a scratchy mystery

pdeeh · Nov 22, 2013

Here we have a bit of a frame (Fomapan 200 135/36) showing myriad tiny scratches in the emulsion layer, all at very similar angles; these are visible quite uniformly over the full length of the roll , over the full width of the roll, and all at the same similar angles. The developed leader has these too, but the undeveloped leader is long gone, so I can't examine that.

The film was loaded into and developed in a Paterson tank on a Paterson reel, in APH09 (Rodinal) and fixed in Ilford rapid fix.

I've developed many rolls from the same batch of Fomapan, without seeing anything remotely similar, so I can't imagine it's a manufacturing problem; Never seen it on any other negatives either, come to that, so I'm assuming it must be something particular to the processing of this roll. I can't conceive how scratches like this - across the width of the film - could come about from a physical cause within camera, or from loading onto the reel.

It's as if there was some quite abrasive material suspended in either developer or fixer that has abraded the emulsion layer during agitation. So perhaps something nasty came out of the tap that night ...

any other hypotheses to account for it?

AgX · Nov 22, 2013

Are those really scratches? As there is seemingly zero-density they must reach quite deep.

I also see a lot of zero-density dots.

pdeeh · Nov 22, 2013

they really are scratches

hdeyong · Nov 22, 2013

I've never seen anything like it. They look like rain.

Lamar · Nov 22, 2013

Weird. Looks like rain to me, especially since it is a negative image. Scratches would be the other way around. Light on the positive and dark on the negative. These are light on a negative.

pdeeh · Nov 22, 2013

let me assure you that no rain fell that day

and scratches on a negative are not dark, and would not be light on a positive ...

Lamar · Nov 22, 2013

Let me qualify my statement. In my scans scratches show up on the negative image as dark. When reversed to a positive they are light. Light doesn't get through or is redirected due to the imperfection in the negative. In this case it does appear that light is passing completely through the film and onto the scanning sensor.

pdeeh said:
let me assure you that no rain fell that day

and scratches on a negative are not dark, and would not be light on a positive ...

Denverdad · Nov 22, 2013

pdeeh said:
let me assure you that no rain fell that day

...especially since the marks appear on the film leader too. So it makes sense to me that these are some sort of film/processing artifact rather than something actually in the image.

How did you store these after processing? Any chance that you placed the strips into film sleeves or top-loading film storage pages, and perhaps the film wasn't 100% dry at the time? My early film experience was frought with all manner of scratching due to inserting strips into film storage pages. Other than that, the only thing I can think of is that it is just some manufacturing defect on that one particular role. It is strange though, and I really don't recall seeing those particular kinds of marks before.

pdeeh · Nov 22, 2013

It really is weird isn't it?
My habit is to cut strips from the hanging roll after drying, scan them, and only then do the strips go into sleeves; contacts or enlargements will get made made when I have time & inclination. So there's no possible way sleeve damage could have occurred at this point (plus I use end-opening sleeves so would get longitudinal marks anyway).

@Lamar, I'm sorry but your rationale still doesn't make sense to me; as AgX says, a scratch is equivalent to an area of zero density - the emulsion layer is missing in the area of the scratch. It will therefore appear on a negative as light line, and it will appear on a scan or a print as a dark line. This is the logical and physical consequence of the negative/positive process. Perhaps you are thinking of scanning transparencies (positives) rather than negatives, however?

George Collier · Nov 22, 2013

Lamar makes a good point about scratches being able to deflect light, but my experience is that scratches on the e-side pass more light and are dark or black on the print, clear on the neg. However, scratches on the base side can indeed, and usually do deflect light and print lighter. Careful inspection needs to confirm which side, not by looking through the neg, but by glancing the light across the surface to see the "marks".
Not to say pdeeh has not done this already.
Either way, this is a strange one for me. It does look like rain or snow in motion, but the density is backwards for this to be the case, if the scan image is negative.

TareqPhoto · Nov 22, 2013

Aren't you feel nut when you see something like this happen? I did see scratches on the first sheet i did develop by myself at home, and i can't figure out how that happened, is it before processing it, or when i loaded the film or when unloaded it to prepare for developing?

Doremus Scudder · Nov 22, 2013

Can you see the defect on the negative through a loupe? (I'm thinking if there is no visible defect in the emulsion, then the film was just covered with dust/lint)

Which side of the film is it on; emulsion side or base side? (Easier to identify a production defect if you know which side the defect is on).

Did you use a stop bath? (I'm thinking pinholes from gas bubbles maybe).

How is your tap water? (I'm thinking iron or some other contaminant that might inhibit development; that is, if it is not real physical damage.)

Otherwise, I'm kind of stumped.

