What Does X Ray Damaged Film Look Like?

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I recently had a strange experience in developing Ilford HP5+ 120 and 220 film in PMK. The first three rolls (developed at the same time in two tanks) were fine. The last three were extremely thin, basically so thin as to be unprintable. Very little stain. All rolls were developed within a couple hours of each other, all from the same stock PMK, all in the same set of tanks, all for the same time, all exposed at the same EI, etc. etc. I did recently pass some of the film through the passenger x ray machine at a US airport. I have no way of knowing which rolls went through and which was hand inspected but in the absence of any other obvious explanation for why this happened, I'm wondering whether by chance the film that is unusable was damaged by the x ray machine. Does x ray damaged film appear to have been extemely underexposed/underdeveloped?

-- Brian Ellis (bellis60@earthlink.net), May 22, 2002


120 and 220 rolls with xray damage will show the exact opposite of what you're describing. They will appear overexposed and fogged, and there will often be an image of the spool itself or the printing on the backing paper.

Luckily, it's almost impossible to find film with airport xray damage, but people have xrayed film deliberately to see what the damage would look like.

-- Brian Yarvin (brian@brianyarvin.com), May 22, 2002.

Brian: If the damage is accumulated low dose exposure from the hand carry line (and I understand it takes very fast film or many, many trips through) it should look like regular fog, as seen in long- expired film. Color film begins to look a little grey. If the high power machine for checked luggage gets it (and this could be a one time event regardless of film speed), it looks like a stripe of very high density, the width and the number of stripes would depend on how interesting the examiner found your bag. So I agree with the above post, very thin negatives couldn't result from this.

-- Kevin Crisp (KRCrisp@aol.com), May 22, 2002.

Check the kodak web site, there are photos showing film that had been x-rayed. You might have to do a search looking for "traveling with film" to help find it. What I saw was banding though the negs, not density problems. You might want to check other things that could cause thin negs. Just a thought.

-- David L. (lazman@earthlink.net), May 22, 2002.

Check here for some pix of of film irradiated, or somesuch, in the mail!...:

http://www.smithsonianmag.si.edu/smithsonian/issues02/apr02/images/lin es_slides_jpg.html


-- Tim Atherton (tim@KairosPhoto.com), May 22, 2002.

"...it should look like regular fog, as seen in long- expired film..."


It should, but something from the packaging or surrounding objects is very likely to be imaged. In my own experience with 120 and 220, it's been the spools and the slots in them.

I've also seen the writing on the backing paper imaged.

However, I've never seen a spec of trouble at an airport carry on machine and thousands of rolls (maybe tens of thousands) of my film have gone through them.

Other xray machines; for checked baggage, at places other than airports with very tight security, and in controled tests, have given me the results I'm describing here.

-- Brian Yarvin (brian@brianyarvin.com), May 22, 2002.

Thanks to all who responded. I suspected that x ray damage didn't produce thin negatives but thought I'd ask since I have no other explanation for the loss of these three rolls of film in their development. As an aside, three different airport people gave me three different film speeds at which the new passenger x ray machines fog film. One said 800, another said 1200, and the third said 1600.

-- Brian Ellis (bellis60@earthlink.net), May 22, 2002.

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