Making a VC Cold Light Head?

[Sevo]

I know one needs two tubes, one for Green (Low contrast) and the other Blue( high contrast). I know you place the B. tube above the G. tube in such a way that it looks like G.B.G.B.G.B..... when looked at from the bottom. I know you can use one transformer (60-80W) to power the both tubes, but the tubes must be switched on sequentially.

The ugly thing about tubes is their extremely inconsistent light output during warmup cycles. And that will get even worse if you operate two tubes at different dimmer settings. Serious tube light heads are permanently burning and use shutters for exposure, but that is a requirement that does not really mix well with "affordable" DIY.

Besides, "cold lights" generate quite significant amounts of heat - about half way between LEDs and halogen. The tubes themselves have no issue with a heat buildup to maybe 200°C (at which point their plastics components will start to decompose), but they grow hot enough that the head design has to account for that.

[Mark Sampson]

Zone VI made a variable-contrast cold-light head, and I believe Ilford also offered one- the Multigrade head? Fred Picker mentioned in his newsletters another one called the "Codelight" that was out of production by the '70s, he thought of it as the holy grail of enlarger light sources at the time. I've never used any of them, don't know how popular they are/were, but they are out there if you want to search. Might save some engineering time that way.

[Heroique]

Has anyone here ever made one?

People w/ D2-series enlargers have an inexpensive way to do this.

All you need is an Omegalite (diffusion) head – not so difficult to find, but getting more so w/ time.

If you have one, replace your condenser (or variable condenser) head & lamp house w/ the Omegalite head, and use GE’s “Circline” tube (below). A perfect fit. The tube emits a warm, natural light, making it easy to use w/ multicontrast papers. I think GE calls it “kitchen & bath 22” and the product number is 11084. Most hardware stores should carry it in the $7-10 range.

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BTW, this should work for D-II, D-2, D-3, D-5, D-6 series enlargers (but not the D4).

[Graybeard]

People with D2-series enlargers have an inexpensive way to do this.

All you need is an Omegalite (diffusion) head – not so difficult to find, but getting more so w/ time.

If you have one, replace your condenser (or variable condenser) head & lamp house w/ the Omegalite head, and use GE’s “Circline” tube (below). A perfect fit. The tube emits a warm, natural light, making it easy to use w/ multicontrast papers. I think GE calls it “kitchen & bath 22” and the product number is 11084. Most hardware stores should carry it in the $7-10 range.

Walmart carries these tubes.

I believe that there is also a 5x7 version of the Omegalite head.

[Kevin J. Kolosky]

"Zone VI made a variable-contrast cold-light head"

I am aware of this. They took $150 worth of parts and dolled it all up and painted it up fancy and sold it for $700.00 (which is fine, everybody needs to eat), and since they aren't being manufactured anymore they are still $700.00!!! I have one of their regular cold light heads and it is a fine piece of equipment, but you have to stock 3 different grades of paper if you want to have any contrast control when printing!

[Keith Fleming]

It is still possible to buy new Aristo VC cold-light heads. See at www.light-sources.com.

Keith

[Charlie Strack]

It is still possible to buy new Aristo VC cold-light heads. See at www.light-sources.com.

Keith

It is possible to buy Aristo REPLACEMENT tubes--I don't believe Light Sources is manufacturing complete heads.

Charlie

[Curt]

It is possible to buy Aristo REPLACEMENT tubes--I don't believe Light Sources is manufacturing complete heads.

Charlie

That's correct. Just a small list of the most commonly asked for TUBES. Nothing else.

[Sal Santamaura]

...Nowadays, I think LED's might be easier.

I doubt it would be easier if making one's own, but the technology can certainly be superior. I have one of these

http://heilandelectronic.de/led_kaltlicht

which is adapted to a Beseler 23CIII. Even though that's a 6x9 enlarger, Herr Heiland used one of his 4x5 light sources. Clearances and configuration of the Beseler's upper stage are such that a 6x9 source cannot be close enough to the negative for complete coverage, so the larger source was necessary. Upside is that, when I eventually have a permanent darkroom with enough space for a 4x5 enlarger, the led light source will be usable on it too.

I use this Heiland led source / Beseler enlarger both for enlarging roll film negatives and to contact print large format negatives. It has a finned aluminum heat sink on top of the led array (purely passive cooling) that never gets more than slightly warm during use. Both exposure time and contrast are adjustable in 0.1 increments. There's no drift between exposures. I'm completely satisfied. About the only thing that could make me happier would have been a better dollar/euro exchange rate when it was purchased around four years ago.

[jon.oman]

I doubt it would be easier if making one's own, but the technology can certainly be superior. I have one of these

http://heilandelectronic.de/led_kaltlicht

which is adapted to a Beseler 23CIII. Even though that's a 6x9 enlarger, Herr Heiland used one of his 4x5 light sources. Clearances and configuration of the Beseler's upper stage are such that a 6x9 source cannot be close enough to the negative for complete coverage, so the larger source was necessary. Upside is that, when I eventually have a permanent darkroom with enough space for a 4x5 enlarger, the led light source will be usable on it too.

I use this Heiland led source / Beseler enlarger both for enlarging roll film negatives and to contact print large format negatives. It has a finned aluminum heat sink on top of the led array (purely passive cooling) that never gets more than slightly warm during use. Both exposure time and contrast are adjustable in 0.1 increments. There's no drift between exposures. I'm completely satisfied. About the only thing that could make me happier would have been a better dollar/euro exchange rate when it was purchased around four years ago.

This looks great! Here is a link to the English version: http://heilandelectronic.de/led_kaltlicht/lang:en

I don't see any prices, what did you pay for your 4x5 version?