Another, marks on film question

GraemeMitchell · Feb 17, 2007

Oh, and this is temp related too, right? So I'd probably be safe shooting and rewinding fast if I was in a heated studio...right?

PHOTOTONE · Feb 17, 2007

If it isn't static electricity, then the only other item I can think of would be your changing bag you use for loading film into your reels and tank.

Photo Engineer · Feb 17, 2007

Thiis problem is not due to air bells. The density with air bells is lower, not higher. I agree with George on this.

The regularity and spacing of the dark spots is what bothers me. I cannot think of anything that would cause it. Most everything I think of would cause irregular defects.

Therefore, I would hazard a guess that this is some sort of manufacturing defect. Although, I would hasten to add it must be a rare one. I have never seen this before. It looks as if someone ran a roller with a regularly spaced set of teeth down the film, and it was about 1/4" wide or so. This would have caused a sort of pressure sensitization defect akin to the little half moons you see if you kink film.

You might want to check and see if the film all came from the same batch. If it did not, then it probably isn't a manufacturing defect, but if it did come from the same batch and you don't get it on film from another batch, then it is a manufacturing defect of some sort.

You can try developing a roll that has not gone through your camera, and if it shows the defect, then it raises the probablility of being a manufacturing defect of some sort. That would help you when you return it. Kodak will replace all of the film in that case.

PE

GraemeMitchell · Feb 17, 2007

I'm unable to check if they're from the same batch now, but I suspect so, being purchased at once from BH (50 rolls).

I just did a test:

Shot one roll like the firsts, using motor rewind and unspooling it quickly: the marks repeated. Though not terribly and only on the leader and first frame.

Shot another roll manually rewinding and unspooling the film slowly: no marks.

This is the last I have from that 50 rolls of film.

Now I need to figure out if it is static if it is happening during rewind/shooting or when. I'd like/need to be able to shoot and rewind fast w/o worrying about this. Unspooling I am able to take time with.

Photo Engineer · Feb 17, 2007

Static electricity is generally darker and not square shaped, but I wouldn't rule it out altogether.

The discharge is in the UV range and film is rather sensitive to it, so it is dark. Because it moves like a lightning bolt, it normally has a linear or jagged appearance. It would also not be so uniform nor distributed at the center of the negatives, it would be random.

Again, I'm not ruling it out, but I do feel that is not likely. I have never seen static discharge like that. If it is static discharge though it still poses the question of why it is happening. It implies something wrong with the rewind or the casette.

PE

gainer · Feb 17, 2007

Ground yourself to a water pipe with a bare wire before you handle the film. Ground the camera before rewinding. Especially bad if you have carpeted floors anywhere you handle film. Bad in winter when hot air heat is used.

Bob F. · Feb 17, 2007

As the 35mm film is curved, that might explain why whatever it is causes the effect in the centre of the film. Static for example may jump the gap between whatever the film runs over and the centre of the film, but be grounded at the edges by physical contact between the edge of the film and whatever it is rolling over. Likewise, anything physical on the film may be wiped off the sides but remain in the centre.

Unfortunately, I can only add my voice to those who have never seen anything like that before: not in real-life, or from reports of faults I have seen in other people's posts anywhere...

Good luck!

Cheers, Bob.

Xmas · Feb 17, 2007

The clue is all these marks are in the film gate and they are exposure marks.

I dont want to look any more they may be infenxious, what sort of shutter has a F5?

Noel

dr5chrome · Feb 17, 2007

..this is not a film defect. This is static charge markings, id bet the house on it. If you loupe to this film, 10X you will see the static charges. This is a very bad static charge. The film was likely VERY dry. I have seen this before, both in my own film and clients film. this pattern usually occurs in camera [fast rewind]. The most other common place for static is when you are putting the film on the spool. You can sense static if you are keen to it, either by feel or by sight in the dark. static can leave all sorts of marks. some look like lightning, some like connect the dots. "the proof is in the pudding" as i always say. really look at the film, the emulsion. the spots will appear to be developed that way and will be all over the film, even the edges. if there are no ridges in the emulsion then light surely struck the film, static.

PE, B&W film is different than color film. if it is very dry or the film is very dry and toss in very low humidity, this can and does occur. again, i can show samples of this from our collection. We keep a running tab of film defects and process defects for reference.

graeme; make the highest res scan of an affected area. This will make it easier to see.
Ill bet if you send a sample to kodak they will tell you the same thing.

dw

www.dr5.com

GraemeMitchell · Feb 17, 2007

Xmas said:
The clue is all these marks are in the film gate and they are exposure marks.

I dont want to look any more they may be infenxious, what sort of shutter has a F5?

Noel

Again, doubtful I think, mostly because the other 65% of the film was fine. Not to mention if you look closely the marks also can be observed in the film edges also. These two things make it difficult to come up with a camera related cause.

I'm hoping it's bad film, and keeping static idea in mind.

Anyone have a contact at Kodak I can share this with? Not obvious on their site who to get in touch with regarding this.

Photo Engineer · Feb 17, 2007

DR5;

I'm sure you do keep a record, and your experience must trump mine, but I didn't rule out static, I just said I thought it unlikely due to the way it looked.

Many manufacturers put conductive carbon into the film base to prevent this, as well as antistatic chemicals into the film itself along with humectants that reduce sensitivity to cracking and static in dry weather. Kodak probably uses more than most other companies due to the high coating speeds which make this necessary.

So, I say again, you may well be right.

PE

Bob F. · Feb 17, 2007

Xmas said:
The clue is all these marks are in the film gate and they are exposure marks.

I dont want to look any more they may be infenxious, what sort of shutter has a F5?

Noel

No they are not: they are also between frames, so have not been made at the point of exposure.

GraemeMitchell · Feb 17, 2007

DW, I will make a scan. I supect you're right...mainly b/c you'r the only person who seems to have seen it before. + There is an organic quality to the actual dots upon close inspection, despite their "mechanical" placement.

Organic as some appear to bleed out in a "cat eye" sort of fashion

dr5chrome · Feb 17, 2007

..a real good look at the film will determine this problem, be it static or not.

dw

GraemeMitchell said:
DW, I will make a scan. I supect you're right...mainly b/c you'r the only person who seems to have seen it before. + There is an organic quality to the actual dots upon close inspection, despite their "mechanical" placement.

Organic as some appear to bleed out in a "cat eye" sort of fashion

dr5chrome · Feb 17, 2007

..i think you might find our little record keeping collection very interesting.

yes, i know of the anti static agents put into film. age and conditions change these properties. it was a kodak tech that first explained these markings back when we were loading film on spools, before we had the processor made.

BTW, your experience far 'out trumps' my own. and what do i know anyway, ive only been processing film, 100's of rolls a week for 10+ years, guess that doesn't qualify. It just might be a film defect.....

dw

www.dr5.com

Photo Engineer said:
DR5;

I'm sure you do keep a record, and your experience must trump mine, but I didn't rule out static, I just said I thought it unlikely due to the way it looked.

Many manufacturers put conductive carbon into the film base to prevent this, as well as antistatic chemicals into the film itself along with humectants that reduce sensitivity to cracking and static in dry weather. Kodak probably uses more than most other companies due to the high coating speeds which make this necessary.

So, I say again, you may well be right.

PE

Photo Engineer · Feb 17, 2007

Well, the problem is that I have never seen anything like this at all in nearly 50 years of film work with the following caveat. I have seen it a few times in basket processed film and paper. It looked just like saran net marks from the old basket process of Kodak's. Of course that was not the cause here at all.

The net could touch the center of a sheet of film or paper and leave a net mark down the bowed center that looked like that. This rarely happened. It was usually due to a damp net causing the film or paper to stick.

PE

MattKing · Feb 18, 2007

Does the F5 have a pressure plate with a patterned surface, and could the pattern of defect be mirroring that (whether caused by static, or otherwise)?

Matt

Photo Engineer · Feb 18, 2007

Matt;

Good thought. That explanation would solve the regularity of the pattern. Static electricity would be more random in my opinion. However.....

A pressure plate with a pattern that is becoming worn will do this, or a pressure plate inducing a static discharge somehow might but that is a reach.

A worn plate can induce either a pressure pattern or refelecton patterns. Since this appears between frames, I wonder if there is a pinch point or something that might make the pattern appear.

Static discharge from high spots on the pressure plate might give this sort of regular pattern.

Excellent idea.

PE

GraemeMitchell · Feb 18, 2007

There is not a pattern on the f5 pressure plate. Nor is this one particularaly worn. There are 2 small bolts on the top + bottom of the pressure plate, midway across. They are, I think, indented ever so slightly, and are how it is attached. It looks like the sprocket holes of the film would cross these bolts.

Is it possible/likely there is something electrically "wrong" with the camera that could cause static? Something the dry weather is making worse.

I'm doing a large scan of the film now, and will post it in a few.

GraemeMitchell · Feb 18, 2007

I think these scans (3000dpi, cropped at about %100 or more) suggest static.

Upon closer inspection all of the film is much worse than I thougth. Bummer...

I still would like to find a solution to the problem. Something more convenient than grounding myself or relocating.

I appreciate all the insight and ideas. Thanks.

Photo Engineer · Feb 18, 2007

The first one is static, but the second one IDK. Never seen before.

PE

dr5chrome · Feb 18, 2007

..like i suspected.

the 3rd image is the effect from the flash created on the front layer.
This all likely happened while the film was being unrolled to be put on the developing spool. get yourself a small humidifier in your darkroom. That will solve this issue.

dw

www.dr5.com

GraemeMitchell said:
I think these scans (3000dpi, cropped at about %100 or more) suggest static.

Upon closer inspection all of the film is much worse than I thougth. Bummer...

I still would like to find a solution to the problem. Something more convenient than grounding myself or relocating.

I appreciate all the insight and ideas. Thanks.

Another, marks on film question

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