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11-03-2017, 09:52 AM   #1
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Pentax 6X7 Light leak

Hi All,

I just got back a second roll of film shot on my Pentax 6x7 with the strangest light leak I've ever seen. It is a thick/ soft edge zig-zag line across the entire roll. From end to end. I've ruled out processing already and film. I've done some investigating in the camera with a flash light but can't seem to find the culprit.

Any thoughts would be greatly appreciated.

Thanks!

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11-03-2017, 01:35 PM   #2
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Welcome to the forum!

How do the seals look? If you need to replace them, here is a link for a DIY set:

Pentax 6x7 Light Seals

Phil.
11-03-2017, 11:02 PM   #3
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It looks like a type of airport x-ray that used to show up sometimes. The X-ray machine just scanned small sections and if something seemed suspicious the whole thing would get zapped.
11-04-2017, 12:13 AM   #4
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QuoteOriginally posted by pentaxus Quote
It looks like a type of airport x-ray that used to show up sometimes. The X-ray machine just scanned small sections and if something seemed suspicious the whole thing would get zapped.
I agree with Pentaxus in that it looks like high dose X-ray damage from the type of airport scanner used on checked in luggage.

Did you check the negs to see they are damaged and that it wasn't a problem with the prints?

It certainly isn't from the shutter curtain with that pattern, so on the next roll, get some black camera tape and after loading the 67, tape all the areas around the back door where light could potentially leak. If the same pattern exists on the next roll, it's the film, not your camera. If the film was purchased in the same batch as the damaged negs and the damage does not reappear, then it is a light leak from the camera's back door.

11-04-2017, 02:32 PM   #5
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QuoteOriginally posted by pentaxus Quote
It looks like a type of airport x-ray that used to show up sometimes. The X-ray machine just scanned small sections and if something seemed suspicious the whole thing would get zapped.
Thanks, this was suggested by a friends well, but it seemed implausible, as both rolls of film were 100. I was under the impression the baggage scanners only affected 800+. I'll test with new film to confirm. Also, I researched x-ray damaged film and it looks like a dead ringer, from the oscilloscope pattern.
11-04-2017, 04:38 PM   #6
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Multi-pass x-ray fogging of the film, either before or after exposure. X-ray damage is cumulative — the more passes, the more damage that is imparted to the film, irrespective of the film's speed.
11-04-2017, 04:46 PM   #7
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QuoteOriginally posted by sharksenesac Quote
Thanks, this was suggested by a friends well, but it seemed implausible, as both rolls of film were 100. I was under the impression the baggage scanners only affected 800+. I'll test with new film to confirm.
I've had 100 ISO film affected by X-ray and it is cumulative. For carry-on film, I either use a lead-lined film bag or I request hand-inspection.

Domke Film Guard Bag, Large 711-15B B&H Photo Video

However, I do not think this was caused by the x-ray thru carry-on. It is either the higher radiation x-ray scanners used for checked-in luggage which are similar to what the postal and private courier services use for security. They are not suppose to scan film or photographic paper, but it happens.

Please share with us the results from your next film test.
11-07-2017, 01:00 PM   #8
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If it was in baggage, you are probably looking like x-ray damage, as others have stated.

11-07-2017, 03:10 PM   #9
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Airport hand luggage scanners will not affect film these days, unless it's over 800 ASA. I've put film through airport x-rays machines numerous times and have had zero issues over the last 45 years.

I now use an x-ray proof bag like the Domke one above just in case I go to a small "old" airport, but even without it you won't have any issues. I had a nice chat in September with a TSA agent in Honolulu and he mentioned the modern baggage scanners the airport uses are so minor they are less harmful than a dental x-ray on your teeth.

However if you left your film/loaded camera in your checked baggage then yes you will have an issue. Totally different x-ray machine.

Also be wary of other x-ray machines used for cruise ships and museums/monuments. Best check or have your film hand inspected.

Phil.
11-07-2017, 03:51 PM   #10
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QuoteOriginally posted by gofour3 Quote
Airport hand luggage scanners will not affect film these days, unless it's over 800 ASA. I've put film through airport x-rays machines numerous times and have had zero issues over the last 45 years.
I am glad to hear that youʻve had zero issues with hand luggage scanners, but I cannot say the same. Iʻve lived on Oahu for over 20 years now, and fly out of Honolulu typically three times per year. Iʻve seen x-ray damage to ISO 100 and 400 films that were hand carried, but not hand inspected or in the protection of a lead-lined bag. Yes, TSA has signs and claims that 800 ISO films and lower are not affected by their carry-on scanners, but Iʻve found that is not always true.

