Aristo/Zone VI cold light head for Beseler 4x5

I have a used Aristo/Zone VI cold light head (round type) that fits into my Beseler 4x5 enlarger. I am starting to play with some graded paper again after a long hiatus, and pulled this head out of storage for the first time in about 5 years. I'd bought this on Ebay and never used it. At any rate, I know what the two plugs do, one for the coldlight itself, and one for the thermo connection to keep the lamp warm.

What I do not know is what the round plug outlet is for? There is a small round, 4 prong DIN type plug and I have no idea what it's for. Anyone have any ideas?

Andrew,
I have the same head for my enlarger. The round outlet is for attachment of the photocell, which is probably already installed inside the unit, to a device that measures the light output of the head. The output of a cold light head changes with temperature, i.e., the light is dimmer when you first turn it on, and then increases as it warms up. I have the compensating metronome timer made for the Zone VI cold light that changes the rate of 'ticks' as the output of the head increases. I have found this is a useful device for getting consistent prints with my setup. Let me know if you have any other questions.

All the best,
Daniel

Thanks Daniel. That helps. I wonder whether Aristo makes accessories for this head anymore?

Andrew Moxom said:

Thanks Daniel. That helps. I wonder whether Aristo makes accessories for this head anymore?

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Aristo seem to be quite helpful. As a matter of interest, I also used to use the same head that you have, from Zone VI, made around the late 1970s. The compensating timer ticks accelerated quite markedly as the tube heated up. Personally I would not use the head without at least coming to terms with the varying light output somehow.

As a matter of interest, I have read that Aristo now make replacement tubes for this unit that are better for VC filtration use and have the benefit of varying less with temperature. Although it's not the same, I have the Aristo VCL4500 which is a 2-tube VC head. I have installed one of the light sensors in the head which is connected to a compensating timer, and I've noticed that the light output varies far less than with the old unit.

A refinement of the new unit is that the heater unit is thermostatically cut out when the head warms up. This would go some way to minimizing the variations, I suppose. Although they're called "cold light" heads, they do change temperature a surprising amount.

Hello Andrew,

Looks like you've got your question answered with regard the round DIN plug; as Daniel said this is for the compensating metronome or the coldlight stablizer, both built many years ago by Zone VI. I have both, but I like the stablizer unit better than the metronome because it has a drydown dail built right into the unit.

As John indicated...and for interest sake...Aristo makes--or did, I bought mine many, many years ago--a very nice unit with what they call V-45 tubes that accepts standard Ilford filters. This light source works with either graded or VC papers. Additionally, it doesn't seem to exhibit the "drift" that the Zone VI units did/do so compensating timers, stablizers, etc, aren't necessary. All that said, the old round Zone VI coldlights are fine units for graded printing especially if the monitoring "eye" is installed and used accordingly.

Hope this helps.

I use the filter drawer version (CL4500) of the Aristo V54 head with filters and Forte paper (and will probably switch to Ilford when my Forte runs out). With both papers I have experienced a bit more contrast than graded (I used to use Seagull G series). The separation in the lower values is great, and the split filtering technique solves any problems with contrast.

Aristo will tell you that the single bulb head (like mine) will give more output and shorter exposures than the dual bulb head. For 16x20 and larger, this is important unless your negs are on the thin side. It's also quite a bit cheaper.

You can see their heads and read about them here - http://www.aristogrid.com/prod02C.htm

does anyone know where I can get a replacement bulb for a zone VI variable contrast cold light head for a bessler 4 x 5? The only place I know about is Calumet, in Chicago, and they are out of the one bulb.

Aristo sold them directly in the past, I got one from them a year or so ago. They have a website, not sure what the URL is offhand though.

allan teger said:

does anyone know where I can get a replacement bulb for a zone VI variable contrast cold light head for a bessler 4 x 5? The only place I know about is Calumet, in Chicago, and they are out of the one bulb.

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Try the Aristo Lighting Technologies website at: http://www.aristogrid.com. Click on the customer service email link at the bottom of the page and ask Louise Kessler if they might have what you are looking for still in stock.

And welcome to APUG.

Ken