How did you make your darkroom completely Light Tight???
For years I have worked only in medium format and 35mm. I am now taking the plunge into 4X5. I have always been a loyal follower of the late Fred Picker's technique. Therefore, I plan to tray process my sheet film per the Zone VI technique.
I built a very nice darkroom in my home here in North Carolina. However, I've always used a changing bag to load roll film because my DR has light leaks around the door (fortunately, I designed the room to be window-less). I tested to make sure that the light leaks didn't impact paper, and it has not been a problem. Plus, I only used graded papers which is far more ambient light resistant then VC papers. I know it will be an issue for tray developing films in 'total darknes'. Basically, I have just spent my time taking pictures rather then light tightening the room.
So, I would appreciate any help my fellow APUGERs can provide relative to making my door and exhaust vent light tight. Thanks....
Last edited by esanford; 12-26-2005 at 04:59 PM. Click to view previous post history.
Often wrong, but never in doubt!
I put a frame of wood around the inside of the door frame then stapled black felt around the edge where the door makes contact. It is 100% light tight. I included a few snaps so you can see.
I forgot to mention my frame goes all the way around the door including the bottom, the bottom part of the frame had a larger gap so I used about a 2inch tall piece for the bottom part.
So, in other words, you have to 'watch your step' to avoid tripping as you go into the room?
Originally Posted by Sean
Often wrong, but never in doubt!
it's worth the occasional stubbed toe
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I turned a downstairs bedroom into a darkroom, so I had to light-proof the door, and a window.
To make the door light-tight, I put a thin layer of foam weather stripping around the inside of the door jamb (door opens into the darkroom). The foam is just thick enough that it takes a small extra effort to close close the door - it's perfectly light tight around the top and two sides. The bottom of the door is over an inch above the floor, so I taped a weighted piece of black plastic (culled from a photo paper bag cut lengthwise). This blocks about 95% of the light - the other five percent I either don't worry about, or I just place an old blanket on the floor against the door - that nails all the light.
For the window, I built a box that fits into the window opening (thank god it's a newish house, with square corners!). I then attached a 1" strip of the same black plastic around the frame, so it rests against the side of the window frame - it's 100% light tight, and it's not attached to the window frame like weather stripping (or caulking) would be. The box itself is painted flat black, and features four sliding panels, each about 2/3 the width of the box. I can then open the window, and slide one baffle to the left, the right, the left, and finally right. Since light can't curve (at least in our weak gravity ), and the box is painted flat black, no light makes it's way into the darkroom. Course, since you don't have windows, this isn't an issue for you!
Hope that helps!
about 2 inches
In my darkroom, the door opens out. I bought a pre-hung hollow-core door, and hung it as carefully as I could.
With the door closed, I attached felt weatherstripping to the face of the door such that it formed a second right angle at the point where light tries to enter the darkroom. Light can't go around corners, so the key to light-proofing is to create right angles.
I also bought an oak threshold that I glued to the floor under the door, and then attached a strip of the weatherstripping to the bottom of the door such that it barely touches the threshold with the door closed.
Standard door stops are only about 1/4" thick. I my previous darkroom, I recycled an old interior door by making the frame from dimension lumber. I simply opted to make the door stop much thicker - I used ordinary "1-by" lumber that is 3/4" thick. Thicker door stops are very helpful in managing light leaks.
As to the vent - I constructed a box between a couple of floor joists in the ceiling outside the darkroom - a couple of scraps of wood to close off the ends (fill in the gaps with silicone caulking), and with a furnace filter to make the bottom of the box. I mounted a 4" muffin fan in a hole in one end of the box, and then used a length of PVC bathroom vent ducting to connect that point to a louver inside the darkroom. This way, the fan pulls air from the cellar through the filter, and then exhausts it into the darkroom. Because the duct goes around a courner, it is lighttight.
I also cut a hole in the wall above the sink and mounted a large air-return louver - the kind without a damper. This wall is an outside wall, and the air is exhausted into the dead air space behind the darkroom wall from where it flows back into the main cellar space.
After doing this, I turned off the inside lights (and turn on the lights outside the darkroom), and allowed my eyes to acclimate for a few minutes. Then I was able to actually see any remaining light leaks. Most of these were addressed by stuffing scaps of felt weatherstripping into holes.
My darkroom is my bathroom, and the house is rented, so no permanent alterations...
I made a shield that slips into the window from a full sheet of black/black foam core and some matt board for the inner collar and outer baffle; with gaskets of black masking tape as well, it slides right in and is 100% light tight. For the door, I ran gray weatherstrip around the door frame, and in the two upper corners where it fits the frame loosely enough to leak anyway, I added a couple strips of matt board held to the door with more black masking tape, just simple baffles to block the leaks. A heavy, dark colored towel covers the crack at the bottom, and I'm good to handle film shot and processed to EI 5000, even with bright summer sun outside the window -- providing I remember to keep the fluorescent light over the sink off for at least 20 minutes and use only the incandescent fixture while setting up.
Photography has always fascinated me -- as a child, simply for the magic of capturing an image onto glossy paper with a little box, but as an adult because of the unique juxtaposition of science and art -- the physics of optics, the mechanics of the camera, the chemistry of film and developer, alongside the art in seeing, composing, exposing, processing and printing.
After doing this, I turned off the inside lights (and turn on the lights outside the darkroom), and allowed my eyes to acclimate for a few minutes. Then I was able to actually see any remaining light leaks. Most of these were addressed by stuffing scaps of felt weatherstripping into holes.[/QUOTE]
I found this last paragraph very important. Once your eyes are adjusted (3-5 minutes) you may find that there are light leaks somewhere you hadn't suspected. I used black tar roofing patch in a caulking gun for a good light seal. It dries in a day or two and the smell disappears.
If you are going to have music in the room you may want to put black tape over some of those neat lights that pop up, like when you tune stations and receive stereo, a light has to come on to prove it. Some electrical outlets have a light the shines if you have a good ground. Smoke alarms sometimes have a light that flashes every few seconds.
my darkroom isn't light tight at all -
i built it in the basement and put a drop ceiling in
to keep the dust from the sub-flooring off my "stuff" ...
you can see the light from above a little bit, but not enough to
do any harm ... also i have no door - it is just 2 sheets of black canvas/cloth
that hangs from the door frame. there is a step up (landing is a 3' raised square at base of steps ) and i just have about 1' extra and a piece of wood
to secure it ( if at all ) when i come in the room to process/print.
i used rent space and tacked black felt around the ceiling/top of wall to keep the light out - that place really leaked pretty bad.