In part, it may be a cumulative problem, where Iʻm on my way to Winnipeg and the film is scanned in Honolulu, I spend a day in Vancouver where it is scanned again, and then in Winnipeg on my return flight. Also Iʻve seen security scan it once, stop it, reverse it, scan it again, and even repeat that several times.

Maybe itʻs more of an issue with 120/220 roll film as there is no 35mm metal cassette to offer a bit more protection from radiation. I shoot with 645, and the OP with his 67 would be too.
11-07-2017, 06:10 PM   #11
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35mm canisters are easily identifiable to security in many countries. 120 roll film is less easily ascertained and sometimes can result in packages being opened. All this of course is superfluous if you pack unwrapped 120 film in a clear plastic bag and ask for (nicely!) a hand inspection. The worst that will happen is a swabbing and hand-pass over the x-ray machine, and bingo! A smile, a wave and you're on your way. I have in the past been dismayed in witnessing photographers big-noting themselves (all the while with a snaking queue of impatient and irritable people behind them!) making a scene and arguing heatedly with security people. Well, keep it up. They usually come in for closer and uncomfortable inspection and questioning rather than the hoped-for expediency through security.

The other thing is this: if x-rays are so safe, even to film, humans (including Security staff who operate them) would not be warned to stay clear of the machines (e.g., entry/exit) that emit them, irrespective of how "safe" they are to photographic materials. What would a Radiologist tell you? Same thing.

Lead-lined bags are strongly discouraged because they result in "blocking"of the vision and increased time spent examining the item, if not a dramatically increased level of power to penetrate the block.
11-07-2017, 08:39 PM   #12
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QuoteOriginally posted by Alex645 Quote
Maybe itʻs more of an issue with 120/220 roll film as there is no 35mm metal cassette to offer a bit more protection from radiation. I shoot with 645, and the OP with his 67 would be too.
Yes that may be true, as I have never taken 120 film on a flight through airport scanners.

Before I bought my x-ray bag in 2009, I took 135 film all over the world with no issues. (Mostly 64-100 ISO)

After I started using the x-ray proof bag, I just let the agents try and figure out what that black blob in my camera bag is when it goes through the scanner. It's fun to watch them looking at the screen and re-scanning the bag a few times. Some let it through, other times they want to take a look and after seeing it's film in a x-ray proof bag just let me go. The odd time I get the swab routine.

I've also never had any issues this way either over the last 8 years. Just took a trip in Aug/Sep with 10 separate flights, so the film (Fuji Provia 100F) got scanned at least 8 times. A couple small airports had no scanners and one place (Chile Easter Island) had all your luggage scanned upon arrival to spot fruit/veggies being brought into the country. I also did a few hand scan requests if there was no lineup, but that ends up being more of a pain as the dummies want to remove the film from all the plastic containers!

Phil.

PS Depending on the time of year Honolulu to Winnipeg could be a 60C temp change. Must be quite the shock to your system!

Last edited by gofour3; 11-07-2017 at 09:18 PM. Reason: Correction
11-07-2017, 09:58 PM   #13
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QuoteOriginally posted by gofour3 Quote
Phil.

PS Depending on the time of year Honolulu to Winnipeg could be a 60C temp change. Must be quite the shock to your system!
Yes, we almost always go in February due to the timing of a press check with the publisher/printer. Stopping over in Vancouver always helps and visiting winter for a few days is always easier (IMO) than being a snowbird and visiting our eternal summers for a few days before returning to the long nights and white outs of the northern plains.

With my lead-lined bag, I'm frequently alarmed when it ISN'T hand inspected after scanning. I'd feel safer if they actually checked it. When I travel with film, it's usually the largest lead-lined bag with at least 20 or more rolls. I started shooting Pentax professionally when I found out the CIA was using the 67 in the pre-digital days. I guess I'll know if Big Brother monitors PF next time I fly! Howdy to the MIB.
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