How light tight for print making darkroom

[JBrunner]

Why, I wonder, has nobody mentioned the coin test? Lay a coin on a piece of unexposed paper and leave it for some length of time. Develop the paper and see if you can tell where the coin was resting. If so, you need more light proofing.

Yes, this is the simplest of tests. a better test is to evenly pre-flash the paper just a bit, as paper that is being exposed (like the one your making your next masterpiece on) is more sensitive to light problems because it has "got a start". Takes very little time and effort. Those that have leaky darkrooms, but say they're not getting fogging- Do you really know that? Or are you just guessing? Eensy paper fogging may not be readily observable, but it is a highlight killer. We have the occasional thread "How do I get that glow?". Well, you'll never get it in a leaky darkroom or unsuitable safelight/paper combo, but you might plug away a long time looking for a magic bullet that will never come because you have a fundamental problem that is undetected.. Dark is dark.

 

[nyoung]

I have often wondered if, instead of blackout material, using a red gel sheet over windows etc. would work for an enlarging only darkroom.

When I was allowed to spec a darkroom/classroom in a new building ten years or so ago we put a 4x8 foot plate glass window between the classroom and the printing area of the darkroom.

Window was tinted with an OC Amber film we bought from Calumet, I think.

Let the teacher monitor goings on in both rooms from either room.

 

[hoffy]

Yes, this is the simplest of tests. a better test is to evenly pre-flash the paper just a bit, as paper that is being exposed (like the one your making your next masterpiece on) is more sensitive to light problems because it has "got a start". Takes very little time and effort. Those that have leaky darkrooms, but say they're not getting fogging- Do you really know that? Or are you just guessing? Eensy paper fogging may not be readily observable, but it is a highlight killer. We have the occasional thread "How do I get that glow?". Well, you'll never get it in a leaky darkroom or unsuitable safelight/paper combo, but you might plug away a long time looking for a magic bullet that will never come because you have a fundamental problem that is undetected.. Dark is dark.

Sounds fair. I have done some fog tests, but these were done in either a) total darkness or b) with the safe light, straight from the packet.

When you suggest pre flash, for how long and using what method? Just put it under the enlarger @ F16 for a second or two?

Cheers

 

[JBrunner]

There are others that are far more technical than me. I just flash the paper to a light grey, the exact exposure will vary with your paper choice and enlarger. No need to use an entire sheet, just a piece and the remainder can become test strips.

 

[hoffy]

Thanks J. Next weekend when the darkroom is set up again, I will give it a shot. From the fog tests that I have done thus far (OK, I didn't use a coin, I used the focus scope) everything has been fine.

 

[Ade-oh]

Complete light-tightness is difficult to achieve in a home darkroom but it isn't entirely necessary either. My darkroom is in my garage and it has proved difficult to completely prevent light leaking in around the door but this doesn't affect my prints at all.

Mind you having said that, I do most of my printing on winter evenings when there is no light outside to affect things and I develop film in my kitchen using a changing bag to load the tanks.

 

[JBrunner]

If the preflashed test comes out ok (preflash, then object on paper for twice the time it takes you to make a print) you are good to go. It is good to repeat periodically and whenever you bring a new paper into the darkroom.

 

[brofkand]

The easiest way to lightproof a room is to use cardboard in the windows. Go to your local ABC store and get a few boxes, tape them together (you could even double-up on the cardboard for a window that is in direct sunlight and you're worried) and tape it up using gaff tape or duct tape.

An earlier poster suggested using a huge amount of red gel to cover a window. I don't think that would work, as even proper safelights suggest keeping them at least 2 feet from paper at all times. I would think that much light (even if it were filtered red) would pose a fogging risk.

 

[wogster]

The easiest way to lightproof a room is to use cardboard in the windows. Go to your local ABC store and get a few boxes, tape them together (you could even double-up on the cardboard for a window that is in direct sunlight and you're worried) and tape it up using gaff tape or duct tape.

It all depends on how multi-purpose the room is, and what kind of ventilation you have. Some people have dark rooms in bathrooms and laundry rooms, so whatever is over the window must be removable. What I did one time was this:

I had one window in a laundry room to deal with, I got a piece of plywood, cut it the right size, painted it grey on both sides. Added some weather stripping, and then 2 hinges at the top, and a bolt at the bottom. When closed even bright sun didn't get in. I had a second latch from a bolt on the ceiling, so I could raise it up, slide the bolt and it would stay up.

 

[brofkand]

Wogster:

Good point. For a temporary darkroom I think cardboard and gaff tape would be a good solution. I use it in my full time darkroom as well. It's cheap, light, and doesn't wear out over time like plastic and blackout cloth can do.

 

[wogster]

Wogster:

Good point. For a temporary darkroom I think cardboard and gaff tape would be a good solution. I use it in my full time darkroom as well. It's cheap, light, and doesn't wear out over time like plastic and blackout cloth can do.

Cardboard can get wet though if the humidity is higher and the temperature drops outside, then it turns to mush. You can protect it with a layer of plastic sheeting, but it looks really ugly. If it's a window that faces a wall in close proximity it may be okay. If it's visible from the street, then you may want a different option. The problem with gaffer or duct tape is that the glue residues can be a bear to remove, more so if they have been there for a while.

For the nicest looking from the outside, paint the wood black, put a small block of wood in the corners facing the window so that it sits slightly in from the window frame. Put the weather striping around the edge. Get a piece of sheer cloth twice the width of the window and staple that to your piece of wood, at the top not flat though, you want it to look like a curtain from the outside. It will look like the room is not in use, the curtains are closed and the lights are off.

 

[PeteZ8]

It all depends on how multi-purpose the room is, and what kind of ventilation you have. Some people have dark rooms in bathrooms and laundry rooms, so whatever is over the window must be removable. What I did one time was this:

I had one window in a laundry room to deal with, I got a piece of plywood, cut it the right size, painted it grey on both sides. Added some weather stripping, and then 2 hinges at the top, and a bolt at the bottom. When closed even bright sun didn't get in. I had a second latch from a bolt on the ceiling, so I could raise it up, slide the bolt and it would stay up.

Very similar to what I am going to do in my laundry/dark room. I have very recessed casement windows in that room so plenty of space to stuff something. I'm going to have plywood cut about 3/4" smaller than the window opening then use that split round pipe insulating foam around the plywood. Attach a handle in the middle so I can get it back out of the window frame then just stuff it in place.

The two doors I have to deal with both have windows also (one to kitchen, the other to outside) but they are metal clad doors, so some heavy black plastic and a few magnets will solve that problem.

No modifications to the house and everything should tuck nicely into a corner when not in use.

 

[Sirius Glass]

Plywood, cut to the shape of the window. Added a handle. Covered the window side with blackout cloth. Fits into the window blocking out most of the light. A little tape to hold up the cloth where the light comes around and the room is dark.

I described in an earlier post how I deal with the doors.

Steve