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
