Tanks sensitive to IR?

[olwick]

Hi,

Newbie here, just getting back into developing my own stuff after 30(!) years.

I was looking at developer tanks on Freestyle's site and saw something interesting in the listing for the Jobo Uni-tank 2. It says:

Tip: All Jobo plastic tanks and drums are safe for use with infrared (IR) films. Most plastic tanks are not opaque to IR radiation, but Jobo tanks are. You can use them with complete confidence.

Really? I had never heard of that. I plan on shooting some Efke IR820 so this would definitely have an impact.

Does anyone have any experience with developing IR film in plastic tanks such as Paterson?

Yes, I know the stainless steel tanks wouldn't have this problem, but I was curious about the claim.

Thanks,

Mark

 

[kaiyen]

it's a myth. all plastic tanks are fine. don't worry about it.

 

[oftheherd]

it's a myth. all plastic tanks are fine. don't worry about it.

I am inclined to agree. I never heard that before. I am not an engineer, but from the little reading I have done on IR, and some experience years ago, I don't believe IR could penetrate plastic thick enough to be used in a developing tank.

 

[Roger Hicks]

No, it's not a myth. Some plastics are distressingly IR-transparent -- but very few, and I've not encountered an IR-translucent tank or lid. It's one of those things that is a 'light bulb over head' if you can't explain it any other way.

Process the film; if there is inexplicable fogging, that's one possibility. Another (and likelier) is that the IR820 plastic tubs around the film cartridges are not IR opaque: I have had fogging that suits this scenario. Keep those cassettes in subdued light or wrapped in metal foil. The pattern of the fogging (if any) will give it away.

Cheers,

R.

 

[kaiyen]

Roger - wow - I would have to think that the plastic tank would be really, really beat up.

I agree on handling the film properly. Far more likely to be a problem.

 

[Roger Hicks]

Roger - wow - I would have to think that the plastic tank would be really, really beat up.

No, that isn't the issue. I'm not talking about cracks. There really are a few 'black' plastics that aren't IR opaque, even brand new -- though far from a majority, which is the impression one might gain from the Jobo warning as quoted. That warning might have been true decades ago but I've used Jobo, Paterson and plastic-lid Kindermann without problems. Even so, I'd not say it was never a problem: just that in the event of fogging you couldn't trace any other way, with a very few tanks (probably very old), it's a possibility.

Cheers,

R.

 

[kaiyen]

Roger,
Thanks for the info. Indeed, I've used the Paterson, Paterson knock-offs, Jobo and...I guess that's it and no problems. I'll keep that in mind, though.

allan

 

[David William White]

I was involved in a protracted debate on another site about visible vs. IR opaqueness of film holders. Claims were made that some holders were opaque to visible but would transmit IR. No holder was named, but some insisted it was possible. Roger hints that fogging can occur at many points in the chain, and I maintain it's prudent to look elsewhere first.

It would be great if someday someone will identify a holder or tank that is transmits IR and we can then figure out what kind of plastic it is or what pigments are used. It would be most useful, and it's a fairly easy test, after all.

 

[olwick]

I finally found the IR820 data sheet. It actually addresses this:

Plastic Cameras and Development Tanks
Reports that cameras with bodies made of plastics are not IR-safe have not been substantiated to date. It could be shown, however, that the bodies of, e.g., Minox 35 cameras (thin makrolon) and the Russian panoramic camera Horizon 202 are perfectly suitable for use with IR film. The same holds for development tanks.
All steel tanks are suitable for developing IR films. The same could be shown for the development tanks of JOBO, which are made of makrolon. Problems with other brands are not anticipated. Should you fear that your tank is not IR-safe, it is recommended that you wrap it in aluminum foil.

 

[David William White]

Great. That sounds pretty confident, and with a cheap workaround if IR fog presents itself.

I can also add that a layer of aluminum foil under my toupee keeps ISS transmissions from interrupting my thought. Their broken toilet problem was driving me nuts.

 

[Roger Hicks]

I was involved in a protracted debate on another site about visible vs. IR opaqueness of film holders. Claims were made that some holders were opaque to visible but would transmit IR. No holder was named, but some insisted it was possible. Roger hints that fogging can occur at many points in the chain, and I maintain it's prudent to look elsewhere first.[Bold added]

It would be great if someday someone will identify a holder or tank that is transmits IR and we can then figure out what kind of plastic it is or what pigments are used. It would be most useful, and it's a fairly easy test, after all.

Dear David,

I completely agree. My suspicion is that the IR-transparency dispute can usefully be broken into steps.

1 SOME 'black' plastics are not IR-opaque (this is demonstrable).

2 From there it's a small step to 'what if they made a tank out of this stuff?' Whether there ever was such a tank is another question.

3 If there ever was a non-IR-opaque tank, it probably came from a small manufacturer, long ago.

4 Manufacturers whose tanks are IR-opaque have a vested interest in raising paranoia about the possibility that other manufacturers' tanks aren't.

In other words, almost any source of fogging (except perhaps direct imprinting of images by telepathy) is likelier than a non-IR-opaque tank.

Cheers,

Roger