Doug Smiley 
, Sep 06, 2010; 05:44 p.m.
I've heard that flourescent lights would fog film and paper for sometime after the light was turned off, so I've always used tungsten bulbs for white lighting in my darkroom. Now I've tried a 27 watt "natural spectrum" fluourescent desk lamp outside the darkroom and find the color of the light pleasing to the eye, and much cooler temperature wise than a bright tungsten light. Can anyone tell me what a safe timeframe would be for handling unprocessed 400 speed b&w film within a foot, say, of the light after it's switched off?
Larry Dressler 
, Sep 06, 2010; 05:53 p.m.
IS this a CFL or a full size tube bulb? I think we had a hash over this in the last year here and we decided that it worked for some and not others. Believe it or not you can tell how long the bulb will keep a slight glow by looking at it after you turn it off and your eyes adjust to the dark. I say just slipping a large red gel over it after you turn it off will be fine for B&W Paper but with Color/Colour paper or any ISO anything non Ortho film I would just try a roll that you want to test it with and find out... Or even lay out a piece of film that was un exposed and develop it.. I would leave it out for the amount of time it takes for you to load a difficult roll. :)
Mike Gammill 
, Sep 06, 2010; 07:31 p.m.
Some of the afterglow may be in the ultraviolet spectrum which your film will see just fine. When I turn off a table lamp
which has a CFL I can see it glowing faintly after turning it off.
Larry Dressler , Sep 06, 2010; 07:52 p.m.
Doug Smiley , Sep 06, 2010; 08:06 p.m.
I meant to write "full spectrum" rather than "natural spectrum".
Larry Dressler , Sep 06, 2010; 08:10 p.m.
Same as all the above as Film is full spectrum.
Leigh B. 
, Sep 06, 2010; 08:15 p.m.
Can anyone tell me what a safe timeframe would be for handling unprocessed 400 speed b&w film within a foot, say, of the light after it's switched off?
ZERO, unless the light has been off for a day or so.
Why do you care about the light in the darkroom? You can't evaluate anything in there in the first place.
- Leigh
Frank Schifano , Sep 07, 2010; 07:25 a.m.
I like CFL's but not in the darkroom. Is there enough light emitted after it's switched off to cause a problem? Maybe, maybe no. I know that I can see it still glowing, and that's enough for me to make them incompatible with darkroom work. It takes about 5 minutes or so for the visible afterglow to diminish, and I don't want to wait that long. I work under safelights only when it's needed. For tasks like cleaning negatives, setting them into negative carriers, moving prints to a wash tray, and general housekeeping, I work under white light.
Doug Smiley , Sep 07, 2010; 09:40 a.m.
The darkroom is being used more as an office now than when it served as a commercial b&w lab. For the few personal rolls of film that I process there are no deadline constraints, so I can choose to process film an hour or 12 hours after the light is switched off. I was wanting to get some kind of idea about the leeway involved. The responses pretty much confirmed what I suspected. Thanks to all for your input.
Craig Shearman , Sep 07, 2010; 04:17 p.m.
I don't think this has anything to do with whether it is full spectrum or not. CFLs simply need a few minutes -- at least -- before they stop glowing. I had put them in in my darkroom since I was putting them everywhere in my basement, but took them out and put in regular bulbs once I saw that they glowed. Deadline constraints or not, waiting even a minute or two for them to stop glowing is not practical for me. That might be OK for developing negs but when I'm printing, the white lights are constantly on and off as I come out of the fixer and need to look at a print to see how it came out, then turn them off to do the next print.
