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Thread: DIY 8x10 (or larger) Enlarger Chassis

  1. #71
    Drew Wiley
    Join Date
    Sep 2008
    Location
    SF Bay area, CA
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    15,849

    Re: DIY 8x10 (or larger) Enlarger Chassis

    What happens when the LED technology shifts or advances enough to make obsolete your chosen LED components? It's inevitable. You better have your own set of spares. And hopefully you are trying to devise something for sake of VC papers, not actual color printing. Being somewhat off in the green is going to especially limit hue accuracy, since that the primary our own eyes are most sensitive to. But I'm skeptical in general about the accuracy of LED's in color printing at this stage of the game, while tried and true halogen colorhead options are so readily available. But good luck to you. Not every pioneer made it through the wilderness; but some did.

  2. #72

    Join Date
    Jun 2019
    Location
    Western Massachusetts, USA
    Posts
    246

    Re: DIY 8x10 (or larger) Enlarger Chassis

    Quote Originally Posted by Drew Wiley View Post
    What happens when the LED technology shifts or advances enough to make obsolete your chosen LED components? It's inevitable. You better have your own set of spares. And hopefully you are trying to devise something for sake of VC papers, not actual color printing. Being somewhat off in the green is going to especially limit hue accuracy, since that the primary our own eyes are most sensitive to. But I'm skeptical in general about the accuracy of LED's in color printing at this stage of the game, while tried and true halogen colorhead options are so readily available. But good luck to you. Not every pioneer made it through the wilderness; but some did.
    I'm only planning on doing VC printing myself, but in theory it should work for color as well. Remember that the green hue created by a color head and RA-4 paper is not determined by the frequency of the green light, but the amount of light it is exposed for. RA-4 paper only has 3 colors in it, so the hue will be the same, as long as the exposure is adjusted accordingly. If you look at the Fuji Crystal Archive paper data sheet linked below, the magenta dye curve (which is the one effected by green light) in figure 12 has a density peak around 550nm, and the curve is heavier on the lower end, so 535nm should work fine I think.

    https://asset.fujifilm.com/www/us/files/2020-02/9251484a0eda6ebb4b47cc6fec73173a/Fujicolor_Crystal_Archive_Type-CA-Data-Specs.pdf


    Also, Heiland has had success printing with LED heads, and though I don't know specifically what LEDs they use, but from my research I could not find any narrow band green LEDs with a peak at 550nm. This is their most recent post on instagram:

    https://www.instagram.com/p/CTwmRM9IQh_/

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