How Dark should the Darkroom be?

Kirth Gersen · Jan 21, 2019

Final question for today.

I've got the darkroom pretty dark. After sitting in there for a few minutes, I can just about see my hands move in front of my face... just. Can't see any chinks of light. Must be coming through the masking tape or the air vent.

Anyway, I have seen lots of suggestions as to what is right. Some say 'absolute darkness' is the only way, others say they have chinks of light, but as long as it they are not shining directly at the paper, it should be alright. I came across a youtube guru called Darkroom Dave, and was distracted by the massive chink of light coming from under his door in a safelight situation. Couldn't concentrate on the instruction!

Thoughts?

Thanks

Richard

Neal · Jan 21, 2019

If your paper is not fogging it is fine for printing. Light leakage is more important for film. Personally, I don't trust my darkroom for film.

Alan9940 · Jan 21, 2019

I have very minor light leaks in a couple of spots around my darkroom door. From the sink area, you have to move around a bit to even see them. The door is about 6 feet from the main working area of the sink. I develop sheet film in tanks/hangers and have never had an issue. No problem with printing, either. I do, however, load sheet film into holders at night with most house lights off. I should probably mention that I can't see my hands in the dark.

grahamp · Jan 21, 2019

Well, if it is totally light-tight, you know you are safe. I have to be particularly careful, since some of my blackout is exposed to direct sunlight. A pinhole or two could dona lot of damage.

Light under the door has to bounce off the floor and find a way to the work bench. Reflection losses and inverse square law are your friends in this case. But if you start doing procedures that need the paper out longer, or where you have to handle film, you may begin to notice fogging. Any ambient light is going to risk fogging.

Patrick Robert James · Jan 21, 2019

After you have sat in your darkroom for ten minutes or so in complete darkness, you should be able to see any light leaks. It is best to eliminate them. Do you have to? Depends.

You can test if you want to see if your current situation is ok. Expose a print, then put a coin on the highlight. Turn off all your safelights, then let it sit for ten minutes. If you can't see the outline of the coin after you develop the print then you should be fine.

Kirth Gersen · Jan 21, 2019

I expose my film in a tent, so that's not the issue. It's the paper. I guess trial and error is the only way for each individual dark room. Will try the 50p test.

MattKing · Jan 21, 2019

To make the test fully effective, try to do it two times. Once during the daytime when there is light outside the darkroom, and once at night with all the lights and other potential sources of problems outside the darkroom turned off.
Sometimes light leaks don't result in visible fog, but rather in a change (lowering) of apparent contrast.
FWIW, I've worked for years in a temporary darkroom that isn't absolutely light sealed, but the little strips of lighter area around the edges of the doors don't cause me problems.

guangong · Jan 21, 2019

From your description, what I have done in such situations is to aim safe lights at where light could be leaking, thereby coloring the incoming light to make it safe. Worked for me in the past.

Pieter12 · Jan 21, 2019

guangong said:
From your description, what I have done in such situations is to aim safe lights at where light could be leaking, thereby coloring the incoming light to make it safe. Worked for me in the past.

Bad solution. I'm pretty sure it doesn't work that way.

pentaxuser · Jan 21, 2019

guangong said:
From your description, what I have done in such situations is to aim safe lights at where light could be leaking, thereby coloring the incoming light to make it safe. .

I am not sure that the "physics" actually supports this theory. It clearly works for you but it might work even if your safelight wasn't pointed at the light leaks due to the light needing to turn corners, inverse square law etc

I say this not to start an argument but to caution the OP against this as a foolproof remedy. If the leaks can be seen then if at all possible plug the leaks.

pentaxuser

MattKing · Jan 21, 2019

guangong said:
From your description, what I have done in such situations is to aim safe lights at where light could be leaking, thereby coloring the incoming light to make it safe. Worked for me in the past.

Won't do what you want it to do. You can't colour light by adding other light, even if the visual impression you get from the result appears differently.

Bill Burk · Jan 21, 2019

I think that chink of light coming through under the door jamb is dimmer than you imagine (it's been amplified for video).

Imagine the same strip is hard to see until your eyes adapt, and it's not caused by a light on or full daylight in the other room, but is already coming in from a room with "subdued" light.

That's probably a "good" example of what you can get away with. If the other side of the door was bright though, I'd throw down a towel when using the darkroom.

M Carter · Jan 21, 2019

Every darkroom I've had, I have a small closet for loading film that's 10% light-tight. If I wanted to load film in the main area, I'd have to go turn off every power strip (red pilot lights), the red-LED clock-radio, and cover up the iridescent glowing thermometers and timer knobs. It's easier to make a small space 100% light-tight, and much much easier to keep it dust free (gloss or semi gloss surfaces, small humidifier in the winter and so on). I found shooting 4x5 E6 products that it was really necessary, and I never had a single dust spot on my film.

MattKing · Jan 21, 2019

M Carter said:
Every darkroom I've had, I have a small closet for loading film that's 10% light-tight.

