At 01:01 AM 9/20/2002 -0400, you wrote: >Hello: > >I am curious if anyone has ever used 'tri-phosphor' lamps for enlarging. > >I'm interested in an 8x10 enlarger for b/w only, on a budget. > >I started looking into low pressure pulsed xenon - lotta heat, and nearly >obsolete, $100 for 750W lamp, $3000 for new commercial ballast/power supply, >and it's not a friendly prospect - 52 V at about 18 amps plus 10000 volt >spike to ionize gas...so, I think I'll look into other approaches. > >Ansel Adams used massive array of logo-less incandescent lamps - heat again. > >I'm pondering either full spectrum fluorescent (linear tubes only as far as >I know), or tri-phosphor complact fluorescent (3 spectral peaks spread out >over visible spectrum depending on color temperature, 2700K, 3500 K, 4100K >and 6500K available (CRI 82, but that may not be relevant to film). I got >spectral plot of the 6500K one today because I was unfamiliar with that one, >and the spikey spectrum of the tri-phoshor type does make me nervous...hence >my request for others' fluorescent experience. > >What I'm considering is using seveal GE Biax (folded tube) 18 or 27W lamps >for an 8 x 10 or 11x 14 head, each driven with a high frequency electronic >ballast. Driving the lamps above 15kHz eliminates the 120 Hz (100 for 50 Hz >countries) flicker and produces about 15% more lumens than line frequency. I >have access to a manufacturer of small electronic ballasts (I used to work >there). I am considering running them from a DC supply with individual >regulators so the light output could be adjusted for each lamp. > >My main worry is the strong spectral peaks in this type of lamp. The intent >of this lamp design is that the brain is supposed to 'fill in the spectral >gap', and THINK they are full spectrum lamps. > >Thanks in advance for responses. > >Murray > >_______________________________________________ >Cameramakers mailing list >[EMAIL PROTECTED] >http://rmp.opusis.com/mailman/listinfo/cameramakers >
Murray, Plain ol' cool white lamps work fine for graded or poly papers. If I were you I'd have a lamp custom made at a sign company - cheap$$! I can give you more details. AZ Maker of Lookaround panoramic camera. http://www.panoramacamera.us or keyword.com lookaround _______________________________________________ Cameramakers mailing list [EMAIL PROTECTED] http://rmp.opusis.com/mailman/listinfo/cameramakers
