Cold Light Installation : LUSENET : Large format photography : One Thread

Finally decided to try a cold light after much advice from members of this forum and frustration with condensors. Ordered an Aristo for my Omega D5 and installed tonight. Won't have a chance to print until next week now but several questions came to mind after installing. First, is there any problem caused by the fact that the cold light glows after the power is off? I should have anticipated that since it is after all a flourescent source. Does it fog paper or how do you combat that problem? Second, do you ahve any suggestions for focusing? It seems very difficult to focus the greenish light, much more difficult than with the yellowish light of the tungsten bulb. Finally, a question specific to the Omega. I removed the condensors and set the Aristo head into the can that held the fixed condensors. I removed the adjustable condensor and the lamp housing and fed the cords up through the hole. When powered up I have this bright circle on the ceiling caused by light leaking around the Aristo head. Should I add a felt strip between the Aristo head and the condensor can or what would you suggest.

I don't anticipate these are insurmountable problems, just not ones I anticipated. I can't wait to get back to printing to see the glowing prints that are so easy to create.

-- Dave Schneider (, January 26, 2001


Good questions, Dave. Re: glow - just don't leave your paper out exposed to it for a long time. Focus on a substitute sheet [I use the Micromega critical focuser with no problems] and only bring out the real stuff when you are ready to expose it. By all means, mute any light coming from leaks from the "can". I have a D2 which had cracks all over the place. I used felt, held in place by velcro strips. I also have an area around the negative plane, which I covered with a drop-down "skirt". The darker you have it, the cleaner whites you'll achieve in your prints.

-- Alec (, January 26, 2001.

"Glowing prints that are so easy to create". Really? Pat

-- pat krentz (, January 26, 2001.

"Glowing prints that are so easy to create". Really? Pat

Well, that's what the cold light proponents would lead you to believe. My expectation is somewhat more realistic. I'm hoping for more even illumination than my old scratched and chipped condensors are producing and possibly better tonal gradation in the highlights.

-- Dave Schneider (, January 26, 2001.

Well, your cold light should help compared to chipped and cracked condensors. I got a Saudners/LPL diffuse light enlarger 'cause I couldn't easily focus & compose with my Zone VI enlarger light source, so I sympathize with you there.

-- Charlie Strack (, January 26, 2001.

I've used an Aristo VCL head for quite a while (six years) and have never observed any "glow." After reading your message I checked by looking up through the lens and still saw no glow. Is this something you've seen or are you just expecting that it will occur? Although normal household flourescent lights do glow for a while after turn off, the Aristo light is, as you know, colored and I wouldn't think it would glow like a household light. I'd call Aristo and ask whether it's normal. The guy who runs the company (sorry, I forget his name) has been very helpful to me with several questions over the years. I don't own an Omega but my Beseler had various light leaks both through the power cord that runs into the top of my Aristo head and around the negative stage. I fashioned a cardboard box-like thing out of a shoe box that fits over the head and has sides that cover the negative stage. It prevents any light leaks and has the added bonus of hopeuflly minimizing dust in the head. Of course you have to take it on and off when putting the negative carrier in or removing it but that's very simple since it's just light cardboard and isn't attached to the head in any way. I've also used electrical tape to stop other light leaks.

-- Brian Ellis (, January 27, 2001.

Dave: I have never observed the afterglow with my ol' Aristo cold light head, but maybe it's there. Anyway, it doesn't effect exposure. You will notice that it is a lot easier to get detail in the highlights with the cold light or a diffuser head. And yes, the whites do seem to glow when printed with the cold light head, at least mine do. It is not a magic wand for good prints, but a great tool. I have made comparison prints and there is a difference.


-- Doug Paramore (, January 27, 2001.

I noticed the glow when looking directly at the light after it had been turned off. I don't yet know if I would see any light on the easel. I discovered the glow when sealing the light leaks around the housing.

-- Dave Schneider (, January 28, 2001.

I think I may have discovered the source of the glow. My Gralab 451 timer apparently has some voltage present at the outputs even when off. I discovered this when I tried an interposing relay between the timer and the cold light. My relay buzzed even when de-energized. With the relay in place I don't see the glow, however. Is my 451 timer not working correctly or is it not suited to the cold light. It is listed as capable of a 1/3 HP motor load.

-- Dave Schneider (, January 28, 2001.


I am in awe of how these answers go.

I don't think there should be any residual voltage on your timer in the off state, except maybe for a volt or two. Certainly not enough to make a relay buzz. Contact GraLab and get a real answer.

DIMCO-GRAY 8200 South Suburban Road / Dayton, Ohio 45458 937-433-7600 / FAX: 937-433-0520 1-800-876-8353

-- Charlie Strack (, January 29, 2001.

I had a spare Condenser head so I installed the coldlight head in that and sealed things up. It's much easier to switch between condenser and cold light now. The non-variable condenser head is a drug on the market and if you wanted to you could pick one up for dirt.

If the Gralab has a solid state switch instead of a mechanical relay, it can allow a slight amount of current to flow in the head. This is caused by an RC network across the switch that protects the switch and also reduces any electrical noise that may cause interference.

Other than altering the timer or seeing if it's defective just about all you can do is add a mechanical relay to switch the head. If the buzz is a problem you can add an additional small load on the timer to absorb the current. A 15 W (or so) incandescent light would be great but you'd have to cover it up somehow. The light may also work well to absorb the current and a relay may not be needed.


-- Duane K (, January 29, 2001.

Dave -

First off, the light should not glow on its own. Either your timer or the head itself is defective. As far as focusing goes, get a good grain focuser - the micromega critical enlarging focuser is best. Light leak on the celing ?? Put the lamphouse back on and feed the wires up through the hole in top & if necessary, use electrical tape around wires. You will probably have light leaking between the condenser housing and negative carrier - take a piece of cloth or vinal strapping material, measure it to length, attach velcro to the ends, wrap it around the condenser housing and then snug it down to meet the negative carrier. Sounds like you bought an old light source - you really should have the V-54 bulb, it is much brighter and facillitates the use of VC paper. You will also need to install a probe to watch the light output. The probe is connected to a stabilizing timer (Metro Lux II) or the Zone VI cold light stabilizer. It watches the light output and adjusts same so that you can achieve consistent exposures. Hope this is helpfull.....gordon

-- (, January 24, 2002.

I have a Zone VI enlarger, which uses the same type of tubes, and I have never seen it glowing after exposure....methinks you have a defective light.

-- Jorge Gasteazoro (, January 25, 2002.

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