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Thread: UV Bliss

  1. #11

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    Congrats Jeremy....you are on your way bubba...

  2. #12

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    [QUOTE=Jeremy Moore
    The box was on for about 30 seconds (the first time ever!) so the bulbs hadn't completely come on yet.

    IQUOTE]

    I am just wondering what you meant by this comment? The tubes should come on all at once. Is this not happening with your unit?

    Sandy King

  3. #13
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    I've found with flourescent lights (in my experience with "normal" flourescent bulbs, I'm knew to Black Light bulbs) that they take a while to stabilize--they do all come on at once, my mistake on word choice.

    I had it running for 2.5 hours straight and it stayed quite cool, I think it's a success!
    Let's see what I've got in the magic trash can for Mateo!

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  4. #14

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    Quote Originally Posted by Jeremy Moore
    I had it running for 2.5 hours straight and it stayed quite cool, I think it's a success!
    Did you install a fan? If so you can run the unit indefinitely and it will not overheat.

    Sandy King

  5. #15
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    Nice box and well done. Looks like you could cook some prints with it if the times were a bit too long. Did you use any kind of diffusion glass to even out the light from the bulbs? Any signs of streaking because of the array of the tubes, or are prints coming out evenly?

  6. #16
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    Quote Originally Posted by sanking
    Did you install a fan? If so you can run the unit indefinitely and it will not overheat.

    Sandy King
    I couldn't find a muffin-box fan locally that would work straight with 110V so I cut a hole and use a small deskfan. The deskfan butts right up into the hole and I could literally run the box all the time and it wouldn't overheat.

    Sandy, I was just re-reading your UV source page on www.unblinkingeye.com and you wrote:

    "This type of light source is reasonably fast, provides a large area of even illumination, is quite easy to operate, produces constant output almost immediately on being turned on (especially when using electronic ballast), and may be switched on and off with no delay. A fan should be used to cool the tubes because if they get hotter than about 105°F the light output decreases significantly. Fluorescent tubes do not require any appreciable warm-up time, and they may be restarted immediately."

    Right now I just have it wired right into a plug. Does this mean that I can wire it through a switch and just turn the lights on after I put the contact frame in and then turn it off when the times up--or even better, hook it up to a GraLab timer?


    Noseoil,
    I've only been printing 1.5 x 5.5" step tablets to get my digital negative curves, but I plan on printing a large 11 x 17" to check for any hotspots. The inside of the box was spray painted white but from all of my research I won't have any problems with hotspots, but no reason not to check
    Let's see what I've got in the magic trash can for Mateo!

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  7. #17

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    Quote Originally Posted by Jeremy Moore
    Right now I just have it wired right into a plug. Does this mean that I can wire it through a switch and just turn the lights on after I put the contact frame in and then turn it off when the times up--or even better, hook it up to a GraLab timer?

    Noseoil,
    I've only been printing 1.5 x 5.5" step tablets to get my digital negative curves, but I plan on printing a large 11 x 17" to check for any hotspots. The inside of the box was spray painted white but from all of my research I won't have any problems with hotspots, but no reason not to check
    You can indeed plug the light unit directly to a GraLab timer. I used my UV bank that way for a long time (now run it through a light integrator) and your exposures should be very consistent, so long as the bulbs don't get hot.

    I would recommend positioning the unit so tht the tubes are about 4 inches from the printing plane. This will even out the light and eliminate any possible hot spots, without causing much of an increase in printing times over placement at 1-2 inches. The inverse square law does not apply to diffuse light sources of this type so for all practical purposes your exposure times will not vary very much between positioning at 1-2 inches and 4-6 inches. At more than 6 inches you would start to see some increase in exposure time.

    Sandy King



    Sandy King

  8. #18

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    how did the BL bulbs do with palladium?
    Technological society has succeeded in multiplying the opportunities for pleasure, but it has great difficulty in generating joy. Pope Paul VI

    So, I think the "greats" were true to their visions, once their visions no longer sucked. Ralph Barker 12/2004

  9. #19
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    Thanks Sandy, I'll have to go pick up a Gralab timer then, here I come ebay! The box is built so that the bulbs are about 3.5-4" above the paper plane in the contact frame.

    Mark, I'm hoping to print palladium today, but so far my cyanotype 13-step tablets look great. I am on my last step tablet for cyanotype now, but I need to let it oxidize before I can read it. I will start my palladium tablets next but I can speed up their drying and there's no oxidation so I should have a print today.
    Let's see what I've got in the magic trash can for Mateo!

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  10. #20
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    I just dropped in - I didn't know what prep went into it...

    Magnetic or electronic ballasts?

    Is it uniform in illumination?

    I considered a diffuser for a similar project with Super Actinic lamps. I don't know if you want UV component... acrylic, for example will block quite a bit of the UV. Not sure about white diffuser material, but referencing 98% UVF framing acrylic, it blocks wavelengths shorter than 400 nm. 'Ordinary' acrylic blocks alot, but the curve is so sloppy it's hard to state a percentage of at what wavelength it 'kicks in'. Roughly 70% blockage and I'd assume same wavelength. (Any) glass blocks below 380 nm.

    Murray
    Murray

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