How did you make your darkroom completely Light Tight???

Discussion in 'Enlarging' started by esanford, Dec 26, 2005.

  1. esanford

    esanford Member

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    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....

    Ed Sanford
     
    Last edited by a moderator: Dec 26, 2005
  2. Sean

    Sean Admin Staff Member Admin

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    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.
     

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  3. Sean

    Sean Admin Staff Member Admin

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    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.
     
  4. esanford

    esanford Member

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    So, in other words, you have to 'watch your step' to avoid tripping as you go into the room?
     
  5. Sean

    Sean Admin Staff Member Admin

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    it's worth the occasional stubbed toe :smile:
     
  6. KenM

    KenM Member

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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 :D), 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
     
  7. Monophoto

    Monophoto Member

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    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.
     
  8. Donald Qualls

    Donald Qualls Member

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    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.
     
  9. jp80874

    jp80874 Subscriber

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  10. jnanian

    jnanian Advertiser Advertiser

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    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.
     
  11. esanford

    esanford Member

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    Interesting... you raise another point. What about all the like reflecting numerals on clocks as well as LEDs (I have a zone VI compensating timer with LEDS). Can these items negatively impact film???

    So far, I am getting a lot of good ideas and it is most appreciated.
     
  12. dancqu

    dancqu Member

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    I think many worry too much of a little light leaking.
    I keep in mind that it is the light the film sees and not
    what I see that counts. Baffle with fabric or some other
    sheet good where a real problem exists. A hinged swing
    arm and fabric may be all you need. Dan
     
  13. Bob F.

    Bob F. Member

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    Reflecting light isn't a problem as there won't be any light to reflect... Emitting light however, of any colour, is a big no-no for normal film. Cover them or switch them off. I have a couple of flaps made from black gaffer tape and black fabric that flop over the LEDs that are permanently on in my darkroom (having said that, there is one very feint LED on the light switch that I do not bother covering as it is too dim and so far away from where I load film). Glow-in-the-dark clock numerals etc will not fog film if a few feet away.

    I simply fitted my door as best I could with almost-light-tight draught excluding foam strip and used a curtain of blackout material on the outside to keep it completely light tight.

    You say: "Plus, I only used graded papers which is far more ambient light resistant then VC papers" I do not think this is so... You can typically use brighter safelights around graded paper (unless you use LED or sodium vapour based lamps with VC - in which case you can go just as bright) but not white light - which will as happily fog graded as VC paper.

    Good luck, Bob.
     
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  15. noseoil

    noseoil Member

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    I took over the apartment in our back yard when I finally became disgusted with renters who did various amazing things to defrost the fridge. The rear ingress-egress window was blocked with sheet cardboard (just taped to the wooden window frame, still opens), then a dark curtain was hung in front of it to cut out all light. It worked. The building was originally a one car garage which was converted to a rental unit.

    Similar treatment for the front window. Front door does allow a small amount of light to pass at the edges (metal pre-hung with translucent magnetized weather strip), but it is small and does not affect the papers for printing. Since it swings in, I still may tape an extra flap of felt to the edge. I did place a small black paper box on the alarm system key pad at the entry, but this turns out to be overkill, no problems there with reflected light from cabinet doors and the lighted keys.

    All film handling is done with lights off in the bathroom, which is located in the center of the building and has no penetrations to the outside world. With the door closed it is dark, as in 100% void of light. There is an extra sheet of melamine which covers the sink and serves as a work surface on the vanity.

    Since earlier this year, I've been using BTZS type tubes for film processing, so lights-on for most processing is the rule now. This is so much easier than tray processing, I wonder how I got along without it in the past. This would be a great help for anyone with light leaks and tray development. It is just better. tim
     
  16. Nick Zentena

    Nick Zentena Member

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    Light tight? Mine leaks like a sieve.

    Just remember. Light goes straight. It doesn't sneak around corners. So the light leak at one end doesn't really raise the light level in the other end. If I'm really worried when loading film I put my body between the light leak and the film. Not being made of glass I make a pretty good light blocker -)

    I wonder if just using deep trays would be enough. The higher the walls of the tray the harder it would be for the light to get in. High enough walls and the light would need to be right above the trays.

