Their explanation of why their light source is better is dubious to say the least. Note that the peak sensitivity of their "Average BW emulsion" is right in the red part of the spectrum where safelights emit light!
If you want to do a proper comparison find the datasheet for the paper you use and have a look at the sensitivity curve. They typically fall off at or before 600nm...
Mr. Jensen’s product is a tightly-grouped filament bulb placed in a specially designed reflector, and controlled by a variable power source. By changing the diffuser types and their placement, you should be able to achieve a range of diffusion, from point light through cold light. And I think it's been proven that there is no visible difference in a print made with cold light vs. diffused incandescent light.......Did you understand how they could get a point light, soft light, cold light, and another I can't remember, from one lighting setup?.......
Mr. Jensens product is a tightly-grouped filament bulb placed in a specially designed reflector, and controlled by a variable power source. By changing the diffuser types and their placement, you should be able to achieve a range of diffusion, from point light through cold light. And I think it's been proven that there is no visible difference in a print made with cold light vs. diffused incandescent light.
About 3 years ago, Donald Miller started a very interesting thread on APUG about point light sources and diffusion, and I think he may be worked on a setup that was very similar to Mr. Jensens. (there was a url link here which no longer exists).
I have a spare Durst condenser head, so a few years ago I looked into Mr. Jensens product, or possibly building a setup similar to that described by Mr. Miller. But I decided to avoid an incandescent lamp because it shares a problem with all high-output incandescent lampsheat. Notice the optional cooling fan in Mr. Jensens advert.
I presently use an Aristo T-12 cold light, and I couldn'tt be happier. It is fairly bright, well diffused and, most importantly, very cool. I can print for hours and not appreciably raise the temp in the darkroom.
But if you dont mind the heat, then a variable diffusion semi-point source would be very interesting.
.....the fan he displays as a necessary accessory is four or five hundred as I recall, that's pretty pricey for me. I was ready to get an Aristo but they were bought out and haven't been back in business so I'll try to figure it out.
My CLS keeps my basement darkroom nice and warm
Actually, I did test my CLS head vs the Aristo with a temp gun. It takes me about 5 min to process and dry a test strip. So I measured the head just before the next test or final print. Now, the Aristo has a heater to keep it warm between exposures, and the CLS cools off between exposures. It so happens that the hottest part of the CLS is around 41 degrees centigrade and the Aristo is around 38 degrees. Not much difference.
BTW resummerfield, I discovered how the fan circuit works on the EST2000N. I believe there is a thermistor in the head. I ran a number of short on-off cycles while calibrating the color wheels with a color meter. This heated up the head and finally caused the fan to stay on for a few minutes after an exposure then it shut off once the temp came down. (The fan behavior in the EST1000N service manual is probably a totally different circuit than the EST2000N).
The Aristo is a LOT quieter. The two fans in the CLS2000 sound like two vacuum cleaners running!
When I was thinking about the incandescent source, I was planning to use a simple exhaust fan. I don't remember the exact details, but much cheaper than Mr. Jensen's.... probably way under $100.
I'm very satisfied with my Aristo, which I bought used for $400. Keep watching the classified ads and EbayI see the Aristo T-12 listed occasionally. Or contact the folks that bought Aristo, since they may be able to make-up a unit from parts on hand.
I've seen this after he put it up for me, I still think the design is excellent, I believe it's made of MDF but looks like a nice metal construction. He had the conversion made by someone, can't remember the name, but he did a fine job. When I get it figured out I'll post some pictures.
Thanks for all of your help,
Curt
John, a picture isnt really necessary. I was just interested if your carrier was glass or glassless, and how it was positioned within the housing.
Curt, I thought your carrier would be glass and I was curious as to how you positioned and operated it. Ive never seen or even heard of a Zipper carrier, so thanks for sharing this.
The only glassless carriers for large format that Ive seen required small holes to be punched in the corners of the negative, and used small springs to apply tension.
John, a picture isnt really necessary. I was just interested if your carrier was glass or glassless, and how it was positioned within the housing.
http://cgi.ebay.com/durst-CLS-1000-...ultDomain_0?hash=item1e59be1126#ht_500wt_1182
A Durst 5x7 CLS 1000 head just sold on fleabay. Did you buy it?
http://www.jensen-optical.us/lamp_kit.htm
I saw this for the first time a couple of days ago and have been thinking about it since. I still need a head for my Durst 5x7 and this looked interesting, the only caveat is I would still need a condenser head to hold the light without condensers.
Has anyone converted their head to one of these light sources? I also noticed that they have a financing program, some down and a monthly payment for a year. They also explain why their light source is better than the Aristo cold light. I don't know I haven't seen or heard comparisons.
Curt
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