ventilation necessary for no-smell darkroom?

jp80874 · Aug 12, 2007

I haven't had so many people agree with me in years. Have to tell the wife though she will never believe it.

Panasonic makes a series of "Whisper" brand fans in all types and capacities that are very quiet. Many can fit in the rafters and thus be out of the way. They are a bit more expensive than the average bathroom fans, but the only noise I hear is air moving through 4" PVC pipes. They have been in place three + years now and have worked flawlessly. That seems worth the price when you want to think something out or listen to your favorite music while working in the dark. I bought mine mail order. The price to ship them across country was about the same as if I had purchased them locally and paid sales tax.

John Powers

JBrunner · Aug 12, 2007

tommy5c said:
This is a great thread, especially for me right now. I'm in the process of building my darkroom. and i know i need ventilation. I myself cannot smell most of the chemicals in the darkroom (years of repeated exposure to much worse I'm sure) But i don't want to take any chances for either myself or my family. I was planning on adding two fans (bathroom ventilation type) above the sink. but this thread is making me think. should i mount them on the ceiling or on the wall , like at a 45 degree angle. on the wall is more difficult, but if the wall will make a considerable difference I'll put them there.

The best location is one that moves the fumes away from you, and out. Slightly elevated above the back of the sink is ideal. The overhead (ceiling) fan that is far too prevalent moves the fumes right up your nose on thier way out. Overhead ventilation can actually increase exposure. Not good.

Phillip P. Dimor · Aug 13, 2007

My darkrooms have never really had much air exchange. I've worked in one that had excellent air exchange and it was very comfortable to work in. The smell of fix does not bother me but the lack of fresh air makes me very tired and lethargic.

dancqu · Aug 13, 2007

radiantdarkroom said:
Wow, I am amazed that you can't smell the fix.
I have never been in a lab/darkroom where I could
not smell the fix. The sulfur smell is the fix.

That you've never been in a darkroom where the
sulfur smell of fix was not present is not proof that
there are darkrooms where that smell is not present.
In fact the smell of ammonia, not sulfur, is often
mentioned with the use of rapid alkaline fixers.

The OP and myself both use old fashioned very time
tested sodium thiosulfate based neutral to alkaline fixers.
Neither of our darkrooms are cursed with the odor of
sulfur or ammonia fumes. Dan

Richard Jepsen · Aug 15, 2007

I advocate an alkaline fix, if only for the reduced odor. Using the alkaline fix/water stop leaves the paper developer as the only odor producer. I experienced reduced odors when using fresh, non Metol developers. Small trays and/or covering the developer tray reduces odor. You can use a cheap unicolor drum or more expensive Jobo CP or slot processor. Never tone in a small unvented enclosure. Sulfide toning is nasty. With all the tricks, you can get by without a vent. No doubt venting is the best choice.

panastasia · Aug 16, 2007

Richard Jepsen said:
I advocate an alkaline fix, if only for the reduced odor. Using the alkaline fix/water stop leaves the paper developer as the only odor producer. I experienced reduced odors when using fresh, non Metol developers. Small trays and/or covering the developer tray reduces odor. You can use a cheap unicolor drum or more expensive Jobo CP or slot processor. Never tone in a small unvented enclosure. Sulfide toning is nasty. With all the tricks, you can get by without a vent. No doubt venting is the best choice.

I haven't vented my darkroom because I don't stay in it with the door closed for very long. I use open trays but have the holding (soak) tray outside the darkroom so the door is opened more frequently.

I think a small (quiet) ventilation fan - venting out - is a good idea. It should be noted that the air flow out will equal the air flow in. If you don't allow for air replacement, there's no air flow.

A tight dust proof darkroom wouldn't work, dust is only a problem on dry days (static electricity is the problem). If you hang a wet towel in the dusty area outside the darkroom it increases the local humidity and eliminates/reduces the dust phenomenon.

argus · Aug 16, 2007

How about temperature control of a vented darkroom?

I just rebuilt my darkroom, moved it to an area in the garage and certainly will vent it.

Because of cold winterdays, I plan to have a filtered intake in the garage and an exhaust in the wall.
Should I place the intake high in the wall or is it better to have it placed near the ground?

G

panastasia · Aug 16, 2007

argus said:
How about temperature control of a vented darkroom?

I just rebuilt my darkroom, moved it to an area in the garage and certainly will vent it.

Because of cold winterdays, I plan to have a filtered intake in the garage and an exhaust in the wall.
Should I place the intake high in the wall or is it better to have it placed near the ground?

G

If the exhaust is placed high, I would locate the intake low. Think of intake next to exhaust at the same level - close proximity - and how well that would work. Not very well.

zone6 · Aug 16, 2007

panastasia said:
If the exhaust is placed high, I would locate the intake low. Think of intake next to exhaust at the same level - close proximity - and how well that would work. Not very well.

