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Thread: Darkroom Safe Light

  1. #21

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    Re: Darkroom Safe Light

    One more data point: the superbright red LEDs are not safe for x-ray film when directly aimed at them or anywhere close. With direct bright exposure from 4', the negatives are nearly black after normal development. Reflected light that is just bright enough to work in comfortably also produced a slight fogging. I found that a single red superbright LED reflected off the rear wall of my darkroom to be safe (6' to the wall + 12' back to the sink), by which I mean I can't tell the difference between film exposed to that light and unexposed film by visual inspection. However, at that point the reflected light is so dim that it takes about 10 minutes for my eyes to adjust enough to make out fuzzy shapes in the sink.

    I think these bulbs might be worse than the red LED in the headlamp I tested with before.

  2. #22
    Tin Can's Avatar
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    Re: Darkroom Safe Light

    Please always specify which bulb you refer to exactly

    https://www.superbrightleds.com/ is a company that sells a vast varietyoif LED, most of them not red and very powerful

    I do bounce my choice and I let my eyes adjust for 10 minutes

    Quote Originally Posted by sabeluc View Post
    One more data point: the superbright red LEDs are not safe for x-ray film when directly aimed at them or anywhere close. With direct bright exposure from 4', the negatives are nearly black after normal development. Reflected light that is just bright enough to work in comfortably also produced a slight fogging. I found that a single red superbright LED reflected off the rear wall of my darkroom to be safe (6' to the wall + 12' back to the sink), by which I mean I can't tell the difference between film exposed to that light and unexposed film by visual inspection. However, at that point the reflected light is so dim that it takes about 10 minutes for my eyes to adjust enough to make out fuzzy shapes in the sink.

    I think these bulbs might be worse than the red LED in the headlamp I tested with before.
    Tin Can

  3. #23
    Gary Beasley's Avatar
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    Re: Darkroom Safe Light

    I would think the super brights could be put on a dimmer and run at reduced voltage and get cleaner red light from them. Leds from what Ive seen will bleed other frequencies besides the rated emission, being worse as the driving voltage goes up.

  4. #24
    Tin Can's Avatar
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    Re: Darkroom Safe Light

    Easy to test, as I have a Variac on my CB7

    I will check with a DVD/CD to visually observe color shift

    Later today, hopefully

    Good idea!

    Read more on https://www.specialtyproducttechnolo...e-transformers on my CB7

    Quote Originally Posted by Gary Beasley View Post
    I would think the super brights could be put on a dimmer and run at reduced voltage and get cleaner red light from them. Leds from what Ive seen will bleed other frequencies besides the rated emission, being worse as the driving voltage goes up.
    Tin Can

  5. #25

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    Re: Darkroom Safe Light

    Tin Can,

    I was referring to the ones that are referenced in this thread (not being safe for x-ray film):
    https://www.superbrightleds.com/more...mens/440/1477/

  6. #26
    Tin Can's Avatar
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    Re: Darkroom Safe Light

    Dead link

    Quote Originally Posted by sabeluc View Post
    Tin Can,

    I was referring to the ones that are referenced in this thread (not being safe for x-ray film):
    https://www.superbrightleds.com/more...mens/440/1477/
    Tin Can

  7. #27
    Jim Sidinger
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    Re: Darkroom Safe Light

    Obviously, the safe light you use needs to depend on the paper you are using.
    I use Ilford Classic and Ilford Warmtone and the spec sheets show that anything with a lowest (shortest) wavelength of just under 600nm will work fine for them. Check out the spec sheet for your paper(s) and you should be able to be good-to-go from there.
    Best, Jim

  8. #28

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    Re: Darkroom Safe Light

    Good news for at least some of you amber-safelight-preference B&W printers! As promised, I tested the SuperBrights amber LED S 11 screw base-type bulb, 7.5-Watt equivalent. https://www.superbrightleds.com/more...Specifications

    It’s bright and it works for Ilford Warmtone FB. It’s great to know that I don’t have to worry about switching to red lights if my OC filters fade enough to fog.

    Now, keep in mind, this paper is about half the speed of Ilford Classic FB, of which latter I have none on-hand. I’ll be interested to hear from someone who tests this bulb with it.

    Here is a bit more about how I proceeded and my set-up, as shown approximately in the diagram.

    For decades, I have had just two, “bullet”-style, 5 .5 -inch round safelights, each with a 15-Watt light bulb and a Kodak OC filter. Both units are attached to the wall as high as my 8’ ceiling allows. As shown, one hangs at the wash end of the sink, approximately 4.7’ from the developer tray and aimed down and outward from the wall to cover the sink area. The other is roughly 4’ above the paper cutter, aimed down but angled about 30 degrees toward the dry mount press, simply out of caution.

    I removed the filter of this one and substituted the LED bulb. Though it was certainly brighter, I didn’t fully realize how much until I had had the lights off for a bit while set up the test. It was so bright that I decided to aim it almost horizontally along the (light gray) wall and toward the adjacent wall area above the press. The reflected light was still was much brighter than the OC, so I crossed my fingers.

    With only the sink safelight on, and no negative in the enlarger, I tested for exposure threshold of the paper in 1-second increments with a #2 contrast filter, finding 9 seconds to be threshold. I made a test strip of 1- to 12-second exposures, placed it on the enlarging table to the left of the enlarger, covered half the long dimension of the strip (right angle to the exposure steps) with mounting board, and turned on the LED for a full 8 minutes of exposure, which is about twice as long as any time under the enlarger I have ever had to keep paper in making a print.

    I developed normally. There was zero sign of any darkening anywhere along the uncovered side of the test strip.

    The brighter light from the LED, now spread out much more widely, created much better visibility at the enlarger with softer lighting. But every solution creates a new problem, of course. In this case, the light was bright enough to interfere somewhat with viewing a projected negative image when careful burning and dodging are required. And, since the bullet enclosure front was now open, I foresaw dust inevitably collecting inside. I cut an OC filter-sized circle of frosted mylar (or frosted whatever-it-is) that I use for dodging masks, to cover the open front and dim the light. That brought the illumination level closer to, though still a bit above, what I have had.

    The remaining issue is that I find all that illumination of the press area, art table, etc.—a visually very busy area—a bit distracting; I not used to seeing it while enlarging. I may try making a collar to cut down the spill in that direction a bit.

    Also, the LEDs are so cheap -- ~$3 per -- that I ordered four. I should live so long!

    For now I may leave the sink light as-is; perhaps I’ll try the LED in it and bounce it off the ceiling with some diffusion, to even out the lighting, but it could spill over to the enlarging area…
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    Philip Ulanowsky

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  9. #29
    Tin Can's Avatar
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    Re: Darkroom Safe Light

    I see you are using the 7.5 watt equivalent rating, but these bulbs only consume 2 actual watts NOW, but when I first started using them years ago they were speced at 1 Watt...

    I never turn off my 2 RED ones, unless loading real film as i walk by my DR many times a day. I like the glow

    For Printing, X-Ray and Wet Plate I am ready with Red

    I also use KODAK Bullet Safe Light fixtures as they are beautiful Art Deco
    Tin Can

  10. #30
    Eric Woodbury
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    Re: Darkroom Safe Light

    Quote Originally Posted by denverjims View Post
    ... the spec sheets show that anything with a lowest (shortest) wavelength of just under 600nm will work fine for them....
    Longer wavelength, not shorter. Blue is short, green is middle, red is long.

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