Chemical dust in darkrooms

konakoa · Jul 13, 2011

I've been making several home-made film developers and fixers from bulk dry powdered chemistry over the past year.

As I spoon out and weigh the dry components in my home darkroom, I've become aware of a fine dust that gets airborne despite my best and most careful efforts not to stir up the contents; sodium sulfite in particular I can smell-almost-taste in the air as I start to take it out of the bottle.

Long term continued exposure to this chemical dust is undoubtedly not a good thing. Further, I know it's settling everywhere all over my countertops and printing equipment. Cutting large holes in the walls of the house to install an elaborate ventilation system in my darkroom is not an option.

I spied this in a catalog that showed up in my mailbox: a self-contained fume extraction system. http://www.hakkousa.com/detail.asp?CID=52&PID=4878&Page=1 I really liked the rigid self supporting hose that could be positioned over the project to suck up any airborne particulates right at the source. It's perfect except for the price. The system is meant for heavy electronics soldering with the related acids and smoke, but it gave me an idea--I don't need the fume/vapor part of it, just the dust part.

What about something like a small Shop-Vac with their very best HEPA filter bag and cartridge? I could make something to hold a hose and large nozzle over the bottles of dry chemistry, and turn it on when I'm measuring out the powder for a formula.

What do you APUGers think?

domaz · Jul 13, 2011

konakoa said:
What about something like a small Shop-Vac with their very best HEPA filter bag and cartridge? I could make something to hold a hose and large nozzle over the bottles of dry chemistry, and turn it on when I'm measuring out the powder for a formula.

What do you APUGers think?

Err wouldn't a shop vac just suck up the dry chemistry. Maybe turn it on after your done or use something slightly less powerful like large computer fans..

Bob-D659 · Jul 13, 2011

How about just mix them outside. Yes the vac and a hepa filter will work, so will a central vac that is ducted outside, or a free standing hepa type air cleaner with a "fume hood" made from a cardboard box.

Actually you should never mix powdered chems in the darkroom, any escaping "dust" will do a wonderful job of contaminating paper and film.

Gerald C Koch · Jul 13, 2011

I don;t know why people choose to mix chemicals in the dark room. I can't think of a worse place to do this There is the problem of chemical dust eventually finding its way to film and paper. Then there is the relatively poor ventilation.

Diapositivo · Jul 14, 2011

A balcony is your friend. A garage might be an alternative if your house has no balconies. If really no alternative is present to mixing chemicals in the darkroom, for whatever strange reason, I would just run an air purifier in the room for some hours a day. That reduces the amount of dust in the darkroom.

An example with a programmable timer:
http://www.lacasagiusta.it/idea-regalo-casa-cucina-vendita/shopping/product_info.php?products_id=168

Cheers
Fabrizio

vpwphoto · Jul 14, 2011

I always mix my powdered developers and fixers outdoors.

ic-racer · Jul 14, 2011

I can't imagine mixing chemicals anywhere in my house except the darkroom where I have the containers, filtered water, funnels, ventilation, dust control and spill-resistant surfaces.

BetterSense · Jul 14, 2011

I don't mix powdered chemicals indoors, and I especially wouldn't in the darkroom because it's a dust violation (I work in cleanrooms a lot, and consider my darkroom something of a cleanroom, so the thought of opening and mixing powdered chemicals in the darkroom fills me with dread). You are right; powder gets into the air. Do it outside or in the garage or something.

Jeff Kubach · Jul 14, 2011

After I mix my powered chemicals, I use a straw to snort the left overs!

Jeff

Gerald C Koch · Jul 14, 2011

ic-racer said:
I can't imagine mixing chemicals anywhere in my house except the darkroom where I have the containers, filtered water, funnels, ventilation, dust control and spill-resistant surfaces.

Typically darkrooms had a dry side with the paper and enlarger and a wet side with a sink for the trays. Cheinicals were mixed in a separate room. Most amateur photographers are faced with a floor space limitation and so must make adjustments. But the books that I have that discuss darkroom usage all say you shouldn't do any chemical mixing there. In addition all spills should be immediately and thoroughly cleaned up.

konakoa · Jul 14, 2011

Folks, I appreciate the suggestion of simply mixing formulas outdoors and I have already been doing exactly that when possible.

Yet, problems with mixing outside I have been constantly facing are unpredictable gusting winds, windblown debris and kamikaze bugs that inevitably find and dive into a half finished formula. Then there are the extremes in temperature like this weeks 106 degree summer day--nor can I mix something up outside in the winter when it's below freezing.

My darkroom is the next best place to prepare these formulas--I certainly don't want to use my kitchen! Are there no better methods or alternatives?

jeffreyg · Jul 14, 2011

Your garage if you have one. Better yet a neighbor's garage.

http://www.jeffreyglasser.com/

ic-racer · Jul 14, 2011

konakoa said:
My darkroom is the next best place to prepare these formulas--I certainly don't want to use my kitchen! Are there no better methods or alternatives?

No better place than the chemical preparation area in your darkroom. If it is a home darkroom, you certainly don't want to be doing this stuff in your living areas.

BetterSense · Jul 14, 2011

If you must do it in the darkroom, wear a dust mask, pour carefully, and wipe up after you are done.

Diapositivo · Jul 14, 2011

I only use liquid concentrates and I actually do all dilutions in the kitchen. Never spilled anything, but if it had to happen, it would be on enamel, easy to clean. Easy to change air as well. Powdered chemistry? No, thanks.

Kirk Keyes · Jul 15, 2011

Anyplace you can easily rinse or wipe up the working surface is good for me. I put a shelf on the wet side of my darkroom and place the scale on it, and then when I'm done, I wipe up the working surface.

Just be careful, and keep spills and dropped powders to a minimum. Use lab scoops/spatulas with deep sides for measuring small amounts. Don't put heaping amounts on them that will spill if your hand shakes a little - tap the spatula over the bottle to shake off any material that may fall off as you tranfer it to the scale.

Also, it's really only the organic developing agents that you probably should be concerned about spilling. Sulfite, bromide, carbonate... don't fear those compounds.

Bob-D659 · Jul 15, 2011

Just to add to Kirk's list, dust from fixer or it's components is real bad for film and paper.

Chemical dust in darkrooms

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