How much daylight in the darkroom can film/paper tolerate?

Jerry_K · Feb 17, 2016

Like most people in the world I don't have access to a true, dedicated darkroom and have to resort to utilize my bathroom. And like most bathrooms, mine is too far from perfectly light-tight - there is very little light admitted through the narrow slots between the door and the door jams and the floor.

In general, how much light can B/W film and B/W paper tolerate without measurable fogging for a duration that corresponds to a typical darkroom work cycle (say, an hour or so of exposure).

I'm asking because any major remodelling is out of the question and light sealing all the openings is cumbersome to say the least and I would really like to get into the darkroom at the whim and start working without extensive preparations of the working area. If I can make do without it, that is.

Assume the safelight is present too. On the same note, can the phosphorus on the clock face of my wrist watch fog the film? I always take off my watch before putting my hands into the light tight bag to load my film into tanks; I'm afraid of putting the clock face into close proximity of emulsion, but may be it's just a mild paranoia.

Appreciate your answers,

Jerry.

Photo Engineer · Feb 17, 2016

Neither film nor paper can tolerate much daylight due to the UV. All analog photo products have a lot of UV sensitivity, sometimes more than that to visible light. So be careful.

PE

Bill Burk · Feb 17, 2016

I comfort myself when I see a light leak by trying to guess how long it would take for the light (that leaks in) to show up on film if I wanted it to.

In case you fog film a little, the resulting negative can still be very useful. I think it is worse to fog a print. There are some real good tests for safelight safety, the best tests include a picture of something shiny like a silver plate or hubcap which you print and then cover half the print. You will notice a disgusting degradation in highlights if the darkroom or safelight is bad for printing.

Bill Burk · Feb 17, 2016

Photo Engineer said:
Neither film nor paper can tolerate much daylight due to the UV.

Good point! All the better to print at night in a makeshift darkroom.

Jerry_K · Feb 17, 2016

Photo Engineer said:
Neither film nor paper can tolerate much daylight due to the UV. All analog photo products have a lot of UV sensitivity, sometimes more than that to visible light. So be careful.

Of course, but my question was "how much"? Can it be quantified somehow? I'm talking the amount of light that shows 0.0 on my spotmeter, so that's obviously not very helpful. Also, it's so dark in the bathroom that I would still need the safelight. The daylight I'm talking about is merely three (albeit clearly visible) lines demarcating the contours of the door.

Ron789 · Feb 17, 2016

Don't take any risk with film. If light leaks in during the day then wait until darkness outside. Paper is much less sensitive. If in doubt, simply test it.

Jerry_K · Feb 17, 2016

Bill Burk said:
Good point! All the better to print at night in a makeshift darkroom.

Darn! Why didn't I think of that!

This is not sarcasm, I really really could do that given my floorplan and location of bathroom doors relative to windows. After all, during the day I'm (or should be) out shooting, mostly. Only on some weekends this day light issue would really be a problem.

Wayne · Feb 17, 2016

You may not want this suggestion but 2 pushpins and a 3 x 8 sheet of black visqueen or heavy fabric and your troubles are over. If you don't want holes use velcro. Either way it goes on and comes off in seconds. I bring a sheet with me when I travel to block out light in motel bathrooms closets, etc.

Jerry_K · Feb 17, 2016

APUGuser19 said:
If you see white light, it is too much. It's as simple as that. If you go in and can perceive your hand motion in front of your face after 5 minutes, this is WAY too much for film. As for paper, expect a dingy look that eludes process manipulation to eliminate. This is not to say it requires being in a coal mine on Pluto, but it would be really helpful if it were. Find those leaks and seal them up, preferably after sundown. as for me, my whole house is a the darkroom, at night, at least a week from any full moon.

Thank you APUGuser19, that was very helpful quantitative answer. So I guess, it's going to be a night time hobby for me, unless I'm really motivated during the day and have a roll of black duct tape handy .

frank · Feb 17, 2016

It's very easy to test. Leave a piece of phptp paper, partially covered by an opaque object, exposed in your "darkroom for a few minutes. Then process it to see if the uncovered area was affected by the light that sneaks in.

ic-racer · Feb 17, 2016

You can answer your own question (but only you). Flash a piece of paper to a very light gray (some trial and error to get exposure correct, yes). Put a coin on the flashed piece of paper and place on your enlarger baseboard or where your trays will be. Leave it out for twice or three times as long as you think you will ever have a piece of paper out. Process the paper and see if you can see the outline of the coin.

