Scratch diagnosis

quixotic · Jan 27, 2017

Any idea what might have caused the following? It extends across most of the roll (in the same spot near the top of the image). It was done with a Nikon F3, and processed at home with a Paterson plastic tank. I haven't opened up the camera yet, since I just put another roll in, and took a shot or two. But if the camera is the most likely culprit, I'll open'er up and have a closer look.

Thanks in advance.

MattKing · Jan 27, 2017

Which side of the negative - emulsion or substrate - is the scratch on?

Jim Jones · Jan 28, 2017

A scratch caused by the camera or cartridge is apt to be straight, not wavy. Do you squeegee the film when drying?

AgX · Jan 28, 2017

I agree on the camera issue, but could squeeging produce that wave form? It seems rather too "high-frequency" to me.

iakustov · Jan 28, 2017

I had a similar stuff on one of my recently developed 35mm film. I blamed the plastic paterson reel for the scratches - maybe I put too much effort while rotating it when loading the film. But I used the other reel the same day with no issues.

quixotic · Jan 28, 2017

I'm starting to think more and more that it might be a processing or post-processing issue (could a moderator take the thread over there?).

Yeah, it's on the emulsion side. In a microscope, you can see the little torn patches not too far away from where they got torn from. I'm also thinking squeegee more and more. The scratch starts at exposure #14 and is strongest in those teens. Then it gradually fades away, until the end of the film at #25. Maybe the squeegee grabbed a piece of grit at #14? It just seems strange that the line is relatively straight, and always in the same spot for 11 successive exposures.

And I can't think of any way that the plastic reel could have caused the damage.

iakustov · Jan 28, 2017

quixotic said:
I'm starting to think more and more that it might be a processing or post-processing issue (could a moderator take the thread over there?).

Yeah, it's on the emulsion side. In a microscope, you can see the little torn patches not too far away from where they got torn from. I'm also thinking squeegee more and more. The scratch starts at exposure #14 and is strongest in those teens. Then it gradually fades away, until the end of the film at #25. Maybe the squeegee grabbed a piece of grit at #14? It just seems strange that the line is relatively straight, and always in the same spot for 11 successive exposures.

And I can't think of any way that the plastic reel could have caused the damage.

I dont use squeeguees, but had really similar scratches as you describe.. BTW what is the film ? Mine was Ilford delta 100

AgX · Jan 28, 2017

quixotic, how did you squeege? By finger, rubber lip, sponge?

iakustov · Jan 28, 2017

iakustov said:
I dont use squeeguees, but had really similar scratches as you describe.. BTW what is the film ? Mine was Ilford delta 100

my example below, about 14 frames were affected

quixotic · Jan 28, 2017

Iakustov, mine was also Delta 100. And AgX, I used a Patterson tong-type rubber squeegee. It makes sense now. I had used the sqeegee for perhaps a dozen times before, but in an effort to get the film dried out faster, I started using more pressure in recent processing. So perhaps of instead just pushing a small mote of crud across the top of the emulsion, I was now tending to plow it into the emulsion.

I guess in future, I'll pay more attention to pressure -- and also cleanliness of the squeegee.

Thanks everyone.

R.Gould · Jan 28, 2017

I would not use a squgee if you paid me, I did at one time, but got so many scratched and ruined negatives it was getting stupid, I was young at the time, and I sought out a friend, a very experienced photographer who over time taught me a lot, showed him my negatives, and the advice he gave me has served me well for many years, throw away the squzee, never ever ever let anything near the wet emulsion, after the final wash in wetting agent (He swore by washing up liqued), hang the film up to dry and run a small piece of wet and clean chamois leather down the shiny side once only. the leave to dry, Nowadays I use a folded sheet of kitchen towel, and from that day to this, nearly 40 years, I have not had a scratched negative from 35mm, for 120 I simply shake the reel after the wetting agent, and hang up to dry, I find that it works fine for 120 but for 35mm you need that wipe to avoid drying marks on the back of my films

iakustov · Jan 28, 2017

I doubt this could be caused by a squeegee as the scratch is too thin, no signs on the rest of the film area and there was no squeegee used in my case. May be a film defect? it was delta 100 in our cases..

