Cold Light Timer/Stabilizer

[Enrique Vila]

Hi...

First of all, I'd like to thank everyone that responded to my previous cold ligh t question. That fellowship is what makes this forum great.

Know that i just bought (haven't arrived yet) a Zone VI cold light (the single t ube non-VC version) I would like to ask if it is really necesary/usefull to use a Stabilizer or Compensation Timer.

I've been looking into the RH Designs Stop Clock Vario, which also allows for f- stop printing, but have also considered Metrolux, and the plane Zone VI stabiliz er (no timer).

I'll like to hear coments from fellow cold light users....

Thanks again...

Enrique

[Kevin Crisp]

Enrique: I am familiar only with the Zone VI compensating timer and not the other ones you are considering. I have used it for 10 years with three enlargers. It is very easy to use and read. It seems to handle cold lights without difficulty (including the Beseler 8X10 head) and the dry down feature works well if you have the discipline to test your papers and find out the number for what you use. (It varies a lot from product to product.) If you want to use the feedback feature you need to drill a hole in the your cold light head (very carefully) and install the light sensor for it. I know the old Zone VI ones came with this installed, I can't say for sure this is the case with yours. The exposures are very consistent but I'm not totally convinced that once you let the lamp warm up that it doesn't stay so consistent that the feedback time adjustment is not really necessary. The dimmer is very useful, but once you decided to dim the light, the timer compensates for that by lenthening the time "a second" takes, which can defeat the purpose, depending on how you work. The grey wire which runs up to the head is too short, and with the timer on the table I have many times raised the head and jerked the timer up in the air. I could rig up what amounts to an extension cord for this but I haven't done it yet. The fairly stiff grey wire to the head can get in the way of burning and dodging tools. All it all, I have been very happy with it, I'm just doing my best to point out the negatives.

[James Phillips]

Enrique,

I also have been using the Zone VI head for about a year now. One of the reasons that a stabilizer is recommended is because this is a fluorescent tube light source. The color and intensity of the light can change with temperature and voltage flucuations. If you warm up your Zone VI(leave it on for awhile before your printing session) then you only need to be concerned with the voltage issue that occurs in every household. I found a cheap way to get around this by purchasing a used UPS power supply from a computer store. This is a back up power supply that also conditions the voltage so that it stays relatively constant.

In older UPS's the battery wears out and is costly to replace so computer folks frequently get rid of them cheap. In our case we only need the "power conditioning" feature for our Zone IV head during printing and having one with a weak or dead battery does not usually affect it's power conditioning capability. Make sure to get a UPS though and not just a power bar with voltage conditioning. You can tell the difference because a UPS with a battery is quite heavy.

So far we with my head (after it has warmed up for 15-20 minutes) seems quite constant in the light output it produces while hooked up to my old UPS. Hope this helps.

[kthompson]

Enrique, I use 3 coldlights, all Aristos, and i've never had much of a problem with exposure variations due to drift or the temp of the lamp. I let them heat up for a good 10-15 minutes prior to use, but if I'm in a hurry, I'll just turn them on (focus) for a few minutes or so. I work in an in-house studio/production lab and one of our enlargers has an Aristo High int. D head on it. We've never had a problem (besides frying out a Gralab 505 timer, because of no contactor--long story, but not all timers will work with the basic Aristo heads.) with it in terms of exposure changes either. I have made hundreds of publicity prints all day long, in a row...like 350 5x7s off one neg in a 3 hr. span or so, with this enlarger and you could line the prints up and they'd all look the same....the setup is the head, a contactor (model 1200) and a 545 Gralab.

That said, I have two of my own...one is an old D head that I run off a voltage stabilizer, the other is a VCL4500 that I run off a Metrolux. I have had this for about 7-8 yrs. now, and for the first half of that, I just used a regular timer...and didn't have any problems really. The Metrolux works similar to the Zone VI timer, kbut I use it more for the production, closed-loop timer features, like the metering probe, the projection sensitometry, and the twin channels....in use, you do have to drill a hole in the head, and tie off the sensor to the lamp. With a 2 head coldlight, this is tricky, but with one tube, it should be easier....when it's all calibrated & programmed, it works very well...plus the Metrolux has a built in shutter speed timer that is handy to have as well. I have a Jobo Multitronic timer as well, that is a fancy process timer, that will do some similar things...but it won't monitor the lamp as closely...

Do you need these types of timers? In my experience, no...they're just a luxury really....we don't use them at work, but I like using them myself....good luck with the printing!Opinions expressed in this message may not represent the policy of my agency

[David Walker]

Enrique,

I bought a Zone VI head on ebay and used it for about a year trying the warmup procedure and got very inconsistent results. I then connected a voltmeter to the photocell output and found that the output varied significantly with time and duty-cycle. I attempted to use the meter as an indicator as to how much warmup to use and got very frustrated. I finally bought a Zone VI compensating timer (also on Ebay) and absolutely love it. Rock solid consistency over the entire printing session as well as from session to session. The dry down feature is an added benefit. Highly reccomended.

[Erik Gould]

My experience with the Zone VI head has been very similar to the pervious posts. When I first aquired it about 7 years ago I just used a standard timer and let it warm up before working. That seemed just fine when my darkroom was in my house, but I recently moved the darkroom into a former factory space and no matter how much warm up I did the lamp seemed to drift all over the place, so I got the compenstating timer and it has worked great. My only gripes, to add to Kevin's, (and they are small) is that the timer has no outlet for a safelight, and the outlet for the footswitch cord is on the top of the unit ( just where do they think your foot is going to be?). Anyway, its been a big help, and well worth it IMHO.