I expect you mean 100% light tight here.
And I agree - closets can work for this.

BMbikerider · Jan 21, 2019

You can get away with a few light leaks when using B&W providing they are not in line with the paper when it is on the easel. With colour it is a different matter. It should be as light tight as possible. I have ceased to do colour now but when I did, I was almost paranoid about any unwanted light. Even the LED glow from the enlarger timer was a matter of suspicion. The only light I had was that from my DUKA colour safelight, but that is high up on the wall and reflects the light off the ceiling. I have never had problems when using the DUKA - it does what it is designed for..

Doremus Scudder · Jan 21, 2019

Two things:

I think guangong's post about pointing the safelight at the light leak was an attempt at humor (I certainly hope so, anyway!) It certainly doesn't work.

Being "just about able" to see your hand in front of your face in total darkness can be an illusion. When your eyes aren't receiving any information, your brain often tries to fill in by supplying what it "thinks" you should be seeing. Don't trust that; look around your darkroom and see what you can see. Get on your hands and knees, put a mirror in your processing trays (to see what they see that you don't) and examine all around doors, windows and lightproofing from all possible angles.

Yes, when printing, you can often get by with a small leak or two, but why take the risk. It's not all that hard to track down the leaks and fix them. A lot better than finding out by ruining film or prints. With black and white papers, I don't worry about my red LED timer numbers or the glow-in-the-dark dials on my thermometers and timers. When film comes into play, they all get little black plastic hoods or shields.

Best,

Doremus

Brendan Quirk · Jan 21, 2019

Doremus Scudder said:
Being "just about able" to see your hand in front of your face in total darkness can be an illusion. When your eyes aren't receiving any information, your brain often tries to fill in by supplying what it "thinks" you should be seeing.

Certainly true. I know for a fact that my darkroom is light tight, as I routinely load film right out in the open without problems. Yet it sometimes can seem like I can see my hands. If you move them quickly, though, you may still "see" them in their original position.

Luckless · Jan 21, 2019

A research lab I worked in years ago had a simple solution to the problem of tracking down light leaks:

Photograph them.

Set a camera up, and take a 'reasonably long exposure' while pointing in different directions. We did two sets of tests, a pure ambient light test, and another where we were outside popping off a high powered studio flash aimed at anything we thought might have a crack that could let light in. (And each 'dark' frame was also followed by a normal 'lights on' photo for reference as well without moving the camera. Makes it a LOT easier if you do detect a faint and out of focus light leak, and don't have to try and piece together which test the photo was from...)

We started off with just a general 30 second exposure, and went up to over a day during our final sign off on the space.

Keep in mind to match what you are testing for with the film you use. If you're only going to be using blue-green papers, then filter your film to blue-green, or use a camera that can take paper negatives.

However, chasing down 'light leaks' should be tempered with things like coin-tests. Laying down a small test piece of paper that you place a solid coin or similar object over, and allowing it to be out for longer than you expect the paper to be out normally. If no edge can be seen after developing the test piece, then you didn't have enough light hitting the work area to matter. - If you can still photograph a random light leak, but the coin test passes, then odds are you're probably fine. But only you can decide how paranoid against light you want to be.

Also it just seems like good practice to store light sensitive materials in light tight storage as much as possible. Getting into the habit of spreading stuff out in a darkroom just leaves you at risk of having more damage done in the event of a silly accident, like bumping a switch, or something shorting with a bright spark. - If it is stored away in a redundant light safe, it is less likely to accidentally be exposed to light.

It isn't paranoia if the risk is real...

Kirth Gersen · Jan 22, 2019

Thanks all once again for some tremendous advice. I really like the idea of taking a long exposure photo, and I will do the coin test. I must admit to feeling fairly confident now that my room is dark enough. the way I have set it up, the enlarger is in a corner and all possible light sources will be behind me and will be partially blocked by my body as I work on the print. The comments on loading film in the room aren't relevant as I will continue to use my light tight tent.

First run will be this evening. I have no doubt it will be challenging. Wish me luck!

guangong · Jan 22, 2019

Sorry to disappoint, but my safelight approach worked just fine for me many years ago. Not speaking of a bright stpot of light, but that kind of dimness that sort of seeps through. The room I printed in was large and in rented apartment and was unable to economically make absolutely dark. Used a very large safelight suspended from ceiling with barn doors aimed at troublesome area. This safejight was many feet away from my enlarger. And it did work! I did only BW, used graded enlarging papers, (never tried with multigrade papers or color),:used changing bag for loading film (35mm to 4x4) into daylight tanks as well as other tasks that required complete darkness. My approach was obviously not a solution for unexposed or undeveloped film.
As I understood th OP, his darkroom only revealed not being completely dark after several minutes while his vision adjusted to the darkness. It seemed there were no obvious light leaks, such as cracks under door or windows, so I just related my own experience

The ways mentioned for tracking down light leaks in many of the responses to this thread are very practical. Different conditions require different solutions.

