I'm curently building a darkroom in my basement.
The darkroom will be 2.8 m x 3.8 m and about 2 m high, this goes to a total of 20 cubic meters for the volume.
What would you think is safe for a replacement rate ? I do not want to have to attach the enlarger to the walls to resist the blow ;-) (it is not particulary light, as it is a Durst Laborator 1000)
My setting will be : succion above the sink and inlet of filtered air near the enlarger, flow coming in will be more powerfull than the exhaust (to put a positive pressure to resist dust coming in)
In "The new darkroom handbook" it is mentioned that the air the darkroom should be changed every six to eight minutes. Using simple math you can calculate the volume of the room and find out which fan you need.
What is (I think) important, is to place the exhaust (suction) fan on the wall BEHIND and not the ceiling above the sink (chem. trays), because this way the fumes will not go upwards in their way out (upwards is the way our head usually is, because we bend over the trays).
I made the mistake to put it over the sink and have regretted it...
So directly about the chem trays is not a good idea? Thats how my highschool/college had there's laid out?
Originally Posted by George Papantoniou
"The negative is the equivalent of the composer's score, and the print the performance." ~Ansel Adams
They change the students frequently rather than the air.
taking college photo courses, but working in our home darkroom.
In combination with venting my darkroom, I use a air filter. Most Air filter use a charcoal filter which will remove any chemical vapor. I use a fujimoto cp51 roller transport in my darkroom which generates a lot of fumes. The air filter I use remove about 90% of the fumes and orders.
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It's not a particulary big space, though much bigger than mine which is only 5x6 foot.
Basically a small extraction fan like those used in bathrooms would do the job.
Mine is simply in the hatch up into my loft. It less than ideal but it does shift air. As I use a Nova fibre processor I don't switch it on till the selenium comes out. What I can tell you is that in my tiny darkroom if I have the selenium tray out, and I've been in there for an hour or two without the fan on (sometimes I forget) I do get a bit of a head on me. If the fan is on, no such problem.
Also design and build your darkroom so it will not attract dust, and what dust does build up is easy to remove.
Darkroom Ventilation? Say That Again
Darkroom Ventilation you say. Never heard of it. Never had it.
Originally Posted by GeorgesGiralt
Still don't, unless you call that little exhaust fan in the ceiling
of my bathroom "Darkroom Ventilation".
I was in the service three years. A year, give or take two or
three weeks, was spent in each of three locations; an east and
west coast year each, and a year plus in Etain France. At each
location I was a or the Photographer and a or the Lab. Tech.
My lab at the Air Force Base at Etain was with the Headquarters
Company of the Combat Engineers Battalion also there located. The
other four Companys were scattered so I had quite a bit of travel
in that area of France.
No sink, no wet side, no dry side, just one side. An attached bath
had the sink for rinsing up. As with the other two assignments and
a few other labs I've worked in, NO ventilation.
Currently, at home, I've adopted an oderless, fumeless, chemistry.
That initself needs no more than a now and then
in and out the door. Dan
Since switching to citric acid stop and low-odour rapid fix in a Nova I rarely bother to switch my fans on (I still usually run the developer in an open dish 'cos I like to see the magic happen...). Just the breeze blowing the air through the light trap is sufficient.
However, I can open a window when toning or otherwise using chemicals with an odour so if you do not have a window you can open in the basement you may need more serious forced ventilation. The extractor should, as others have pointed out, be behind and a little above the trays - biased towards the fixer end as that seems to be the most likely source of pongs. Mine are at one end of the sink 'cos that's where the window is and I was too lazy to run trunking...
As I say, I find I need very little forced ventilation as long as I can open a window for the post-processing operations with some toners and I am quite sensitive to fixer fumes which used to give me a two-day sore throat if the ventilation was not working well. Now with low-odour fixer (Fotospeed FX30 in my case but there are others) in the Nova I have zero problems even with the fans switched off. A testament to both low-odour fixer and the Nova methinks...
Have fun... Bob.
In my experience, the rating on a fan is only a guide and may be optimistic. The length and complexity of the outlet ducting, and the aspect of the outlet relative to prevailing winds, will seriously affect the throughput. I tried a bathroom fan and found it inadequate for a 2x4m room, even though it only had a 1m outlet path ( and vented into a still-air area).
Heat or light; it depends on your sensitivity.
Having reflected some on my above post, I think it appropriate
Originally Posted by dancqu
I add a little more context. From that post it may not have been
obvious that NO " fine art archival silver gelatin " processing
was being done.
I'm not opposed to ventilation. I'm aware that for 'fine art' and
archival purposes some use toxic, foul smelling, fume producing
chemistry and do that in confined quarters. Dan