How to get dust off film for scanning.
in [Digital Cameras]
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From: Peter Irwin on 7 Jun 2010 22:36 Eric Stevens <eric.stevens(a)sum.co.nz> wrote: > On Sun, 06 Jun 2010 09:29:30 +0200, Mxsmanic <mxsmanic(a)gmail.com> > wrote: >> >>At least at one time you could buy static brushes with a small bit of >>radioactive isotope built in (electroplated polonium, as I recall). The >>radioactivity was weak but sufficient to discharge static electricity at very >>close range, so as you passed the brush over the film, the isotope discharged >>any static build-up, making it easier to remove the dust for good. >> >>I don't know if these are still sold. People tend to be more fearful now than >>they once were, so perhaps not (although there was nothing dangerous about >>these brushes unless you broke the isotope out of the brush and ate it, and >>perhaps not even then). > > Thanks for the suggestion. I was thinking of doing that except for the > fact that today (in New Zealand) is a public holiday. > Staticmaster brushes are still made: <http://www.amstat.com/solutions/staticmaster.html> The 1 inch brush is rated at 250 microcuries, so it would almost certainly be very bad to eat, but pretty safe when used as intended. The manufacturer can probably tell you if and where you can buy them in NZ. They used to be commonly available in photography stores, but seem to be less common now because of the drop in demand for film related products. As I remember, they were not cheap and the polonium isotope had a relatively short half-life, so you needed a new cartridge for the brush after a couple years or so. Peter. -- pirwin(a)ktb.net
From: rwalker on 7 Jun 2010 23:11 On Mon, 07 Jun 2010 17:55:44 -0700, clw <clw(a)ohsu.gov> wrote: >No, kill the cat first. But, of course, that is what should have been >done the moment it was Dipshit.
From: Al Dykes on 7 Jun 2010 23:52 In article <2010060720442816807-savageduck1(a)REMOVESPAMmecom>, Savageduck <savageduck1@{REMOVESPAM}me.com> wrote: >On 2010-06-07 19:36:03 -0700, Peter Irwin <pirwin(a)ktb.net> said: > >> Eric Stevens <eric.stevens(a)sum.co.nz> wrote: >>> On Sun, 06 Jun 2010 09:29:30 +0200, Mxsmanic <mxsmanic(a)gmail.com> >>> wrote: >>>> >>>> At least at one time you could buy static brushes with a small bit of >>>> radioactive isotope built in (electroplated polonium, as I recall). The >>>> radioactivity was weak but sufficient to discharge static electricity at very >>>> close range, so as you passed the brush over the film, the isotope discharged >>>> any static build-up, making it easier to remove the dust for good. >>>> >>>> I don't know if these are still sold. People tend to be more fearful now than >>>> they once were, so perhaps not (although there was nothing dangerous about >>>> these brushes unless you broke the isotope out of the brush and ate it, and >>>> perhaps not even then). >>> >>> Thanks for the suggestion. I was thinking of doing that except for the >>> fact that today (in New Zealand) is a public holiday. >>> >> Staticmaster brushes are still made: >> <http://www.amstat.com/solutions/staticmaster.html> >> The 1 inch brush is rated at 250 microcuries, so it would almost >> certainly be very bad to eat, but pretty safe when used as intended. >> The manufacturer can probably tell you if and where you can buy >> them in NZ. They used to be commonly available in photography stores, >> but seem to be less common now because of the drop in demand for >> film related products. As I remember, they were not cheap >> and the polonium isotope had a relatively short half-life, so you >> needed a new cartridge for the brush after a couple years or so. >> >> Peter. > >Damn! >You just reminded me. I have two of those brushes packed away with >about 1500 LPs, turntable, speakers, a Marantz amp, a Denon amp, and >plenty of dust. >I haven't gone through any of that stuff in about 20 years. k Don't rush. The Staticmaster web site says the active bit should be replaced annually. I dunno if they used the same radioactive element years ago but I'd check. If you call up the manufacturer about 20 years old goods you might find people in hazmat suits knocking at your door. -- Al Dykes News is something someone wants to suppress, everything else is advertising. - Lord Northcliffe, publisher of the Daily Mail
From: Mxsmanic on 8 Jun 2010 05:40 Al Dykes writes: > Don't rush. The Staticmaster web site says the active bit should be > replaced annually. I dunno if they used the same radioactive element > years ago but I'd check. Polonium in a protective capsule has been used for this purpose for many decades. > If you call up the manufacturer about 20 years old goods you might > find people in hazmat suits knocking at your door. Unlikely. The half-life of the isotope used for brushes is only 138 days, so after twenty years, the radioactivity of the polonium source would drop to only two percent of the level it had when new. It's best not to try to open the polonium source, though, and I recall that you weren't supposed to just throw it into the trash to discard it (also true of things like smoke detectors, which sometimes contain radioactive sources like americium). Unlike polonium, americium stays radioactive for the life of the product it's in (half-life over 400 years). I don't recall using this kind of brush myself but my father used one. By the time I had film to be scanned, I had forgotten that they existed. Never had any problems with dust, though. The film didn't collect dust so much as the optics in the scanner, especially scanners like the Nikon LS-2000 that had mirrors facing up inside the case, which would get dusty all the time (fortunately I was able to clean those myself).
From: Mxsmanic on 8 Jun 2010 05:58
Mxsmanic writes: > Unlikely. The half-life of the isotope used for brushes is only 138 days, so > after twenty years, the radioactivity of the polonium source would drop to > only two percent of the level it had when new. Sorry, that's way off--I overlooked part of the calculation. The actual radioactivity of a polonium source after 20 years is 1/(2^53), or about 0.00000000000001.1624731 % of the original level. It decades into lead, which is not radioactive. So after 20 years, a polonium source is no longer hazardous (and it is actually lead rather than polonium). |