Re: IR Film and Airport X-Rays

[stephen Frazier <sfrazier@xxxxxxxxxx>]

Ken:

I very much doubt that IR film is less sensitive than "ordinary" film to
x-ray for this reason:
it is my understanding that it is the sensitizers added to the silver
halides that gives the extended IR sensitivity. X-ray sensitivity is
more on the basis of the size of the silver halide crystals, which more
or less determine the film "speed". Kodak IR film is "high speed" with
coarse, lumpy grain structure and prone to random exposure or "fog" like
any other
high speed film.  X-rays have a broad spectrum of energies that can be
manipulated by the equipment that is generating them.  Some of this
energy has to be absorbed by the
film otherwise it would be invisible on the inspection equipment.  I
have never seen serious
degradation of my film--on the other hand, IR has a rather high base fog
anyway, so that a slight increase would not be noticeable, given all the
other variables that can screw-up this touchy film.  Of greatest concern
to me are the storage conditions of the film--ever see a load of luggage
cooking on the tarmac?

Steve Frazier, M.D. (radiologist)
Barry, Ken wrote:

> Jeff:
>
> I have also not had problems traveling with IR film.  When traveling
> with 4x5 it is very hard to get a visual exam. (a hundred sheet box is
>
> too big for them not to open or x-ray).
>
> I suspect that IR film is less sensitive to x-rays than regular film.
> It is more sensitive to heat (IR range) not x-rays at low doses.
> X-rays
> are at the opposite side of the electromagnetic spectrum from IR.
> (remember your high school physics?)
>
> X-rays - Visible Light - Infrared
>
> Hope this helps.
>
> Ken Barry (kbarry@xxxxxxxxxxxxxxx)
>
> >----------
> >From:  Pedro Cote[SMTP:pcote@xxxxxxxx]
> >Sent:  Tuesday, September 30, 1997 9:52 AM
> >To:    infrared@xxxxx
> >Subject:       Re: IR Film and Airport X-Rays
> >
> >Jeff Spirer wrote:
> >
> >> Is there any reason to believe that scanners at the airport will
> have
> >> any
> >> more effect on IR film than regular film.  I don't want to try a
> hand
> >> check, since I am sure that some guard somewhere will insist on
> >> opening the
> >> canisters.  However, I expect to be in country (ies) that a) may
> have
> >> the
> >> machines turned up, and b) are highly unlikely to have processing
> >> facilities.  They will have to go through unprocessed and processed
> at
> >>
> >> least two times (i.e., at least four times total.)
> >>
> >> Jeff Spirer
> >
> >Jeff:  I've never had a problem with HIE.  I always try to be careful
>
> >and request a visual inspection, but several years of crossing
> airport
> >X-rays  have not produced any fog in the film.
> >
> >Good luck, -Pedro
> >
> >*
> >****
> >*******
> >******************************************************
> >*  To remove yourself from this list, send:          *
> >*         UNSUBSCRIBE INFRARED                       *
> >*       to                                           *
> >*         MAJORDOMO@xxxxx                            *
> >*----------------------------------------------------*
> >*   For the IR-FAQ, IR-Gallery and heaps of links:   *
> >*  http://www.a1.nl/phomepag/markerink/mainpage.htm  *
> >******************************************************
> >
> *
> ****
> *******
> ******************************************************
> *  To remove yourself from this list, send:          *
> *         UNSUBSCRIBE INFRARED                       *
> *       to                                           *
> *         MAJORDOMO@xxxxx                            *
> *----------------------------------------------------*
> *   For the IR-FAQ, IR-Gallery and heaps of links:   *
> *  http://www.a1.nl/phomepag/markerink/mainpage.htm  *
> ******************************************************



*
****
*******
******************************************************
*  To remove yourself from this list, send:          *
*         UNSUBSCRIBE INFRARED                       *
*       to                                           *
*         MAJORDOMO@xxxxx                            *
*----------------------------------------------------*
*   For the IR-FAQ, IR-Gallery and heaps of links:   *
*  http://www.a1.nl/phomepag/markerink/mainpage.htm  *
******************************************************

------------------------------

End of Infrared-Digest V0 #231
******************************