light tight darkroom entry door

trudee yama · Aug 18, 2007

Still in the process of building my dream darkroom. Entry door is 36" wide, solid core and swings in....how do I frame for it to be light tight?
Thanks, Trudee

Dan Henderson · Aug 18, 2007

When I built my darkroom, I framed conventionally, then stuffed fiberglass insulation around the door framing. The darkroom side of the wall has ordinary finished drywall and trim. The only thing I did differently was to caulk the juncture of the trim and drywall, then installed weatherstripping around the door. I then closed the door, shut off the lights, waited for my eyes to adjust, then looked for light leaks that I plugged as needed.

Mark Fisher · Aug 18, 2007

I did not bother to weatherstrip. Instead, I painted the door edges and door frame flat black. That blocks out the light well. If that did not work, I considered adding an additional molding mounted on the door as close the opening as I could to add one more 90 degree turn for the light. The harder part is at the bottom of the door. I added an adjustable threshold that is usually used for an exterior door. The bottom has a small leak, but it is plenty good enough.

winger · Aug 18, 2007

My first darkroom had an external type of door. The only slight leaks were at the bottom. There was an added threshold, but it wasn't totally flush to the bottom of the door. I just taped a few of those black bags the paper comes in to the bottom.

glbeas · Aug 18, 2007

A sweep, a rubber flap dragging the floor, helps when used with the threshold. The aluminum and rubber type air seals for exterior doors are a good light tight seal too. My darkroom door only has a few pinholes at the bottom corners.

CBG · Aug 18, 2007

Three basic strategies:

1. Paint edges flat black - already mentioned.

2. Force light to go round corners, add if you can tolerate a clunky look, 1x2" strip or similar to make the path light a zigzag. Every added corner where light must bounce to get in darkens the darkroom greatly - already mentioned.

3. Make the gaps small in width. Often difficult, but in places where it is possible to do it without making the carpentry a pain, go for it. It helps since the amount of light getting through is something of a function of the area you give it to enter.

Best,

C

Ken Nadvornick · Aug 18, 2007

Here's something I did that works not just well, but perfectly, for my darkroom.

I simply purchased one of those pre-built weather resistant doors intended for an external entry. The door is covered with thin sheet metal and built into the frame are those flexible magnetic sealing strips, same as a refrigerator door. A threshold with a rubber sweep that seats into a groove completes the seal.

No special construction effort on my part other than to slip it into the wall frame. It opens and closes like any normal door, but is absolutely light-tight. (Tested by me with floodlights outside and me inside for 30+ minutes in total darkness...)

Ken

jp80874 · Aug 19, 2007

All of the above are very good ideas. I used several constructing my basement darkroom. An additional approach is to look at the light sources. Since my darkroom is 1/4 of the basement I simply turn off the other lights in the basement. No one is using them. If I leave open the door at the top of the stairs some light comes down the stairs giving a guide point so I don't blindly walk into a shelf when I come out of the darkroom.

John Powers

zone6 · Aug 19, 2007

I've always used a pocket door. When it slides shut it is sealed deep into the pocket. They come pre fabricated at home depot. No modification needed. Totally light tight when installed.

Monophoto · Aug 19, 2007

The objective should be to create at least two 90-degree angles all around the door. Light travels in a straight line and won't go around a corner. If will, however, reflect off the surfaces adjacent to a corner, but providing two corners essentially eliminates those reflections.

1. If possible, use oversize door stops. The stops provided with ordinary pre-hung doors are about 1/4" thick. A 1/2" stop is better and can be made by ripping down a piece of "1-by" clear pine. Also, to prevent light from coming under the door stop, apply caulking or a continuous bead of construction adhesive between the door jamb and the door stop

2. Apply weatherstripping on the door stop. I prefer felt weatherstripping for this purpose. Attach it using staples.

3. With the door closed, apply another strip of weather stripping on the door itself, butting it up to the door stop to create a second 90-degree corner.

4. Put some kind of threshold under the door. You can purchase a variety of thresholds at the home center ranging from a 3/8" strip of oak to an aluminum track with rubber weatherstripping. I have found that the oak strip is adequate if combined with step #5.

5. Apply a flexible rubber sweep at the bottom of the door, aligned so that it barely touches the floor with the door open, and covers the threshold when the door is closed.

Mark Fisher · Aug 19, 2007

CBG said:
Three basic strategies:

3. Make the gaps small in width. Often difficult, but in places where it is possible to do it without making the carpentry a pain, go for it. It helps since the amount of light getting through is something of a function of the area you give it to enter.

