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How light tight does a darkroom need to be?

Carriage

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Not sure if this is the right forum but I've been working on ways to temporarily light proof my bathroom and seem to have the window sorted but there's a bit of light coming around the door frame edges and through the ceiling exhaust fan. However, while I can see that light, I can't see a black notebook on a white piece of paper after 5 minutes (rule of thumb according to a kodak leaflet I found online), even when trying to it within about half a metre of them. Is this okay or do I need to block them off completely too? I'm wanting it dark enough for loading film into a developing tank as well as printing.

The door shouldn't be too bad as I can buy some fabric and removable sticky hooks to make a curtain if necessary, but I would like the fan so I can have it running.
 
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Light tight enough so that the light sensitive photographic materials that you are using do not fog when exposed for the maximum times your particular darkroom processes require them to be at risk.

This duration can vary significantly depending on the materials and processes you are working with. It can also vary significantly with the safelight technology you use, if your processes allow the use of safelights at all.

And the only way to find that safe duration for your particular conditions is to test for it. If testing fails, then the space is not yet dark enough.

And welcome to APUG. Good to have you here...



Ken
 
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Here's a very unscientific response but the darkroom in Glen Echo Photoworks leaks all kinds of light under the door but the actual working area on the counter remains very dark. Doesn't seem like anyone has any issues with it.
 
This is theory only but if you cover the door with curtain and you have the window light-proofed then wait maybe 10 mins and see if any light penetrates beyond the fan. The fact that you can look into the fan and see light doesn't mean to say that it necessarily escapes out of the fan to the extent that it will affect even film especially if you load film as far away from the fan as possible.

You might want to expose a film and then load and process it without protection over the fan to see of there is any light damage first. If there is you have two options:

1. Load film after dark.
2. Erect a baffle below the fan to prevent light escape. It can't turn corners

When printing you might get away with more light in the room than film loading.

It is "suck it and see" to an extent


Best of luck

pentaxuser
 
When I started out and was making my own darkroom, I was told it had to be dark enough that you could not read a newspaper. if you are using printing paper (which has a very low ASA rating), that works quite well - the short time you have the paper out is not long enough to cause any fogging. For film with a ASA rating in the hundreds, that might not work - I never used film exposed to the ambient light in my darkroom so I don't know for sure.
 
Thanks for the help everyone, I'll let you know how I go.
 
Welcome to APUG

Not completely dark, but dark enough so that the paper does not fog. I use a changing bag for all film always.
 
The only thing that I think you could possibly run into a problem is with the film loading aspect. I am in a similar position you are and I have always loaded film in a darkbag just to be sure, but I have never tested it. You might be okay though. Hard to tell without being there
 
the human eye is so amazingly sensitive to light that, after 5 minutes, even the little green glowing thingies on my enlargers and the faces of my timer clocks seem to be bright enough to see what I'm doing, but even loading Tri-x into reels, and then pushing it to 1600, doesn't seem to fog the film.

And yet I can damn near see well enough to load the film. Very freaky.

I asked a friend of mine with a lot longer darkroom experience than mine what he does when that happens.

He said "I close my eyes."
 
I can see light around the frame of my door if I put my head near it and look, but it has to go around 2 90 degree turns to get to the enlarger and my safelight tests show no fog on pre-flashed paper. For handling film I wait for night and turn the lights off in the outer room too, although I mostly use a changing bag. A bigger problem for me is a line of light that comes out the side of the negative carrier stage and bounces off a white wall. A piece of black foamcore taped to the wall, tilting over to shield the baseboard area solved that problem.
 
Those tiny little glowing things on the hands of old darkroom timers, or little glow dots here and there, will actually fog certain films if
even several feet away for more than a few seconds. The darker the better. Papers are less sensitive than film, and high-speed films more than slow speed (duuh). But long-scale films, even if relatively slow like 100 TMax, can easily get their shadow values muddled by very little
light. Air intake and outlet ducts obviously have to be well designed in the first place, and black inside.
 
During the day, I can see light around the edge of the darkroom door but the light does not get to the enlarger nor the trays. I do most of my darkroom work during the day.
 
Sounds like I'll probably be alright for printing but it may be easier to get a film changing bag for loading the developing tanks.
 
For what it's worth, sometimes the greatest payback for going to the trouble of creating a totally light-proof space is the peace of mind of knowing that particular variable absolutely cannot be the cause of any future problems.

