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Kodak Alaris warns the TSA's new airport CT scanners can damage undeveloped film

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Re: Kodak Alaris warns the TSA's new airport CT scanners can damage undeveloped film

#141

Post by ohazi »

zitterbewegung wrote: post #43
ohazi wrote: post #37

How much radiation would it take to flip a bit on an SSD? What about RAM (many people send their laptops through in a suspended-to-RAM state)? I would assume that RAM is more susceptible, since we still store a single bit per RAM cell, while some SSDs now store multiple bits per cell, but I've never tried to do the math on "what would it take to actually make these problems start to appear?" Might be a fun exercise..…

How many bits are you carrying with you ? 4MB be 4TB has two orders of magnitude so you have to first specify that.

The math is going to be back-of-the-envelope OOM analysis anyway, so you could work it out per bit or per unit area and multiply it out from there, given your particular configuration.

The statistics get more complicated when multiple bits are flipped (either by a single event, or over time) before an error correcting pass can look at the bits in question. In those cases, the particular flipped bits and where they are spatially will matter a lot more.

Re: Kodak Alaris warns the TSA's new airport CT scanners can damage undeveloped film

#142

Post by tinus_hn »

CamperBob2 wrote: post #116
thedance wrote: post #105

Earlier quoted context omitted.

I posted the same comment yesterday and for some reason got downvoted to oblivion. SSDs do not rely on bits being correct. Raw bit error rates in multi-level flash are generally over 1%. In other words if you read a 4K page you are guaranteed to get several wrong bits. The only reason a of it works at all is because of sophisticated error-correcting codes.

I posted the same comment yesterday and for some reason got downvoted to oblivion. Probably because of the "90% bit error rate" part of the comment. Obviously SSDs can't tolerate anything close to 90% bit errors. If that kind of error rate could be corrected in the general case, it would have profound implications for information theory in general, not just hard drive manufacturing. It would be equivalent to a data c…

Anyway it’s irrelevant because to the filesystem the SSD is supposed to look like it does not in fact have all these errors. ZFS doesn’t really care about the storage format apart from perhaps supporting TRIM.

Re: Kodak Alaris warns the TSA's new airport CT scanners can damage undeveloped film

#143

Post by harikb »

ChuckNorris89 wrote: post #28
JustFinishedBSG wrote: post #12

Can wait until very important data is lost to bit flips / corruption from scanner. " Cure to cancer lost to TSA scanner "

If you're working on a cure for cancer you should have double, triple, quadruple backups on and off site and not fly around with the only copy of your data.

I bet GP meant it to ironic. That said, having a backup and knowing that the data was just corrupted are two different things. In a word without storage level CRC checks, it is possible an otherwise successful test is overlooked and we move on to 'n + 1' in the iteration.

But that said, hopefully all filesystems have some sort of error to show the file has been damaged.

Re: Kodak Alaris warns the TSA's new airport CT scanners can damage undeveloped film

#144

Post by cdjk »

freeone3000 wrote: post #110
welly wrote: post #39

Earlier quoted context omitted.

Why do people use hand saws and chisels when powered table saws, compound saws and biscuit joiners are available to us? As someone who shoots film, there are a number of reasons, one being the asthetic you get from film that you can't (even with x hours in Photoshop) get from digital. I shoot large format and there are no (within my budget, at the very least) 8" x 10" digital sensors. Film also more or less forces yo…

What makes a digital picture any physical size? Is there a standard assumed pixel density?

Diffraction and airy disks have an impact as mentioned by a sibling comment, but the simplest explanation I've used is that ultimately you're capturing photons, and if you have a larger sensor you can capture more photons. More photons are better. Of course you need a larger lens with a longer focal length to match the same field of view, but that's the basic idea.

Re: Kodak Alaris warns the TSA's new airport CT scanners can damage undeveloped film

#145

Post by philpem »

madflo wrote: post #90
anfractuosity wrote: post #47

On the topic of film, this little short video "Behind the Film - Inside the ILFORD factory" is cool - https://www.youtube.com/watch?v=JXpoALotxf0 They also have a lab that do b&w prints from digital files on photo paper interestingly.

ILFORD is still selling photo paper in rolls with the specific chemicals required for regeneration of baths. It does allow a skilled lab operator to use Durst Lambdas or even a 1hour laser-based minilab like a Noritsu QSS or Fuji Frontier to print on real b&w paper! However, the same skilled operator should be able to calibrate her minilab in order to obtain decent looking b&w prints on color-based paper (RA4 process…

Slight nitpick, if memory serves the Fuji process is CN-16S (though I may be wrong - it's been many years since I ran a Frontier minilab!). To all intents and purposes it's regen RA4 though.

