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  1. #11

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    I agree that for exposing alternative processes where exposure times are usually over four-five minutes, there is no reason to be concerned about warm-up. It takes the spiral BLB tubes about one minute to warm up to full output. Using a light integrator to compare total output of radiation in one minute, counting warm-up, I measured 213 units. The output in the second and subsequent minutes was 240 units. In other words, the output is only about 10% more in the second minute with the bulb warmed up than in the first starting from cold. If your exposure time were two minutes, you would get a total of 453 units starting from scratch, and 480 if you started the exposure after one minute of warm-up.

    Observe, however, that if you were using the spiral BLB tubes to expose AZO, where exposure times would be on the order of seconds, not minutes, the warm-up would be absolutley essential to consistent results.

    Sandy




    Quote Originally Posted by juan
    I'm using a box of spiral BLBs very similar to Martins - same sockets, bulbs vertical. My bulbs are only about an inch and a half above the printer glass. I'm using 15-watt bulbs as I can get them locally. Exposures on negatives made for the last Grade 2 Azo run about 10-12 minutes, so I don't believe the unstable warmup period makes much practical difference. I'm able to get repeatable prints in VDB.
    juan
    Last edited by sanking; 03-07-2006 at 08:18 AM. Click to view previous post history.

  2. #12

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    Of course they are not digital!!! Who do you take me for, really?

    They are 8x10 LF I shot because I was so proud of my new UV box. :rolleyes:

    Regards,
    Martin

  3. #13
    kudzma's Avatar
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    Just catching up on APUG threads after a hard drive crash. Thanks monophoto for the nice comment about my work! Did we meet at the View Camera conference in Springfield, MA?

    Yes, I now use a box of 12 20W spiral screw-in fluorescents. I only switched to these lights because I needed to rebuild my UV box to be longer. My box with fluorescent BL tubes (built exactly as described in Sullivan and Weese's book) wasn't long enough to evenly illuminate the ends of 8x20 negs. For my new box I opted to use a 3x4 array of spiral BLB's rather than 48" fluorescent BL tubes. Exposure times and contrast between the two boxes are almost identical. I only wish I had known about the 27W bulbs. Although, my exposure time in the box of 12 20W bulbs is fine. For Pd/Pt I need 20-40 min for in-camera Pyrocat negs and get maximum black in 11.5 min through Pictorico OHP. I always warm up the bulbs for 1 min prior to inserting the contact frame.

    I agree with Sandy, such a box would be extreme overkill for Azo. Exposure would be less than a second. I use one 15W spiral BLB bulb suspended 3 feet above the frame for Azo and get exposure times of 1-2 min.
    Linas Kudzma

  4. #14
    Monophoto's Avatar
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    I have used my new UV box a couple of times and can now provide some feedback.

    My design involves a 2x3 array of bulbs on 6" centers, with the tip of the bulb about 6" above the glass surface of the contact frame. The inside top of the box is lined with aluminum flashing. My limited experience is that this produces even illumination. I included a small fan in the box, and preheat the bulbs for 30 sec or so before starting an exposure.

    I have chosen to start the alternative process adventure with VDB, and have had two printing sessions so far. For the first, I used a single application of sensitizer on Stratford Bristol paper. I got decent (but unexciting) images with exposures in the range of 12-15 minutes. In the second session, I used two applications of sensitizer on Aquarelle paper. I don't know much about this paper other than it has a relatively smooth surface, but appears to be fairly thin. This time, the exposure had to be about 20 minutes. In both cases I was using 4x5 negatives (but not the same negative in both sessions).

    The conclusions so far:
    1. Choice of paper is very important, with thicker, more absorbant papers working better than either thinner papers or very smooth ("bristol") papers. This morning I purchased some fine grain Aquarelle cold press water color paper that I think will work better than the thin stuff.
    2. Double coated applications (per Wynn White's article) seem to work better than single-coat applications.
    3. I'm using in-camera negatives, and selecting negatives that are marginally contrasty for traditional enlarging/silver printing.
    4. I prefer selenium toned prints to non-toned prints. I know that selenium toning tends to bleach the image, so I have been careful to use very dilute selenium (2 ml per liter of water) and limit the time in the toner bath. I think I need to print darker, and then let the print stay in the toner longer to get the result that I prefer.

