How Dark should the Darkroom be?

dmr said:

My current "darkroom" is the bathroom, which I use to load film into the tank. If it's daytime, I'll stuff a dark towel in the crack under the door to be sure, but at night it's totally dark. No windows and no windows in the adjoining hallway.

However! Once I realized, right after I started to wind the film on the reel, that the little green LED in the electric toothbrush charger was on and quite visible! I quickly turned so as to load the film in the shadow. No fogging at all. (WHEW!) After that I unplug it before I load the tank.

Click to expand...

Be careful as well about wrist worn fitness trackers, cel phones that light up, watches that illuminate, etc., etc.

Doremus Scudder said:

You simply cannot change the color or intensity of a light source by pointing another light source at it; both color and intensity are additive and the result will be a more intense light with an intermediate color.

Click to expand...

Absolutely correct. I do research in near-infrared spectroscopy, photobiomodulation, and photodynamic therapy. Previously, I worked in light-cured (UV) polymers. Any light energy in the offending wavelengths continues to exist, regardless of any added energy in whatever wavelengths.

dmr said:

My current "darkroom" is the bathroom, which I use to load film into the tank. If it's daytime, I'll stuff a dark towel in the crack under the door to be sure, but at night it's totally dark. No windows and no windows in the adjoining hallway.

However! Once I realized, right after I started to wind the film on the reel, that the little green LED in the electric toothbrush charger was on and quite visible! I quickly turned so as to load the film in the shadow. No fogging at all. (WHEW!) After that I unplug it before I load the tank.

Click to expand...

Before I built my darkroom, I would load film in the laundry room with the door closed and a blackout curtain tacked over the doorway. It wasn't until the third or fourth time that I realized that the water heater in the same room had an LED that would blink occasionally to show the pilot was lit. After that I taped over the light with some gaffer's tape.

MattKing said:

Be careful as well about wrist worn fitness trackers, cel phones that light up, watches that illuminate, etc., etc.

Click to expand...

I don't wear a watch and I don't carry a cell phone with me at home. Since that incident I checked for anything else that might light up.

One thing that's strange about the bathroom lighting is that I have both the overhead and vanity lights on dimmers. For the vanity lights, if you turn the dimmer all the way down but not clicked off, sometimes, not always, after several hours they will actually light up, barely, with a very eerie brownish-red glow. I do make sure that both are all the way off before doing any film loading in there.

Doremus Scudder said:

Just for posterity and for others who might be beginners and are just researching the topic:

The approach guangong describes above is contrary to the laws of physics and simply will not work! It reflects a basic misunderstanding of the principles involved. Whatever "success" was achieved with this method was coincidental and unrelated to pointing the safelight at a light leak. You simply cannot change the color or intensity of a light source by pointing another light source at it; both color and intensity are additive and the result will be a more intense light with an intermediate color.

I would recommend to the poster to do a bit of research on the basic science behind light. Wikipedia is a good place to start.

Click to expand...

I wasn’t referring to a an obvious light “leak”, but to that kind of seemingly invisible kind of light seepage for some very, very weak unnoticeable translucent light seepage, somewhat like that described by the OP. He said that even sitting in the dark for a while he couldn’t determine the source of the weak light source. 50 years ago I had a similar situation. Your comments on the nature of light are absolutely correct and it would be folly to try to color an obvious light leak of any noticeable intensity.
Unless working in a room with no windows and a professional light safe entrance, an absolutely dark room is very difficult to achieve under modern circumstances, and we have to make do with what is practically possible. Even in my rural area , after a neighbor a quarter of a mile down the road installed security lights, on a night with only a sliver of moon my surroundings are still visible.

Frankly speaking, from my experience, if conditions are as OP described, if he uses an old sheet of paper to focus and compose and then replaces with a new sheet of enlarging paper, exposes, develops and fixes in rapid sequence, he should be ok. I use a NOVA developer so paper spends little time out of the box. A paper safe will also make things move smoother and safer.

The last time I was able to use a purpose built dark room was 1989. That room was totally dark, no windows and two doors for entry (imagine a door to the outside world, a little hall way then a second door to the dark room). The walls, cupboards and benches were all painted black and you could sit in there for 30 minutes without the safe light on and see nothing. I remember struggling once with a pesky roll of 135, getting it on the spiral did take 30 minutes and in all that time I could see absolutely nothing.

