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  1. #11

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    I tried printing Azo on my Gravure plate burner. It has a bank of 10 UV tubes. Exposures were less than 3 seconds for most pyro negatives. I ordered one of those spiral UV bulbs and thought I would stick it into my d6 condensor and see if I could enlarge 6x7 negs on Azo paper.
    Don Sigl
    www.drs-fineartphoto.com

  2. #12
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    We tried printing Azo with a UV contact printer used at the Formulary last summer and even at the shortest exposure time, the prints were severly overexposed. This was about 1/2".

    Of course, that was overkill, but we were just experimenting. Azo is very fast in the UV.

    PE

  3. #13

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    My gravure burner is home built, and I can adjust the light source to be up to 30" away from the vacuum frame. Even at this distance, the times were to short to be workable. About .5-3 seconds.
    Don Sigl
    www.drs-fineartphoto.com

  4. #14

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    Quote Originally Posted by Photo Engineer View Post
    Sandy, I've found that most tungsten and especially fluorescent bulbs put out enough UV to expose AZO paper in reasonable exposure times.

    PE
    Ron,

    A couple of years ago I compared curves exposing, 1) with the 13 watt BLB spiral bulb, and 2) the R-40 flood with a UV cut-off filter. I basiclaly wanted to know if there was any difference in curve shape or contrast exposing with UV versus blue light. The curves were for all practical purposes identical. Is this typical of silver chloride emulsions?

    Sandy

  5. #15
    Will S's Avatar
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    I use 2 spiral blb with one spiral flourescent in the head of my Omega D2V to enlarge onto Azo. The times are a little long (40-60 seconds usually) and I have to use a larger aperture than I would sometimes like, and I had to get Nikkor enlarging lenses. But it works. Have to let the bulbs stay on all of the time. I just use a black card to cover the lens and I taped up the enlarger well to stop light leaks. But, it cost me about $40, not $1000 so I can deal with it. Mostly I'm enlarging from 4x5 and 645 too, though I have done a couple of 35mm.

    If two spiral blb can work I don't see why an led light source can't be used. I keep hoping someone will design and sell a head that will work on a D2 or a Besseler. Provided, of course, that the price is reasonable.

    Thanks,

    Will
    "I am an anarchist." - HCB
    "I wanna be anarchist." - JR

  6. #16

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    Quote Originally Posted by Will S View Post
    I use 2 spiral blb with one spiral flourescent in the head of my Omega D2V to enlarge onto Azo. The times are a little long (40-60 seconds usually) and I have to use a larger aperture than I would sometimes like, and I had to get Nikkor enlarging lenses. But it works. Have to let the bulbs stay on all of the time. I just use a black card to cover the lens and I taped up the enlarger well to stop light leaks. But, it cost me about $40, not $1000 so I can deal with it. Mostly I'm enlarging from 4x5 and 645 too, though I have done a couple of 35mm.

    If two spiral blb can work I don't see why an led light source can't be used. I keep hoping someone will design and sell a head that will work on a D2 or a Besseler. Provided, of course, that the price is reasonable.

    Thanks,

    Will

    What wattage spiral bulb did you use? These bulbs first came out in 13 watt size, but I recall seeing recently 30 watt bulbs for sale.

    Sandy King

  7. #17

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    Quote Originally Posted by sanking View Post
    The curves were for all practical purposes identical. Is this typical of silver chloride emulsions?
    I forget the name of the effect, but with panchromatic films, red light exposures will give lower contrast than blue light exposure. It's not a huge effect, but it has been measured.

  8. #18
    Will S's Avatar
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    Quote Originally Posted by sanking View Post
    What wattage spiral bulb did you use? These bulbs first came out in 13 watt size, but I recall seeing recently 30 watt bulbs for sale.
    I got these. I'd be interested to switch to 30W though if they aren't longer/wider. It's a tight fit in the head as it is, though if I could find a much smaller source of white light I could probably get 3 blb in there.

    https://www.saveonlighting.com/i-sun...lb_bx-1091.htm

    Thanks,

    Will
    "I am an anarchist." - HCB
    "I wanna be anarchist." - JR

  9. #19
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    Quote Originally Posted by sanking View Post
    Ron,

    A couple of years ago I compared curves exposing, 1) with the 13 watt BLB spiral bulb, and 2) the R-40 flood with a UV cut-off filter. I basiclaly wanted to know if there was any difference in curve shape or contrast exposing with UV versus blue light. The curves were for all practical purposes identical. Is this typical of silver chloride emulsions?

    Sandy
    Sandy, the wedge spectrograms of AZO and my chloride AZO substitute are pretty much symmetrical around the visible and UV regions. Mine is not spectrally sensitized. So, although I agree with Kirk, since these papers are not spectrally sensitized, what you observe appears to be normal.

    Spectral sensitization tends to decrease contrast, so when I sensitize the Azo emulsion to green light, it becomes lower in contrast. This agrees with Kirk's comment and my previous observations. It is not always true though, it depends on the dye. Some dyes do not decrease contrast.

    PE

  10. #20
    Will S's Avatar
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    OK, I found this 100W(!) but it is 280mm long. Still might be worth a shot:

    http://www.bulbman.com/index.php?mai...ducts_id=14804

    and this 27W:

    http://www.bulbman.com/index.php?mai...ducts_id=13846


    Thanks,

    Will
    "I am an anarchist." - HCB
    "I wanna be anarchist." - JR

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