Selenium meter storage

M

matthew J Shaw

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So, here's a question that I'm sure will start something of a debate...

I have far to many old RFs (all of which I love) and many have either original separate, or built in light meters.

I usually have them sitting in a cabinet, in a shady corner of the house, but I have been told a few times that I should keep the meters away from light sources.

I have a lovely Ricoh 500 which gets used loads so lives in it's ERC, the camera has been out getting serviced lately, so the meter has been left in the case. It now seems very slow to react, I left it facing a window all day today and it seems much quicker now.

So here is my question, should I keep my old selenium meters away from light, or keep them exposed to light, in which case should this be bright, moderate etc?

Any help would be great, I've spent a long time collecting some of these kits and would love to know I'm keeping them in the best possible way...

Thanks for the help

m
 
Well, looking at the few Selenium celled meters that I own they all come in cases that cover the entire meter therefore keeping them in the dark...other cameras that I've seen have covers over the cells as a means to turn them off...I believe that I've also read that you should keep them stored in the dark in a low humidity environment...
 
I believe the meter in my Rollei 3.5 F works so well because the meter remained covered. When I bought my Rollei it came with the case and was a shelf queen, but I had to send it out to get Fleenored because it jammed. I couldn't get even a roll of film through it.

Also I read a lot of comments about the built in meters as being inaccurate, but I found this to be untrue in my case. Again I credit this to the meter being covered for decades.

Cal
 
I've heard mixed reports about this. Age-old wisdom was that selenium "wears out" with use. An engineer, however, once told me this is nonsense; more often than not, what really happens is moisture gets into the cell, often through a small, almost imperceptible crack, and it's this that destroys the cell. His theory was that the reason old meters like Westons seemed to be more reliable if they were kept in cases was simply that they'd been looked after better and better protected, and it had nothing to do with light exposure at all.

Of course, this seems to go against all popular wisdom, so perhaps you should take it with a pinch of salt. Keeping them covered is certainly not a bad idea - it can't do any harm - but it might have absolutely no relevance whatsoever.
 
Coldkennels said:
I've heard mixed reports about this. Age-old wisdom was that selenium "wears out" with use. An engineer, however, once told me this is nonsense; more often than not, what really happens is moisture gets into the cell, often through a small, almost imperceptible crack, and it's this that destroys the cell. His theory was that the reason old meters like Westons seemed to be more reliable if they were kept in cases was simply that they'd been looked after better and better protected, and it had nothing to do with light exposure at all.

Of course, this seems to go against all popular wisdom, so perhaps you should take it with a pinch of salt. Keeping them covered is certainly not a bad idea - it can't do any harm - but it might have absolutely no relevance whatsoever.
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I've heard exactly the same, and would second every word you have written. It's hard to see hw they could 'wear out', but I've never been inclined to push my luck either.

Also, older Westons seem to keep better than newer ones. They were (proportionately, inflation-adjusted) quite a bit more expensive and, I suspect, better made/better sealed.

Incidentally, being from St. Dennis near St. Austell, I'd not say that Falmouth was in England...

Cheers,

R.
 
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I have three selenium meters. One is a Leica Meter MC, another is a Weston V, another is some no name thing from the 60s. The only meter out of these three that works, is my Weston, coincidently also the only one kept in its case. All three meters were kept in the same leather bag for years. Again this could just be because the case kept out the moisture...
 
I have always understood that moisture plays hell with them too. I think keeping them in the dark does make sense. In the basence of confirmation it should at least do no harm. I have one on my M3 that I found a few years ago and was still reasonably accurate (in good light.) I keep it in a darkened cupboard on my M3 so hopefully this helps its longevity.
 
tlitody said:
I thought that pointing a selenium meter at the sun(very bright light) will wreck it permanently.
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Not unless you heat it up to the point of destruction. Selenium meters do not deplete - that they age and fail is solely a problem of oxidation. The cell is coated with lacquer or even potted in plastics (polystyrene, acrylic or epoxy), or it would only last for hours - but even the best seal can fail (and many cells use rather primitive sealing technologies by modern standards). Most often the problems occur around the connecting wires, where the sealing is most strained.

Oxidation is massively accelerated by electrochemical processes and moisture, so that dark (i.e. current-free) and dry storage will increase the lifetime of meters with leaking cells. A meter without sealing issues would not need either - but you'll only know that by trial-and-error, there is no telling the seal condition in advance of a failure.
 
I was under the impression that Selenium cells functioned because of a irreversible photochemical process. So the light also degrades the cell.

Also from Ian_partridge.com:
Over time, the cell protective lacquer layer shrinks and reticulates (crazes) allowing the atmosphere to oxidise the selenium layer and destroy the electro-conductive properties of the cell. Water damage, damp, and overheating with the lightmeter being left in hot sunlight also cause cell failure.
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I should point out that my Weston 3 is actually experiencing problems of late, and sometimes I pull it out of my pocket and it's unresponsive. The problem here, however, is a loose connection; if I pop the flap and move the selenium cell in one direction, there is current again. I suspect some (or even a lot) of failed selenium meters may actually be similar problems, but no one's bothered to take them apart to check.
 
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Well well well....

Lots of useful info, and storage wise I cant see that Im doing anything that will be causing problems, I might open it up and have a check to see whats what inside.

And nice to see such a strong cornish fraternity, Im a Bodmin boy myself, just in exile in the south due to work etc :(

Still, I go home as often as I can...

Thanks all

M
 
For the meter, sounds like a poor connexion before the wires get into the cell.

Cheers,

R.
 
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Thanks Roger

That seems to be the consensus for the Ricoh meter... Me thinks I shall have some restoration work on the go this weekend :)

Thanks

M
 
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Selenium meters work by photons (light) kicking electron to higher energy levels and allowing them to move, creating electric current. As has been said, moisture and oxidation are the prime "killers" but light *will* degrade anything, given sufficient time. That includes the "packaging" of the cell and the plastic lenses used on most meters. Storing them in dry and dark conditions is prudent - light will, so to speak, "wear" them out.

I have a couple of Westons, a III and a IV, both of which still work fine and have been kept cased. Some of my FSUs also have unprotected cells that still work properly, however they're kept in the camera cases mostly.
 
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