Cyanotype exposue

Discussion in 'Alternative Processes' started by fschifano, Jan 3, 2011.

  1. fschifano

    fschifano Member

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    I know that sunlight works for making cyanotype prints but I'm looking for something a little more predictable. A 4ft. shop light outfitted with 2 40 watt BLB black light florescent tubes looks like it might work for this application and a few others requiring UV light. All the stuff can be sourced from Home Depot for about $50, but before I go and drop the cash, I was wondering if anyone else has used this combination and what were your results?
     
  2. michaelbsc

    michaelbsc Member

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    Not yet, but several people have posted plans for a plywood box with light fixtures.

    Apparently keeping it in a box with reflective sides (tin foil) not only keeps more UV on the work piece, but keeps UV out of other places you might not want it - like all over film or paper that isn't put away as neatly as it could be. I know that no one here on APUG would even leave things laying around, but some of those other folks might, so we need to set a good example for them.

    I've got the bulbs and bulb bases :smile:, but so far I haven't had the time to get the lumber or assemble the box. :sad:

    My plan is to use the compact fluorescent party black lights in plain old screw in bases. As far as construction plans go, well, you make a kinda squarey looking rectangular wood box.....
     
  3. fschifano

    fschifano Member

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    My idea is to just hanging the fixture over a workbench in another part of the basement. I already have a contact printing frame. Btu you've given me an idea to surround the frame with a fold up temporary box made of white foamcore to make tings a bit more efficient. My real concern is whether these Phillips BLB 40 Watt lamps emit useful wavelengths of UV for the process.
     
  4. michaelbsc

    michaelbsc Member

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    Don't know. Maybe someone else can comment. I found the CF bulbs worked fine. But if you can get those cheaper, then saving a buck is saving a buck.
     
  5. Mainecoonmaniac

    Mainecoonmaniac Subscriber

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  6. R Shaffer

    R Shaffer Member

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    Those bulbs will work just fine. Only having two of them x 4' long would restrict your print size ( I'd guess to around +/-6" to 48" long ), unless your doing really long pano's. Either BL or BLB are common for fluorescent UV exposure, but the actinic bulbs from the aquarium shop work too. I recently replaced my bank of T8 BLBs with BLs and that has shortened my exposures.

    Take a look here http://unblinkingeye.com/Articles/Light/light.html for comparison of various bulbs

    or here http://www.hybridphoto.com/forums/showthread.php?t=2045 if you want to see a really cool set-up. ( I'm wiping the drool from my keyboard )
     
  7. Nicholas Lindan

    Nicholas Lindan Advertiser Advertiser

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    BL bulbs are the right ones to use for exposing. BLB bulbs are heavily filtered to produce a black light effect and the filtering cuts out a deal of the light that goes into exposing the material - how much depends on spectral sensitivity of the material you are exposing. Some speciality materials, such as Cromalin color proofing, require only short wavelength UV because exposure to bright visible light is used to 'clear' the material by the action of a second light activated chemical.

    If you are going to build a box then it works better to paint the inside of the box with flat white paint. White paint has a higher reflectance than aluminum foil and is also diffusing so it reduces hotspots and provides even illumination.
     
  8. fschifano

    fschifano Member

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    This is all good to know. If I can source the BL type lamps , I'll get those instead. Thanks to all.
     
  9. alexhill

    alexhill Member

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    Spending the extra cash to build a exposure box is worth it. Doing something right the first time saves time and money. Mine cost me 250 usd to make. I bought the bulbs over amazon, and the electronic ballasts and bulb holders at home depot. My cyanotypes expose in 12-45 minutes.

    Makings a totally encased box is also a safety consideration. Exhibit A .
     
  10. jp498

    jp498 Member

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    That first link is very interesting and informative. I also happened to make some van dyke prints this past weekend with a 400w metal halide light, and it rocked.

    It's the light pictured here. An electrician acquired it for me without cost in the course of an upgrade he performed for a customer. I put the contact printing frame about a foot under the light.

    [​IMG]
     
  11. patrickjames

    patrickjames Member

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    I haven't made a cyanotype in a really long time, but I used to use two ready made simple under the counter fixtures made by Lampi. They plugged in and had a switch too. They took 24" bulbs. I don't know if those are available anymore, but the exposure for a bulletproof 4x5 was about 20 minutes. If I recall, they weren't that expensive and something like that would save you from having to wire up a box. In fact, you don't have to do anything else except buy them.