point but I am concerned whether this residue will degrade the negative over time. That is the main reason for trying to work out what it actually is. The enlarger seems to print through it without problems so far although the frames that I have printed have not had broad areas eg: sky where it could possibly show up.

 

[John Wiegerink]

I read over this very fast so might have miss something. Can I ask what camera you are using?

 

[Elmarc]

I read over this very fast so might have miss something. Can I ask what camera you are using?

Hasselblad 500c/m

 

[Saganich]

calcium sulfite scum? Can you wipe it off with a sponge while the negs are wet? Does it clear off in an acid fixing bath (with agitation)? Doesn't look like photoflo to me.

 

[Elmarc]

calcium sulfite scum? Can you wipe it off with a sponge while the negs are wet? Does it clear off in an acid fixing bath (with agitation)? Doesn't look like photoflo to me.

Quite possibly. There is a lot of calcium in the water here. I do however use distilled for the developer and final wash. The remainder is filtered through a Paterson filter.
The residue will semi easily wipe off. I was able to do that on the dry leader.
I haven't tried soaking in stop bath as yet.
I am not sure it is photoflo either. Especially as the negs are hung up at a diagonal and these streaks are vertical. They would not be so uniform either. The uniformity is the part that I actually find quite puzzling.

 

[koraks]

Eliminate one variable at a time. Try a process run with only demineralized water to see if the tap water does anything - so one film processed without it getting into touch with any tap water whatsoever. Same with the photoflo; do one roll without using any photoflo. Do a film with a different developer. Fresh fixer. Etc. etc. It's a process of elimination. By following it diligently, you'll encounter the factor that causes this.

 

[BobUK]

.............. Especially as the negs are hung up at a diagonal and these streaks are vertical...................

Why are they hung up at a diagonal?
Vertical would seem the simplest.

 

[John Wiegerink]

Hasselblad 500c/m

Are you sure these lines/streaks you're seeing aren't really lightly exposed ares instead of streaks. The reason I ask is that the infrequency and the direction of the lines. I even took a guess as to what camera you were using and would have guessed right. There are several areas where Hasselblad cameras can form mini-light leaks. Rear barn doors, shutter problems (rare), gap between back and body (again rare) and the light seal in the back itself (a much more common problem) and one you can test yourself very easily if you have another back. I'd guess you might have a light seal issue in one of your backs????

 

[BobUK]

I use Paterson tanks. They sit upright on the bench. Any chemistry streaks would most likely be across the film.
The only streaks along the length of my films would be from the final rinse etc. when hung up to dry vertically.

Are you using horizontal rotary tanks?

If so, that could be contributing to the stains along the length of the roll.
Remove the spiral of developed film and soak it in the final wash with the wetting agent. Placed horizontally, with the spool sitting in a bowl of wetting agent rinse.

 

[pentaxuser]

John re your # 45. That may be an explanation but the OP in his #31 has said that the problem had disappeared but then returned. So is there any way that with a Hasselblad leaks might not show on every occasion? One thing is certain and that is something had changed somewhere in the process from loading a film in the camera to unloading it from the developing tank

As Koraks has said, it's the elimination of each possible cause at a time and maybe starting with the camera

pentaxuser

 

[Sirius Glass]

If you used PhotoFlo mixed per the instructions and you still have streaking, then the problem may be your local water. In that case use distilled water for the final wash. Others will have solutions [pun intended] using isopropyl alcohol. Please do not refer to isopropyl alcohol as IPA, because that generates posts about using either bottled or draft micro brewed beer.

 

[koraks]

In that case use distilled water for the final wash.

I do however use distilled for the developer and final wash.

 

[Elmarc]

Why are they hung up at a diagonal?
Vertical would seem the simplest.

So that the water does not pool at the bottom.

 

[Elmarc]

John re your # 45. That may be an explanation but the OP in his #31 has said that the problem had disappeared but then returned. So is there any way that with a Hasselblad leaks might not show on every occasion? One thing is certain and that is something had changed somewhere in the process from loading a film in the camera to unloading it from the developing tank

As Koraks has said, it's the elimination of each possible cause at a time and maybe starting with the camera

pentaxuser

I don't see how this can be the camera at fault. This is a (removable) residue not a light leak.