To that end, my darkroom is totally and completely dark. As I've described it before, sensory-depravation dark. You can sit in there for days and still see no light leaks. No glowing tape. No glowing dots. No glowing timers. No power strip LEDs. No door cracks. No ventilation leaks. Nothing.

Thus, when I load my 8x10 film holders I can lay the box containing the sheets out on the counter without worry. If the phone interrupts loading I can talk for as long as necessary without worry. And if I later see fogged negatives, whatever might have been the cause, I know for certain it didn't happen during loading. Not a chance.

Ken
 
I had number of "darkroom" that weren't all that dark.

My very first darkroom was a closet. (real closet) Shut the door and plenty of light leaking around the doors. I made contact prints inside it.
My second or third darkroom was a master bedroom and a bathroom. Turn all the lights in the house off, block the window with a thick cardboard, and only operated at night. Enlarger was in bedroom area. I timed and hoped car won't come by because big window only had a mini-blind. I made 8x10 prints.

Up to this far, my sequences were, paper comes out, exposed for 20 or so seconds, right into processing. No fogging but I didn't let paper hang around too long without processing.

My current darkroom is a smaller bedroom. A window is covered with thick layers of black plastic garbage bags. Leaks were sealed with duct tape. Door has a seal all around gaps. Some light leaks though the bottom but it's dark enough that my eyes has to get used to it before I an see my own hands. I'm not concerned to leave paper out in this darkroom. I sometimes spend minutes burning and dodging.

So it all depends on what you want to do. If you just want to play around with it, you don't need to be that critical.

If you are going to handle FILM, that's a different story. It really has to be DARK.
 
A very easy way to block light fro your door frame is: get two decent diameter dowel sticks that are wider than the frame and attach blackout cloth (longer than the height of the frame to floor and available at fabric stores), place two "L" hooks above the frame, slide one of the dowels over the hooks and just unroll the cloth with the other dowel on the floor weighting the cloth down. When not in use just roll it up like a scroll. My has worked very well actually there are two doors in my darkroom that I block out that way. It has worked well for 39 years.

http://www.jeffreyglasser.com/
 
The light that comes around the edges must either:

1) not reach your film or paper; or
2) be of sufficiently attenuated intensity so as not to matter.

You cannot really measure that light with a meter, so you have to test.

If you really cannot see a piece of white paper on a black background at your working surface after several minutes, most likely you will be fine for film, and will definitely be fine for black and white papers (assuming normal eyesight).

I load film at night, with the lights in the outer room dimmed or off. I also shield the film with my body when I am loading my reels.
 
Shouldn't be able to see your hand in front of your face.
 
"Sounds like I'll probably be alright for printing but it may be easier to get a film changing bag for loading the developing tanks".

That's about it in a nutshell. A very small amount of light leakage in the darkroom area is usually OK as long as it's not directly on where you print and where you have your papers. For film, just get a change bag (the bigger, the better). I had to tape up a lot of areas on my enlarger that were leaking light, and that type of light you want to avoid, as its bright and directional. Don't forget to throw towels over the mirror and shiny stuff in the room.
 
film would be my biggest concern. changing bags are not expensive
 
It takes the human eye approximately 30 minutes to fully adapt to the dark. You should start looking for light leaks only after this period of time. However the eye is much more sensitive to light than any photographic materials. So leaks that do not directly impinge on photographic materials are less important than those that do.

As an aside, people tend to paint the walls of dark rooms black. This is exactly what you should not do. You need to take advantage of the small amount of illumination that safe-lights provide. The only portion that needs to be black is the wall directly behind the enlarger to reduce the effect of light leaks from the enlarger.
 
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I absolutely despise using changing bags. I would strongly suggest avoiding them, if you can.

As is probably obvious from this thread, some are happy to use them.

In my opinion, it is worthwhile taking extra steps to lightproof your working area for film (including limiting the times you load developing reels), and performing tests.
 

My darkrooms have white walls which improve the effectivity of the safelights. The dry darkroom is a bedroom turned into a den and the wet darkroom is a master bathroom.
 
MattKing said:
I absolutely despise using changing bags. I would strongly suggest avoiding them, if you can.
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Hi Matt, I remember you writing this before, and can understand but it makes me chuckle. I always spool film in the changing bag even if it's after dark and I could sit in my darkroom. Funny how habits are and that we get used to and comfortable with doing things a certain way. I like to sit back on a couch and relax while spooling... it's a calming relaxing thing to do. I do handle sheet film in the darkroom.
 
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