Jerry_K · Feb 17, 2016

frank said:
It's very easy to test. Leave a piece of phptp paper, partially covered by an opaque object, exposed in your "darkroom for a few minutes. Then process it to see if the uncovered area was affected by the light that sneaks in.

ic-racer said:
You can answer your own question (but only you). Flash a piece of paper to a very light gray (some trial and error to get exposure correct, yes). Put a coin on the flashed piece of paper and place on your enlarger baseboard or where your trays will be. Leave it out for twice or three times as long as you think you will ever have a piece of paper out. Process the paper and see if you can see the outline of the coin.

Excellent suggestions, I may end up doing that with a piece of paper and a last or first inch of 120 film that was normally exposed in camera. This way the comparative sensitivities of both film and paper will be separately accounted for.

Wayne said:
You may not want this suggestion but 2 pushpins and a 3 x 8 sheet of black visqueen or heavy fabric and your troubles are over. If you don't want holes use velcro. Either way it goes on and comes off in seconds. I bring a sheet with me when I travel to block out light in motel bathrooms closets, etc.

I do like the push pin idea! They leave holes almost invisible in the a textured wall. Thanks, Wayne!

bdial · Feb 17, 2016

You can add some weather stripping around the door frame and a rubber door sweep on the bottom to eliminate most of the leakage from a door without affecting the function and with minimal impacts on the looks.

It's hard to quantify how much is too much, as it depends on what sort of path that light has to your materials, and what surfaces it might be bouncing off of. Every situation is different.
In general terms, any is too much, but what you might get away with requires testing.

NedL · Feb 17, 2016

Jerry_K said:
Darn! Why didn't I think of that!

This is not sarcasm, I really really could do that given my floorplan and location of bathroom doors relative to windows. After all, during the day I'm (or should be) out shooting, mostly. Only on some weekends this day light issue would really be a problem.

Mine is a walk-in closet, but similar. I only work with film at night, and close the shades and door in the outer room when I do. For paper and making enlargements, I close the shades in the outer room, and I have two thick blankets that I can hang up to cover the two windows if needed. There are some times of year when the sun hits the windows directly aimed at my closet door... usually I just don't bother if that's happening, but inside the closet there are some heavy black cloth strips that I can roll down on either of the door frame ( the top of the door fame has a loose sheet of heavy cloth permanently hanging over it from the inside ). My bigger problem is controlling light leaking out from the negative stage of my enlarger and reflecting around.... I use a lot of black tape to prevent that. I also have some black foamcore "baffles" that I can lower down on either side of the baseboard to help shield it.

Sirius Glass · Feb 17, 2016

I cover the windows and doors with black out curtains held in place with velcro. The door covers on the outside of the doors. I remove the covers when I am not using the darkroom.

removed account4 · Feb 17, 2016

Jerry_K said:
Like most people in the world I don't have access to a true, dedicated darkroom and have to resort to utilize my bathroom. And like most bathrooms, mine is too far from perfectly light-tight - there is very little light admitted through the narrow slots between the door and the door jams and the floor.

In general, how much light can B/W film and B/W paper tolerate without measurable fogging for a duration that corresponds to a typical darkroom work cycle (say, an hour or so of exposure).

I'm asking because any major remodelling is out of the question and light sealing all the openings is cumbersome to say the least and I would really like to get into the darkroom at the whim and start working without extensive preparations of the working area. If I can make do without it, that is.

Assume the safelight is present too. On the same note, can the phosphorus on the clock face of my wrist watch fog the film? I always take off my watch before putting my hands into the light tight bag to load my film into tanks; I'm afraid of putting the clock face into close proximity of emulsion, but may be it's just a mild paranoia.

Appreciate your answers,

Jerry.

hi jerry

can you get black felt from a local fabric store ? that and some velcro or push pins
might help with your windows and doors. a rolled towel on the floor by the door bottom
will also keep light out. i can't help you if you have light coming in from where the ceiling meets the walls
when i had lots of that i had to glue a bead of black felt in the meeting of the wall and ceiling, luckily it was
cheap accommodations it really wouldn't be acceptable if it was a bathroom, it didn't really look very good ..
no idea about glowing - stuff. i still put an over turned box on my enlarger timer because it glows, and the
gralab doesn't glow enough that i can see it in the dark ...

MattKing · Feb 17, 2016

I use a bathroom as a temporary darkroom. I have weather-stripped the door that is most exposed to outside light, and when light levels are high I put a towel on the floor.

You can see faint light around the doorway, but on the other side of the relatively narrow room, I cannot see the reels when I load them with exposed film.

I have had no problems with exposed or fogged films. I do sometimes wait until night if I am spending a lot of time with film (e.g. when loading multiple rolls into reels and tanks) but that is often because it is easier to ensure uninterrupted "darkroom" time then.

