Airport x-ray machines

Is it true ...? Is there someone with definitive knowledge on this ...

 

Dave Perkes - "Lead bags are a total waste of money and give a false sense of

security. The operators increase the x ray power to see inside; which is

potentially far more damaging, than the very slight risk of affecting high speed

film. The only time I have had film affected is when I used one; so never again."

 

In another thread this was a comment about using leaded containers to limit film

exposure. I am not aware that TSA has variable machines. This would not be a

surprise. There is some risk to long term exposure to radiation. The machines

are not shielded well at the open ends. We assume that a distance of about six

feet is sufficient to avoid excess exposure to passengers. However, our

industrious TSA workers are closer to the machines for longer and closer

exposure. OSHA standards would indeed be interesting to read. I have not seen

TSA workers wear radiation badges that x-ray techs wear to check for chronic

exposure. And what's with those wild and crazy colors on the monitors ... as

though explosives and weapons show up in "blinking red" or something as to

signal contraband. X-rays are black and white - it's a density thing.

 

While I have a keen curiosity regarding the X-ray machines and film, I don't

recall seeing anyone ever adjusting the exposure. More likely the TSA would

simply use the highest setting and not bother with adjusting the setting

constantly. Beaurocracy being what it is, the most expedient way is to keep it

simple and leave the machine at max. And that's what they have hand checking

luggage for.

 

Another reason - with sufficient shielding, the average x-ray machine cannot

penetrate the container no matter how much exposure is used. Again, I don't know

how much shielding is built in. The containers are not very heavy.

 

I think that international travel standards are more lax from my observation. So

foreign travel has more vagaries and the leaded containers may indeed be

helpful. Nonetheless, I have not had any problem using leaded containers and

have had no film damaged. Of course, I've gone digital in recent years ... much

more room in my luggage now :)

It is safe to take film once or twice thru modern x ray machines without a lead bag unless it is very fast film.

Carry-on x-ray scanners cannot be "turned up" by the operator.

 

I've taken film, even high-speed film (Delta 3200), through carry-on x-rays multiple times with no noticeable damage to the film.

It just goes to show that you can't believe everything you read on the Internet. Carry-on machines are strictly limited in dosage and not adjustable (look up the manufacturers' sites if you want). The machines for checked luggage, on the other hand, will AUTOMATICALLY step up the dosage until they "burn" through. Now, in my experience, you do have to be careful with carry-on because the inspector will put a bag through several times if necessary to try to see what is inside, so I NEVER put film in a bag with anything else. If you are concerned, lead bags DO WORK - if they work too well, they will insist on a hand-inspection. But that's what you really wanted in the first place and were afraid to ask for. See this link:

 

http://www.tsa.gov/travelers/airtravel/assistant/editorial_1035.shtm

 

By the way, I have had film ruined by these machines under a combination of circumstances in just one pass - high speed, pushing, Arctic flights (exposure to cosmic radiation), so I am not saying there is no problem.

There is a measurable affect from the carry-on X-ray machines on film. But not one that really is of any importance to a normal traveler, it is a very small change to Dmin, a bit of background fog.

 

Your film probably gains as much background fog from cosmic rays DURING the plane flight as it does in the X-ray machines, and nobody ever worried about that!

 

As for the colors, I presume it is some expert system in the software...

then does it make sense to keep the film in clear plastic for hand inspection (or lead bags to trigger a hand inspection) and put it in the lead bags for the flight?

Isaac: It is my belief that lead bags offer little or no protection against cosmic radiation, so that is not important here. Also, one downside of hand inspection is that the inspector will often open the film can, even if it is transparent. That has the effect of accelerating the aging process for unexposed film since you have lost the dry nitrogen atmosphere it was packed in. For just a few rolls, I use lead bags in my carry-on. For large quantities (50+) I run them through the x-ray in a separate travel bag without any shielding, but I watch them carefully to make sure they don't start to make multiple scans. And I keep track of how many times a given batch of film has been x-rayed, and try to limit it to 5.

Curt, thanks.