Compact Fluorescents and UV output

Discussion in 'Darkroom Equipment' started by WarEaglemtn, Mar 20, 2008.

  1. WarEaglemtn

    WarEaglemtn Member

    Messages:
    464
    Joined:
    Aug 4, 2004
    Shooter:
    Multi Format
    Do the spiral type of Compact Fluorescent lights put out enough UltraViolet to use a batch of them for alt process exposure light sources?
    I know they can be slow to get to peak power but that can be remedied by a screen blocking them until I put the coated pt/pd paper in front with the vacuum frame.

    Anyone with experience or info is welcome to chime in.
     
  2. mark

    mark Member

    Messages:
    5,270
    Joined:
    Nov 13, 2003
    Last edited by a moderator: Mar 20, 2008
  3. keithwms

    keithwms Member

    Messages:
    6,070
    Joined:
    Oct 14, 2006
    Location:
    Charlottesvi
    Shooter:
    Multi Format
    Most fluorescents give emissions from mercury vapour, which produces strong but narrow lines peaked at various wavelengths in the UV:

    [​IMG]

    The lines are or course not as narrow as they are depicted in this plot, but they are indeed rather narrow. So narrow that you might miss the sensitivity curve for your particular alt process. We had a discussion about this recently at hybridphoto. So, my [amateur] feeling is that fluorescents are sort of hit and miss for alt process stuff, even if you do get up to significant output at a particular wavelength. The side effect can be inability to build enough contrast in the print and so forth.
     
    Last edited by a moderator: Mar 20, 2008
  4. David A. Goldfarb

    David A. Goldfarb Moderator Staff Member Moderator

    Messages:
    18,005
    Joined:
    Sep 7, 2002
    Location:
    Honolulu, Ha
    Shooter:
    Large Format
    Not normal ones. I can work with sensitized albumen paper under CFL room lighting, and I don't get any fog. I tested some scrap paper fairly close to a CFL lamp, and it took quite a while to produce a visible effect. I don't know if there are UV CFLs, but if they are, I assume they would have the same output as normal UV fluorescent tubes like BLBs and such.
     
  5. Monophoto

    Monophoto Member

    Messages:
    1,691
    Joined:
    Aug 27, 2004
    Location:
    Saratoga Spr
    Shooter:
    Multi Format
    BLB spirals are available and work very well for alternative processes. They have the advantage of being self contained and not requiring an external ballast. On the other hand (and there is always that other hand), most home centers don't carry them. But there are bulb wholesalers on the web who do offer them. Here's a link:
    http://www.bulbman.com/index.php?main_page=product_bulb_info&cPath=4351_8839&products_id=16788

    My UV printer uses six 27watt spirals on six inch centers, and with the ends of the bulbs six inches above the surface of the contact printing frame.
     
  6. epatsellis

    epatsellis Member

    Messages:
    907
    Joined:
    Jan 1, 2006
    Shooter:
    Multi Format
    the other option is a plate burner, they're nearly always inexpensive, just take a little legwork or a few $$ on ebay. One benefit is that they already have a vacuum frame, as well as having significant UV output, as printing plates are sensitive to UV.


    erie