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  1. #1

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    UV Point light source options

    Would like to try point light for contact printing but am wary of the size and ramp up time of some of the industrial HID fixtures. Anyone try any of the smallish metal halide or mercury vapor bulbs with the built in reflectors? This would be for pt/pd and kallitype, possibly carbon later, no bigger than 11x14. Thanks for any advice.

  2. #2
    gr82bart's Avatar
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    You mean units like this? http://www.elationlighting.com/produ...ecial%20Effect

    I have two of these that I bought used from a local nightclub. To me, as a beginner, they work fine and provided me with consistent light. In terms of ramp up time, both units turn on instantaneously. The Elation units are also the perfect size for an 8x10 contact printer - it can fit snugly against the unit. An 11x14 printer would require a bit of distance to get the coverage.

    Regards, Art.
    Visit my website at www.ArtLiem.com
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  3. #3

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    That looks very promising, thanks. What sort of exposure times are you getting with it? And do you think the light is more collminated that a bank of tubes?

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    9circles's Avatar
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    Just bought a philips facial tanning studio don't laugh. £20 off of the auction place. It has a built in timer and variable output. Done a Van Dyke in 3 minutes, the salt in my gallery in 3 and a half at a distance of 12 inches. Might not be what you were after, but its another option. ( can also get a nice tan if you're inclined that way :P)
    All the best

  5. #5
    gr82bart's Avatar
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    Quote Originally Posted by Colin Graham View Post
    What sort of exposure times are you getting with it?
    Well, depends on the negative, but I recently did 200 cyanotypes a few weekends ago at about 12-15 minutes each.

    And do you think the light is more collminated (sic) that (sic) a bank of tubes?
    Don't know.

    Regards, Art.
    Visit my website at www.ArtLiem.com
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  6. #6

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    Translation: Do you think that the light is more collimated than a bank of tubes? Sorry, been a bit short of sleep lately.

    9circles, that sounds interesting, though I don't think I'd know one if I saw it. I'll do some research. Thanks for the suggestion.
    Last edited by Colin Graham; 05-06-2007 at 10:13 PM. Click to view previous post history.

  7. #7
    9circles's Avatar
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    No problem Colin, the one I have is the Philips HB171. Hope thats of use.

    ian

  8. #8

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    While I am not a alt process printer, I do know about point light and light sources in general having designed and built a point light source for my Durst 138 S enlarger...A true point light source will require a short filament or arc length in order to produce the capability for maximum collimation...notice that I said capability for collimation and not collimation. Collimation requires an optical system in the light path to produce collimation. This is accomplished with the condensers in a condenser enlarger system. In consideration of a well designed light source two things are required for the greatest resolution and accutence...those being a short filament or arc length and collimation...these are not one and the same.

    Any lamp that is of the BL or BLB designation will not have the capability for maximum collimation since the point of light origination is a large envelope relative to illuminated area...this is true whether that is any of the T (linear) lamps or any of the other spiral or wrapped lamp designs.

    While the results obtained with a true point and collimated light source will be quite noticeably different when one is enlarging a negative...the result will not be quite as noticeable when one is contact printing...this is because there is less space for light ray dispersion in the negative/print interface in contact printed negatives when printed with a diffuse lamp. Yes, there will be a difference but not as noticeable as one may initially think.

    The optimal in sharpness and resolution could be obained if one were to install a short filament carbon arc lamp in a well designed condenser system...this would require that one would install a lens shutter since the lamp fires slowly...this carbon arc/condenser enlarger would then be used as the light source for exposing your contact prints. Carbon arc has a high UV output and would be especially suited for exposing alt process prints.
    Last edited by Donald Miller; 05-07-2007 at 02:35 AM. Click to view previous post history.
    Art is a step from what is obvious and well-known toward what is arcane and concealed.

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  9. #9

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    Thanks a bunch Donald for the detailed answer. I'm new to alt printing so I'm not sure what I'm after exactly just yet, but did want to explore some options before I built a bank of tubes. It's good to know that sharpness need not be a deciding factor.

    Ian, yes that's very helpful. Thanks
    Last edited by Colin Graham; 05-07-2007 at 08:54 AM. Click to view previous post history.

  10. #10
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    Quote Originally Posted by Colin Graham View Post
    Translation: Do you think that the light is more collimated than a bank of tubes? Sorry, been a bit short of sleep lately.
    Still don't know. Honestly, don't care either. By the looks of it, my entire contact printer is 'bathed' in UV light and I get decent, repeatable images (true - there are a dozen other contributing factors). That's all that matters to me.

    If you do care about the parallelness (sic - will this pass the scrabble muster?) of the light, buy the bulbs and make your own unit. I think you'll need UVA bulbs - wavelength peaks around 300 nm. For example, buy a bunch of these - http://www.bulbman.com/index.php?mai...ducts_id=13846, sockets, household purpose electrical wire, some plywood and other materials, and voila! UV lighting bank with collimated light. Though, your local authorities might think your growing certain 'herbs'. And it'll still cost you as much as the Elation units, plus your time and aggravation.

    Good luck whatever you do. Oh and join a print exchange so we can see first hand the results of your work.

    Regards, Art.
    Last edited by gr82bart; 05-07-2007 at 09:42 AM. Click to view previous post history.
    Visit my website at www.ArtLiem.com
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