Arvee · Jan 28, 2017

iakustov said:
I doubt this could be caused by a squeegee as the scratch is too thin, no signs on the rest of the film area and there was no squeegee used in my case. May be a film defect? it was delta 100 in our cases..

I agree; I have seen a lot of scratches caused in many different ways, including a burr on the pressure plate, and have never seen anything this severe. I am going with a film defect, especially since they both occurred on D100 and look so similar..

BMbikerider · Jan 28, 2017

When you remove the film from the developing reel can I ask how do you do it? I used to get similar scatches if I just eased the film leader over the edge of the spiral and unwound it. Not every time but more often than not. I started pulling the spirals apart (Jobo type) and the problem went away. Since I went on to use stainless spirals and tanks that to has not replicated the problem.

Like R Gould, I would not let a sqeegee within a mile of a wet film. Living in an area with very soft water, I find rinsing the film in a wetting agent solution for one minute without agitation, then hanging it up straight away I never get drying marks and of course I eliminate the possibility of any scratches.

BMbikerider · Jan 28, 2017

Looking at the images again, this seems more and more likely to be a fault in manufacture rather than in the camera or during processing. The irregularity of the line tells me it isn't likely to becaused by a squeegee or in the camera.

quixotic · Jan 28, 2017

BMbikerider said:
When you remove the film from the developing reel can I ask how do you do it?

On this particular one, I just pulled on the leading edge of the film, and the rest of it followed. I had a closer look at the plastic reel, but there doesn't seem to be anything sharp enough to catch on the emulsion. Maybe I should just invest in a stainless steel unit.

silveror0 · Jan 28, 2017

If your film is bulk loaded into a cassette, do you insure the cassette's light trap is free of debris?

Also, if you want to dry film quickly without squeegee, consider using a travel-size hair dryer while it's hanging; that's what I do when testing 4x5 sheets for EI and dev time.

quixotic · Jan 28, 2017

BMbikerider said:
Looking at the images again, this seems more and more likely to be a fault in manufacture rather than in the camera or during processing. The irregularity of the line tells me it isn't likely to becaused by a squeegee or in the camera.

What makes me doubt a manufacturing fault is that under a microscope, I can see the little divots of emulsion (still with their jagged edges exactly matching the scrapes) lying on top of the rest of the emulsion. I would guess that if it was a manufacturing fault, the divots (after processing) would at least have lost their jagged edges.

AgX · Jan 28, 2017

That there are flakes of the emulsion indicates the emulsion being wet when harmed.

quixotic · Jan 28, 2017

silveror0 said:
If your film is bulk loaded into a cassette, do you insure the cassette's light trap is free of debris?

It's just a plastic Patterson tank with 3 shiny plastic corners on the circumferential edges that keep out light. So there's very little there to trap grit, and the washing agent helps to clean things also.

quixotic · Jan 28, 2017

iakustov said:
my example below, about 14 frames were affected

iakustov, how do you dry and/or wipe your film?

silveror0 · Jan 28, 2017

quixotic said:
It's just a plastic Patterson tank with 3 shiny plastic corners on the circumferential edges that keep out light. So there's very little there to trap grit, and the washing agent helps to clean things also.

I was referring to bulk loading the casette prior to exposing in the camera.

Sirius Glass · Jan 28, 2017

I do not use a squeegee ever. I use PhotoFlo or an equivalent [follow the dilution directions, not a drop here and a splash there] and let the water drain off.

Other reasons: The scratch could be caused by camera rollers, camera surfaces, the cassette, or if bulk loaded the bulk loader. Check all surfaces carefully.

quixotic · Jan 28, 2017

I see that in John Hedgecoe's book, he says to "clean the blades of a squeegee to remove any minute grit particles"...something that I've never bothered to do, but will be sure to in the future.

quixotic · Jan 28, 2017

silveror0 said:
I was referring to bulk loading the casette prior to exposing in the camera.

I just buy the loaded units off of the store shelf.

Scratch diagnosis

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