The official answer to your question
is that you need only to be concerned about possible damage
during airport x-ray examination to films with ISO ratings
of 400 or greater. This is the official answer given by Kodak
Public Information Services and by the airport security authorities.
Now, with all the complexities and uncertainties we have to
deal with as underwater photographers, isn’t it just
wonderful that your question was so simply handled—and
with the full weight of credibility of the public relations
department of a trusted major corporation, and that of an
extension of a government agency? Who would have thought that
there could be such a sure, simple, and comfortably reassuring
answer to a question that might have been rephrased "will
the latent images on my film (which are all I have to show
for the thousands and thousands of dollars that I spent on
all this camera gear, film, and the cost of this here trip)
be screwed over by that hunk of atomic hardware operated by
a team of nuclear technicians that airport security hires
for six bucks an hour?" With all due respect to the people
in security who do a fine job in helping to see to it that
each of us arrives at only one destination at a give time,
I question the depth of their intimacy with the principles
of physical chemistry.
So a conversation with the department’s technical
expert on x-radiation and its effects on photographic film
emulsion might (and did) go something like this:
"If the film you’re carrying is than 400 ISO,
you don’t have to worry about it."
"But what if I’m boarding more than one flight
both outbound and return, and the film goes through the machine
"Well, the effects of x-rays are cumulative, but you
don’t have to worry if the ISO is 400 or less."
"If you expose 200 film twice to the same amount of
light required to get a given density on 400 film with one
exposure, you’ll get the same density. Doesn’t
it work sort of that way with x-rays?"
"I guess so, but you don’t have to worry if your
film is rated at 400 ISO or less."
As a matter of fact, a reportedly exhaustive "study"
was recently conducted by the National Association of Photographic
Manufacturers on the effects of radiation upon carry-on baggage
from x-ray inspection machines in US airports. Based on the
subject evaluation of photo experts, it was reported that
no detectable effects were noticed from 100 passes through
the machine on film rated at 200 or less. Fog levels were
not measured and the results were based on whether effects
from the radiation were noticed when low contrast scenes (which
should be a worst case) were evaluated. It was concluded that
an "airline passenger has virtually nothing to be concerned
about when his or her film is subjected to x-ray at an airport
But what about ambient radiation—from the cosmos? Kodak
stores its film 100 feet underground in a facility constructed
of ten-foot-thick walls made of brick and gypsum in order
to protect the emulsion from radioactive bombardment from
space. Could there be something to this? Are effects of ambient
radiation additive to effects of rays from airport security
inspection? No problem for those of us storing our film in
Kodak-style bunkers, but how about the rest of us who keep
it in a drawer for several months? Was the above-cited study
conducted with cosmically-ripened film?
Moreover, x-ray machines in the US are very strictly regulated
so that it’s unlikely that there is a great variation
in the amount of radiation your hand-carried luggage will
receive from airport to airport in the US; however, it’s
at least a little bit optimistic to assume this would be the
case all over the world. Have you ever watched the images
from the x-ray camera on the monitor screen as the security
person is passing baggage through the machine? It’s
fascinating! They have a button they push when they see something
in a piece of luggage that interests them. The screen gets
much brighter as they try to get some shadow detail. They’re
cranking up the REMS—at least double—maybe more.
I’ve seen them do this a couple of times to the same
piece of luggage, then call over another security person,
back it up, and zap it a couple more times—for a second
opinion. Generally, carry-on baggage belonging to a few passengers
passes through the machine at the same time. If they become
interested in the contents of the baggage before or after
yours, your film will be treated to an extra helping of radiation—perhaps
a very generous one since there’s plenty to go around.
If you’re fortunate enough to get a very conscientious
operator, you could be watching your film do a sort of conga
line over hot coals—barefoot! All rides on the conveyor
belt are anything but equal. I could have sworn that on at
least one occasion, they were reading a book in a passenger’s
luggage! If your carry-on is going to have to run the gamma
gantlet for each of several flights, the fog level could start
You could just pack your film in your checked luggage and
forego the boarding check. Problem is that if they do an x-ray
exam of your checked luggage, as they sometimes do, the radiation
levels used will not only far exceed a worst case scenario
boarding check, they could exceed a worst case scenario for
radiation levels achieved in an all-out nuclear holocaust!
People have had images of their hairbrushes on processed film
after packing their film in checked luggage!
How about just checking your film in one of those lead-shielded
bags? No good! Either they’re going to see through the
bag (and you know how) or they’re going to ask you to
open it up and show them the contents. This is certainly reasonable,
since anyone could hide whatever it is security’s looking
for in the first place in a shielded bag, making the whole
game a waste of time.
In the US, you’re legally entitled to request an receive
a visual inspection of your carry-on pieces. Most airport
security personnel in most countries around the world will
accommodate such a request. You can make the whole process
much easier if you remove the film from the boxes (and even
the plastic canisters) and put it in a large transparent zip-lock
bag. This makes it quick and easy to inspect, and you’ll
enjoy an added bonus in doing this as you can easily stuff
the bag in any irregular spaces in your carry-on.
I’d suggest that you hand-check your film whenever
possible. You certainly won’t have any fogging problems
from x-rays if your film is never x-rayed. I f they insist
on an x-ray check? It’s kinda like a lot of other decisions
we have to make in life. You protect yourself when you can—and
if you can’t, and since it’s probably safe anyway,
just jump on board and don’t worry about it. And if
you get something back from the lab you weren’t expecting—well,
you can’t win ‘em all!
A final thought: A human being is going to decide whether
your film is x-rayed, just as a human being decides whether
you get that traffic citation or you pay that excess baggage.
Some respect and friendly smile can make the difference.