Very Unusual Parabola on my Film!

Discussion in 'B&W: Film, Paper, Chemistry' started by corposant, Oct 22, 2011.

  1. corposant

    corposant Member

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    I just got back from a trip to San Francisco and I was very surprised with what came back from the lab. At first I thought these were light-leaks, but when I finally saw the negatives, I realized that there were perfect parabolae imprinted on two rolls of my film. I can see them from the first two frames I advanced, and then vaguely (or not so vaguely as the links to the images will show) throughout the roll. At first I thought it might be scanning, but these weird parabolae are perfectly continuous.

    - I was using different lenses, so I know that's not it.
    - Meter is working fine (Zeiss Ikon).
    - Pressure plate is straight
    - Both were ISO 400 - the shots below are TMAX 400 pushed two EV. The other roll was Legacy Pro 400 (shot at box speed). The parabolae are on different parts of the film. The ones below go right through the middle, the ones I am not posting are close to the top.
    - They went through carry-on X-ray scanners twice (there and back). I know this is the easiest explanation, but seems hard to believe.

    Any thoughts?

    http://corposant.smugmug.com/North-America/San-Francisco/Alcatraz/i-SNK2KpP/0/L/000012070026-L.jpg

    http://corposant.smugmug.com/North-America/San-Francisco/Alcatraz/i-4cXmjSb/0/L/000012070027-L.jpg

    http://corposant.smugmug.com/North-America/San-Francisco/Alcatraz/i-7kvtHNF/0/L/000012070010-L.jpg

    Granted these aren't keepers, but I find it really irritating that I don't know what is causing this to happen. My ISO 100 shots are fine.
     
  2. nhemann

    nhemann Member

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    Odd effect - my only question is: Were you, and the light house, very near a black hole? lol
     
  3. corposant

    corposant Member

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    Well, they say there are ghosts on Alcatraz, but the Legacy Pro roll was shot on the mainland with the same effect.:blink:
     
  4. keithwms

    keithwms Member

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    Out of focus hair somewhere in the camera?
     
  5. AgX

    AgX Member

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    X-ray scanning.
     
  6. corposant

    corposant Member

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    I don't think so - it's a perfect wavelength, even on the advance frames (I take two shots at 1/2000 with the lens cap on to advance to "1" on the counter). It's something technological that's causing this. A hair would be too random.
     
  7. corposant

    corposant Member

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    That was my first thought - but I though X-Rays will just fog whole regions of the film, not narrow bandwidths?
     
  8. ath

    ath Member

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    These sine wave patterns are most probably from X-ray. Somewhere on the Kodak site there are illustration pictures.
     
  9. Sirius Glass

    Sirius Glass Subscriber

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    Was your film in the luggage area or did you carry it on board?
    It is was in the luggage area, then it is almost guaranteed to be from the X-rays.

    Steve
     
  10. corposant

    corposant Member

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    Carried on - twice.
     
  11. Sirius Glass

    Sirius Glass Subscriber

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    Ok, now we have eliminated the number one cause of x-ray problems.

    I have to think about this more ... I will take a time out for now.
     
  12. hpulley

    hpulley Member

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    The signs say 800 ISO film is fine but 400 pushed to 1600 probably qualifies. Obviously you should have asked for hand inspection of your film. Sorry about your luck.
     
  13. Sirius Glass

    Sirius Glass Subscriber

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    Again, hpulley nails the problem!
     
  14. Newt_on_Swings

    Newt_on_Swings Member

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    A very interesting effect! I am trying to picture the Xrays hitting the film as its rolled up in the cassette. I still cant get my brain around it as the effect is so concentrated on these frames.

    I guess next time get a lead bag! They turn up from time to time on auction sites. I have one that can hold like tons of film, its about 1.5' on each side flat and weighs a ton lol. but they made various sizes, opt for the nylon covered ones and not the thin plastic one time use bags.
     
  15. polyglot

    polyglot Member

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    Think of the X-rays occupying a flat plane, cutting your film roll at a bit of an angle. The intersection of roll and plane is an ellipse, which when unwrapped along the length of film will look like a sinewave. If that's too complicated, think of the plane intersecting the roll at right angles, describing a circle around the roll, which unwrapped will look like a straight line. Then tilt that circle.

    However, that style (scanning beams) is really only used on checked luggage so far as I know; the hand-luggage ones are a diffuse beam and large imaging sensor. I just took a bunch of flights and had most of my film xrayed more than 11 times around the world (including Russia and China) and my TMY2 at 800 has no strange marks like this. There might be a bit more base fog (hard to say) on the pushed rolls of TMY2, but definitely no patterns. Are you sure one roll didn't accidentally go in the wrong bag?

    I deliberately put a blank roll of Ektar in my checked luggage for the last flights (Guilin-Guangzhuo-Sydney-Adelaide), so I'm looking forward to seeing what comes of that.
     
  16. ath

    ath Member

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    Maybe the film got X-rayed and damaged before you bought it? How did other films from that batch turn out?
     
  17. polyglot

    polyglot Member

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    Update: I just souped the roll that was in my checked luggage. There is not a single mark on it, so clearly some airports are using the new lower-power imaging xrays. I would still encourage people not to trust their film to checked baggage though as there are endless anecdotes of it being destroyed and it just depends on how (un)lucky you get with the screening tech in the airport(s) you traverse.
     
  18. cmacd123

    cmacd123 Subscriber

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