Very Unusual Parabola on my Film!

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.

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

nhemann said:

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

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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.

Out of focus hair somewhere in the camera?

X-ray scanning.

keithwms said:

Out of focus hair somewhere in the camera?

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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.

AgX said:

X-ray scanning.

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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?

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

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

Sirius Glass said:

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

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Carried on - twice.

corposant said:

Carried on - twice.

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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.

corposant said:

...
- 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.
...

Click to expand...

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.

corposant said:

- Both were ISO 400 - the shots below are TMAX 400 pushed two EV. The other roll was Legacy Pro 400 (shot at box speed).

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.

Click to expand...

Again, hpulley nails the problem!

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.

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.

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

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.

The effect in the original post is a bit like one of the examples shown on the Kodak Motion pciture site in the manual on travel film x-ray effects.
http://motion.kodak.com/motion/Support/Technical_Information/Transportation/index.htm
Movie film is wound on much larger rolls, so the effect on still film would be more together.