Best,

Doremus

pdeeh · Nov 22, 2013

Yes, I've examined the negatives with a 10x loupe and they're scratches in the emulsion. I'd be really very surprised if it came from Foma like this, especially because, as I say, I have shot quite a few rolls from the same brick without seeing anything similar. I use a water stop by the way. The water here is very hard ("permanent" and forms only a tiny amount of limescale) , but short of sending a sample off to an analytical chemist I have no idea whether it is iron-rich.

When I have the energy I'll see if I can get a bit more of a "macro" image to post.

I don't, by the way, want to make a big deal of this, it's simply that it seems so peculiar that I'd like to have at least an idea of what might have happened

rubyfalls · Nov 24, 2013

Do you add the water directly from the tap? If so, how long had it been since you last drew water from that tap? I am wondering if it is sediment that accumulated in the faucet/pipes.

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AgX · Nov 24, 2013

How could any particle in the processing bath scratch the emulsion deep, and for a miniscule, uniform lenght?

And what about those dots?

pdeeh · Nov 24, 2013

rubyfalls - this tap gets used all the time.

AgX, I've been out taking photos in the world in preference to taking photos of negatives, but when I have a moment and the inclination, I promise I'll get my macro lens out
(I know, the particle theory makes only a small amount of sense, but at least it's a working hypothesis ... hmm, "particles" ... perhaps I got caught in a Cosmic Ray shower?)

eddie · Nov 24, 2013

I've never seen anything like this, where scratches are of uniform length, and going in the same direction. I'll offer a guess just to add to the confusion :confused: : If there was some residue left in the cap (or baffle), it's possible to get it to move in the same direction, as your tank is tilted, while pouring in the developer. Just a guess...

Lamar · Nov 24, 2013

I sacrificed a B&W negative and scratched it on both sides to show my point. The top scratch is emulsion side and the bottom scratch is base side. If the scratch gets into the base the optical characteristics at the scratch don't allow light to pass normally and will appear black in the negative and white in the print. In a couple of places in the top, emulsion side, scratch you can see where the scratch did not extend into the base and light will pass because the emulsion was mostly removed without damaging the base.. This produces the opposite effect.

Negative:

Positive:

pdeeh said:
It really is weird isn't it?
My habit is to cut strips from the hanging roll after drying, scan them, and only then do the strips go into sleeves; contacts or enlargements will get made made when I have time & inclination. So there's no possible way sleeve damage could have occurred at this point (plus I use end-opening sleeves so would get longitudinal marks anyway).

@Lamar, I'm sorry but your rationale still doesn't make sense to me; as AgX says, a scratch is equivalent to an area of zero density - the emulsion layer is missing in the area of the scratch. It will therefore appear on a negative as light line, and it will appear on a scan or a print as a dark line. This is the logical and physical consequence of the negative/positive process. Perhaps you are thinking of scanning transparencies (positives) rather than negatives, however?

pdeeh · Nov 24, 2013

I admire your persistence, but I still can't understand what this has to do with my little mystery.

Just to be clear, in my original post, I attached an image of a negative as it appears to the naked eye.
It happens to be a scan, but the scan has not been inverted, and neither is it a print.
If I took a photograph of the negative on a lightbox, it would appear the same as it appears in my attachment.

On that image the appearance of the scratches is white, within areas of high density (sky in this case), whose appearance is dark.
To me, this indicates that light is passing through those scratched areas without being unduly obstructed by the presence of the emulsion layer that remains on the rest of the negative.

DAK · Nov 24, 2013

false stars

If it were a print, it could be a long exposure at night with the short light streaks being the result of the world turning.

Dave:

Lamar · Nov 24, 2013

Actually I meant to reply the post just below yours. I must have hit the wrong "Reply" button, sorry. I agree your's is missing emulsion though. Why, I don't know. It looks like little scratches from something that brushed across it. It would have been a very light abrasive action though because I barley pressed to get the scratch in my emulsion side sample and it obviously went into the base. I was actually trying to show just the opposite of the base scratch.

pdeeh said:
I admire your persistence, but I still can't understand what this has to do with my little mystery.

Just to be clear, in my original post, I attached an image of a negative as it appears to the naked eye.
It happens to be a scan, but the scan has not been inverted, and neither is it a print.
If I took a photograph of the negative on a lightbox, it would appear the same as it appears in my attachment.

On that image the appearance of the scratches is white, within areas of high density (sky in this case), whose appearance is dark.
To me, this indicates that light is passing through those scratched areas without being unduly obstructed by the presence of the emulsion layer that remains on the rest of the negative.

rubyfalls · Nov 24, 2013

pdeeh said:
rubyfalls - this tap gets used all the time.

AgX, I've been out taking photos in the world in preference to taking photos of negatives, but when I have a moment and the inclination, I promise I'll get my macro lens out
(I know, the particle theory makes only a small amount of sense, but at least it's a working hypothesis ... hmm, "particles" ... perhaps I got caught in a Cosmic Ray shower?)

Well, the sun's polarity IS flipping...

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a scratchy mystery

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