Cold Light Head and Durst

[frotog]

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

The timer you mention above plus others like it (the metrolux or the zone vi) are designed to compensate for variations in the intensity of light output. AFAIK, they are not designed to read the color temp. of the source nor can they compensate for problems of edge to edge eveness.

[ic-racer]

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

My Aristo W-45 tube from 1988 has no flaking and provides a full contrast range with filtration.

I documented the output of the lamp over five minutes. The intensity fell one-half stop.
http://www.apug.org/forums/forum43/5...mperature.html

[Mahler_one]

My Aristo W-45 tube from 1988 has no flaking and provides a full contrast range with filtration.

I documented the output of the lamp over five minutes. The intensity fell one-half stop.
http://www.apug.org/forums/forum43/5...mperature.html

Thanks for going to the trouble of doing the experiment. Very thoughtful of you, and much appreciated.

[ic-racer]

Thanks for going to the trouble of doing the experiment. Very thoughtful of you, and much appreciated.

Basically I needed to answer the question for myself if I need a compensating timer or light stabilization system. Now that I know how the lamp behaves I can work around it with my current setup.

[Valentin Trandafir]

Hello ! I am Valentin, an amateur photographer from Romania. I just bought a DURST 138 enlarger and I want to buy a D57 cold light head from ARISTO. They say this unit has 1 lamp. Does anyone use this kind of cold light head ? Is this a good one ? I saw that some specialsts consider that the dye from the lamp dry and evaporates,, producing un-eveness. Is that true ? Shoud I buy also an compensating timer ?

Best regards,
Valentin