Afraid of airport X-rays?

[frank_menesdorfer]

You shouldn't be its not going to damage or affect your film! It doesn't

matter how many times you cross those borders! X-ray devices not causing any

fog on your film! If you got those blame on your manufacturer or on your old

chemistry or on you as don't know how to develop your film!

 

Some D = 0.15 is normal and it varies deepens of the film base they are using!

The polyester base has different base fog and it varies from manufacturer to

manufacturer! It could be higher or a little bit lower but now it common

accepted in both ANSI and ISO standards and given in D=0.15

 

Here is why!

 

First! Radiation from any X-rays devices is between 0.001 up to 10 nm (that's

nanometre) which is very, very low radiation and your film is not sensitized

for it! Silver chloride (AgCl) materials are not sensitive for X-rays in any

case as film only sensitive on that aria which is critical for registering

your image which is from 300-670 nm for panchromatic films and its a same for

both colour and black and white. Some has extended aria like films which goes

up to 760 a little bit into hyper-chromatic or infra red films which reach 950

nm. None of those goes under 300nm which is mostly UV.

 

Now the x-ray films are rich in AgBr (silver bromide) and coated in both side

with very thick layer between 10g square metre or 30-40g for industry as its

better receiver for X-rays and even those must be placed in the so called

intensifier holder (florescating) which really is nothing else but an

aliminium holder coated with Zns, CaWO4, Gd202S or similar to increase the

sensitivity of the film.

 

Frankie!

[ky2]

Frankie! Take it easy on the caffeine buddy!

[michael_briggs2]

Frankie, all photographically useful film is sensitive to x-rays. An x-ray photon has more energy than a visible light photon, so if a silver halide grain is capable of forming a latent image from a visible light photon, it will also be able to do so from a x-ray photon. Short wavelength = high energy. The reason that airport x-ray machines are either a problem or not is a matter of dose -- the number x-ray photons used. The machines used for carryon baggage use very low doses of x-rays which won't cause fog if film goes through up to ten times.

 

Films made to be x-ray films are thick, and fluorescent screens are used, to maximize the x-ray sensitivity so as to reduce the x-ray dose to the patient. This doesn't mean that regular films are insensitive to x-rays.

 

Some machines used for checked baggage can damage film. So never place your undeveloped film in your checked baggage.

Kodak shows some examples of the damage caused by this type of machine at http://www.kodak.com/global/en/service/tib/tib5201.shtml

(Also, I think a few airports may use these machines for secondary inspection of carryon luggage after using the regular machines.) In the US, the dangerous machines are required to have signs instructing you to remove your film from your luggage.

[frank_menesdorfer]

Hello Michael!

You wrote:

"all photographically useful film is sensitive to x-rays. An x-ray photon has more energy than a visible light photon, so if a silver halide grain is capable of forming a latent image from a visible light photon, it will also be able to do so from a x-ray photon. Short wavelength = high energy"

 

 

Yes it does, otherwise I couldn't done any x-rays! But that is not that simple! And there is significant differences how AgCl and AgBr react to x-rays also a thin layer have a very low sensivity to x-rays. The thick double layer increase sensivity a 100 up to 1000 times

 

What I meant to say is the time the film is in the regular airport scanner so short and the radiation used there is so low in energy that it couldn't cause any harm! Material with high atom numbers absorbing radiation better than low! Low atom number as silver needs a very we called hard radiation and longer exposure time with out intensifier screens which would be of course impossible to use in any airports and would be catastrophic to all patients! The reason is that they use low energy scanner is that low radiation can be stopped easier than hard so it can be isolated in the scanner box which of course not a case of the hard X-rays as it passing through materials! But also observe that low energy radiation is more dangers to your health than high energy because its absorvs in the body and can cause genetic changes.

 

Now I have crossed many, many borders and never anything happened with any of my films! Of course I always have my films expose or unexposed in my hand luggage. I thought if I die than I will die with my art!:-):-)Sometimes not if I have a lot but never anything happened! Of course some countries (US) might use harder radiation as secondary checking (we all know why because we never forget those who lost their life) but I have never found myself into that! I think undeveloped countries is either not a problem as they don't have a money to spend to high sophisticated equipment to harm your film!

