Info about cold light for Durst 138

[Cesar Barreto]

Hi, all.

Found on the bay an interesting but strange cold light made by Durst for 138 enlargers, which seems to replace a condenser on a b&w head and I would like to know if anyone has ever tried this, also which kind of bulb does it take. The seller doesn't even know if it's working, but I think the same idea could maybe be adapted for LED light. Who knows?
Here's the link: http://www.ebay.com/itm/321172934757?ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1438.l2649

Thanks!

[ic-racer]

A member of our local group uses one of those in his Durst. I think he uses it all the time instead of the condensers. That particular listing is a little off on price; for $250 I'd want the power supply too!

I agree that a LED panel that slides in would be a great project.

[gleaf]

My Durst Laborator 1000 has a Zone VI cold light source adapted to it. Consists of adding back foam strips block side leakage and it sits on 'switches back' rather than 'switches front'. Works well.

[Cesar Barreto]

Hi, ic-racer.

Does this fellow of yours feels really happy about this light source or did he managed some kind of improvement?
I have found an old thread on Apug forum where someone claims those cold light to be awfully uneven, which scares me a lot. I guess trying a sliding LED panel would be a best bet for the money.

Thanks again.

[Drew Wiley]

The slide-in cold lights work rather poorly -relatively weak and uneven. What you need is simply to replace the whole condenser head with an oversized cold light.
You can even convert these units for 8x10 cold light printing, if you can still find someone to make the light itself.

[ic-racer]

Hi, ic-racer.

Does this fellow of yours feels really happy about this light source or did he managed some kind of improvement?
I have found an old thread on Apug forum where someone claims those cold light to be awfully uneven, which scares me a lot. I guess trying a sliding LED panel would be a best bet for the money.

Thanks again.
He is "Peter Spangenberg" on this forum, try to send him an email.

[Cesar Barreto]

Hi, Drew.

I understand that raplacing the whole condenser head would be easyer, but down here in Brazil those things are a bit more difficult to achieve and that's why I keep my eyes open to new ideas and oportunities. Anyway, I like to print with the condenser head and just considered the diffusion solution for some specific cases, but I agree that it would be nice to be able to print also 8x10' format. Maybe one day I can buy one those big diffusion head. Maybe!

[quine]

I use one with my enlarger from time to time. Native contrast is lower than with the condenser head, which is often nice for portraits. I normally prefer the condenser head, so it's nice to be able to swap it out without converting the whole enlarger.

It looks like the offering on ebay is missing the LACOTRA transformer, which is necessary for operation. The LACOTRA takes the form of a square power pack or a second condenser-shaped unit.

It's also not clear if the LACOLI includes a working bulb. Aristo is making the D57 V54 bulbs again, but they run $275 each.

Cheers,

-andrew

[frotog]

I had one before I sold it on ebay approx. 10 years ago. My experience with cold lights is that they're terribly uneven compared to condensers. I'm not convinced of any upsides to printing with a diffuser head other than the suppression of dust.

You can convert your condenser head to a cold light diffuser head by simply taping a sheet of white diffusion gel to the bottom condenser. http://www.filmandvideolighting.com/lee216fulwhi.html

[Drew Wiley]

They're uneven only if they're undersized, poorly designed, worn out, or have a bad power supply. These slide-in ones are in fact undersized unless you're printing something smaller than 4x5 with them. I gave one away once that I had received in a horse trade, and replaced it with a big Aristo unit. But as already mentioned,
there are easy ways to effectively diffuse a condenser source. I happen to particularly like the blue-green V54 Aristo light, however, because it's so responsive to
split printing VC papers.

[Larry Gebhardt]

Hi, all.

Found on the bay an interesting but strange cold light made by Durst for 138 enlargers, which seems to replace a condenser on a b&w head and I would like to know if anyone has ever tried this, also which kind of bulb does it take. The seller doesn't even know if it's working, but I think the same idea could maybe be adapted for LED light. Who knows?
Here's the link: http://www.ebay.com/itm/321172934757?ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1438.l2649

Thanks!
I've taken the idea and created an LED version. I've documented it here http://www.trippingthroughthedark.com/category/equipment/led-head/

I wouldn't bother with this cold light head unless you have a power supply for it, or know how to rig one up.

[JMB]

[QUOTE=Cesar Barreto;1051633]Hi, all.

Found on the bay an interesting but strange cold light made by Durst for 138 enlargers, which seems to replace a condenser on a b&w head and I would like to know if anyone has ever tried this, also which kind of bulb does it take. The seller doesn't even know if it's working, but I think the same idea could maybe be adapted for LED light. Who knows?


Hello Cesar,

I have one. In my view the light is way too weak. I was very disappointed with it, and I never use it. In fact, I think that at one point I tried to take it apart to see if I could put a brighter tube in it. Now it does not work at all.

[resummerfield]

...You can convert your condenser head to a cold light diffuser head by simply taping a sheet of white diffusion gel to the bottom condenser....

+1

[Cesar Barreto]

Hi, all.

My previous experience with diffusers over or under the condensers always led to some sort of uneveness, mainly when printing 5x7 negatives. On my view, Durst condensers are so optimized that anything you do just adds to spoil its efficiency and I'm very concerned about this.
But I'll take a look at the LED alternative and I thank for the link.

[Drew Wiley]

Correctly made diffusers not only have to take into account the light source above, but any potential falloff of illumination in typical working apertures for your specific enlarging lenses. In other words, you might need more than one diffuser. They are typically ground plano-convex from white acrylic. But there are other
ways to improve eveness, like using two diffusers of white sign acrylic. True Lambertian diffusion using white opal glass takes a significant toll on light intensity.

[William Whitaker]

I've posted this before somewhere, but it may merit inclusion here. This is an aluminum plate I had made so I could mount a Zone VI 5x7 VC Cold Light head to my Durst 5x7 enlarger. It's made from 3/8" aluminum plate and replaces the entire condenser head. The ruler is shown for scale. Four 6mm bolts secure the head and are replaced in this case by four 1/4-20 bolts. It was much easier for me to find a 1/4-20 tap than a metric one. The cold light head merely rested on top of the aluminum plate and was secured with gaffer tape. Crude perhaps, but no great precision was required. It was both simple and effective. Cost was minimal; I believe it was under $50. I had it made at a local machine shop.
99553

[Larry Gebhardt]

Hi, all.

My previous experience with diffusers over or under the condensers always led to some sort of uneveness, mainly when printing 5x7 negatives. On my view, Durst condensers are so optimized that anything you do just adds to spoil its efficiency and I'm very concerned about this.
But I'll take a look at the LED alternative and I thank for the link.

I had poor luck with a diffuser under the condensers. It was uneven and relatively dim.

[Drew Wiley]

The easiest way is just to get rid of the condenser head and install a new flange and dedicated cold light. But there are fairly easy ways to put in more powerful
light sources, which might require better ventilation; but doing this might compromise later use as a condenser source per se. Glennview does these kinds of conversions.