Onboard late 1950s selenium meter - care?

[jay moussy]

I just acquired a Balda rangefinder with built-in (but not coupled) working selenium meter, circa 1958 or so.
The camera does not show much wear, and meter seems to work (window with needle and follower type)

Do I need to exercise any kind of caution, or provide special care with this meter system, beside not trusting it entirely...!

 

[Kino]

Cover it up when you store it. Don't leave it out in even indirect sunlight. If you have a case for it, use it. If not, store it in a bag.

 

[flavio81]

What Kino said. More time in darkness, more life of the meter.

When the light hits, the current is established and it promotes oxidation of the contacts, until the cell stops working. It seems it can be repaired by cleaning the contacts though.

 

[BrianShaw]

... and keep it moisture free.

 

[russell_w_b]

Out of interest, does a selenium cell degrade gradually (if left exposed to light) or is it sudden death? My Weston Master III and Yashica Minister II both have working (and accurate) selenium cells, and are kept in darkness.

 

[eli griggs]

I've long, read and practiced occasionally exposing my meters Selenium Cells to Sunlight, through a bright window, for a day or so, to keep them working properly, and, I've had no adverse effects to report.

Moisture is the real killer of these Cells/Meters, so keep bags off floors, where changes in temperature contribute to added moisture and put kit into the trunk of your car, when shooting in freezing conditions, so your gear can come to a lower temperature, or open the car windows so the back seat of your automobile, 20 minutes before you arrive, as to slowly bring down your kit's temperature, so there is no significant condensation.

I have some extra coolers, no only for keeping films at a modest temperature,summer and winter, but to keep kit in while traveling with cameras/lenses/etc in the car or car trunk.

Grocery stores also have lined cold/warm-bag which are large enough to keep a Hasselblad, lens, and meter in, with handles to carry.

That's also a good 'Disguise' for carrying kit on the street, elsewhere, when you do no want thieves to know you've a valuable (to you) camera kit with you, just like a baby bag, but with some insulation.

IMO.

From Photonet from Jim Momary;

"Selenium cells were vapor deposited as an amorphous layer of material. Sometimes they crystallize. If the cell looks silvery it's shot, if it's still 'black--blue' it's likely ok. Now, resting the cell in light may in fact regenerate it a bit, as selenium is a photovoltaic - photoconductive - photoreceptive material. Possibly other electronic issues may also be present. DIY would involve not only replacing but probably calibrating.

I'm the manager at facility that makes selenium copier drums, so we've had a bit of experience. 30 years now, yikes! But we don't make cells alas.
Jim"

jim_momary, Nov 12, 2009

Also from this thread, is a suggestion that the oxidation that stops these meter from working, is, in fact, the wires/connectors of cell to meter, which you can try to clean-up and get working again by using a good current conduction paint, to paint over them.

I do wonder if, the current conducting inks some folks work/play with will work as well?

Eli

 

[Kodachromeguy]

Eli is correct. It is oxidation, often of the contacts at the back of the selenium cell's substrate, that causes older cells to fail. A selenium cell does not have a fixed number of electrons that gradually trickle out until they are all gone. You are not using them up, and it is not sun exposure that causes the damage. But cleaning the cell, unfortunately, does not always revive it.