Safelight question

Discussion in 'Black and White' started by Rick Helmke, Nov 27, 2017.

  1. So many opinions - so much misinformation. I have used a Thomas Duplex Safe Light in my darkroom since 1982. The safe light comes with two sets of filters. One for use with black and white paper, and the second set is added on top of the B&W paper filters with the vanes closed for color paper (RA 4 process).

    The safe light is installed by hanging it from the ceiling. The light is aimed at the ceiling and reflected off of the ceiling. By opening and closing the two safe light filter vanes (or doors) you can adjust the illumination level in the darkroom. Since the light is reflected from the ceiling, the safe light is, in effect, the distance from the safe light to the ceiling, plus the distance from the ceiling to the printing paper - meaning, if you have a standard (in the U.S.) eight foot ceiling in the dark room, the the safe light is hanging about 1-foot below the ceiling, the light has to travel at least 8-10 feet to the B&W paper.

    This makes the intensity of the light far less than a standard bullet safe light aimed downwards. In the entire time I've used the safe light, I have never had it fog any paper I've used that includes; Agfa, Kodak, Ilford, Seagull, DuPont, and Forte. As a test, I've put a piece of Polycontrast Rapid paper, Portriga Rapid, Kodabromide, and Varilour out on the enlarger easel with another piece in the processing sink with 1/2 half of the paper covered to block the light. I left the paper illuminated by the safe light for 30 minutes. No piece of paper was fogged by the exposure to the safe light.

    The idea that the safe light cannot be used with fast B&W paper is ludicrous and pure speculation as, in the 35 years I've used my Thomas Duplex Safe Light - no piece of B&W paper was fogged regardless of the manufacturer, whether the paper was multi-contrast or graded paper, and MORE IMPORTANTLY regardless of the paper's shadow speed.

    Further, there is NO NEED to switch the safe light ON / OFF. You leave it on the entire time you're in the darkroom as it will not fog B&W paper. In use, I have the vanes on my safe light opened about 1/4 inch, with most all of the light going through the B&W filter on the safe light.

    This provides a nice, low overall illumination for the darkroom. For developing the paper, I have Kodak bullet safe lights over the sink with OC filters in them. I turn these safe lights ON / OFF as needed for processing the paper.

    Please, just stop with the misinformation. If you've never used the piece of equipment, you have no reason to speculate about its operation since you have absolutely NO idea what you're talking about.
     
    Last edited: Dec 21, 2017
  2. BTW - lamps for the Thomas Duplex Safe Light are still available. They cost $99.99 from Freestyle Photo (as one source). The lamps have an average life of 18,000 hours. Few people will be in a home darkroom for 18,000 hours making the safe light a one time purchase for most people.
     
  3. You have to pre expose your darkroom paper before doing the safety test because the paper is increasing in sensitivity 5-10 times more. About Heiland: They are building state of the art darkroom analysers in Split Grade with all sensiometric parameters of available papers in the software and in one measurement the exposure time and grade for the variable contrast paper. Available for over 30 types of enlargers.
    They are selling on all points increadible smart products for the darkroom. Split Grade, Densitometers, TAS inverse developing robot, Selected LED darkroom lights etc.
     
  4. There's no need to pay $100 for one when they can be had all over the place for less than half that.

    Philips 35W T17 Clear Low Pressure Sodium SOX Bulb | S0X35 | Bulbs.com

    BTW, what's this "misinformation" you're talking about?

    FWIW, I use one as my only darkroom lamp.
     
  5. A quick google turns up this interesting object that fits a common socket:
    Light Efficient Design LED-8039EAMB 15W Amber Post Top Light, 590 nm, 120/277V

    I don't much care for red lights, but I'm using this little guy for xray film:
    G11 LED Bulb - 8 SMD LED Globe Bulb - 27 Lumens | LED Globe Bulbs | LED Home Lighting | Super Bright LEDs

    The amber version specs at 596 nm, which might be good for the current discussion, except I observe that the amber spectral chart at the bottom of the specs page looks pretty dirty, where the red is nice and tidy.
     
  6. It is usual to turn off the safelight when the enlarger is on, not because it will expose the paper, but because it is easier to compose and meter when it is off.

    Some times have the ability to do that.

    As far as I know, the only one that is likely to cause problems is with RA-4 paper, which has a dip at an appropriate wavelength, but still some sensitivity.

    To me, the number 13 should not have "light" in its name. I once dropped paper on the floor, and couldn't find it with the "safelight" on. Dark is more like it.
     

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