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Forum: Film SLRs and Compact Film Cameras
08-12-2008, 02:07 AM
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That is a factor of 1000x - and does not much to answer my question. We can easily find values for high altitude radiation (which is very mixed, too) and for the definition of X-rays. But at what exact frequencies do the X-ray scanners work. You won't find any info on the market leader's Smiths Heimann website, for example.
And how is the film's response to these different wavelengthes?
If we know the scanner's energy levels (modern scanners employ multi-energy X-ray sources) and the film response, we could deduce, how much a certain film is affected, how often it could be X-rayed, before the damage is visible etc.
Ben
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Forum: Film SLRs and Compact Film Cameras
08-12-2008, 01:04 AM
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This is in theory true. What I have never found is a spectral response curve for X-ray damage to films. That would be very interesting, as a simple intercontinental flight might cause more damage (exposition to high altitude radiation) than a simple X-ray scan. This is at least, what security people tell you at the airport to calm you down and to avoid any handsearching…
The point with any kind of radiation is: Some does expose the film, others don't. It is dependend on the energy of the radiation and the most energetic radiation might not be the one, that causes the damage. High energy radiation might just "go through" the film layer, without any interaction.
The question is, what energy (wavelength)) does a X-ray scanner use, what energy level do we have at high altitudes (that is the easiest to answer) and to which kind of wavelength does the film respond the most? Anybody got any info on that?
Ben
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Forum: Film SLRs and Compact Film Cameras
08-11-2008, 01:34 PM
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Several years ago, Kodak had a big warning article on their website, which warned the photogs communitity to put ANY film through the then new X-ray scanner generation. After Sept. 11th, this article vanished. It is of no need anymore, as since that day I had not a single officer looking through my films by hand. Especially in the US, but also in the UK, HK, China and many other countries, I was simply asked: Do you want to get onboard that airplane or not? So I put my films through the machines and was lucky. For travelling, digital is godsent - at least in that respect. No damage to digital files by X-ray machines…
Otherwise the old rule was, that only 800 ASA and faster films are at risk.
Ben
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