Page 1 of 4 123 ... LastLast
Results 1 to 10 of 32

Thread: Potentially useful LEDs for darkroom/alt applications

  1. #1

    Join Date
    Sep 2014
    Location
    Montreal, Canada
    Posts
    816

    Potentially useful LEDs for darkroom/alt applications

    In the process of exploring for really good plug-and-play LEDs, I came across Waveform Lighting. What’s good about the stuff this company sells is that they provide some of the specs you want for LEDs to help avoid potential pitfalls depending on what you are doing.

    For example, rather than just indicating a CRI, which can be a murky measure, they give you Ra, R9, Re, what the continuous spectrum looks like, photometric reports, TLCI etc.

    I was looking at their Absolute line for a specific purpose (currently they offer strips and modules, and I think individual components for those more skilled). They are supposed to be effectively flicker-free, and their dimmers are >25kHz (to accommodate high video frame rates).

    Not exactly cheap of course, however they have other product levels a little less overkill and it occurred to me these might be of some use for making LED enlarger light sources, UV alt exposure devices, perhaps even safelighting.

    Anyhow just mentioning for thought, discussion or whatever.

  2. #2
    Tin Can's Avatar
    Join Date
    Dec 2011
    Posts
    17,400

    Re: Potentially useful LEDs for darkroom/alt applications

    Why no link?
    image

  3. #3

    Re: Potentially useful LEDs for darkroom/alt applications


  4. #4

    Join Date
    Sep 2014
    Location
    Montreal, Canada
    Posts
    816

    Re: Potentially useful LEDs for darkroom/alt applications

    Quote Originally Posted by Tin Can View Post
    Why no link?
    Sorry about that...

    https://www.waveformlighting.com/

  5. #5
    Tin Can's Avatar
    Join Date
    Dec 2011
    Posts
    17,400

    Re: Potentially useful LEDs for darkroom/alt applications

    Thank you both!
    image

  6. #6
    bob carnie's Avatar
    Join Date
    Jan 2004
    Location
    Toronto, Ontario,
    Posts
    4,633

    Re: Potentially useful LEDs for darkroom/alt applications

    thanks for the link Michael - the UV flood light is interesting , I wonder if it is stronger than the current 1ks metal halide uv lights on Nuarks. Potentially with diffusion and attached to a Ian Leake measuring device which is linked to a timer shutoff device this could be exactly what I am looking for . I have the vacuum easels and am trying to source a very strong UV light to replace the Nuarc lights. I have need to do up to 30 x 40 and need lots of power as now its over 20 minutes for pt pd with the units I have.

  7. #7

    Join Date
    Sep 2014
    Location
    Montreal, Canada
    Posts
    816

    Re: Potentially useful LEDs for darkroom/alt applications

    I don’t know enough about typical alt process wavelength ranges (UVA or UVB) and power requirements, or the efficiency/efficacy of the Nuarc lights. Someone else would have to answer.

    My first though is wouldn’t you need a whole bunch of these?

    Most UV lights are quite inefficient in actual UV output (mostly wasted power in violet/near UV). The Waveform UV LEDs seem to be significantly more efficient in this respect but the flood light is still just one 20 watt (power consumption) LED. You can generate more power with one of their 16’ strips I guess.

    Quote Originally Posted by bob carnie View Post
    thanks for the link Michael - the UV flood light is interesting , I wonder if it is stronger than the current 1ks metal halide uv lights on Nuarks. Potentially with diffusion and attached to a Ian Leake measuring device which is linked to a timer shutoff device this could be exactly what I am looking for . I have the vacuum easels and am trying to source a very strong UV light to replace the Nuarc lights. I have need to do up to 30 x 40 and need lots of power as now its over 20 minutes for pt pd with the units I have.

  8. #8

    Join Date
    Jan 2007
    Location
    New York
    Posts
    1,802

    Re: Potentially useful LEDs for darkroom/alt applications

    Andrew Lock, the Australian gaffer who presents the YouTube channel Gaffer & Gear, is probably as on top of what's happening with LED lights as anybody. He also gets into the technical details and often talks about the relative utility of scoring systems such as CRI.
    Last edited by r.e.; 21-Aug-2021 at 13:44.

  9. #9

    Join Date
    Sep 2003
    Location
    South Carolina
    Posts
    5,418

    Re: Potentially useful LEDs for darkroom/alt applications

    Quote Originally Posted by Michael R View Post
    I don’t know enough about typical alt process wavelength ranges (UVA or UVB) and power requirements, or the efficiency/efficacy of the Nuarc lights. Someone else would have to answer.

    My first though is wouldn’t you need a whole bunch of these?

    Most UV lights are quite inefficient in actual UV output (mostly wasted power in violet/near UV). The Waveform UV LEDs seem to be significantly more efficient in this respect but the flood light is still just one 20 watt (power consumption) LED. You can generate more power with one of their 16’ strips I guess.

    The NuArc metal halide lights radiate in several UV bandwidths and for this reason are useful for a wide range of processes that have different bandwidth requirements for exposure. The downside is that they are quite inefficient and can create a lot of heat with the long exposures sometimes required in alternative printing.

    LEDs radiate in a very narrow bandwidth around the stated wavelength and are very efficient, but may not work at all for processes well outside of the bandwidth. For example, LEDs of 385 nm, work fine for dichromate and iron based processes which are sensitive in this bandwidth, but are virtually useless for photopolymer which requires bandwidth of around 350 nm.

    With regard to Bob Carnie's question, the most efficient and least expensive way to put together an LED unit of 30X40" that would print well with gum and iron processes would be to fabricate a bank of 6-8 100 watt LED flood lights. The best one to use in my opinion would be the 100 watt Everbeam flood that radiate at 365 nm. https://www.amazon.com/Everbeam-Blac...58&sr=8-5&th=1

    You could save few bucks with 385 nm floods, but for a range of processes the 365 nm flood is far better.

    Sandy
    http://www.sandykingphotography.com/
    For discussion and information about carbon transfer please visit the carbon group at groups.io
    [url]https://groups.io/g/carbon

  10. #10
    Tin Can's Avatar
    Join Date
    Dec 2011
    Posts
    17,400

    Re: Potentially useful LEDs for darkroom/alt applications

    Thanks for the reminder Sandy, just bought 5 @ 365mm 50 watt

    1 as spare, I will be making smaller prints

    100 watt out of stock
    image

Similar Threads

  1. LEDs for enlarger light source.
    By Martin Courtenay-Blake in forum Darkroom: Equipment
    Replies: 16
    Last Post: 25-Oct-2012, 07:35
  2. Table of Rapax shutter dimensions/applications?
    By John Schneider in forum Lenses & Lens Accessories
    Replies: 2
    Last Post: 16-Feb-2009, 15:59
  3. Toyo 810M Wide Angle Camera Applications
    By Michael Kadillak in forum Cameras & Camera Accessories
    Replies: 5
    Last Post: 26-Apr-2004, 10:02
  4. Field cameras for wide angle applications
    By Matthew Phillips in forum Cameras & Camera Accessories
    Replies: 1
    Last Post: 2-Jul-1998, 20:02

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •