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FP4 sparking off the reel


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#1 Nick Mulder

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Posted 05 February 2007 - 10:57 PM

Hi,

was just loading some old FP4 stock onto some daylight reels and noticed a dim blue/green light emanating from the film as it wound off the 400' spool - the light intensified as I wound the spool faster...

weird, anyone experienced this before ? I suspect its a friction/static thing as the film is a little sticky being at least 20 years old...

I know your just going to tell me to chuck the stock, but I'm still interested in the physical phenomenon ...

anyone ? yes no ?


cheers as always
:ph34r:
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#2 Chris Keth

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Posted 06 February 2007 - 12:17 AM

That's static. Your film is flashed. It won't really look all that cool, especially in black and white. I'd pitch it and not waste money on it.

Edited by Christopher D. Keth, 06 February 2007 - 12:18 AM.

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#3 David Venhaus

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Posted 06 February 2007 - 12:36 AM

I've seen it happen before, especially on 2000 ft rolls. Sometimes seen static sparks just pulling the film out of the black bag, introducing some humidity by softly blowing into the bag will usually prevent that. Also seen static from contact of the edge of the film against the side of a split reel. Usually if you wind slow enough, it will completely stop static discharge. I have used some slow speed stocks that that has happened to and there was no appearent flashing or anything visable apparent. It seems that the static isn't producing enough light to cause any exposure on a 6-25asa film. Higher speeds films may be questionable as to its effects.
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#4 K Borowski

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Posted 06 February 2007 - 12:37 AM

I *wouldn't* chuck the stock unless the sparks were bright enough that you could actually see color. There might be a slight bit of edge fog, but I've had this experience a few times myself (not with FP4, but with some color stock), and you'd be surprised, a couple of times there was no fog at all. I'd have coverage on another roll, and maybe not put anything important near the edge of the frame, but I don't think you'll have any problems unless, again it was sparking so bright you could clearly make out the film and not just saw a dim outline.

This is caused by simple static discharge, static electricity due to a charge differential between your film and the air. I believe Kodak has actually changed the tape they use at the ends of a roll of film to keep it from unraveling in the black bag, because detaching the tape used to always produce a slight spark, especially if one did it quickly. It doesn't seem as prone to doing it anymore though.

~Karl

Edited by Karl Borowski, 06 February 2007 - 12:37 AM.

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#5 Nick Mulder

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Posted 06 February 2007 - 03:51 AM

thanks for the feedback - I had only heard of people talking about static flashes with regards to 120 stills film, when ripping of the paper backing apparently the sticker thing can cause a flash - I've tried my hardest to get it too happen with my MF developing but was unsuccessful so thought maybe it was just a myth. Imagine my surprise as it appeared today.

Anyway, the stock is very old and we are just using it for sh&*s and giggles, trying out stuff for interests sake and developing it ourselves so I'm not too fussed about the potential fogging issues -

The intensity of the discharge increased when I wound faster so I wound a reel with the first 50' fast then the second slow enough not to cause the effect - I'll see if I notice a change in contrast in the developed footage half way through...

... hmmm, imagine if I had just loaded the 400' into a mag and not seen it ...
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#6 K Borowski

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Posted 06 February 2007 - 01:57 PM

Nick: was it a continuous static discharge? Rereading your post, it sounds as if it wasn't just a momentary flash, as I had assumed in my prior post. A continous light can cause fog.

Yeah, most of the times I've seen the flash is with 1- and 220 still film. I'm pretty sure the same adhesive used to connect the film to the paper base is what is used at the ends of a reel of movie film. It looks the same at least.

There's also a plastic adhesive tape Kodak uses at the ends of rolls of 35mm still film, so maybe this is present too.

I'm not sure if Nick's case here has anything to do with tape though, after rereading his post.
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#7 Nick Mulder

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Posted 06 February 2007 - 02:17 PM

its continuous...

the film is sticky and makes noise when you first wind it off the 400' core, this is also when the light is produced and the more energy you put into the system (ie. the faster you wind) the more light you get, right on the surface of the film - once its off the 400' core and on a daylight load its no longer sticky and winds fine but has already had its flash...

I was wondering why you said it would be ok :lol:
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#8 Leo Anthony Vale

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Posted 06 February 2007 - 03:24 PM

I was wondering why you said it would be ok :lol:


It'll probably produce cool looking lightning bolts on the film.
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#9 Nick Mulder

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Posted 06 February 2007 - 03:56 PM

Flash - a-ah - saviour of the universe !
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#10 David Leugers

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Posted 06 February 2007 - 07:17 PM

This of course is not the same as "flashing" a film stock. I had this happen to me once and the film exhibited
random static marks throughout the roll making the footage pretty unusable. Maybe for some advante garde or experimental fim... With the costs of developing these days, I would personally either pitch the film or at least do a short test to see if it can be used for the purpose you intended. Whenever rewinding film stock make sure you ground both rewinds and make sure you are not carrying a static charge.
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