not cosmic rays but actually muons cause film fog

removed account4 · Sep 12, 2014

i was lucky enough to have dinner with a physicist the other night
and she and i had a conversation about cosmic rays ..
it turns out she has access to a device that records cosmic rays as
they enter the atmosphere ( or they come into contact with her device )
i asked if she knew anything about light sensitive photographic film
and how cosmic rays are able to degrade the film, cause fogging,
even if a freezer &c and she said it isn't the cosmic rays but muons
that are created when cosmic rays come into contact with other particles ...
not sure if it is just semantics or not but incase you want to know ...
it isn't the cosmic rays you and your precious film need to fear but muons ..
and the best way to not let muons wreck your film, is to actually USE IT

summicron1 · Sep 12, 2014

Use it?

I am, honey. Every chance I get, and then some.

DannL. · Sep 12, 2014

Are you sure it isn't just oxidizing agents in the film (and paper) oxidizing the film (and/or paper)?

E. von Hoegh · Sep 12, 2014

jnanian said:
i was lucky enough to have dinner with a physicist the other night
and she and i had a conversation about cosmic rays ..
it turns out she has access to a device that records cosmic rays as
they enter the atmosphere ( or they come into contact with her device )
i asked if she knew anything about light sensitive photographic film
and how cosmic rays are able to degrade the film, cause fogging,
even if a freezer &c and she said it isn't the cosmic rays but muons
that are created when cosmic rays come into contact with other particles ...
not sure if it is just semantics or not but incase you want to know ...
it isn't the cosmic rays you and your precious film need to fear but muons ..
and the best way to not let muons wreck your film, is to actually USE IT

So still, stop the cosmic rays and you stop the production of muons.

Why am I thinking of the Skylab film vault?

E. von Hoegh · Sep 12, 2014

DannL. said:
Are you sure it isn't just oxidizing agents in the film (and paper) oxidizing the film (and/or paper)?

That too, but there is still the radiation. Freezing can nearly halt the oxidation, but not the cosmic radiation.

lxdude · Sep 12, 2014

I read this some time ago. Not much we can do about it, I guess.
If the Higgs Boson is the God Particle, are muons the Cow Particle?

DannL. · Sep 12, 2014

E. von Hoegh said:
That too, but there is still the radiation. Freezing can nearly halt the oxidation, but not the cosmic radiation.

An interesting topic. Case in point . . . When I purchase old and outdated Kodak papers I can expect with almost 99% accuracy that the paper will be fogged to some degree. Whereas Ilford papers of the same age, and stored in the same environment, will be perfectly fine and exhibit no such fogging. This has happened to me countless times over the years. It has been my understanding that Kodak papers of the type in question (b/w MGXX, etc), generally have built-in developers in the emulsion. Or could it be the insertion anti-radiation agents in the Ilford emulsion?

I recently finished up using a box of Kodak 4x5 film from 1964. The film came in 100 sheet boxes with bundles of 20 or so sheets packaged in aluminum sealed bags. The film that was exposed to air via opened and partially opened bags was unusable because of fogging. Whereas the film that was still sealed, had only a small amount of base fog. That film was still usable.

http://www.youtube.com/watch?v=NzlG28B-R8Y

georg16nik · Sep 12, 2014

The ISO 18928 says it well.

3.5 Extraneous radiations
Photographic materials shall be protected from extraneous penetrating radiation until they are processed. Storage rooms and housings shall be measured for their radiation level before being used. For most materials, a maximum of 1,29 ⨯ 10−4 C/kg is recommended. However, the maximum may be 0,1,29 X 10−4 C/kg for X-ray materials and certain other films.

Some stones or stone aggregates in concrete can emit sufficient radiation (average up to 0,516 × 10−4 C/kg/yr) to fog very sensitive films after long storage. However, most films and papers are not damaged under normal conditions.

The radiation exposure during airport inspection of carry-on baggage is usually small. Recently, new technology for inspection of checked baggage at airports uses radiation that fogs many, if not most, unprocessed photographic products. This has been a special problem with international flights, but may also be serious for flights within national borders.
Government regulations in many countries provide for hand inspection of photographic materials which is strongly recommended, thus avoiding the X-ray inspection. Repeated X-ray exposures can damage films faster than ISO 400, scientific films and X-ray films.

and it goes further...

Annex B

Background radiation

The radiation dosage of naturally occurring background radiation is expressed in coulumb per kilogram (C/kg), which is a measure of exposure and can be applied to X-rays and γ-rays.
The gray (Gy) or micro-gray (μGy) is a measure of dose due to any ionizing radiation, so there is no exact equivalence between the two basic units. However, an exposure of 0,00258 × 10−4 C/kg results in a dose of 8,69 μGy in air, or 1 Gy in air results from a 296,70 × 10−4 C/kg exposure. Hence, the average dose of 500 mR per year cited in 3.5 is only appropriate for naturally occurring background radiation.

