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Thread: OC filters in our future?

  1. #11
    8x10, 5x7, 4x5, et al Leigh's Avatar
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    Lightbulb Re: OC filters in our future?

    Quote Originally Posted by adelorenzo View Post
    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 have a Thomas hanging 6" below the ceiling toward one corner of my 10'x12' darkroom. It's bright enough to read small print on a bottle label anywhere in the room, even if shaded by my body.

    Absolutely no issues... completely safe with all the various papers I use.

    - Leigh
    If you believe you can, or you believe you can't... you're right.

  2. #12

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    Re: OC filters in our future?

    Thanks to all. The rave reviews of the red lights are encouraging, but when I said I prefer the OC filtration, I referred to the effect of the color of the light. To my eye, seeing everything in red, illumination level notwithstanding,is harsh or garish in comparison with the amber of the OCs, or of the Thomas under which I worked in college and other darkrooms. Interesting, Leigh, to hear your situation. I almost bought a Thomas back in the day, but couldn't justify the cost. For now, I have two beehive OCs, and one unopened OC filter I discovered after posting. I'm happy with the light level; it's both functional and calming for me.

    I wonder a bit about the orange and yellow gels idea. One attractive feature of the amber is its low color saturation.

    Perhaps the red is just a matter of getting used to. I guess time will tell.

    I'm surprised that no info emerged on why amber lighting has not been reproduced.
    Philip U.

    Sine scientia ars nihil est.
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  3. #13

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    Re: OC filters in our future?

    Quote Originally Posted by Ulophot View Post
    ... I'm surprised that no info emerged on why amber lighting has not been reproduced.
    I just took a quick look at the OC transmission spectrum. It peaks at ~580mn and passes no wavelengths shorter than about 550nm.

    Then I did a quick Google search on spectra for amber LEDs and got this: https://www.google.at/search?q=amber...stUMLNC2b3hBM:

    From a quick glance at the spectra, it seems that amber LEDs should be a viable substitute for OC filtration; many of the spectra match the OC spectrum very closely.

    Has anyone here tried out amber LED as a possible safelight? With what results?

    Doremus

  4. #14

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    Re: OC filters in our future?

    Quote Originally Posted by Doremus Scudder View Post
    I just took a quick look at the OC transmission spectrum. It peaks at ~580mn and passes no wavelengths shorter than about 550nm.
    Then I did a quick Google search on spectra for amber LEDs and got this: https://www.google.at/search?q=amber...stUMLNC2b3hBM:
    From a quick glance at the spectra, it seems that amber LEDs should be a viable substitute for OC filtration; many of the spectra match the OC spectrum very closely.
    Has anyone here tried out amber LED as a possible safelight? With what results?

    Doremus
    Possibly depends on whether you plan to use Foma papers. Quoting from the datasheet of Fomabrom Variant III: "It is routinely processed at indirect safety illumination with wavelength of 625 nm and higher". While I agree that amber light is more comfortable, the lower cost and the quality of Foma paper (to me equivalent to Ilford) carries a higher weight.

    Or is their spec overly protective? Anyone used Foma Variant with amber light?

  5. #15

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    Re: OC filters in our future?

    Several years ago, I decided to run some safelight tests as suggested by Richard Henry and others -- on both my B&W and Color papers. I was shocked by the results, and reconfigured my safelights in several, significant ways. Most darkroom workers that I have met have never even tested their safelights, and the few that did, basically just did the "penny test'.

    Here's a page of some good tests based on several suggested publications. If you are lucky, you won't be shocked. If you are not lucky, don't be surprised.

    http://www.subclub.org/darkroom/henry2.htm

  6. #16
    Jim Jones's Avatar
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    Re: OC filters in our future?

    The safelight test in the previous post is useful, but more informative is one where the paper is exposed to imageless white light from the enlarger with the lens well stopped down and the exposure doubling from 1/2 or one second to perhaps a minute. The same sheet of paper is then exposed to safelight alone in a series as described above. Both tests should include one strip of no exposure to provide a base reference. One feature of this test is to demonstrate the sometimes significant effect that a safelight can have on subtle light tones. The methodology permits using the same test for comparison with other papers and safelights.

  7. #17

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    Re: OC filters in our future?

    Quote Originally Posted by Jim Jones View Post
    The safelight test in the previous post is useful, but more informative is one where the paper is exposed to imageless white light from the enlarger...
    The test includes that and that is a VERY important part of the test. When you manage to exposure the paper to white light that does not create any density, you will probably be surprised at how even a weak safelight can "push the paper over the edge" and create density where there should be none.

  8. #18

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    Re: OC filters in our future?

    Dicks-MacBook-Pro:~ dick$ nslookup subclub.org
    ;; Got SERVFAIL reply from 216.165.129.158, trying next server
    Server: 192.168.0.1
    Address: 192.168.0.1#53

    ** server can't find subclub.org: SERVFAIL
    Principal Unix System Engineer, Yoyodyne Propulsion Systems

  9. #19

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    Re: OC filters in our future?

    Quote Originally Posted by Old_Dick View Post
    Dicks-MacBook-Pro:~ dick$ nslookup subclub.org
    ;; Got SERVFAIL reply from 216.165.129.158, trying next server
    Server: 192.168.0.1
    Address: 192.168.0.1#53

    ** server can't find subclub.org: SERVFAIL
    Sorry. It's there and has been for over two decades. Perhaps the new FCC rules negating Net neutrality have already gone into effect!

  10. #20
    8x10, 5x7, 4x5, et al Leigh's Avatar
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    Re: OC filters in our future?

    Quote Originally Posted by Old_Dick View Post
    Dicks-MacBook-Pro:~ dick$ nslookup subclub.org
    ;; Got SERVFAIL reply from 216.165.129.158, trying next server
    Server: 192.168.0.1
    Address: 192.168.0.1#53

    ** server can't find subclub.org: SERVFAIL
    192.168.x.x is a non-routable IP address block.

    It cannot be accessed by anyone outside of its own physical domain, like over the internet.

    I tried it and got:
    Non-authoritative answer:
    Name: subclub.org
    Address: 69.49.101.19


    I tried that IP address and it failed.
    It also fails a PING, so it is not accessible over the internet.

    However, when I accessed subclub.org, it worked.

    - Leigh
    If you believe you can, or you believe you can't... you're right.

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