Caveat - my night vision is poor

These days, I use a blacked out bedroom or bathroom for making prints via enlarger and I do find that a small amount of light leaking into the room is OK for printing. In the bedroom, when I black out the windows and block under the door with a towel I can just about see that there is some light from the street lights outside. But it doesn't shine onto the enlarger easel or my trays. The developing tray is, in any case, red so any light that comes through the tray sides should be fairly "safe". The light from my safe light is sufficient for me to see what I'm doing.

For developing film I use a changing bag and on occasion have been forced by circumstance to use this in bright sunlight but generally I do this indoors in an area not affected by direct light. Film will be fogged quickly unless in total darkness as I've found out in the past - though often just a few frames.

In the dark room I am careful to tun my phone's mode into one where the screen will not light up if someone contacts me. I remove my watch just in case I accidentally press the light button. I also remove the watch for using the dark bag...the last thing I need is my developing tank nudging the watch and the light coming on. I've heard of people using tablets to provide music while they use their dark rooms only for the tablet screen to light due to an incoming communication and a print or roll of film be spoiled. Also be wary of power lights on any radios or other equipment you might have in the dark room.

The bottom line is that for photographic paper, a small amount of light may be OK.

Oh and as a physicist....you cannot add red light to another light to make it "safe"...as others have said. That isn't how it works. You could perhaps find a large gel filter and filter the incoming light to the right shade for your paper.

My darkroom is an even better dark room ...... at night.

My bathroom has no window. I checked it out for darkness by sitting on the throne for 10 minutes. Could just about see the outline of the bath and the washbasin but couldn't figure out where the light was getting in.

It was an illusion. The bath and the washbasin were not where I was 'seeing' them.

Kirth Gersen said:

Final question for today.

I've got the darkroom pretty dark. After sitting in there for a few minutes, I can just about see my hands move in front of my face... just. Can't see any chinks of light. Must be coming through the masking tape or the air vent.

Anyway, I have seen lots of suggestions as to what is right. Some say 'absolute darkness' is the only way, others say they have chinks of light, but as long as it they are not shining directly at the paper, it should be alright. I came across a youtube guru called Darkroom Dave, and was distracted by the massive chink of light coming from under his door in a safelight situation. Couldn't concentrate on the instruction!


Thoughts?

Thanks

Richard

Click to expand...

After bringing a comfortable chair into my darkroom and getting comfortable, I set an audible timer for 6 minutes, turn on the timer while turning out the lights. After the timer notifies me that six minutes have passed, I look all around the darkroom, hopefully not seeing any light whatsoever. If I can see my hand in front of my face, there is too much light. If I can't see a thing after being in the dark for 6 or more minutes, I know the room is safe for film, both unexposed and exposed, which, to me, is important. All I need to worry about with paper will then be whether my safelight is "safe". My motto for all of this is:"what can happen WILL happen. I do this test at least once a year just for peace of mind if for no other reason.. Remember, it is not all about complete fogging, indirect light leaks can degrade your image.......Regards!

Per Kodak,
However, after getting military training on night vision adaptation, I would sit in the dark for 10 minutes before evaluating per Kodak standards, as night vision acclimation is a slow process. Per military doctrine, it takes about 30 to 45 minutes to fully dark-adapt or get your eyes used to seeing things under low light conditions, when going from a brightly lighted area into the dark!

Then, for handling of B&W materials during printing

dmr said:

I don't wear a watch and I don't carry a cell phone with me at home. Since that incident I checked for anything else that might light up.

One thing that's strange about the bathroom lighting is that I have both the overhead and vanity lights on dimmers. For the vanity lights, if you turn the dimmer all the way down but not clicked off, sometimes, not always, after several hours they will actually light up, barely, with a very eerie brownish-red glow. I do make sure that both are all the way off before doing any film loading in there.

Click to expand...

Making your iPhone screen RED: https://ios.gadgethacks.com/how-to/...sharp-with-iphones-hidden-red-screen-0173903/

Sirius Glass said:

Making your iPhone screen RED: https://ios.gadgethacks.com/how-to/...sharp-with-iphones-hidden-red-screen-0173903/

Click to expand...

I would not trust a standard backlit LCD screen of any style to be or remain photo-light-safe - Heavily tinted overlays are likely to make at least some use of green and blue if you're not working with pure red graphics, and even then I wouldn't advise assuming any given panel is actually blocking 100% blue and green. (Most screens are still noticeably 'bright' while displaying pure 'black' in a truly dark room.)

Even if using a screen that has per-channel LED backlights, you're still leaving yourself at the mercy of assuming no software glitch will pop up with a nice bright white error message or something.

I "can't see a damn thing in here" dark.

I "can't see a damn thing in here" dark.