When it comes to printing, sometimes I'll spend long periods of time in the room with the lights on outside. I can still see those faint lines around the door, but have no problems with paper fogging or loss of contrast.

Paper has quite low sensitivity. Light is quite directional. I recommend limiting extraneous light, but I would suggest that reasonable care will solve any problems you might encounter.

As for the face of your watch, I wouldn't bring it into contact with your paper and really wouldn't bring it into contact with film. Short of that, I wouldn't be too concerned.

gone · Feb 17, 2016

I worried far too much over this issue. Finally just shut my bedroom door w/ a doubled over blanket stuffed into the top. A few towels hung strategically took care of small light leaks on the side and bottom. Two window blockers were made from 1x1's and cardboard, w/ a bit of black paint for insurance. These were placed over the two bedroom windows, and rested on a piece of 1x1 that was screwed to the wall on the bottom of the window. A budgie cord hooked to 2 little hooks on either side of the windows pulled things taut against the wall, and a towel took care of any light seepage around the edges. Takes no time to set up and take down, lives under the bed when finished. I'd been holed up in the bathroom before this, and the bedroom was a BIG improvement for printing, let me tell you. Total cost was about $20.

The first time, I stood in there for 15 minutes at high noon in Florida and couldn't see a thing. Prints look real fine. Another small towel is draped over the enlarger head when I'm printing to deal w/ light around the usual places. Later I bought $4 worth of dark fabric from Walmart to work better than the towels, but it's not necessary.

This really doesn't answer your question of how much light can be tolerated, but why add another variable? Just get it good and dark, and you don't have to sweat it.

Photo Engineer · Feb 17, 2016

The answer is a red safelight for paper and nothing for film and there is no other answer out there.

PE

bence8810 · Feb 18, 2016

I also heard that film has no tolerance what so ever so whenever I need to work with film (unreeling a 400ft roll into 4 x 100ft rolls) I do it in a darkbag - in my darkroom. This may sound funny but my dakroom is only dark enough for paper but not for film so I do everything in the darkbag and should I ever need to pull my hand out for whatever reason midway (an hour process to unreel the film), i figured sitting in the 99% darkness would help.

For paper I just go with the flow, make sure the little light that comes in besides the door should not directly hit the paper and I've been okay. I put black tape around the doorframe so it wouldn't reflect anywhere but after 5 or so minutes sitting in the dark with safelight off, I can clearly see where the light comes in by the door.

If I were you, I'd keep printing daytime too - no need to limit yourself to nights only. Get a black cloth from someplace and hang it above your door - problem solved. A rolled up towel pushed against the door at the bottom will take care of the light coming in from there.

Ben

mooseontheloose · Feb 18, 2016

APUGuser19 said:
How many of us here have gone in our makeshift darkrooms and closed their eyes when loading the tank? Be honest, now.

Apparently, it's quite common....(there was a url link here which no longer exists)

pdeeh · Feb 18, 2016

Jerry_K said:
but my question was "how much"? Can it be quantified somehow? .

Hmm Maybe first you need to establish (perhaps from the manufacturers) what the exact value (in whatever SI units) at which the film or paper will start to form development sites (above any base fog I suppose?), and then get some measuring equipment into your darkroom that will give you an accurate reading of light levels that low, and compare the figures.

But it's just possible this may not be practical.

Meanwhile, am going to devote my energies to establishing how long a piece of string is (and not just one particular piece, either)

removed account4 · Feb 18, 2016

APUGuser19 said:
How many of us here have gone in our makeshift darkrooms and closed their eyes when loading the tank? Be honest, now.

it doesn't matter if it is a makeshift or an established dark room, rotary door, pitch black, no windows, light creep&c.
I know I close my eyes every time I load a reel, been doing that since the first time, 35 years ago

pdeeh · Feb 18, 2016

I've just remembered there's an excellent thread on makeshift/bathroom/temporary darkrooms here: (there was a url link here which no longer exists)

Neal · Feb 18, 2016

Dear Jerry,

First, get a changing bag for loading film onto reels for developing or bulk loading. I splurged on Dead Link Removed and I can unload two Graphmatic holders and load the 12 sheets of 4x5 film onto two Jobo reels and into the 25XX tank.

Next, simple weatherstripping will do 99% of the work for you around doors. Tiny leaks are not a problem for paper. Quantifying how much is too much can only be done by you. My "darkroom" is the garage. After weatherstripping the garage door and cutting a couple of two by fours to lay down at the base the light leakage problem was sufficiently solved.

Good luck,

Neal Wydra

How much daylight in the darkroom can film/paper tolerate?

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