The big problem with Frontiers was it was near impossible to fully eliminate the colour cast on B&W prints. You can kick the machine into B&W mode manually, but there are still limitations the RGB laser exposure engine and process puts on you. Practically that means you can't get a true black like you can with silver-halide processes.

They are still fabulous machines though. Awful user interface, but the technology behind them is pretty incredible.

Re: Kodak Alaris warns the TSA's new airport CT scanners can damage undeveloped film

#146

Post by i_am_proteus »

klodolph wrote: post #129
i_am_proteus wrote: post #124

Earlier quoted context omitted.

Tri-X 320 pushes to 800 pretty well.

I’m not happy with it. YMMV. I don’t like Tri-X in general though.

Fair enough. I should mention that I use diluted Ilfosol 3 when pushing and get better results than DD-X/D76.

Re: Kodak Alaris warns the TSA's new airport CT scanners can damage undeveloped film

#147

Post by octorian »

tgflynn wrote: post #86
scblock wrote: post #8

Earlier quoted context omitted.

I don't know that I believe this is a "genuine question", because it's quite easy to look up that yes, people still use film, and the article itself is a clear indication that Kodak still produces and sells film. As far as not understanding, there are things about film that are different than digital. It's may not necessarily be a technical discussion any more (though others may disagree with me), but artistic choice…

> Kodak still produces and sells film Kodak Alaris != Kodak (ie. the original Eastman Kodak) The later went into bankruptcy in 2012, selling off most of its remaining assets (though I think it still makes film for movie production). The reason for the bankruptcy is that the market for film died off in the 2000's. That, incidentally, had a huge impact on Kodak's (and my) home town of Rochester, NY. So yeah, I can see…

Its my understanding that the company you think of as Eastman Kodak is still the one who is actually making the film. Meanwhile, Kodak Alaris is handling the marketing and distribution side of things for still photo film (while the Rochester company does still handle this for motion picture film.)

Its an awkward split, and one I often see re-explained whenever one or the other makes a press announcement.

Re: Kodak Alaris warns the TSA's new airport CT scanners can damage undeveloped film

#148

Post by LeoPanthera »

hadtodoit wrote: post #9

Flying out of SFO, the security gave me a heads up about putting aside film. They are not TSA, but at least they had been briefed.

SFO is one of the few US airports that doesn't use the TSA for security - and it shows. The experience there is so much better.

Re: Kodak Alaris warns the TSA's new airport CT scanners can damage undeveloped film

#149

Post by octorian »

lm28469 wrote: post #84
colejohnson66 wrote: post #2

Genuine question: Why do people still use film anymore? I know some big movie studios do sometimes use it (The Hobbit comes to mind), but I don’t understand why anyone would use film when we have DSLRs that can have resolutions over 30 megapixels. EDIT: added “why” at beginning

It's fun and it looks good. Sure, if you only look at the technical specs it's inferior in almost every way, resolution [0], no image stabilisation, poor autofocus, slow shutter speeds, poor high ISO performances, 10 to 36 shots per roll &c. I bought a d3400 to get into photography, never really liked it. One day I visited my parents and my dad showed me an old Nikon FE, the one he used to take my childhood pics with…

You can still get the good autofocus, good metering, good shutter speeds, and image stabilization with 35mm film. You just need to pick up a Nikon F100 or F6, and slap on a modern F-mount VR lens.

Of course to get better resolution, you need to go up to medium format. (where those niceties become harder to come by)

Re: Kodak Alaris warns the TSA's new airport CT scanners can damage undeveloped film

#150

Post by neetdeth »

supernova87a wrote: post #113
kailuowang wrote: post #79

I have been traveling with a Filmguard bag. Sometimes they take it out and ask for a hand inspection, sometimes they don't they rarely insist on scanning the films themselves outside the bag. Regardless never check-in your films. Nothing can protect them from the powerful scan for check-in luggages.

Those bags do not do what you think they do. When a TSA x-ray operator sees an opaque bag on the screen, he/she just turns up the exposure until the contents are visible. Not much help there for your film.

Turning up the exposure on the screen does not do what you think it does.

With a line-scan X-ray, the bag is well out of the beam path by the time the operator sees the image. But it's probably coming in through a 12 or 16-bit ADC, so there's a lot more range than can be effectively displayed on screen (at least with a simple linear+gamma mapping). It's a matter of adjusting the display mapping to see inside denser objects.

The X-ray source power needs to be high enough to deal with the worst case scenario of large/dense luggage. If you can give your film a 10x lower dose while still allowing enough X-rays through that the operator can clear it, that sounds like a good idea.

It just has to be traded off against the fact that deliberate shielding is likely to be frowned upon, and they may take the film out and run it through "naked" anyway. Seems worth a try, but I'd definitely use a commercial product marked for the purpose and resist the temptation to DIY it.

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