    One other thing is to consider the time of your leak. My leaks are all east side and are worse early in the morning. When the sun goes down they totally disappear but even during the afternoon the leaks drop off in intensity.

    FWIW I load film [sheet and roll film], cut down colour roll paper and process VC B&W paper. All in a room with many leaks.
     
  17. jp80874

    jp80874 Subscriber

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    I don't know if they are a problem. From what I have read others do, perhaps I go overboard, perhaps I am protecting the investment of time and effort I have made on that film.

    When I am loading film (8x10) I cover a Gra-Lab timer #450R and sweep second hands with a paper towel and put the read in the dark thermometer in a stainless pitcher. I don't know if these would fog the film, but when you consider all the work that went into making the film, why risk it now?

    I wear a shoulder harness in the car even though I haven't been in an accident since about 1974. As a salesman I covered a lot of miles and it seemed a worth while investment.

    John Powers
     
  18. Ole

    Ole Moderator Staff Member Moderator

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    My darkroom leaks too - so much that I do film development by inspection without turning on the safelight.

    I feel worrying over light leaks may be far more damaging than the light leaks themselves.
     
  19. Tach

    Tach Member

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    I waved my profisix around in the darkened room, before trying to lightproof it, and got times like 30' at f/1.0, ISO 6400. Given that result, I don't care anymore for small light leaks.
     
  20. Bruce Schultz

    Bruce Schultz Member

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    I got some black-out curtain material from a fabric store and hung this in front of the door opening. It stops all light, even though the sliding door I built is far from light-proof. The material can be hung to the side to allow easier entry and exit.
     
  21. Early Riser

    Early Riser Subscriber

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    I use fire doors on the entrance to the darkroom and the archive room from which the darkroom is accessed. Fire rated doors usually come with a thick black seal around them, designed to keep smoke from entering I assume. However they are also the best light trap I have yet to see on a door. In the past I used the light seals that you can buy and screw to the doors and they worked ok, but they still leaked. With the fire doors I can have direct sunrise light hit the door, which it does and zero light comes through. One down side is that you may need to add a light tight vent as these doors literally seal a room. When I first got them and turned on the AC in the room the positive pressure made it very difficult to open the doors.

    The problem with hanging a fabric curtain is dust, they attract it, create it (small fibers) and shed dust every time you open them.
     
  22. Chazzy

    Chazzy Member

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    Closing my eyes has always worked for me. :smile:
     
  23. jeroldharter

    jeroldharter Member

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    In my old darkroom, I used a solid core steel exterior door with a magnetic weatherproof gasket around the perimeter and an aluminum threshold. It worked well.

    My new darkroom has a wood interior door with weather stripping along the jamb on 3 sides. A rubber door sweep on the bottom blocks out alot of light. On the exterior, I nailed up some rubber gasket material that usually goes on the exterior of a garage door and that helps alot. I still get a few leaks at the lower corners so I just put a couple of Jobo drums there to block the light.

    I found that on sunny days I get leaks through electrical outlets because there is an outlet in the same spot in the adjacent room. I taped a piece of mat board over the outlet in the other room and that solved the problem.

    I have also found light leaks along the baseboards if the adjacent room is sunny. I did not want to do anything elaborate so I rolled up some old T-shirts and put them along the baseboard in the sunny room.

    I use black electrical tape to cover miscellaneous LED's.
     
  24. leeturner

    leeturner Subscriber

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    I'm using a Durst Modular 70 colour head. Will the light from the colour dials affect anything as I can't find how to switch them off?
     
  25. severian

    severian Member

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    lights

    Yes. Those little lights can add up and fog film. Abolish all little lights.
    Jack
     
  26. leeturner

    leeturner Subscriber

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    OT, there's a little switch on the front of the head but it doesn't seem to do anything. Should this switch off the colour dials light? I have two of these heads but it's the same on both.