My darkroom is 7x11 and moving 400 CFM of cool, comfortable HEPA filtered air in and out. I have an air conditioner / intake unit mounted high on my back wall, and an exhaust fan mounted high on my sink wall (above and behind my trays). They are both at the same hight but about 10 feet apart from each other. I'm thinking they're working pretty good. Are my missing something?

panastasia · Aug 16, 2007

zone6 said:
My darkroom is 7x11 and moving 400 CFM of cool, comfortable HEPA filtered air in and out. I have an air conditioner / intake unit mounted high on my back wall, and an exhaust fan mounted high on my sink wall (above and behind my trays). They are both at the same hight but about 10 feet apart from each other. I'm thinking they're working pretty good. Are my missing something?

Moving air @ 400 CFM along with simple convection in the room should solve any ventilation problem, regardless of location, as long as your venting out and not just recirculating the same air.

jp80874 · Aug 16, 2007

argus said:
Because of cold winterdays, I plan to have a filtered intake in the garage and an exhaust in the wall. Should I place the intake high in the wall or is it better to have it placed near the ground?

G

Geert,

Heat rises as we all know. In my basement darkroom there is usually a five degree F difference between floor level and ceiling. I would suggest taking advantage of that with a high intake from the garage and a low exhaust. Don't let someone else warm up the car in the garage while you are breathing that air in the darkroom.

John Powers

John Powers

panastasia · Aug 16, 2007

jp80874 said:
Geert,

Heat rises as we all know. In my basement darkroom there is usually a five degree F difference between floor level and ceiling. I would suggest taking advantage of that with a high intake from the garage and a low exhaust. Don't let someone else warm up the car in the garage while you are breathing that air in the darkroom.

John Powers

John Powers

Heat does rise and so do the fumes with it. What about the summer months? During cold winter months a simple space heater would add heat to the darkroom if that's an issue.

I'd vent where fumes are most concentrated, and it would be more advantageous to have the replacement air intake at the opposite corner of the room from the exhaust location - for best ventilation - to clear the whole room, end-to-end, bottom-to-top.

dancqu · Aug 16, 2007

GFDarlington said:
My darkroom is also very small but its in a house with
40" thick sandstone walls and no windows, ...Graham

I've not yet seen scrubbers mentioned. In a nut shell a scrubber
is a box with a down flow of misted water and an up flow of air.
Fumes and dust are absorbed by the water. I think one may
be an easy DIY and a very effective solution. No darkroom
intake or exhaust needed. Check the WWW for details.

My use of odorless fumeless chemistry has eliminated any need
for ventilation. I'm in and out often enough to satisfy any
fresh air requirements.

FWIW, I've spent years working in un-vented darkrooms at
a time when acid stop and fix were Required. Those two
darkroom chemistries are most guilty of fumes and
odor production. Dan

john_s · Aug 16, 2007

dancqu said:
I've not yet seen scrubbers mentioned. In a nut shell a scrubber
is a box with a down flow of misted water and an up flow of air.
Fumes and dust are absorbed by the water. I think one may
be an easy DIY and a very effective solution. No darkroom
intake or exhaust needed. Check the WWW for details.

My use of odorless fumeless chemistry has eliminated any need
for ventilation. I'm in and out often enough to satisfy any
fresh air requirements.

FWIW, I've spent years working in un-vented darkrooms at
a time when acid stop and fix were Required. Those two
darkroom chemistries are most guilty of fumes and
odor production. Dan

Such a scrubber would add humidity to the air in the darkroom. It would reduce the dust problem both by trapping dust in the scrubber and reducing the possibility of static electricity in the air which is partly responsible for keeping dust airborne.

Too much humidity could be a problem, though. I'm thinking of comfort (depends on temperature) and corrosion of the enlarger. (my old Beseler has some rust).

I find that a small (80mm?) computer fan is quite adequate, but I use a Nova vertical slot unit and non-acidic processing. I can barely smell anything much in the darkroom, but it still does have a very little of the darkroom smell that I've been addicted to for very many years. Brings back many happy memories.

dancqu · Aug 16, 2007

john_s said:
Such a scrubber would add humidity to the air in the darkroom.
It would reduce the dust problem both by trapping dust in the
scrubber and reducing the possibility of static electricity in
the air which is partly responsible for keeping dust airborne.

Too much humidity could be a problem, though. I'm thinking of
comfort (depends on temperature) ...

Some additional humidity could be a plus. Likely too much
would not be the case. Fresh or by small pump recirculated
water at room temperature has only modest humidifying
potential. For that mater a small included heater
would allow for varying the humidity.

So dust and fumes AND humidity under control.
I'm sold. Dan

jp80874 · Aug 17, 2007

panastasia said:
I'd vent where fumes are most concentrated, and it would be more advantageous to have the replacement air intake at the opposite corner of the room from the exhaust location - for best ventilation - to clear the whole room, end-to-end, bottom-to-top.

Sorry, I may not have been clear. In my own 10x13 foot darkroom my two exhaust fans are at the back of an eight foot sink eight inches above tray level. I stand on the other side of the 30 inch deep sink. My intake fan is about shoulder high on the wall behind me. I have followed smoke about the room and there seems to be a pretty even flushing of old air with new. The intake has a high grade furnace filter. All wall seams are taped. The door has rubber gaskets.

John Powers

ventilation necessary for no-smell darkroom?

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