Darkroom test

Truzi · Jul 14, 2017

Since I'm such a procrastinator, I wasn't going to ask this until I was completely ready, but I might as well get advice now since I snagged my thumb with a bow saw while taking care of a large fallen branch. That thumb is needed to hold tools and such, so I can't finish constructing my light seals for a week or two. I have all the materials to light-seal the bathroom, am 80% done with the door coverings, and 50% done with the window covering/ventilation.

When complete, I will do a safe-light test as described in many APUG threads. No issues/questions there.

My thought is to also see if it's safe enough, WITHOUT A SAFE-LIGHT, to develop film. (Caps for those who respond w/o fully reading.)

My questions:
Is it sufficient to use a strip of 35mm film in the same manner as when testing paper? Progressively uncovering it as time goes by? (Obviously with no safe-light.)

I plan on using a length of Delta 3200. Would results from this be applicable to color film as well? (I'd think yes, but want to make sure.)

If my plan is sound, does the developer matter? It would be nice to kill two tests with one developer.

Finally, since this is a bathroom darkroom, how many flushes of a 1.6 GPF toilet will archivally wash an RC print?

bdial · Jul 14, 2017

Your eyes work well for this, though it might be a bit boring.
Turn the lights off and wait for 10 minutes or so. If you can't see any light, as in leaks from a door frame or window, nor anything else (like your hand in front of your face, for example), you're good.
Testing with film or paper would be more difficult, because you need a controlled way to get it over it's threshold before it will react to the light (or lack of it) you're testing. That's fairly easy with paper for a safelight test. But would be difficult with film.

jimjm · Jul 14, 2017

Easiest way is to close the door, shut off the light and wait 10-15 mins for your eyes to adjust. Examine all around the doors and windows for any light peeking through. If you can't see it, your paper and film will be safe. Have some extra weather stripping on hand to plug up any leaks you might see.
No idea about toilet flushes, but I usually rinse RC paper in an open tray with a Kodak tray siphon for a minimum of 5 mins. I'd guess it doesn't even use up a gallon of water in that time. Just don't let your prints soak in the fixer for too much longer than the recommended time. and you should be OK.

Arklatexian · Jul 14, 2017

bdial said:
Your eyes work well for this, though it might be a bit boring.
Turn the lights off and wait for 10 minutes or so. If you can't see any light, as in leaks from a door frame or window, nor anything else (like your hand in front of your face, for example), you're good.
Testing with film or paper would be more difficult, because you need a controlled way to get it over it's threshold before it will react to the light (or lack of it) you're testing. That's fairly easy with paper for a safelight test. But would be difficult with film.

Those are good instructions (above) to follow. After ten minutes in complete darkness, you will be able to "see" if your darkroom is dark enough for film. I am convinced that there is no "allowable" amount of light in a film darkroom and the test of, after ten minutes in the dark, not being able to see your hand in front of your face is a very good test. When working with photo paper, I like to start with the room just as dark and then light it with "safe" lights.......Regards!

mshchem · Jul 14, 2017

Truzi said:
Since I'm such a procrastinator, I wasn't going to ask this until I was completely ready, but I might as well get advice now since I snagged my thumb with a bow saw while taking care of a large fallen branch. That thumb is needed to hold tools and such, so I can't finish constructing my light seals for a week or two. I have all the materials to light-seal the bathroom, am 80% done with the door coverings, and 50% done with the window covering/ventilation.

When complete, I will do a safe-light test as described in many APUG threads. No issues/questions there.

My thought is to also see if it's safe enough, WITHOUT A SAFE-LIGHT, to develop film. (Caps for those who respond w/o fully reading.)

My questions:
Is it sufficient to use a strip of 35mm film in the same manner as when testing paper? Progressively uncovering it as time goes by? (Obviously with no safe-light.)

I plan on using a length of Delta 3200. Would results from this be applicable to color film as well? (I'd think yes, but want to make sure.)

If my plan is sound, does the developer matter? It would be nice to kill two tests with one developer.

Finally, since this is a bathroom darkroom, how many flushes of a 1.6 GPF toilet will archivally wash an RC print?

You know that toilet would probably work better with fiber base. Maybe put your prints into 8x10 film hangers. Probably would want to print early Thanksgiving morning. This way you could kill two birds with one stone. And your guests would be none the wiser
Best Regards Mike

tedr1 · Jul 15, 2017

I use my darkroom to load 120 film onto development tank reels. I light-proofed it using the dark-adapted naked eye test, which I believe to be very sensitive because one is able to perceive small areas which allow light to penetrate but which contribute almost nothing to the ambient light level in the room. Having remedied those small areas the ambient light level is for all practical purposes zero. (If you want to go further perhaps night-vision goggles might be used?)

