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Building a Darkroom: Light tight room

Contents

Black Walls?
Test for light leaks
Plugging leaks
Light proofing your enlarger
Light proofing a viewing box

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Black Walls?

Many people believe that a darkroom should be painted black inside, I don't agree. I've worked in darkrooms for several years now, and I'm most comfortable with white walls. A low wattage safe-light (7w or 15w) provides plenty of light in such a room. I point the light at the ceiling or the wall, and the entire room lights up, not enough to really see, but enough that I don't bump into anything, and can tell what I'm doing comfortably. I also can use a low enough wattage bulb that I have no problem with fogging.

Here are my reasons for having the walls white
  1. If the room is truly light tight, then when the lights are turned off inside the darkroom, there will be no light to affect the process, so wall color is immaterial.
  2. When you turn on a safelight in a room with dark walls, the light does not reflect, so it can be very dark, but if the walls are white, then the light is reflected, and the entire room appears lighter, making it easier to see.
  3. If you shine the safelights up, at the ceiling, the whole room is lit up, making it easier to see things, and avoid bumping into things.
  4. If you shine the safelights up, it increases the distance from the lamp to the paper, making the safelight actually safer.
  5. White walls in a darkroom (or some other lighter color, pale yellow for example) are much cheerier, and make the room "feel" bigger.
  6. White walls, instead of a light pale color, don't affect the "color" of the light in the room. (others people use pale yellow, or some other light color with success, so I don't know if this is really a concern)
  7. When you turn on the white lights in a darkroom with dark walls, you need a more intense light to have the same level of light as you need in a room with white walls (I use a 40 watt bulb in the darkroom, and the light is REALLY bright, I could use 15 watts), if you're using a higher wattage bulb (60 or 100 watts) to make up for the dark walls, your eyes take longer to adjust when you switch from room lights to safe lights.
  8. In disucssions on the newsgroup rec.photo.darkroom most people are using light colored walls in their darkrooms for these reasons.
  9. In looking at darkroom magazines, or photo magazines when they show the interior of darkrooms, I've seen that most of the printers prefer white walls, some even go so far as to put white tile on the walls, so the lights are reflected.
BUT, in order to have white walls, you really need to make sure you have plugged any light leaks, I talk about doing that on this page. Some people, even with white walls, have enlargers that leak light profusely, so they paint the wall behind the enlarger flat black, to absorb the stray light. I have a cold light head, so I can put a cover over the lamp housing so that it doesn't spray light.

The most important thing you can do is have walls and ceilings that are covered on bothsides with drywall, this will prevent most of the light leaks.

You should light proof the door also.

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Test for light leaks

To see if the room is light tight, turn all the lights on you can on the outside of the room, let in the sunlight if possible, close the door, and turn off the darkroom lights. Now wait for a couple of minutes. Unless you are a freak you will have some light leaks at this point. It is close to impossible to identify them so that when you turn the lights on you will be able to find them again. If you have safelights already, using a very low wattage bulb (7 watts), you can get enough light to be able to mark the leak with a pencil or something without injuring yourself. If not, try to orient yourself inside the room (3 foot lengths from this corner, straight up, etc.)

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Plugging leaks

Once you have the leaks identified, it's time to plug them.

When you think you've plugged all the light leaks, try the dark test again. After 5 full minutes in the room you should not be able to see your hand 6" in front of your face.

Don't get frustrated, my first time, I did the process at least a dozen times before I was happy with the results.

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Light proofing your enlarger

Inside the darkroom, you generate white light in the enlarger, and if it has any leaks that light can be reflected off of walls, metal, or other objects, and fog your paper.

You can't put a black plastic photo enlarger paper bag over the enlarger, because they generate heat, even cold light heads create enough heat to not try this. But you can baffle the light so that it does not get anywhere dangerous.

Some people paint the walls and ceiling around the enlarger flat black, I don't like that idea much.

Each enlarger is different, I removed the egg shaped cover on my enlarger when I switched to a cold light head, the head slips into a tube of metal, but it is not a tight fit. I put fabric around the light head, then slide it into the tube, and now no light leaks out. (I used the elastic portion of a sock)

There are two small openings on the sides of my enlarger (not where the negative carrier goes!) that let light out, I covered those with pieces of black plastic from enlarger paper.

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Light proofing a viewing box

If you make a negative / slide viewing box, and use fluorescent lighting, you need to make sure that no light escapes from this box, even when the lights are turned off! Fluorescent light emit UV light for some time after they are turned off, and papers are sensitive to UV light.

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Visitor Comments

The comments stated below are not necessarily the opinions of Andy Hughes or DarkroomSource

If you have small light leaks you can always use duct tape to stop the light. When I made a dark room with drywall on one side I covered my outlets with duct to stop light.
Contributed by   on 2002-07-02 00:00:00

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