Darkroom portraits

[PKM-25]

Just got mine done ( middle photo ), about 15 square feet of working space in the storage closet of our 820 square foot 2-bedroom apartment, vertically stacked trays, over 2,000 rolls of film in the fridge / freezer combo to the right. The 16x20 Eco-Wash connects to a diverter valve in our shower. Have been printing for two days and already sold three prints, 10 x 10's from Hassy.

My other darkroom goes over 100 MPH, gets close to 20MPG when not doing those speeds, has 235 watts of solar, a freezer, fridge and lets us stay out in the field for not days but weeks in the same location. I don't print in it yet but do soup film.

[dambo29]

I ended up with the smallest available "split system" heat pump which serves only the DR. There is no air communication to the outside (no light leaks), as it recycles room air (I have separate outside fresh air by negative pressure exhaust). It is very efficient and effective for both heating and cooling as well as dehumidifying (really, cooling). I cannot recommend these systems highly enough. They are used widely throughout the world and are beginning to replace forced air systems in the U.S. The unit cost for small units sufficient for small rooms is not much more than a stand alone cooling or window-type unit (actually the same as better units, ~$200-$400). The extra cost (either judged to be worth it or necessary) is in the installation, where it pays to obtain someone with experience in split systems.

Hi ROL, I'm in the process of designing my own darkroom and the whole ventilation system is the one I need more help with. Can you specify which split system you have?

Thanks,
Alejandro

[Roger Thoms]

Hi ROL, I'm in the process of designing my own darkroom and the whole ventilation system is the one I need more help with. Can you specify which split system you have?

Thanks,
Alejandro

Yes ROL, I would be very interested in more specifics also.

Roger

[dambo29]

Positive pressure: the pressure in the darkroom is greater than the surroundings; air is pushed into the darkroom with a fan; it escapes through a free-flow exhaust and/or cracks and leaks; you need to place an air filter on the fan that blows air into the darkroom, dust exits the darkroom through the exhaust and the cracks and leaks and is blown from the room when you open the door - thus positive pressure is the way to go for a dust-free darkroom.

Negative pressure: the pressure in the darkroom is less than the surroundings; air is drawn from the darkroom with a fan; it enters through a free-flow vent and/or cracks and leaks in the room; you need to place air filters in the intake vent and the the cracks and leaks, however, you can never seal all the cracks and dust gets sucked into the darkroom every time you open the door - in general, negative pressure is a bad idea

I totally agree with what you're saying in that a positive pressure system is better, I just don't know how to create it. I'm currently designing my darkroom and the whole ventilation (and room temperature) system is the one I need most help with. I of course want to put an exhaust above and real close to the sink (thinking of using a Doran A1212 fan) and then using one or two louvers in the opposite wall so as not to create a vacuum. So I feel I'm creating a negative pressure environment which is what I don't want.

Any suggestions?

Thanks,
Alejandro

[dambo29]

David... regarding your EARLY setup. OMG... those were the days. I remember COUNTLESS hours painfully holding my water while trying to concentrate on my printing. But that was when I was just a young lad between the ages of 13 and 18. Later, I didn't have the room in my little apartment and after that the wife (wicked witch of the west) never put up with any of my hobbies but now that I'm alone I have all the room I need and, as Mel Gibson put it, "FREEDOM!!!".

Hey... maybe I'll have the 120 ft2 storage shed plumbed and convert that into a DR. No wicked witch to say "no".

This is the funniest post I've read on APUG! --- Thanks for a great laugh.

[Neal]

Just got mine done ( middle photo ), about 15 square feet of working space in the storage closet of our 820 square foot 2-bedroom apartment, vertically stacked trays, over 2,000 rolls of film in the fridge / freezer combo to the right. The 16x20 Eco-Wash connects to a diverter valve in our shower. Have been printing for two days and already sold three prints, 10 x 10's from Hassy.

My other darkroom goes over 100 MPH, gets close to 20MPG when not doing those speeds, has 235 watts of solar, a freezer, fridge and lets us stay out in the field for not days but weeks in the same location. I don't print in it yet but do soup film.

That is true dedication!

Neal Wydra

[mike c]

Push processing Tri X would be a snap at 100mph.

Mike

[John W]

So I feel I'm creating a negative pressure environment which is what I don't want.

Any suggestions?

Hi Alejandro,

You definitely want an exhaust fan. A common approach for positive net pressure is to use two fans, one for exhaust and one for intake. The exhaust fan should move less air per minute than the intake fan. Likewise, you will want to make sure that the intake fan has a replaceable (or cleanable) filter on the air inlet, to prevent it blowing dust into the darkroom. For my part, I'm working for a period of time without the intake fan. I'll install one in a later upgrade. I'll need to be diligent about cleaning the darkroom, and may get a HEPA in-room air filter.

As for the fans, I have a Panasonic WhisperWall fan in the darkroom and upgraded a bathroom to a WhisperLite. These fans are fantastic -- they move air well yet are very quiet when in use.

-- John

[Nicholas Lindan]

positive pressure system is better ... want to put an exhaust above and real close to the sink ...

The darkroom would have one large blower blowing into the darkroom and pressurizing it. The 'exhaust' above the sink doesn't need to have a fan - it is just a duct leading to outside of the darkroom. Since the pressure in the darkroom is higher the air flows out the duct carrying the 'fumes' out with it - I don't know why you would want to do that, though. "I love the smell of fixer in the morning".

If needed, a small 'assist' fan could be added to the exhaust duct, but it should not overpower the main blower that is pressurizing the darkroom.

[dambo29]

Thanks to both Nicholas and John!