  5. #15

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    I put some information on how I built my UV light box with spiral BLB on my website. Anyone interested can view it here:

    www.extantimages.com

  6. #16
    Donald Qualls's Avatar
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    Apropos of this thread, I've been printing alt-process recently with a 13 W spiral BLB in a reflector clamp-on lamp. I've been using my Graylab 300 timer; I set it to focus, turn it on, and switch to "time" when the flickering stops. For multi-minute exposures, this ought to be more than accurate enough, and it makes me feel good.

    FWIW, I've been getting good salt print exposure (now that I finally found a paper that doesn't fog before the silver nitrate dries) with around ten minutes, lamp about eight inches above the printing frame. Same lamp requires a similar time for cyanotype rex (ferric ammonium citrate sensitized) and VDB rex (ferric ammonium citrate sensitized, developed with 12.5% silver nitrate). And I don't have to fight with variations in sun exposure, try to find a place that isn't shaded by the trees, heck, I can even print at night if that's when it's convenient...

    And the Strathmore Bristol is the *best* paper I've tried so far (though on a budget, I haven't wanted to order $50 worth of some specialty paper in order to find out if it'll work) for silver processes -- almost no fog, and it takes up enough chemical (at least on salt prints) to print with good density. Now I just need to figure how to keep it from fading in the pre-fix wash and fixer; goes from a near-neutral black to rusty-looking brown -- but I'll post elsewhere on that if I don't find the answer pretty quickly.
    Photography has always fascinated me -- as a child, simply for the magic of capturing an image onto glossy paper with a little box, but as an adult because of the unique juxtaposition of science and art -- the physics of optics, the mechanics of the camera, the chemistry of film and developer, alongside the art in seeing, composing, exposing, processing and printing.

  7. #17

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    Hi Donald,

    What size prints are you doing with the 13w BLB? You may want to look into a 27W BLB next time you order, they are about the same price.

    I noticed I was getting very fast exposures with my UV box.

    I don't know much about other alt printing (I've only been working with Kallitypes), but I always tone my prints before fixing and this prevents bleaching when they are fixed, and I don't notice much change from when developed.

    Regards,
    Martin

  8. #18

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    I'm using an identical setup to Donald -- 13W BLB in a reflector clamp-style lamp. I print 6x9" VDBs, and my typical printing time is ~8 min or so. Works really well.

    Donald, are there substantial differences in image quality between the VDB Rex and traditional VDB?

  9. #19
    Donald Qualls's Avatar
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    I'm printing 4x5 and 9x12 cm contact prints at this time, though I'm considering whether to get some 8x10 ortho film to make enlarged negatives for bigger prints. My printing light is about 9-10 inches above the contact printing frame. I'd have much rather had the 27 W bulb, but this one was a gift -- at some point I'll order the hotter bulb, but as things stand, my exposures for salt prints are running under 10 minutes and anything done with a rex process (ferric ammonium citrate alone during exposure) takes the same 10 minutes or so.

    I'd say a VDB rex, as I've been doing it (budget method) is clearly inferior to the VDB I've seen, but I've only done 3-4 of them, using a too-stiff brush to apply the silver nitrate that develops the image; I was, at that time, just improvising, trying to make a silver-based print with what I had on hand after realizing I was missing some ingredients for what I had intended when I ordered the silver nitrate. With some experimentation relative to solution strength for the silver nitrate and better means of applying it (without disturbing the latent image in the ferric ammonium citrate), I'm confident I could equal the conventional VDB images I've seen -- and it's a lot faster to just coat the paper with ferric ammonium citrate and let dry than it is to mix VDB juice, let it age, coat, and dry.

    I'm aware toning before fixing reduces bleaching -- but toning is LOT more expensive than printing, given silver nitrate is about $1/gram, or less if you can buy an ounce or more at once, while gold chloride is more than ten times that price, last I looked. My VDB rex hasn't faded, but did darken in the wash because I didn't wash before fixing (I now know how to solve that problem).
    Photography has always fascinated me -- as a child, simply for the magic of capturing an image onto glossy paper with a little box, but as an adult because of the unique juxtaposition of science and art -- the physics of optics, the mechanics of the camera, the chemistry of film and developer, alongside the art in seeing, composing, exposing, processing and printing.

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