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12-25-2009, 01:56 AM   #1
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How dark, darkroom has to be?

Are there any special measures and materials available to seal a room completely off the light, or simple solid doors are enough.

The only room i could use for film processing basically has no direct source of stray light (windows, keyholes, doors with gap to frame) BUT....

After checking the room for 5 minutes staring in complete blackness, your eyes start to adapt and you see that the step-like door frame still is able to leak light.
If i pack the perimeter of doors with paper, i can start to see a fain fuzzy glow around the doors after 30 minutes.

How do you determine if the "darkness" level is enough for film processing.

Btw. some people have told me that you cannot work with B&W film under red light, because most current films are sensitive to it.
Is this true for B&W as well?
How do you make prints then, or is the paper still insensitive ?


Last edited by ytterbium; 12-25-2009 at 03:36 AM.
12-25-2009, 04:22 AM   #2
Dom
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Just as long as your darkroom is mostly light tight you'll be alight.

Colour film has to be handled in brown light, if I remember right. B & W can be handled in red light, unless it's changed since I used to do it for a living. The film data sheet should give you the safe light you can use in a darkroom.
12-25-2009, 05:28 AM   #3
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at school they had floor to ceiling curtain, U shaped bend painted all black, another curtain and the B&W dark room with red lights

then off that was another door with seals for the colour dark room which had no lights and you never got used.
12-25-2009, 06:01 AM   #4
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Basically a darkroom should be so dark, that you can't see anything there, even after adapting your eyes.

The usual test is
: lay out a fresh sheet of printing paper on your workspace and leave it there for an hour. Place an object on the paper during that exposition time. After an hour develop the sheet. If you can't see the outline of the object, the darkroom is fine. If the paper darkens visibly, you should improve light tightness.

Avoiding ALL light is especially important for colour work. Though you can have a look of colour printing paper (only standard paper for printing from negs) in this strange brown light, handling/processing film and reversal paper (printing from slides) should be done in complete darkness. It is not as hard as it sounds, as you would usually use drums fro colour processing or a developing machine. In both cases darkness is only required while loading the machine or drums and the real processing can be done under normal light.

Ben

12-25-2009, 09:38 AM   #5
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Sealing around doors is best done with weather stripping.
If you have the floor space, put in a light trap, or design your darkroom in such a way that the working area is not in line with the door.
You cannot handle any camera film under any kind of light. Film has to be handled entirely in the dark until fixed.
There are some graphic arts films that can be handled under red light.
Lithographic films are an example.
One used to be able to handle panchromatic B&W film under VERY dim green light for short periods of time, and only after they had received partial development, but I don't know if this still holds true. A lot of films have either gone away or have been reformulated since I learned this stuff.
I remember one time loading film and realizing after a few minutes that I could see what I was doing.
No harm done, the film was fine, but I closed off that light leak right quickly.
It sounds to me like the room you have will be dark enough on it's own, but if you really want to make it darker, hang a blanket in front of the door.
Ben's method of determining if a room is dark enough is the classic method and is still the best one. I use film instead, and test for 15 minutes.
The standard OC safelight (or equivalent) is fine for B&W papers, colour papers need to be handled in total darkness.
12-25-2009, 11:23 AM   #6
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You can't have any light at all for any common film type. I'm not sure what size film you're dealing with, but normally you'd load your film in a changing bag, not a darkroom. You wouldn't use a darkroom to process film.

With printing, each paper type will have a recommended safelight variety, but my experience (thirty years ago) was that most b&w papers were pretty tolerant for short exposure times.

Paul
12-25-2009, 12:35 PM   #7
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QuoteOriginally posted by tibbitts Quote
You can't have any light at all for any common film type. I'm not sure what size film you're dealing with, but normally you'd load your film in a changing bag, not a darkroom. You wouldn't use a darkroom to process film.


Paul
Heck, if you have a darkroom set up and it's sufficiently dark, there is no reason to use a dark bag. Bags are clumsy to work in. I only use them when I have no choice, such as when changing film holders in the field.
12-25-2009, 01:34 PM   #8
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It sounds like the weatherstripping idea is best for that door, anyway.

