I use a multispeed exhaust fan that draws air directly across my sinks into a slotted plenum chamber. The fan draws about 1500 CFM at maximum speed, and produces about 50 to 75 FPM (feet per minute) air velocity across the sink top towards the slot. So far I have not had a problem using Poly Sulfide toner in an open tray.
The air enters from a slotted soffit where the ceiling meets the wall opposite the sink. The Dark room is 10’ wide between the sink slot and back wall. The length of the dark room is 20’. The low air flow of 200 CFM is handled by a smaller fan in the same exhaust system. The air intake has a 24”x 24” fine dust filters installed in the air path. The darkroom is on the second story therefore the exhaust stack containing the fans is on the roof, as is the air inlet. They are located far enough apart and designed to prevent contamination of the inlet air.
I had considered other lab venting systems such a hoods etc.
I used a roll of Congolium floor covering laid with adhesive on particle board. This was used to provide a smooth surface and so that the floor covering could be removed at a later date. I made a pattern of the floor perimeter with Kraft paper. I precut the roll of flooring before hand allowing for a rolled edge along the perimeter where the floor met the wall. Installation went very quickly with two people. I use runners of anti fatigue mat in front of the 15’ of sink, and counters.
Jonathan
From: pure-silver-bounce@xxxxxxxxxxxxx [mailto:pure-silver-bounce@xxxxxxxxxxxxx] On Behalf Of Eric Nelson
Sent: Friday, May 07, 2010 8:18 PM
To: pure-silver@xxxxxxxxxxxxx
Subject: [pure-silver] Re: New old home, new lab questions
That's why I had mentioned that as presently I tone outside the darkroom, but in the new digs, (such a disaster down there presently!) I'll have to do that outside the darkroom itself I guess as well. Was hoping someone had magic formula (there's always thiourea based sepia Eric) of ventilating that works. I plan to take wet prints to a screen dryer outside the darkroom as that creates too much wind from the fan.
There's already a floor down although a plumber today offered to dig some of it up to put in a pit (for a possible bathroom) to guarantee against backup. I may just go up 2 flights to avoid that although now would be the time to commit to doing it...ack, can't decide!
My darkroom presently was made to be a bedroom, print washing and toning and drying area was a kitchen. Digital area and print spotting area was a living room. It will revert back to those uses after I leave this month and some considerable rehab is done.
From: Richard Knoppow <dickburk@xxxxxxxxxxxxx>
To: pure-silver@xxxxxxxxxxxxx
Sent: Fri, May 7, 2010 2:39:40 PM
Subject: [pure-silver] Re: New old home, new lab questions
In reference to toning: If possible do not do it in the darkroom or where sensitive materials are stored. The gasses emmited by sulfiding toners are fogging agents and are quite toxic as well as being unpleasant.
The usual recommendation is to have separat dry and wet rooms but there may not be room. If possible the darkroom should have a wet and dry side.
If possible have a laundry type tub as well as a regular darkroom type sink. The tub is very useful for washing trays, etc, and can also be useful in other ways. It does not have to be large and can have a removable duck board over it for more tray or tank space.
If you use an "archival" type print washer make sure you have a place for it that will support the weight and allow it to drain when overflowing.
See if its possible to have a floor drain. If concrete is already poured this is probably not practical but if a new floor is going down ask about what it would cost. It will make cleaning easier and prevent flooding.
I am still doing with a darkroom that masquerades as a kitchen most of the time.
--
Richard Knoppow
Los Angeles , CA , USA
dickburk@xxxxxxxxxxxxx
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