E. von Hoegh · Sep 12, 2014

DannL. said:
An interesting topic. Case in point . . . When I purchase old and outdated Kodak papers I can expect with almost 99% accuracy that the paper will be fogged to some degree. Whereas Ilford papers of the same age, and stored in the same environment, will be perfectly fine and exhibit no such fogging. This has happened to me countless times over the years. It has been my understanding that Kodak papers of the type in question (b/w MGXX, etc), generally have built-in developers in the emulsion. Or could it be the insertion anti-radiation agents in the Ilford emulsion?

I recently finished up using a box of Kodak 4x5 film from 1964. The film came in 100 sheet boxes with bundles of 20 or so sheets packaged in aluminum sealed bags. The film that was exposed to air via opened and partially opened bags was unusable because of fogging. Whereas the film that was still sealed, had only a small amount of base fog. That film was still usable.

http://www.youtube.com/watch?v=NzlG28B-R8Y

I scored a LOT of TriX 8x10 film, frozen since the late 80s. If it's fogged, I need a densitometer to see it. It was stored in a basement chest freezer. It hasn't slowed down much either.

Ken Nadvornick · Sep 12, 2014

georg16nik said:
The ISO 18928 says it well...

Emotionally hysterical pleas to personal experience aside, there you have it. The ISO-certified best-practice recommendations.

Are these practices required for everyone? Of course not. The quality and nature of some work does not even come close to requiring adherence to these recommendations. But for other more careful work, it very well may. YMMV...

"The radiation exposure during airport inspection of carry-on baggage is usually small. Recently, new technology for inspection of checked baggage at airports uses radiation that fogs many, if not most, unprocessed photographic products. This has been a special problem with international flights, but may also be serious for flights within national borders. Government regulations in many countries provide for hand inspection of photographic materials which is strongly recommended, thus avoiding the X-ray inspection. Repeated X-ray exposures can damage films faster than ISO 400, scientific films and X-ray films."

Ken

georg16nik · Sep 12, 2014

Ken Nadvornick said:
Emotionally hysterical pleas to personal experience aside, there you have it. The ISO-certified best-practice recommendations.

Are these practices required for everyone? Of course not. The quality and nature of some work does not even come close to requiring adherence to these recommendations. But for other more careful work, it very well may. YMMV...

"The radiation exposure during airport inspection of carry-on baggage is usually small. Recently, new technology for inspection of checked baggage at airports uses radiation that fogs many, if not most, unprocessed photographic products. This has been a special problem with international flights, but may also be serious for flights within national borders. Government regulations in many countries provide for hand inspection of photographic materials which is strongly recommended, thus avoiding the X-ray inspection. Repeated X-ray exposures can damage films faster than ISO 400, scientific films and X-ray films."

Ken

Yep,
the quotes are from the recent, third edition of ISO 18928, published 2013, 02, 01.
previous edition was from 2002 but both docs are generally identical, sans some appendix changes etc.

Photo Engineer · Sep 12, 2014

Leaving out airport exposure...

All photo products are subject to aerial oxidation. This can be tested with some products quite easily. Take a small snip off the sheet or roll and then repack the roll. Turn on the lights and fog the small snip. Place 1 drop of 40% Sodium Hydroxide on the snip in the light. (Protect hands and eyes as this stuff is bad bad bad)

If the snip does not change, but just becomes wetted, then it may keep quite a long time in air, but if it blackens or darkens, it may not keep well in air. I have found Kodak products are worst for this test and Ilford products best. Others fall in between.

PE

Ken Nadvornick · Sep 12, 2014

While I certainly don't pretend to understand the principles behind it, that's a damn interesting test. I've never heard that one before.

Makes me want to stop working and call in sick right now and go play in the darkroom for the rest of the afternoon...

Ken

Photo Engineer · Sep 12, 2014

Ken, I have posted that test nearly a dozen times here. It is based on the fact that incorporated developers will blacken the film when base is applied to fogged film or paper. The degree of darkening is based on the amount of incorporated developing agent.

PE

Ken Nadvornick · Sep 12, 2014

Thanks for that test, Ron. That I haven't to date seen any of those nearly dozen previous times probably serves best to relieve any anxiety on your part that I may have been stalking you online...

Ken

pentaxuser · Sep 12, 2014

lxdude said:
I read this some time ago. Not much we can do about it, I guess.
If the Higgs Boson is the God Particle, are muons the Cow Particle?

