Caution X-RAY fog!

[Don Dudenbostel]

For those of you that will be traveling to Europe be prepared for possible film fog on 400 ISO and higher. My wife and I traveled to Italy last week and passed through US x-ray inspections four times and in the Paris airport three times and Florence twice. I have extensive experience with x-ray imaging and have worked with x-rays for nearly forty five years so I know exactly what x-ray fog looks like. My film is still drying so I haven't had a chance to closely examine the 100 ISO but at this point I don't think there was any problem. I shot 1 roll of Neopan 400 35mm and 7 rolls of 100 Acros. The Acros shows no fog or pattern that would indicate any problem but the one partial roll of 400 was still in my camera and the portion that was in the cassette shows a distinct fog pattern from the end cap of the film cassette. The rest of the roll wound up on the take up spool shows a distinct increase in base density. By distinct it's probably a 10% increase in density. I had three other rolls of 400 in my bag and will run on to see if it is on it too. This is a batch of film I have been using out of for a year or so with no problems.

When I get a chance this week I will scan the fogged portion and post it.

[Gene McCluney]

Was all your film in your carry-on luggage? Did you run it through the carry-on scanners?

[Don Dudenbostel]

Yes all of my film was on my carry on and was run through the x-ray system.

[Robert A. Zeichner]

I just got back from Greece and passed through Detroit, Amsterdam, Athens, Santorini, Paros and Paris with a total of 6 passes through the belt and no problems with TMX100. I also brought TMX400, but didn't shoot any. The next time I process TMY I will snag a sheet from this batch and test, but the last time I made the same trip, I did shoot TMY with no problem.

[Don Dudenbostel]

For a few years I traveled shooting for clients and was flying 11-13 weeks a year five days a week and never had a problem. In Paris I noticed as I was picking some of my stuff off the x-ray belt that my camera/film case was in the x-ray machine and it had stopped for a few seconds. I'm guessing this is where it was cooked.

Here's a sample of the damaged film.

[BrianShaw]

Just because the film stopped in the machine doesn't necessarily mean that it got extra dosage... I would guess that nine exposures of the 400 was just one too many exposures. I can't recall the exact details of the studies on xray exposure and film damage but I seem to recall that nine exposures at 400 ASA was near (or past) the "limit".

Sorry to hear about (and see) your xray damage!

[BrianShaw]

Don,

Here is an excerpt from the report:

135 ISO 400 and ISO 3200 black & white film

Film manufacturer’s report
“ISO 400 and ISO 3200 films exposed to varying doses of X-ray, i.e. passes through an
X-ray hand baggage check, have been processed and evaluated. I have tabulated the
results below and given a brief description of the effects seen on them.

...

Between 5 and 10 passes through the X-ray hand baggage scanner caused fog on the ISO 400...

Its is clear that on this occasion the dose given by this particular X-ray machine was not
very safe for film with relatively few passes causing significant fogging.”

[Don Dudenbostel]

Thanks Brian. I understand the European machines are set to a higher dosage than US machines. Can you confirm that?

[BrianShaw]

Thanks Brian. I understand the European machines are set to a higher dosage than US machines. Can you confirm that?

Unfortunately I have no information on that. I've heard that rumor, but to the best of my knowledge the dosage level was set by the manufacturer at the factory. That led me to an unconfirmed belief that all (for example) Rapiscan model XXX's had the same x-ray dose no matter where they are located.

I do know that much of the time when the screeners are examining bags using a variety of radiation doses. A lot of people looking over the shoulders of the screeners have started a rumor that ever time they fiddle with the display the bag is getting re-zapped.

[Don Dudenbostel]

I suspect the x-ray system is a broad spectrum x-ray source and that the visual change on the screen is most likely increasing the brightness / contrast or image processing rather then increasing the KV of the source. I do however believe the source is constant in output and the longer the subject sits in the machine / beam the more the dosage. My bag was stopped in the machine for closer inspection.

[GPS]

Don, the source is not constant. Otherwise it would make impossible any prediction of its effects on films - 5 passes or 1 long would be the same or not depending on the length of the exposure. They stop the belt to have the time to examine the still picture taken by the burst of rays before. The toggled colors are from the different processing not from an additional exposure. Additional exposure is done by returning the belt back and taking a new screening with a different position of the bag if they cannot identify it from the former position - that's rare.

[dng88]

I heard it is French X Ray normally. Is that applied or even true?

[BrianShaw]

I do know that much of the time when the screeners are examining bags using a variety of radiation doses. A lot of people looking over the shoulders of the screeners have started a rumor that ever time they fiddle with the display the bag is getting re-zapped.

Don, et al: I was distracted last night when writing this and it is not what I intended to say. Sorry for any confusion introduced intot eh discussion by my inadvertant misinformation.

Here is what I really meant to say:

I do know that much of the time when the screeners are examining bags THEY ARE using SOFTWARE TOOLS, NOT a variety of radiation doses. A lot of people looking over the shoulders of the screeners have started a rumor that ever time they fiddle with the display the bag is getting re-zapped.

[BrianShaw]

Don, the source is not constant.

This is my understanding also: the item is pulsed with x-ray and the collected "image" is then examined using a variety of software tools by the screener. I'm not sure if the screener has a "re-pulse" button or not. The specific software tools, penetration capabilities and shielding (radiation safety) characteristics are openly discussed in the manufacturer's data sheets. The exact operating mechanisms of the machine (pulse vs constant, irradiation dosage, etc) is not so openly discussed.

[Albrecht Namatdurer]

In Mumbai recently, in the line up for scanning-- a BIG cricket match was playing on the other monitor, my bag was in the scanner, the ball was hit to the fence, all play stopped while a catch was taken and appealed- all work stopped as all this took place, my film cooked and cooked andCOOKED for what seemed an eternity,THEN the guys started to examine my cooking bag of goodies- MINUTES later after much conversation and chat about the catch and viewing the REPLAY and MORE chat, my bag was finally released-

all OK- slow film ,

just a softly glowing bag!

[Brian K]

From what I understand the film was x-rayed 9 times. Plus you were on multiple flights from the US and in Europe and back again. Whenever you are on a plane at flight altitude, 30,000', your film is also getting a serious dose of cosmic rays, equivalent to additional x-rays. It's no wonder your film got fogged.

In the US you can demand a hand search, that would have right away eliminated 4 x-rays. When I travel I make my flight plans with my film in mind. I minimize flights, minimize any stops or terminal transfers that would require additional security screenings (x-rays) and minimize time in the air. If I can't be certain to get the film back safely, I cancel the trip.

[SAShruby]

People,

My rule No1 and only one.
When I pass film through scanner I pay a close attention it isn't with other items and, I send my film through scanner with a good distance from other bags on the belt. I face film side ways and I can assure you, after 100x going through film will be ok.

Those marks you have is a projection of some metal or other material blocking x-rays.
Repetition on the film is caused not by a pulse, but because of a roll film.