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Thread: OC filters in our future?

  1. #1

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    OC filters in our future?

    I know from our forum here, that bright red LEDs are available and working well as safelights for many, but as one whose eyes find OC light much preferable to red, I wonder if anyone knowledgeable in such matters as filter manufacture might chime in on the future possibility of similar filtration returning.

    As others have noted, the rare round OC filter that shows up in the auction site demands a king's ransom, and sodium-vapor units such as the Thomas are equally rare, and problematic to lamp. (For many, such a luminaire is overkill or otherwise unsuitable for the darkroom space anyway.) I was recently delighted (and relieved!), starting my darkroom up after more than a decade, to find that my old Kodak OCs still test fully safe at 5 minutes or longer as placed. But all things wear out, and now that I'm getting active again, the question is one of those on my mind.

    I assume that either the Kodak patent is still in force somehow, or that the restricted bandwidth is particularly difficult to manufacture (I wonder why, though I know that LEDs have a tricky wavelength distritbution) and financially unfeasible for a few thousand, or even tens of thousands of potential buyers lacking Swiss bank accounts in the coming x-number of years. It would be grand to win a lottery and be able to invest enough money in such projects as this, new Poloroid 55, and others to make them high-quality and affordable -- just as a good deed -- but holding our breath for that to happen would keep us from our work far too long. (Yes, 45 seconds is too long. Tempus fugit.)

    Anyone have an informed perspective in this domain?
    Philip U.

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  2. #2
    Eric Woodbury
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    Re: OC filters in our future?

    Sodium vapor will fog paper.

    If you prefer OC, you could make with Lee or Rosco lighting gels and white LEDs. Or you can use the yellow-orange LED lights. I have a few of those in the darkroom. They give pretty good time before threshold exposure. I still prefer the red as it doesn't fog any of the papers, even the Russian stuff.
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  3. #3
    Randy Moe's Avatar
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    Re: OC filters in our future?

    Don't try just any bright red led, you will be disappointed.

    There is one that is recommended here over and over again.

    So again. I know you didn't ask.

    And keep it 4 ft away.

    https://www.superbrightleds.com/more.../attributes/13

  4. #4
    Corran's Avatar
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    Re: OC filters in our future?

    I love the bulb Randy posted. I bought a couple and they are way brighter than my normal safelights. If/when they burn out I will replace the units with plug-in socket converters and those bulbs (I have plugs wired up in the ceiling for safelights). Really I should just do it now and have a brighter darkroom (that sounds funny!).

    I tested them once and held up a piece of paper literally against the bulb for about a minute. Only fogged it to about middle grey. Another test with the paper just lying out nearby for a long time showed no fogging at all. Mine is in a lamp at the end of the dev/stop/fix tray set. Just for convenience it's plugged into my timer and so it does switch off while clocking out the dev time.
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  5. #5

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    Re: OC filters in our future?

    Quote Originally Posted by Corran View Post
    I love the bulb Randy posted. I bought a couple and they are way brighter than my normal safelights. If/when they burn out I will replace the units with plug-in socket converters and those bulbs (I have plugs wired up in the ceiling for safelights). Really I should just do it now and have a brighter darkroom (that sounds funny!).

    I tested them once and held up a piece of paper literally against the bulb for about a minute. Only fogged it to about middle grey. Another test with the paper just lying out nearby for a long time showed no fogging at all. Mine is in a lamp at the end of the dev/stop/fix tray set. Just for convenience it's plugged into my timer and so it does switch off while clocking out the dev time.
    Same with me. Randy is on the mark.
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  6. #6
    Randy Moe's Avatar
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    Re: OC filters in our future?

    Chosen with this Spectral Graph from, https://www.superbrightleds.com/more...Specifications

    LED Spectral Graph Z1R by moe.randy, on Flickr

  7. #7
    jp's Avatar
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    Re: OC filters in our future?

    If you really want belt+suspenders, get the red screw-in led bulbs Randy and others (myself included) use, and put a red gel over it. I don't bother with the gel. No problems with paper. It will add some fog to Xray film over time (fine for loading, but too much for tray developing with the LEDs on), but I have my darkroom lit with red bright enough to record cell phone videos with no low-light-noise, and we know how bad cell phones are in dim light.

  8. #8

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    Re: OC filters in our future?

    I agree about amber being preferable to red.

    Ilford's safelight for B&W materials is the SL1, they publish a good technical note on safelights that includes response curves. They may also be still producing safelights and safelight filters.

  9. #9
    Randy Moe's Avatar
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    Re: OC filters in our future?

    I like the Ilford Safelight test

  10. #10
    adelorenzo's Avatar
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    Re: OC filters in our future?

    Quote Originally Posted by Ulophot View Post
    As others have noted, the rare round OC filter that shows up in the auction site demands a king's ransom, and sodium-vapor units such as the Thomas are equally rare, and problematic to lamp.
    Are you looking for some kind of weird size or something? I have a stack of the 5.5 inch OC filters for Kodak beehives that had no interest when I tried to sell them recently. I bought some of them new in the last few years for like 30 bucks each from KHB Photographix. Last I checked they were easy and cheap to find.

    I have a Thomas as well sitting in a closet, was given to me free. From what I have read in my small darkroom it would definitely fog my papers, never tried it.

    I switched to red LED bulbs in my Kodak beehives. They are many times brighter than using my old OC filters and have tested 100% safe with all my photo materials. They cost $4/each, hard to beat that. I can't downplay how much more visibilty I have in my darkroom now, I can seriously read a book in there. I can't imagine why I would ever want to go back to my old filters.

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