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  1. #21

    Join Date
    Feb 2008
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    spiral tubes work great

    I do some cyanotype printing but mainly Pt/Pd and purchased two of the B&S higher wattage bulbs and mounted them in two work reflectors as you described. I print up to 8x10 and while it worked OK I found I needed to rotate the print frame every minute or so to make a more even exposure. I decided to buy a total of six and mounted them in a bamboo storage box that I bought from a local importer. A wooden box would work fine too. I used ceramic sockets and did two rows of three bulbs. I allow the bulbs to warm up a few minutes to stabilize the output and place my contact frame about three inches from the bulbs. The illumination is very even and my exposures for Pt/Pd run an average of 4-5 minutes and cyanotypes are about the same. This works perfect and the cost was reasonable plus the size is very compact and easy to store.

  2. #22

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    Dec 2009
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    So, I ran my first test with the work reflectors and bulbs today. I found that up to 4x6 was easy with the two reflectors, and I'll be able to get good prints at about 2x the time for direct sunlight. 8x12 will take a little more experimentation; I exposed one for 20m, and it was horribly underexposed compared to the 4x6 I exposed for 25m. I'll continue to experiment with the placement, but I think up to 5x7 or 6x9 could work very well and easily with this setup.

  3. #23

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    Jul 2010
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    I'm suprised no one has yet tried UV led lamps. I just bought a pair on ebay. it's just as big a as a regular light bulb but is composed of 80 leds emmiting UV light. I haven't tried it yet but it seems to be the best alternative to bulky spiral or tubes.

  4. #24

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    Sep 2006
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    "I'm suprised no one has yet tried UV led lamps."

    I have! 552 of them in a home-made 15" x 20" box. Easy to store away, quite thin, very low heat while it's on. However, even with that many LEDs in my box, it's about a half to a a third as fast as printing with sunlight. But, on the plus side exposure times with the box are very consistent.

  5. #25
    donbga's Avatar
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    Nov 2003
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    Quote Originally Posted by Danny Spence View Post
    "I'm suprised no one has yet tried UV led lamps."

    I have! 552 of them in a home-made 15" x 20" box. Easy to store away, quite thin, very low heat while it's on. However, even with that many LEDs in my box, it's about a half to a a third as fast as printing with sunlight. But, on the plus side exposure times with the box are very consistent.
    What are you printing and what are your exposure times?

    Thanks,
    Don Bryant

  6. #26

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    Sep 2006
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    Cyanotype and Van Dyke Brown. I want to do gum when things are slow this winter.

    I'm a little reluctant to give printing times as how I'm mixing the formulas or my processing of the paper may not match everyone else's. I don't know how anyone else is exposing, the range of tones they look for or the density of their negatives. But for what it's worth, I used a Stouffer 21-step wedge and tested how long it took to get a maximum, uh, blue. And brown. I got about a eight stop range for cyanotype and a seven stop range for VDB. Two hours under the UV LEDs to do this for a cyanotype and one hour for VDB. When I print with actual camera negatives instead of the step wedge it varies a bit on both sides of those times.

    Just for comparison exposing with the sun I've had printing times from fifteen minutes to one hour. It varies a lot for the time of day, weather and the season. With a single 25 watt spiral fluorescent BLB bulb I have from Bostick and Sullivan, a 8x10 cyanotype took from four to eight hours to expose. Again, I don't know what everyone else out there is using, but this is what I got.

    The UV LEDs aren't as impressive compared to the speed of printing out in sunlight, but they are faster than my single BLB. The lack of heat from the LEDs is also a real plus -- even after being on for hours, they're only warm to the touch. I worry about cooking my contact printing frame and the delicate negatives out in the summer sun.

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