C

I'd be a little cautious here.....I just had to re-cut my door due to the high summer humidity(I could't get it shut!). Now the gaps are small, but I'm not sure what will happen this winter!

Wilbur Wong · Aug 19, 2007

I'm a general contractor. If you are doing the framing from scratch or installing the door frame from scratch, there are special door frame moldings (wood) which have a saw kerf which accepts a foam rubber gasket which is very light tight. For the floor edge, I like the type of door sweep which has a continuous strip of brush like bristles. The sweeps generally have black bristles, the foam gaskets are available in brown or white.

For my own darkroom (interior room) painting the edge of the door as well as the overlap of the door stop, and the mating door frame area flat black has been quite suffiicient.

John Koehrer · Aug 19, 2007

There are also "drop down" weather seals available at the big box shops.
A ramp is installed on the floor and as the door is opened the weather(now light) seal is lifted. When closed it drops back down.

Michael Kadillak · Aug 19, 2007

zone6 said:
I've always used a pocket door. When it slides shut it is sealed deep into the pocket. They come pre fabricated at home depot. No modification needed. Totally light tight when installed.

Got a pocket door from Home Depot and I found it to not be light tight at all. Light screams in from the bottom and seeps a bit from the edges. When you spend the 15-20 minutes necessary to acclimate your eyes to the dark you can see the leaks.

Solution? A black double thick dark cloth with velcro around the inside edge of the pocket door trim and a long tail at the bottom. My wife sewed it in no time. Easy to use and install.

grahamp · Aug 19, 2007

My pocket door was a salvage item, but I made a point of painting the inside of the door pocket black, painting the edge of the door inside the pocket black, extending the stop side with some 1x1 on both sides to make it deeper (more black paint), and built a channeled threshold. The threshold is not as much trouble as I thought it might be as I do not need to roll equipment in or out. I have a double fluorescent lamp immediately outside the door, so it had to be good. The only thing about the pocket door is that it is not going to be air-tight.

I would have used a swung door if I had the space, I think, but I didn't and I was framing out a wall anyway.

zone6 · Aug 24, 2007

My pocket door is both air and light tight! I built up the threshold so it slides within and seals shut into a deep pocket. I guess I meant the door itself didn't need any modifications. Only the frame.

jeroldharter · Aug 26, 2007

A solid core, flush, steel entry door will be the easiest, cheapest, most light tight without modifications.

As a DIY project, you can use the vinyl flange that seals garage doors and put that around 3 sides of the door and then use a floor sweep at the bottom.

JHannon · Aug 27, 2007

Would a black curtain (weighted bottom) across the door help? I saw this used in one of my darkroom books.

dancqu · Aug 28, 2007

JHannon said:
Would a black curtain (weighted bottom) across the door
help? I saw this used in one of my darkroom books.

Just what I've been thinking of doing. Perhaps a hinged
one end wall mount arm with a dense dark fabric hanging.
Or a rod across as mentioned and looped drape. Some little
room above the door required. Dan

jp80874 · Aug 28, 2007

The curtain solves one problem but adds another. That large a piece of fabric becomes a dust magnet over time. Then as you move it aside or simply pass by, some dust shakes off. Hello little spots.

John Powers

trudee yama · Sep 3, 2007

is there an anti-static spray one can apply on the curtain to avoid dust clinging?? this may sound silly, but WD-40 or LPS-1 or Silicone ....

trudee

richard ide · Sep 3, 2007

A graphic arts supplier should have anti static spray available. WD40 or silicone spray would be a definite no no.

Kilgallb · Sep 3, 2007

Use black out curtain material. It is a white rubberized material that leaks no light and I have never had a dust problem with the material. I used the leftover material to make a dark cloth.

I cut sheet of the black out material that was 6" larger on all sides of the door. I folded each edge over so the light has to turn a corner. The curtain hangs on velcro hooks at the top of the door. I added velcro pads along all the edges for a good seal. The hook material is stapled on the wall and the loop is sewn to the material. Total cost is about $40

cowanw · Sep 3, 2007

My darkroom enters through an outside wall in the basement and I mounted two doors, painted black, with stops all around, so that I or anybody could enter one door shut it and enter the second door at no risk to the darkroom. the doors are about 14 inches apart.
Regards
Bill

Keith Pitman · Oct 10, 2007

I've tried a lot of different things in past darkrooms, but accidentally found a good solution in the current one. In the design, I placed a short wall next to and perpendicular to the door and between the working area of the darkroom. The wall creates a light trap and, even though the door leaks a little light, none of it gets to the work area.

light tight darkroom entry door

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