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?"

Comments

Premature

[Phanatic1a]

Fujifilm recently said they were bringing Velvia 50 back:

Valhalla, NY, November 14, 2006 - FUJIFILM U.S.A., Inc. is pleased to announce plans to re-introduce an ISO 50 Fujichrome Velvia professional film, tentatively named Velvia II. Fujichrome Velvia (RVP 50) was the first high color saturation, high contrast transparency E-6 compatible film when it was introduced in 1990 and was a favorite among photographers. Its discontinuation was announced last year due to difficulties in procuring some of the raw materials used to produce the emulsion.

"Since we announced the discontinuation of Velvia 50, we have been inundated with requests from photographers worldwide to continue production," said Christian Fridholm, Director of Marketing, Picture Taking, Imaging Division, Fujifilm USA. "They had used Velvia for many years and consider it unmatched in terms of quality and character. One of Fujifilm's main priorities is to nurture the culture of photography, so we took those requests very seriously."

As a result, Fujifilm research and development teams have developed substitute raw materials and new manufacturing technologies that enable the company to restart production. The new film is expected to be available in late spring 2007. The characteristics of the new emulsion will mirror that of the previous product.

I note that it's now past late spring 2007.

Re:Faraday cage

[VitaminB52]

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.

Meh..

[evel aka matt]

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.

Re:Meh..

[PsndCsrV]

Ugh, holy crap. Don't shoot Velvia 100F and expect it to look like Velvia 50. It doesn't. Shoot Velvia 100 (notice the missing F). It's pretty darn close to Velvia 50 (close enough that I was willing to switch, saving myself from the need to stockpile).

The place to go

[BenEnglishAtHome]

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.

Graded Z shielding

[mollymoo]

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.

Re:I won't be the same

[198348726583297634]

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,