Interesting thought. Before Edison darkness was easy to achieve. Now light can be pollution. Read Tale of Genji or Brantome’s Tales of Gallant Ladies (history written in 16th century) for possibilities of romance in total darkness before electric lights. Today, analog photographers may be the only folks who experience total darkness.

Pieter12 · Jan 22, 2019

Kirth Gersen said:
Thanks all once again for some tremendous advice. I really like the idea of taking a long exposure photo, and I will do the coin test. I must admit to feeling fairly confident now that my room is dark enough. the way I have set it up, the enlarger is in a corner and all possible light sources will be behind me and will be partially blocked by my body as I work on the print. The comments on loading film in the room aren't relevant as I will continue to use my light tight tent.

First run will be this evening. I have no doubt it will be challenging. Wish me luck!

Don't ignore the processing area. Paper is more sensitive to light after exposure.

RalphLambrecht · Jan 22, 2019

Kirth Gersen said:
Final question for today.

I've got the darkroom pretty dark. After sitting in there for a few minutes, I can just about see my hands move in front of my face... just. Can't see any chinks of light. Must be coming through the masking tape or the air vent.

Anyway, I have seen lots of suggestions as to what is right. Some say 'absolute darkness' is the only way, others say they have chinks of light, but as long as it they are not shining directly at the paper, it should be alright. I came across a youtube guru called Darkroom Dave, and was distracted by the massive chink of light coming from under his door in a safelight situation. Couldn't concentrate on the instruction!

Thoughts?

Thanks

Richard

as light-tight as you can get it is almost dark enough.

Sirius Glass · Jan 22, 2019

Neal said:
If your paper is not fogging it is fine for printing. Light leakage is more important for film. Personally, I don't trust my darkroom for film.

Alan9940 said:
I have very minor light leaks in a couple of spots around my darkroom door. From the sink area, you have to move around a bit to even see them. The door is about 6 feet from the main working area of the sink. I develop sheet film in tanks/hangers and have never had an issue. No problem with printing, either. I do, however, load sheet film into holders at night with most house lights off. I should probably mention that I can't see my hands in the dark.

For printing my darkrooms, dry and wet are dark enough. If I want to do color work or work with film, I can make it completely dark.

Doremus Scudder · Jan 22, 2019

guangong said:
Sorry to disappoint, but my safelight approach worked just fine for me many years ago. Not speaking of a bright stpot of light, but that kind of dimness that sort of seeps through. The room I printed in was large and in rented apartment and was unable to economically make absolutely dark. Used a very large safelight suspended from ceiling with barn doors aimed at troublesome area. This safejight was many feet away from my enlarger. And it did work! I did only BW, used graded enlarging papers, (never tried with multigrade papers or color),:used changing bag for loading film (35mm to 4x4) into daylight tanks as well as other tasks that required complete darkness. My approach was obviously not a solution for unexposed or undeveloped film.
As I understood th OP, his darkroom only revealed not being completely dark after several minutes while his vision adjusted to the darkness. It seemed there were no obvious light leaks, such as cracks under door or windows, so I just related my own experience

The ways mentioned for tracking down light leaks in many of the responses to this thread are very practical. Different conditions require different solutions.

Interesting thought. Before Edison darkness was easy to achieve. Now light can be pollution. Read Tale of Genji or Brantome’s Tales of Gallant Ladies (history written in 16th century) for possibilities of romance in total darkness before electric lights. Today, analog photographers may be the only folks who experience total darkness.

Just for posterity and for others who might be beginners and are just researching the topic:

The approach guangong describes above is contrary to the laws of physics and simply will not work! It reflects a basic misunderstanding of the principles involved. Whatever "success" was achieved with this method was coincidental and unrelated to pointing the safelight at a light leak. You simply cannot change the color or intensity of a light source by pointing another light source at it; both color and intensity are additive and the result will be a more intense light with an intermediate color.

I would recommend to the poster to do a bit of research on the basic science behind light. Wikipedia is a good place to start.

Best,

Doremus

dmr · Jan 22, 2019

My current "darkroom" is the bathroom, which I use to load film into the tank. If it's daytime, I'll stuff a dark towel in the crack under the door to be sure, but at night it's totally dark. No windows and no windows in the adjoining hallway.

However! Once I realized, right after I started to wind the film on the reel, that the little green LED in the electric toothbrush charger was on and quite visible! I quickly turned so as to load the film in the shadow. No fogging at all. (WHEW!) After that I unplug it before I load the tank.

How Dark should the Darkroom be?

Kirth Gersen

Neal

Alan9940

grahamp

Patrick Robert James

Kirth Gersen

MattKing

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guangong

Pieter12

pentaxuser

MattKing

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M Carter

MattKing

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BMbikerider

Doremus Scudder

Brendan Quirk

Luckless

Kirth Gersen

guangong

Pieter12

RalphLambrecht

Sirius Glass

Doremus Scudder

dmr

How Dark should the Darkroom be?

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