Cold Light Head and Durst

[Mahler_one]

Does anyone know if a cold light light source head can be fitted on a Durst enlarger...in this case the 1200? If so, might you furnish the source for such a head, as well as any adaptor needed to fix the head to the enlarger body?

Thanks for any help.

Edwin

[mono]

Ask Juergen Heiland at www.heilandelectronic.de.
I have his LED Coldlight head with the Splitgrade system for my Laborator 1200.
It came completely mounted and could be fitted with 4 screws, even easy for me ;-)

[resummerfield]

I believe Aristo makes one that fits in the mixing box for the CLS 500 head.

[jp80874]

Edwin,

See my gallery. There is a full frontal picture and a 1/4 view of an Aristo 1212 (12 inches x 12") head on a Durst 138S. This is a 5x7 enlarger converted to an 8x10. The conversion was done by Michael Mutmansky.

Aristo has a web site. I am assuming their DL 1200 is a cold light for your enlarger. Here is a link to their installation page.

http://www.aristogrid.com/dl1200_instal.htm

If you go from that page to their home page and then their contact page, I am sure they can tell you where you can order this if they don't sell it directly. I believe B&H Photo in New York, USA, will order it for you, but they don't stock it. You don't say where you are so this route or the German route may be better.

John Powers

[Mahler_one]

What a great group! Thanks very much for the help. I will "take it from here", and then report back in a month or two.

Edwin

[Mahler_one]

As an aside, late last evening I had the opportunity to look about the Durst site to see if there were any comments concerning the Aristo cold light source and Durst enlargers. Mr. Jensen stated that the Aristo source was not good ( my words, not his ) in that the paint that was on the tubes had a tendency to peel and change, and thus the colors from the lamp grew unreliable. Hence, the waranty offered with the Aristo cold light head was exceptionally limited. I don't think I should post a direct quote from his site without his permission. However, I wonder if any of you have noted "color degradation" in the Aristo cold light tubes.

Edwin

[jp80874]

Since I posted before I suppose I should give an unqualified answer. I am 85% color blind and would not likely see a color change. I am not aware of any degradation of quality in the images produced over a three year period. I am retired, taking college photo classes with critiques every two weeks, working on a book and a museum show. There are plenty of critics that would have caught deterioration in quality and commented.

John Powers

[resummerfield]

.....the paint that was on the tubes had a tendency to peel and change, and thus the colors from the lamp grew unreliable......

Several years ago, probably 6 or 7 years ago, I was shopping for a cold light head for my 8x10 Durst. I spoke with an engineer at Aristo, and he mentioned the paint on the tubes of older 2-tube (separate blue and green tube) variable contrast light units had that flaking-off problem. The newer tubes were better, but still the Aristo engineer suggested that I would be much happier with the single tube V-54 light unit, as opposed to the 2-tube VC unit. I followed his advice, and have had no problems with my T-12.

And I have found that using filters below the lens for a 2-exposure split-print on VC paper gives me better results than trying to use a single filter.

[frotog]

Mr. Jensen stated that the Aristo source was not good ( my words, not his ) in that the paint that was on the tubes had a tendency to peel and change, and thus the colors from the lamp grew unreliable.

Edwin

Jensen also claims that his handpicked FEL tungsten bulbs are full spectrum hence the $190 mark-up on a $10 bulb. What a scam!

So what if the color temperature of an Aristo source gets colder or warmer over time. Guess what? This is the case with all light sources. None of this matters unless you want the precision repeatable results one might get from a closed loop head without actually having a closed loop - a strange intent indeed. Even so, it's a moot point since accuracy of light output in a cold light source is notoriously difficult to achieve.

A "cold light" is nothing more than a diffuse source. You can change your collimated light into a diffuse source by placing a $2 sheet of diffusion (try lee 216 or 251 gel) on top of your negative carrier( or just tape to the underside of the lower condenser lens). Or, if you're so inclined, you could purchase a thin 5x5 piece of white plexi from Jensen for $10. You'll actually get better results than the aristo as the durst condenser system has terrific edge to edge eveness.

[jp80874]

So what if the color temperature of an Aristo source gets colder or warmer over time. Guess what? This is the case with all light sources. None of this matters unless you want the precision repeatable results one might get from a closed loop head without actually having a closed loop - a strange intent indeed. Even so, it's a moot point since accuracy of light output in a cold light source is notoriously difficult to achieve.
.

If I understand you correctly the RH Design StopClock Vario takes care of this problem with a probe that measures output of the first exposure and duplicates it for the next unless of course you set it for a fraction of an f stop longer or shorter exposure. This new exposure is relative to the old measurement rather than starting over.

http://www.rhdesigns.co.uk/darkroom/...ock_vario.html

John Powers