 

Here in Europe they using harder X-rays for cargo goods or for X-ray containers but its mostly on international cargo airports or harbours!

 

Frankie

[frank_menesdorfer]

To Yaron!

 

I can't! I'm living on that stuff!

[frank_menesdorfer]

By the way it's very intresting Michael! I hope they won't use this type of higher energy secundery x-rays here in Europe! I can think that maybe London have it but I do try to find out what's happening here! The last time I used air travelling was last year twice! That was here in Europe and no damage caused by any airport scanner but we might be a little more careful here to as proboly they won't advertise it on TV!:):)

[stwrtertbsratbs5]

"An x-ray photon has more energy than a visible light photon, so if a silver halide grain is capable of forming a latent image from a visible light photon, it will also be able to do so from a x-ray photon."

 

Sorry, but that isn't how quantum mechanics works.

[dan_fromm2]

Robert, more than enough is also enough. And Dr. Briggs is a physicist.

[frank_menesdorfer]

Now I don't know what you referring to but the harder the ray is (energy) than it's more capable to go through the material than soft low energy x-rays! That's why there is a relative classifying the X-rays to hard and low X-rays! Now as I sad before material with low atom numbers relatively insensitive to soft X-rays so as silver! And need a very long time under constant exposure under soft X-ray which is not therefore if any harm caused to the film during airport handling than it exposed under hard rays, which is not used in regular airport scanners. Only in secondary checking of cargo which may be your bag!

 

I have never ever got any film damaged during my entire life and they all went through airport scanner but observe that my films is always on me for most of the time not in my bag which might be hard X-rayed now days but it's still not spread to Europe. I'm going to of course check it out!

 

Now in The US some changes happened and they begin to use some so called bag scanners which using higher energy x-rays as secondary back up system in their intention to stop terrorism. This they do because an eventually bomb will show in details which doesn't in soft X-ray specially if it packaged in led! Soft x-ray probably only shows as Shadow on their monitor but most of the stuff you carry in your hand bag shows clear in soft x-ray! If not they will open your bag and checked!

 

Click on that image I insert and you might understand what I mean! It had been made with soft X-ray with high intensity green screen on Agfa CURIX RP1 film. Than you must understand that this film is double layered and much more sensitive than thin AgCl film. Also this film is un sensitized!

[pico_digoliardi]

<b>Robert Budding</b><i>(addressing Briggs)

Sorry, but that isn't how quantum mechanics works.</i><p>

 

This might be interesting; an MBA challenging a Physicist on physics.<p>

[frank_menesdorfer]

Pico! It's not a challenge! I just say or write what I know! And I really didn't know that Michael had MBA! That's good because than he always going to tell me when I'm wrong and believe me or not I'm not going to get hurt! So Michael if you read this so stop me time to time because I do run on caffeine!:-) But I'm going to be more careful next time how I'm going to express myself that's for sure! :-)It's not that easy all the time sometimes I just can't find the right English words for everything!!

[frank_menesdorfer]

I got it wrong I guess! Who has the MBA? Robert? And Michael is a Physicist? It doesn't matter! Michael you stop this coffein junky any time you wish!

[michael_briggs2]

My explanation was simplistic and not intended to be a full explanation of silver halide image formation or photon interactions with matter. I was reacting to the initial statements that regular film has NO response below 300 nm since this might cause some photographers to incur damage to their film. The machines for checked baggage will damage undeveloped film. A sufficient number of exposures in the regular machines will cause some fog, especially of very high speed films such as Delta 3200 or TMax 3200. I don't know how many exposures are needed to make a difference -- the manufacturers and the TSA generally advise that these films shouldn't be x-rayed in any machine.

 

Agreeing with Frankie, I've had regular film go through the x-ray machines for carry-on luggage up to about 6 times with no ill effects.