Nice one Not true about being powerless. If Scotland votes for independence next Thursday I have it on good authority that films will be inspected by hand on request at all Scottish airports and muons will be denied entry at the border.

pentaxuser

Alan Klein · Sep 12, 2014

jnanian said:
not cosmic rays but actually muons cause film fog

This is why I wear lead-lined boxer shorts.

pentaxuser · Sep 12, 2014

Alan Klein said:
This is why I wear lead-lined boxer shorts.

Good thinking. Some of the neutrinos didn't. That's why they became neutrinos

pentaxuser

Photo Engineer · Sep 12, 2014

Muons are very similar to electrons except in mass. Thus they love to be captured by protons to form ordinary elements, but ones in which the muon spirals into the core. This causes annihilation and the muon and a proton are destroyed. Just one of natures vacuum cleaners that sweeps up muons.

A friend of mine did a thesis on this at UP/CM in Pittsburgh. They made muon analogs of common elements to determine half life. My part in this? I got a pint of liquid He to play with, and we froze a dozen roses!

PE

removed account4 · Nov 24, 2014

sniop

Emotionally hysterical pleas to personal experience aside, there you have it. The ISO-certified best-practice recommendations.

there were no pleas or want for personal experience in this thread.
that was a different thread ...

while it was nice for georg to post the iso best practice recommendations &c ( thanks georg! )
this thread has nothing to do with airport scanners &c

i suppose georg's post was relevant, if cosmic rays and muons are used in current airport scanner technology ...
but i have a feeling, they aren't ...

georg16nik · Nov 25, 2014

You are welcome, John,
thou, you need to read it carefully.

Annex B

Background radiation

The radiation dosage of naturally occurring background radiation is expressed in coulumb per kilogram (C/kg), which is a measure of “exposure” and can be applied to X-rays and γ-rays.
The “gray” (Gy) or micro-gray (μGy) is a measure of “dose” due to any ionizing radiation, so there is no exact equivalence between the two basic units. However, an exposure of 0,00258 × 10−4 C/kg results in a dose of 8,69 μGy in air, or 1 Gy in air results from a 296,70 × 10−4 C/kg exposure. Hence, the average dose of 500 mR per year cited in 3.5 is only appropriate for naturally occurring background radiation.

(there was a url link here which no longer exists)
and

Muons arrive at sea level with an average flux of about 1 muon per square centimeter per minute. This is about half of the typical total natural radiation background.

http://cosmic.lbl.gov/SKliewer/Cosmic_Rays/Muons.htm

jnanian said:
sniop

there were no pleas or want for personal experience in this thread.
that was a different thread ...

while it was nice for georg to post the iso best practice recommendations &c ( thanks georg! )
this thread has nothing to do with airport scanners &c

i suppose georg's post was relevant, if cosmic rays and muons are used in current airport scanner technology ...
but i have a feeling, they aren't ...

Old-N-Feeble · Nov 25, 2014

So... would something like a dual-level Faraday shield work?

removed account4 · Nov 25, 2014

georg16nik said:
You are welcome, John,
thou, you need to read it carefully.

(there was a url link here which no longer exists)
and

http://cosmic.lbl.gov/SKliewer/Cosmic_Rays/Muons.htm

thanks again georg ... i did read it carefully, again. while parts seem like i am reading greek, i got the gist of what was being explained.

as i said i am now under the assumption that muons not the cosmic rays directly ( even though they indirectly do, since they cause the muons )
... from what i can understand ) that cause the fog in the deep freeze. i guess muons are a type of cosmic radiation ( so they are a type of cosmic ray ? )
but according to the person i spoke with who has a device to measure cosmic rays ... the muons are frequent ( as stated also in the articles you linked to )
and the cosmic rays ( not cosmic radiation ) are less frequent, and as far as i understand from my conversations with her ( 2 now )
the cosmic rays don't make i to the film, but the background radiation / muons (?) do. i am clueless when it comes to this sort of stuff
i appreciate you explaining it to me the point of this thread wasn't to have an argument, but to clarify if what i have been told for 20+ years is true
or if it is just word play ( cosmic ray=cosmic radiation= background radiation=muon ?).

are you suggesting the physicist i spoke with was wrong, that cosmic rays are plentiful and penetrate freezer walls and fog film, and the muons
don't have much if anything to do with this ? i am not doubting you at all, as i said i am clueless ...
and i will be able to ask her another silly-lay-person's-question
the next time i see her and get a chance to chat.

thanks

georg16nik · Nov 26, 2014

John, the muons are part of the cosmic radiation.
The Technical Committee ISO/TC 42, responsible for the International Standard ISO 18928 don't differentiate muons from the cosmic radiation.
This graphic might help you out.

georg16nik · Nov 26, 2014

dup post, somethings up with the APUG text editor.

not cosmic rays but actually muons cause film fog

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