You can probably use the inexpensive flat foam kind for doors, and just tuck it in the gaps: it comes in a few thicknesses, and no one'll ever see it. And there's the clay-string kind which can basically do anything.

I like to use a changing bag to load my tanks, regardless. (After one had become ruined, I used to use the bedroom comforters at night, which wasn't precisely convenient, but perfectly adequate. )

If conditions aren't ideal, you can also put a cardboard box on your table and work inside there: it'll basically block any stray light, too.

12-25-2009, 01:37 PM   #9
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QuoteOriginally posted by Wheatfield Quote
Heck, if you have a darkroom set up and it's sufficiently dark, there is no reason to use a dark bag. Bags are clumsy to work in. I only use them when I have no choice, such as when changing film holders in the field.
my way, too. It's much easier to work on a table, even in full darkness. Changing bags are tedious, especially when loading film holders. I would not like to load 4x5 inch sheets into the drum holder in a changing bag.

There are these nice pop-up changing tents, but they are quite expensive. I

Ben
12-25-2009, 07:18 PM   #10
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Well, its not that spacy. Just a small shower/toilet - no tables or other accommodations. But its still cheaper than buying anything (like changing bag), already available, possibly more easy to change and probably most sutable for chemical work (sink, water, ventilation, tiles).

Btw, to reduce costs, can you use a DSLR for the light leak test - ISO1600, F1.4, few minutes, pointed at possible leak sources.

It seems that the only source are doors, still there is a theoretical chance that light might bounce in trough ventilation system, but it had to take long way trough grill, matte concrete walls and dimly lit attic and what not...

I plan on sticking that long tube like foamy thing (it seems to be called "Self adhesive weather seal") around the perimeter of doors, but im not sure how light proof it is. Something like this in a way like that (attached):
Attached Images
 
12-25-2009, 09:05 PM   #11
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I had the same problem converting a mostly unused bathroom to a darkroom, but trying to keep it easily reversible. I have an old pier & beam house on expansive soil so it does move a bit and I found I had problems keeping a good seal. I added a black curtain over the door (floor to ceiling) and had no problems after that.
12-25-2009, 09:26 PM   #12
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I'm turning my basement into a darkroom and I gotta cover up the windows. I plan on going to Home Depot and picking up some black landscaping polyurethane on a roll. 5mil thickness should be good enough for windows, so it would definitely be sufficient for covering up a door, and it's rather inexpensive too.
12-26-2009, 05:58 AM   #13
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The weather stripping is a good idea. When I was a bachelor I turned a large room into a darkroom painted the edges of the doors and jamb flat black and added a threshold at the bottom black also. I made plywood for the windows and made them removeable by putting L channel around the window frame which the plywood fit in and then L channel to the plywood to form a labrynth and painted them black. I would change film in the closet just to be sure. I would keep a plastic tub of water for finished prints after fixing and then take them to the bathroom to wash in a tray in the bathtub when done. I had to give up the darkroom when I got married and we had a baby, but I still have the enlarger if we ever get a bigger house I would love to set it up again.
12-26-2009, 06:32 AM   #14
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If the black and white films is a panchromatic type, it must be handled in total darkness. If it is an orthochromatic type, it can be handled under red safe lights. As for color film, just "thinking" of light will ruin it.
12-26-2009, 07:14 AM   #15
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My answer to film developing is a big cardboard box, gaffer tape and a large piece of black cloth.

Basically I seal the bottom of the box with the tape and any other hols or 'thin bits'. Place box on its side on a table in a room at night and as dark as you can make it. Drape cloth over open front of box so it will act as a curtain and then use this mini darkroom to load film, sort cameras etc by reaching up and under cloth. It's a solution I came to after changing bags proved to be impracticable, mainly due to my sweaty hands that dampened the reels and prevented the film from running smoothly, if at all, in the plastic channels.

Now all I need is some method of blacking out Velux type roof windows so I can do some printing. Their so called blackout blinds are nothing of the sort.

Justin.
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