UV light sources for pt/pd, would these work?

Discussion in 'Alternative Processes' started by Sean, May 20, 2006.

  1. Sean

    Sean Admin Staff Member Admin

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  2. bill schwab

    bill schwab Advertiser Advertiser

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    I can't say if those would work, but I have built a similar unit to this using these bulbs. It was very easy and works very well. I realize shipping will be an issue for you, but perhaps there is somewhere in NZ that will handle the F20T12-BL bulbs. I was able to find them locally at a lighting shop fo 9.50US each.

    Previously to building the box, I simply used 4 of these bulbs side by side in 2 separate fluorescent fixtures. I hung them so they were about 8 inches from the table surface with both plugged into a graylab timer. It worked great and only cost about 60 dollars.

    Good luck Sean!

    Bill
     
  3. ras351

    ras351 Member

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    Hi Sean,

    Not sure about the bulbs mentioned - interesting that they say ES only and then show a picture of a BC unit. What size unit are you thinking of building? Jaycar have the 40W 1225mm UV-BL tubes if they would suit but they're somewhat expensive when you need an array of them. A good electrical wholesaler should be able to point you to an alternative retail outlet for some smaller 20W versions.

    Roger.
     
  4. sanking

    sanking Member

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    Hi Sean,

    Based on my testing of this type of UV tube (i.e. sprial UV BLB tubes) an array of 20 watt tubes should provide enough UV radiation to print with UV sensitive processes.

    For best resuls place the bulbs as close together as possible, and plan for a bulb to printing frame distance of no more than about four inches..

    Sandy
     
  5. Sean

    Sean Admin Staff Member Admin

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    That sounds promising since they are pretty cheap, if I am printing 8x10 should my array be 11x14 to be safe? Thanks
     
  6. Donald Qualls

    Donald Qualls Member

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    Sean, I've been exposing cyanotype, VDB, and salt prints using the 13 W version of those bulbs, a single lamp in a reflector, with excellent results. I get exposure times only about twice what I'd need in sunshine, with the lamp about 20-25 cm from the printing frame (though with a single lamp, you'd need more distance for a larger print, the higher wattage lamp will help keep your printing times down). BTW, I've heard there are also 27 W versions of these bulbs available, which ought to give still shorter times.
     
  7. sanking

    sanking Member

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    Yes, I believe a 11X14" light box should give you plenty of even light for printing 8X10. If you can find the 27 watt tubes that Donald mentions use them as they will give you almost 1/3 more radiation.

    Sandy