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Protecting Unexposed Film from Cosmic Radiation?
iblink asks: "Last year Fujifilm stopped producing a color slide E-6 sheet film called Velvia 50. It has unique color characteristics that I love so I decided to purchase the remaining stocks in Europe. I now have hundreds of boxes that need to be stored for up to thirty years. A number of film experts assured me that freezing the Velvia would stabilize the dyes for long term use. However, they all mentioned that cosmic radiation would eventually fog the film, and they offered little help in finding a relatively inexpensive barrier. I found various ideas on proton cosmic radiation barriers — a big bucket of water, lead, certain plastics — but nothing convincing or sufficiently detailed (which plastic? How thick?). The film is currently in a freezer, unprotected. Any ideas?"
I note that it's now past late spring 2007.
A Faraday cage won't stop particle radiation, nor will it protect against short wavelength radiation like gamma rays (unless you build a Faraday cage from massive lead plates, without any holes in it).
It also won't protect you against radioactive radon gas seeping out off the ground.
Forget about Velvia 50 & just move onto Velvia 100F like the rest of us have. 50 has little to no (most people would say the latter) advantage over 100f.
Cosmic Radiation is very very very very short wavelength.... light for example is just nanometers order. Cosmic radiation is even shorter. Gamma Rays are as far (or close, it depends which side you are ;-) as 10e-16 meters (pico meters or less).
a tion#Electromagnetic_spectrum
http://en.wikipedia.org/wiki/Electromagnetic_radi
Obviously, there's a problem, know-nothing slashdot smartmouths be damned. Here's what Kodak says:
Like lots of photo buffs, the first thing I thought of was the Rochester Institute. And that led me to an answer.
I'm not going to put directly on Slashdot the name and phone number of a real person. However, if you visit the Image Permanence Institute web site and poke around, you'll find a name and phone number you can call to get in touch with an expert on these subjects who will either know the answer or know where to find it.
You may want to investigate "Graded-Z shielding". The name comes from the fact that it uses layers of shielding with decreasing atomic numbers. You might first have a layer of lead, then a layer of tin, then one of copper. The lead stops the cosmic rays (protons, electrons, light atomic nuclei), but generates X-rays in the process. These X-rays might also fog your film. The X-rays produced as the lead absorbs the cosmic rays have a characteristic energy (88keV) which is not well absorbed by the lead itself - that's where the tin comes in. Again, the tin stopping the X-rays from the lead generates X-rays with a lower characteristic energy (29keV, which is in medical X-ray energy territory), which it doesn't absorb too well. The copper absorbs the X-rays from the tin and again emits X-rays with a yet lower characteristic energy. I don't know if the 9keV X-rays produced by the copper are a problem for Velvia. If they are, you'll need a yet lighter layer; a glance at the periodic table shows aluminium is a likely candidate.
I have no idea about the sensitivity of Velvia to cosmic rays or X-rays, so can't suggest thickness of the materials. My wild-ass-guess is somewhere in the 10s of mm. 30 years is a hell of a long time though. There are companies which specialise in shielding of this type (search for 'radiation shielding', 'graded-z shielding' and the like), they may be able to provide advice and sell you enclosures.
Chernobyl 'not a wildlife haven' - BBC News
About 20 years ago I had a small surplus stock of Kodak E6 professional transparency film left over at the end of a project. The storage recommendations from Kodak were to store E6 cold and dry, so I bagged and sealed the films and put them in low-humidity cold storage. As an experiment I left the films there. The films developed ok at 8 years age with excellent quality, and again at 15 years age, but by then slight fogging was visible. Maybe the fogging was due to cosmic rays, or perhaps the photochemicals had degraded. Anyway, the experiment ended when the E6 processing lab I used to use closed down (soon followed by its rival firms). I kinda miss E6. Really excellent true color reproduction and high resolving power (IIRC, over 100lines/mm).
A quick google of dr pepper cane sugar revealed: Dublin, TX - and they sell it online.
Warning: Apple/Nintendo fangirl. Likes her electronics cute & cuddly. May be rabid.
Note that he's talking about sheet film, not 35mm. He's presumably using 4x5" sheets with a field or view camera which generally don't have any electronics in them.
We're talking about something like this or this.
In additional to the Dublin Dr. Pepper already mentioned, most grocery stores here in Austin sell Mexican Coke (heh) and Sprite, and others on occasion. It has real sugar instead of corn syrup as well.
It doesn't hurt to be nice.
Sadly that is part of the family of urban legends surrounding the New Coke fiasco. It is not true. Coke actually switched from cane sugar to HFCS several months before the introduction of New Coke. (You can still get Coke made with cane sugar in the U.S. if you get the glass-bottled kind imported from Mexico.) But in general, no one noticed or cared. New Coke came later and was an entirely different fiasco.
Snopes, as per usual, has good info on this subject.
Thanks,