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  1. #21
    Jim Jones's Avatar
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    Quote Originally Posted by johnielvis View Post
    HAHHAHAHAHA.....man--it's like there's this mindset of people that are smarter than everyone else . . . . anybody who can't afford the proper equipment should not have photography as a hobby--it just doesn't work. . . .
    Some of us are smart enough to make the most efficient and economical use of whatever is available, and to post information here for other's elucidation.

  2. #22

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    So where does one go to find theses LED's?

    Quote Originally Posted by Ken Nadvornick View Post
    My DIY safelight consisting of six 635nm red LEDs reinforced with a single layer of Rubylith to suppress tiny slivers of non-red emission spikes, is hideously safe, as well as quite bright. Pre-flashed to just below threshold, Ilford MGIV FB & RC tested absolutely safe—to both the eye and a reflection densitometer—out to a 60 full minutes, at which time the test was voluntarily terminated as being pointless beyond that.

    And the LEDs were far, far less expensive than a traditional safelight. And are rated for 50,000 or so hours of continuous use. That's 10,000 5-hour darkroom sessions.

    What's not to like?

    Ken

  3. #23
    Ken Nadvornick's Avatar
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    Quote Originally Posted by scheimfluger_77 View Post
    So where does one go to find theses LED's?
    This post of mine from 20 months ago has a link to an online source for the same type of OptiLED red LEDs I used. Interesting that the spec sheet shown claims only 35,000 hours. That's different from the 50,000 I saw from a previous online source. Oh well, 7,000 5-hour darkroom sessions will just have to do...

    I chose these based on wavelength (also not listed by this vendor) and the fact they used a standard socket base, thus making them very flexible to place. I think they would work great in the Kodak bullet-style lamps if an existing filter was reworked to hold a circle of Rubylith.

    These guys are pretty bright even when used individually. Six of them in a row sitting on top of my ceiling-mounted Duplex can light up my 9x11-foot space very nicely.

    [Edit: After looking around a bit just now I think the bulbs referenced in the above link may have been discontinued and replaced by these even more powerful (2-watt vs 0.5-watt) Festival H13-VF versions. This link also provides a chart showing wavelengths. Interesting that the amber LEDs are rated at about the same wavelength as the Duplex sodium doublet (~589.29 nm, albeit nowhere near as tight a spread) making them possible replacements for the Kodak OC safelights, if filtered with a sheet of Amberlith.]

    Ken
    Last edited by Ken Nadvornick; 09-06-2012 at 01:12 PM. Click to view previous post history. Reason: Added [Edit]...
    "They are the proof that something was there and no longer is. Like a stain. And the stillness of them is boggling. You can turn away but when you come back they’ll still be there looking at you."

    — Diane Arbus, March 15, 1971, in response to a request for a brief statement about photographs

  4. #24

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    Thanks Ken. I may have seen some of these at Lowe's yesterday. That internal structure looks real familiar, I'll have to investigate some more. One has to wonder if the blue and green ones could be adapted as a light source for a VC enlarger head.

    Steve

  5. #25

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    I work in total darkness when tray developing film or working with color paper. I've had even small
    red LED's fog shadows with certain film. My LED timer is now UNDER the sink where the film can't
    see it at all. For black and white paper, I use an old Kodak barrel safelight, but it's connected to a
    rubberized (shockproof) footswitch, which I momentarily step on when needed. I've heard plenty of
    stories about Thomas safelights fogging things.

  6. #26
    Ken Nadvornick's Avatar
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    The reason some red LEDs and the Thomas sodium safelights fog is because they also emit small amounts of non-safe wavelengths.

    Look at the emission spectrum of a low pressure sodium tube. See all of those small blue and green spikes beyond the dominent sodium doublet? There's no way to visually detect those in the flood of monochromatic orange light, but they are there. Remove them (using a Roscoe #19 Fire filter) and the fogging disappears.

    Same for the red LEDs. Remove them (using a Rubylith filter) and the fogging disappears.

    Try this. Hold up the business side of an ordinary CD disc to your red LEDs (or to a Thomas tube) and look at the discreet wavelengths that are reflected. I'll bet if you look carefully you'll see a few narrow green and/or blue stripes mixed in with the red or orange. I know I did.

    My red LEDs showed small telltale green bands and my Ilford MGIV VC paper was faintly fogging. The Rubylith cured that out to 60 minutes tested. My Kentmere Bromide graded was severely fogging under the Thomas. The Roscoe cured that out to 30 minutes tested.

    Ken
    "They are the proof that something was there and no longer is. Like a stain. And the stillness of them is boggling. You can turn away but when you come back they’ll still be there looking at you."

    — Diane Arbus, March 15, 1971, in response to a request for a brief statement about photographs

  7. #27
    Robert Hall's Avatar
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    If you really want to go down this road, David, we could talk about those who spend thousands on a new camera setup but wont spend $250 on a decent workshop or class. (Where, I might add, they would learn that a red screen from an iphone just won't work as a safelight.)
    Robert Hall
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    Technology is not a panacea. It alone will not move your art forward. Only through developing your own aesthetic - free from the tools that create it - can you find new dimension to your work.

  8. #28

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    "Hold up the business side of an ordinary CD disc..."

    Clever!! I have a couple hundred spectrographs I never thought of! Thanks.

  9. #29
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    I have all the different safe lights, including the thomas but I am settled on LEDs and a few red christmas bulbs. The Thomas makes a lot of noise. I hate that. The red LEDs are the best.
    Dennis

  10. #30
    Leigh B's Avatar
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    Quote Originally Posted by Ken Nadvornick View Post
    ...the Thomas sodium safelights fog is because they also emit small amounts of non-safe wavelengths.
    Could you explain the mechanism, please. Sodium is monochromatic (two closely-adjacent spikes).

    - Leigh
    “Wise men talk because they have something to say; fools, because they have to say something.” - Plato

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