 

Plain silver halides are naturally senstive to blue and UV photons but not to longer wavelengths -- it's an energy threshold effect. The discovery of sensitizing dyes made possible the panchromatic films that we use today. On the other short wavelength side, x-ray photons have more energy than blue photons, above the threshold for image formation, either directly, or more likely indirectly. The indirect process is that the x-ray will produce an energetic electron by the photo-electric effect, which can then react with a silver halide grain. Frankie is correctly pointing out that regular film is thin, and that frequently x-rays will go through the film without interacting. But some fraction will interact, and a sufficiently strong dose (e.g., checked baggage machines) will cause fog.

[BrianS1664879711]

Michael... oh, thank goodness... a physicist! I'm not, so forgive my possibly inept question.

 

There is sufficient data available on-line, from TSA and x-ray screening machine manufacturers to support your comments on what films are likely to survive without damage and which are susceptable. There is also an industry consortium report that did scientific studies to prove that. Add to that many people's experiences of multiple exposures without problems. I don't sweat this issue any more... but I do request hand inspectiohn and hope that TSA complies. If they don't, I smile and put my film on the belt.

 

Can you address the checked baggage machines (InVision CTX), however. They clearly state that film will be damaged. I believe that they claim it is not an x-ray threat, but a CT threat. Isn't this a very strong magnetic field... and isn't the real damage static rather than fogging? At least that is my understanding from the InVision documentation.

[michael_briggs2]

The product literature for the Invision CTX machines states that they use Computed Tomography -- in one mode, they are basically CAT scanners, which these days is abbreviated as CT. The advantage of x-rays is that penetrate the item; the disadvantage is that depth information is loss and that all you see are "shadows" of the various materials and structures. From one x-ray view, understanding the 3D structure can be difficult or impossible. The CT technique uses many cross-sections to compute the 3D view -- see http://en.wikipedia.org/wiki/Computed_axial_tomography. The technique makes multiple "slice" images and then reconstructs the 3D image. It seems that higher x-ray doses are needed. Some of the example damaged films in http://www.kodak.com/global/en/service/tib/tib5201.shtml that went through CT-type machines show evidence of the "slice" exposures, e.g.,http://www.kodak.com/global/images/en/service/tib/tib5201r.jpg or http://www.kodak.com/global/images/en/service/tib/tib5201h.gif. If the film was in a roll during the exposure, the damage on the unrolled film can show curved patterns.

 

The technique that uses high magnetic fields is Magnetic Resonance Imaging (MRI) (http://en.wikipedia.org/wiki/Magnetic_Resonance_Imaging).

[BrianS1664879711]

Ah... I see my confusion: CT vs MRI. How could I get them confused?? I saw the Kodak TIB and the I3A studies from which that derived, but was remembering some material I thoguht I saw that attributed static-like marks with CT-damaged film. It must have been a bad memory. Indeed, CTX damaged film looks like X-ray damage... because it is! Thanks for the clarification.

[magicord]

Can anyone tell me if it is OK to ship fresh films by airmail oversea? It is getting extremely

difficult to buy films in the place I am living so I am thinking to mail order from places

oversea like USA and UK.

[syd]

Indeed ...

 

In 2001 I bought a bulk load of Velvia 35mm 100F for a trip to Spain walking the Camino de Santiago. My journey took my film through Sydney x-ray ( 1 ) - ( I carried the film as hand luggage - if you let it go through the hold luggage x-ray, that's when you can kiss it bye bye! ) - then x-ray at Narita ( 2 ) for a 24hr stop over; then out from Japan again ( 3 ) on the way to London.

 

On arrival at London it went through X-ray ( 4 ) another time. I stayed in the UK with family for a month and then it went through X-ray twice more ( 6 ) going from London to Madrid. When I got through shooting all my film after four weeks in Spain it went back the same way again to Sydney. So all up my film went through X-ray 12 times and when I had it developed it was absolutely 100% perfect. I still have the same Velvia stock left over from that bulk buy and use it, it is likely out of date by now and still develops fine - I keep it in the fridge ofcourse but there you have it.