UV Light Source for Pl/Pd Printing

[Mike Castles]

Steve, not sure it proves/disproves but I have a UV box I built using the plans that are in the back of the Sullivan & Weese Plt/Pld Printing book and there is less than 1 inch between the bulbs (they do not touch but are very close) and I print up to 7x11/8x10 without any banding issues. Matter of fact I can print one 11x14 frame and another 8x10 frame at the same time using the max space (the box is 22x26) using 12 BLB T12 bulbs. Hope that helps..

[D. Bryant]

Obviously, my calculations are only theoretical, and I would appreciate any empirical evidence to support/disprove my calcs.

Steve

Your calculations are totally off by my experience. I've made several UV units using BL tubes spaced less than 1/4 inch apart and never had any shadows, banding or other anomalies.

Don Bryant

[John O'Connell]

I use a big 1000W HID fixture. It was about $250 when I bought it, yields 8-12 minute printing times, and required about 20 minutes to set it up. The article, though, convinced me to get one because of the higher contrast it offers. Free, grainless contrast is a good thing when printing Pt/Pd.

I've never heard of banding with tubes, by the way, from spacing them too close together.

[Ken Lee]

You might find this site helpful. I have an 11x14 model (with vacuum pump, frame, etc), and it works like a dream.

Jon Edwards s a great fellow, and has given me lots of info and advice.

See http://www.eepjon.com/uv.htm

Note: He also sells do-it-yourself kits. See http://www.eepjon.com/Ubldit.htm

[Eric Biggerstaff]

On ebay right now there is a 1200 watt Sandman plate burner for a buy it now price of $75.00.

Is this what Jorge is talking about?

[Steve Kefford]

Your calculations are totally off by my experience. I've made several UV units using BL tubes spaced less than 1/4 inch apart and never had any shadows, banding or other anomalies.

Don Bryant

Is this based on any measurements, or just by visual inspection?

Steve

[Scott Davis]

I have fixtures in my home-concocted printing unit like the ones you found - mine are GE, which I found at Home Depot. I have six of them, spaced about 2" from center of tube to center of tube (maybe 1" or so gaps between tubes). I can print one 12x20 under this without getting falloff or banding. I have no complaints about contrast with this setup, and my printing times are in the 6-8 minute range with good ambient temperature and humidity. In the winter, when it is cold and dry in my basement, printing times drop down to the 14-18 minute range.

[D. Bryant]

Is this based on any measurements, or just by visual inspection?

Steve

It's based on years of printing with these units.

Don Bryant

[Chauncey Walden]

I just measured the bulb spacing on my Kepro commercial uv printing frame and found about 2.5 inches. The key is that it has the work separated at a distance that evens out the light distribution to any point on the glass.

[David Aimone]

Scott,

I know this is an old thread but I have a question: How much distance (height above the surface exposed) is the unit that you were talking about below? I am building a similar setup with 6 32w T8 bulbs in one fixture, and I'm thinking 6-8" height from paper to bulb surface....

David

I have fixtures in my home-concocted printing unit like the ones you found - mine are GE, which I found at Home Depot. I have six of them, spaced about 2" from center of tube to center of tube (maybe 1" or so gaps between tubes). I can print one 12x20 under this without getting falloff or banding. I have no complaints about contrast with this setup, and my printing times are in the 6-8 minute range with good ambient temperature and humidity. In the winter, when it is cold and dry in my basement, printing times drop down to the 14-18 minute range.