Darkroom fans?

[Tori Nelson]

I'm hoping that some of you can give me your advice on the best type of fan system to get for my new darkroom. Any help will be greatly appreciated.

The room will be 12x15 with air conditioning and heat, which will have industrial filters. The door will open into a garage so if I need to but a vent in the door it will have to be filtered somehow also. One of the walls will be an outside wall (does that make sense?) The house is still being built so I have the ability to locate the fan anywhere in the attic that I need to and I'm hoping to keep the noise down by venting it all elsewhere. I really want to do this right and have no clue what I should be looking for. My last darkroom had a POS bathroom fan in it that was truly useless.

Thanks in advance for any help!

Tori

[Robert Budding]

Don't forget to plan for an air intake vent.

[Michael Graves]

Don't know if they're still around, bur Porter Photographic used to sell an inexpensive light-proof fan.

[Jerry Flynn]

I bought a darkroom fan from Calumet a few years ago. I has the necessarty light baffles and is reasonably quiet. I forget the manufaturer (Darco?) and I'm not sure Calumet carries such items any more, but you might check.

[Peter Collins]

Darkroom fans??? I'm a fan of darkrooms!

[Louie Powell]

Tori -

The ideal ventilation system for a darkroom is a positive pressure system in which the fan blows air into the darkroom. A positive pressure system allows you to filter the air entering the darkroom much more efficiently giving much better control over dust.

A second criterion for darkroom ventilation is sound - the quieter the better. Most bathroom ventilators are pretty noisy, and are distracting when installed in a darkroom.

I built a quiet positive pressure system in my basement darkroom. It consists of a box constructed between a couple of floor joists outside the darkroom with a computer-style 'muffin' fan installed in one end. Air is drawn into the box through a filter, and then pulled out by the fan. The exhaust side of the fan connects to a vinyl duct that extends over to the darkroom to a louver next to the enlarger. Air enters the darkroom at that point and exits via a large louvered opening over the sink. The fan is naturally quiet, but because it is totally outside the darkroom (and not even mounted on a wall of the darkroom), it is almost totally silent. I have it wired to a master switch that controls all of the electrics in the darkroom so that when the darkroom is "on", the ventilator is also on.

Here's a picture of the filter box - you can see the duct exiting to the left. The duct and louver are readily available at home centers - they are designed for bathroom ventilation systems. The fan came from Radio Shack.

[Herb Cunningham]

depends on how much heat your enlargers, etc produce. I got one of those fans from calumet and it is noisy and not very powerful, wimpy I think

If you can put the fan out of the darkroom in another location, and duct to the darkroom , provide some fresh conditioned air that you can regulate the flow of, that would be the best of both worlds.

I have a big enlarger that heats up the room if I don't have the door to the ac open.

[John Cahill]

I kept it simple. I have a circular duct I placed through the ceiling and in to the Ac/heat duct. It is adjustable. The whole AC/Heat system flows through filtered cold air return ducts, plus the regular AC filter, which is a high efficiency anti allergen filter.

Inside the opposite wall, at just above the molding, I have a hole cut between the joists and covered with a louuver. At the top of the same area between the same joists, but on the outside of the darkroom wall, I have another hole cut, also covered with a louver. No light gets in, obviously. As pointed out, the slight increased pressure of the filtered air keeps dust from coming in.

[John Powers]

I have been using Panasonic inline whisper fans for about three years. They are very quiet and come in a range of capacities and types. I read about them here and decided to give them a try. The only sound you hear is the sound of wind in the four inch duct. The air coming into my darkroom goes through a high grade furnace filter which I can replace as needed.

Here is a link to the US source I used and product description http://www.rewci.com/panwhisvenfa.html
Panasonic inline whisper fans are more expensive than the hardware store type bathroom fans, but the hours of peaceful quiet work in the darkroom, or the ability to hear your music without mechanical noises, have been well worth the price.

The input air comes through a wall filter and a wall model whisper fan that pushes air at my back when I am standing at the sink. For exhaust I use a model that goes in the rafters and exhausts outside the house. It is a common mistake to put the exhaust fan in the ceiling over the chemical trays. The fumes come up from the trays into your nose on their way out of the room. To avoid this I dropped white 4 inch PVC pipe to the opposite side of the sink from where I stand. The fumes now go away from me, helped by the input fan behind me, into the two exhaust pipes, through the fans and outside. Much safer.

Enjoy,

John

[Tori Nelson]

Thanks everyone for all the help, there are some great ideas here and I will pass it all on to my contractor. This is not to say I don't want/need more input if anyone else has something to add.