Finding the Vent

<p>I have a chance to changed a studio bathroom into a small darkroom. The one thing I'm having trouble figuring out is what kind of vent I need. Is there a vent that I can buy at stores like Home Depot that would have the vent I'm looking for?</p>

<p>Search darkroom ventilation at Adorama -- inexpensive light tight louvers of various sizes (to use with Home Depot type fans),and more expensive complete fans.</p>

<p>Hello David and others. While you have the chance to plan this darkroom, put the exhaust vent close to the floor, with the air entry vent higher up the wall. This way you will be sucking fumes from your chemicals DOWNWARD, away from your breathing area. Bill</p>

<p>I looked back among my old files and magazine articles about building your own darkroom, and found that they were amazingly cavalier about the subject of ventilation.</p>

<p>Passive darkroom louvers, as Sandy pointed out, are a cheap and easy path.</p>

<p>Forced air fans are another possibility, but you want to consider the question of dust when using fans.</p>

<p>In either passive or active ventilation, intake into the room would ideally be filtered. An active system that keeps the inside air pressure just a little higher than outside will prevent the darkroom from becoming a large dust magnet/vacuum cleaner. ;)</p>

<p>Veneration fans from the hardware store are not generally light-proof. I have built many darkrooms and I always install venation. I use common wall fans from the big warehouse vendors. I use the smaller variety. I cut the entryway for the fan high up on the wall about a foot from the ceiling. Now most construction is drywall on both sides of 2 by 4 framing. When you cut this entry, you will see that the drywall on back side of the wall and that it will block the air flow. With a weight on a string or fixable probe, check the hollow space between the two drywall walls. You are checking to see have far down you can probe before encountering wood. Most walls will have a 2 by 4 at about the mid-point, others will be completely hollow inside. <br>

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After discovering the location of a wood fire break (horizontal in the wall), on the other size an exit on the other side of the wall. This will be covered by an inexpensive air-condition vent placed lovers down. <br>

<br /> After the holes are cut, using flat black spray paint, spry as best you can inside the wall. The idea is, the air can make a U-turn but light can’t. Best if the entry and exit holes are as far apart as possible. It doesn’t take a big fan, you can even use small ones from the computer store. I have used these, normally 12V DC, use a wall plug-in transform, the kind used to charge battery power tools. </p>

<p>You may not need a vent of any kind. My latest custom built darkroom specifically excluded a vent and incorporated an air conditioner instead. The key factor was the use of <em>odourless stop bath</em> and <em>odourless fixer</em>. The only volatile in the room is benign water vapour and the air con makes for a really pleasant workplace during heatwaves or cold snaps.</p>

<p>Thanks so much. This gives me a starting point.<br>

Part of the challenge this the building is too old. Meaning I can cut or tear down the wall since they have asbestos. The idea that I have come up with is using the bathroom vent that is already there to bring in the air and put an out vent in the door.<br>

Anyone try this out?</p>

<p>If there is already a bathroom vent there, that is all you need. I'm assuming it's a standard vent with its own on-off switch there in the bathroom like you would have at home. As opposed to some commercial buildings where the bathroom vent is just an air intake for a large vent up on the roof somewhere. No need to put anything in the door -- the bathroom is not air-tight and enough incoming air will get in.<br /><br />I have worked in many bathroom darkrooms and the existing fan was always more than sufficient. A vent is not essential -- you are not likely to be in there eight hours a day. Opening the door from time to time as you take breaks is fine. But the fan/vent helps.<br /><br />If you were putting in a vent, it's not necessary that it be a special darkroom fan. As Alan said, you can put something in the wall and if there is a turn or two, that creates its own light trap. Same thing if the vent has an exhaust pipe that goes to the outside that makes a turn or two.<br /><br />If the walls have asbestos in them you absolutely do not want to be cutting holes. That would release the toxic asbestos. Ideally, anything asbestos should be professionally removed. But at the very least leave it alone.<br /><br /></p>

<p>I have the exhaust fan (light proof, Doran brand I think... pushing the memory a bit) in the roof above the back of wet area and a light proof vent in the door (down low). The theory is the fan sucks the air/fumes up the wall and away from the trays. Seems to work, standing at the sink I can't smell the fixer. I also have a portable A/C that is vented (the hot air exhaust) into the roof.</p>

<p>Two passive darkroom vents seem to do the job, provided they are well placed. To facilitate even temperature I intake and vent out to another room in the house, which has good air exchange. Every once in a while I open the small window and darkroom door to further ventilate the room. You should check your exhaust fan and its position relative to your trays to avoid chemical fumes being swept up via your face, and consider where to place a passive intake vent in the room to minimize that flow pattern. Air filters provide some resistance to fllow, so they should be used where you can provide enough forced ventilation to make them work and in conjunction with a passive vent properly placed in the darkroom.</p>

<p>Unless you are using color development chemicals or certain toners or pyro developers, short term use of a darkroom (an hour or two, or three) is not really a problem, as in between sessions you can clear the air by opening up the room to more positive air movement.</p>

<p>Force air heating of the room may be a source of dust, but it guarantees certain air movement in and out of the room. However, as a precaution I usually close that system off before vacuuming and washing down the room surfaces and engaging in a long session. </p>