I have several darkroom lights based on red LEDS. Even cheap bicycle taillights.
I'm not terribly concerned with paper, and that is cheap and easy to test anyway. I do however use a Zone VI compensating timer, whose smallish red led dim-able (for film) display has no effect within 4 feet of my sheet film developing trays. There is little or no light directed outwards of the display, as say in the manner of a red LED flashlight, ...or taillight (i.e., I cannot see my hand, or anything else, working in my trays – only the display). The lowest intensity of the display is barely visible when the room lights are on, but clearly visible in the dark. I certainly wouldn't feel comfortable using anything close to bicycle taillights in my lab for film. The mammoth red display of this clock would certainly give me pause, unless (inconveniently) turned off for film. It would though be nice to replace my safelight (ambient) lit wall clock, whose sweep second hand is often inscrutably visible (all the more with age ), for paper processing. Since there don't seem to any other objective or manufacturing criteria, please let us know of your testing results.
Last edited by ROL; 06-19-2013 at 02:47 PM. Click to view previous post history.
I once bought a clock with a second hand for use in a darkroom. I then discovered that, when illuminated by a red safelight, a red second hand is almost invisible against a white background.
I have done that, but I took the plastic face off and painted the second hand black and then put the plastic cover back on (problem solved). However, don't you think that flashing L.E.D's in a darkroom spoils the atmosphere of peace and relaxation?
Last edited by cliveh; 06-19-2013 at 03:38 PM. Click to view previous post history.
I stick with an old gralab 300 for film development. It drives a 555 timer circuit that chirps every 15 seconds while the gralab has time on it.
I find that once film is in the daylight tank I can read magazine articles and agitiate to the tone of the chirp.
If doing trays of large format pan film, the chirps in the darkness remind me to shuffle sheets.
I use the gralab for timing paper fixer times too, and the chirps remind me to agitate the tray.
I have a Vivitar Process Time Commander for the more complex timing sequences, like e-6 and c-41.
To actually tell the time I have a small LED alarm clock with a few pieces of Rosco ND gel filter media hung over the front of the display where it sits on a shelf.
To see the time in other than lights out you need to lift the ND out of the way.
Most of the time I tell time in the darkroom from the radio.
At midnight the classical radio station changes announcers.
I know I should go to bed then, or I will be grumpy that morning, when my wifes 6:20am alarm goes off.