I have never heard of making a film exposure test for ambient light leakage in a darkroom, although in theory it should work.

The recommendation by Ilford for washing RC papers is 2 minutes in running water above 41F.

Doremus Scudder · Jul 15, 2017

Are you are developing sheet film in trays, not just loading reels, drums, tanks, etc.? If so, then add this to your darkroom test: After your eyes have adjusted to the dark and you've plugged all the holes you see, place a mirror in the bottom of the developing tray and look at it from as many angles as you can to see what the film "sees." You might find a hole or two that still needs plugging.

As mentioned above, if you can't see any light with your eyes, then your darkroom is safe enough for film. There is no need to do a film exposure test.

Best,

Doremus

pdeeh · Jul 15, 2017

Got a smartphone? Or a kitchen timer that pings or beeps or whatevers?
Take it in with you when you're doing the "10 minutes in the dark" thing, because in my experience, sitting in a totally darkened room with nothing to do except to wait for ten minutes to pass, 30 seconds can easily feel like an hour ...

bdial · Jul 15, 2017

Think of it as 10 minutes of refuge from all distractions and worries.
You may want to extend the test to an hour, "just so you can be really sure".

Jim Jones · Jul 15, 2017

Music is one of those things we can enjoy in total darkness.

Arklatexian · Jul 16, 2017

pdeeh said:
Got a smartphone? Or a kitchen timer that pings or beeps or whatevers?
Take it in with you when you're doing the "10 minutes in the dark" thing, because in my experience, sitting in a totally darkened room with nothing to do except to wait for ten minutes to pass, 30 seconds can easily feel like an hour ...

In my darkroom there is an old Gralab darkroom timer which I set for ten minutes, sit down in a lawn chair that I brought in from outside and relax. Should I fall asleep, that timer will waken the dead and if you are wondering about the luminous dial (luminous paint), I have made 10 minute exposures with a strip of 120 Tri-X taped to the dial with no exposure........Regards!

ac12 · Jul 16, 2017

Don't just stand in one place.
Walk about the darkroom, bend down low, look at the ceiling, etc.
IOW, LOOK ALL AROUND.

I was in one FILM darkroom, which seemed DARK.
Until I bent down to pick up the spool from the film cassette, then I saw light coming in from under the door

Truzi · Jul 16, 2017

Thanx for all the advice.

I was going to use a simple oven timer that will repeat by pushing one button... or bring an alarm clock with me and take a nap first. I've a used Gralab timer, but the dial may throw me off when making sure the room is absolutely light-tight. I guess I could just use my eyes, but it's been a while since I've been in a darkroom, and I know how the mind can "see" things when deprived of actual input.

I've color and B&W sheet film, but only one Jobo 2523/2509n that I've rolled (probably too fast) w/B&W in the bathtub. Until I get more equipment, I'm thinking trays may be an easier way to get a lot of sheets done in one session - I'll try the mirror idea. I also think doing a dip-and-dunk with color roll-film may work better for me - I'd make a plywood stand to hold lid-less daylight tanks steady in a tempered bath.
I don't have a problem with a changing bag, but loading reels on a card table would be so much better.

The film-hangers in the toilet-tank idea is great, lol. My joke was more about the bowl - never thought about the tank. I do have a Premier tray washer.

RalphLambrecht · Jul 16, 2017

Truzi said:
Since I'm such a procrastinator, I wasn't going to ask this until I was completely ready, but I might as well get advice now since I snagged my thumb with a bow saw while taking care of a large fallen branch. That thumb is needed to hold tools and such, so I can't finish constructing my light seals for a week or two. I have all the materials to light-seal the bathroom, am 80% done with the door coverings, and 50% done with the window covering/ventilation.

When complete, I will do a safe-light test as described in many APUG threads. No issues/questions there.

My thought is to also see if it's safe enough, WITHOUT A SAFE-LIGHT, to develop film. (Caps for those who respond w/o fully reading.)

My questions:
Is it sufficient to use a strip of 35mm film in the same manner as when testing paper? Progressively uncovering it as time goes by? (Obviously with no safe-light.)

I plan on using a length of Delta 3200. Would results from this be applicable to color film as well? (I'd think yes, but want to make sure.)

If my plan is sound, does the developer matter? It would be nice to kill two tests with one developer.

Finally, since this is a bathroom darkroom, how many flushes of a 1.6 GPF toilet will archivally wash an RC print?

I like to only answer the last question:
archival washing is not achieved by violently flushing a print with water. It is however achieved by allowing the fixer in the emulsion to seep into the print-surrounding water and then being washed away. Hence, the Ilford procedure works best and can be done easily in a bathroom darkroom.

Darkroom test

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