Actived charcoal filter and light gray water.

Fellipe de Paula · Sep 23, 2009

I'm using an actived charcoal filter and the water is very light gray, I can't see it (the light gray) if I have just a small qty, but I can see it's not incolor when I have a gallon. This isn't normal, is it?

Photo Engineer · Sep 23, 2009

Some charcoal filters have fines in the charcoal that pass into the water that are non-filterable except with millipore style filters. Some cannot be removed at all by simple methods. You need a coarser grained charcoal, or the filter itself is not good enough for the charcoal.

You can sometimes get rid of the gray suspension by running some water through to wash (but not exhaust) the filter. This washes out the fines and leaves behind about 90% of the good charcoal. It may take a deft touch to do it properly though.

PE

Fellipe de Paula · Sep 23, 2009

Thanks, but is this prejudicial (water with a little charcoal suspension) to the development process?

Photo Engineer · Sep 23, 2009

Yes and no. It depends on the quality of the charcoal. Some charcoal is made from burning poor organics with lots of sulfur and metals. These affect film sometimes.

OTOH, the actual charcoal particles can become trapped in film and will then cause white spots in prints. This is not good as you can see. And, you cannot remove them.

PE

Ray Rogers · Sep 24, 2009

Is the filter new?
I seem to recall a notice to run one filter X liters before use....

jeffreyg · Sep 24, 2009

I'm not familiar with charcoal filters but I use a 5-micron sediment cartridge which also comes in an activated carbon version so you might want to check the micron size of the filter you use because they also come in 20 or 25 micron sizes.

Peter De Smidt · Sep 24, 2009

Some charcoal filters can leave a very fine (and impossible to remove) film of particles on film. This is most likely to happen when the filter is new. I put in one of the standard filters, the Omni brand I think, going to my darkroom, and I lost a couple of rolls of film this way. So if you're going to use one of these filter, I recommend that you run a fair bit of water through it and check it with a test roll to make sure there's not a problem.

ic-racer · Sep 24, 2009

Is there any role for charcoal filters in filtering for photographic purposes? I'd not use that type of filter.

Actived charcoal filter and light gray water.

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