Durst head light source

Discussion in 'Darkroom Equipment' started by Curt, Nov 29, 2009.

  1. Curt

    Curt Subscriber

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    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
     
  2. ic-racer

    ic-racer Member

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    Thats just a bulb and power supply. I suspect one could buy a lifetime supply of standard bulbs for the Durst 5x7 condenser head for that price even though they are no longer made.

    I'd try these three-dollar bulbs (PH213) and see if they are a good replacement or not before considering a $1500 replacement bulb option.

    Or for $1000, how about a 5x7 Durst condenser head, Chromega II 5x7 head and a Ferrante Codelite (?5x7) and they throw in a spare 138 chassis for free :smile:

    If I had a 5x7 enlarger and could pick any head, I'd go with a Super Chromega II E.
     
    Last edited by a moderator: Nov 29, 2009
  3. David Grenet

    David Grenet Member

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    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...
     
  4. Curt

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    Remember I don't have anything above the head mounting plate, I do have a Zipper 5x7 negative carrier. If I don't find anything reasonable I'll make a head for it.

    Did you understand how they could get a point light, soft light, cold light, and another I can't remember, from one lighting setup?

    pm request for info sent to the ad you mentioned, I just want a head, no chassis, shipping would be easier to take too. And first on the list is a NuArc so this is second on the want/need list. I have to get going on Carbon Transfer printing soon.
     
  5. Curt

    Curt Subscriber

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    It could be another dead end then.
     
  6. resummerfield

    resummerfield Subscriber

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    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.

    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. Jensen’s. Here is a link to that old thread.

    I have a spare Durst condenser head, so a few years ago I looked into Mr. Jensen’s 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 lamps—heat. Notice the optional cooling fan in Mr. Jensen’s advert.

    I presently use an Aristo T-12 cold light, and I couldn’t 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 don’t mind the heat, then a variable diffusion semi-point source would be very interesting.
     
  7. Curt

    Curt Subscriber

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    I see, thank you for explaining the concept for the various lighting modes, I know what you mean by heat, 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.
     
  8. resummerfield

    resummerfield Subscriber

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    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 Ebay—I 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.
     
  9. ic-racer

    ic-racer Member

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    My CLS keeps my basement darkroom nice and warm :smile:

    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!
     
  10. Curt

    Curt Subscriber

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    ic, you mentioned the Super Chromega II E, what would you offer someone for that model head? Just curious if I'm going to be looking.
     
  11. Curt

    Curt Subscriber

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    I have had an Aristo cold light unit that has a light source with plexi that measures 10x12 and has a big heavy separate transformer on a long cable to the head unit that has a switch and dimmer knob that goes from slightly dim and full bright. It's so bright you can't look at it in full brightness. I contacted Aristo a long time ago and even with a number on it and pictures sent they couldn't tell me what it was made for. I kind of think it was a "transilluminator" unit but I can't be sure as Aristo wasn't sure.

    I wonder if it could be used for an 8x10 head for the Durst 138, it definitely covers 8x10 without a sweat. I have used Aristo units in all of my enlargers for years but I'm concerned that if I make a box and fit it on the bulb should it fail would be impossible to get. Wow I can't stand uncertainty.
     
  12. ic-racer

    ic-racer Member

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    JP80874 is somewhat an expert on 138 to 8x10 conversions. This is his enlarger.

    [​IMG]
     
  13. Curt

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    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
     
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  15. resummerfield

    resummerfield Subscriber

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    I'll agree with Curt, the design and construction of JP80874's conversion is excellent!

    A key component to any conversion is the negative carrier. Does anyone have any detailed pics of this one?
     
  16. Curt

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    I don't have a picture of that one but there are designs where holes are punched in the corners and rubber bands are used to stretch the negative by clips.

    I'm using a "Zipper" brand 5x7 for mine. A 4x5 can be used in it also by turning the negative and masking off the sides of the 4x5 sheet. I have a Negaflat 4x5 also which can be adapted to a new head design.

    It has a bar frame that sits in like an "A" frame then presses down until the steel bars slide under the brass angles pulling the negative with it making the negative very taut.

    For an 8x10 model I'd have to make my own Zipper carrier, with one on hand it would be much easier. This design is old and the Zipper negative carriers are rare, this is the only one I've seen. I bought it for next to nothing, probably because the seller didn't know anything about them either, I bought it because I was needing a 5x7 negative holder and one without glass.

    These pictures were taken with an old digi camera so the color is off and it looks worse than it is. It's made of aluminum, brass, and steel.
     

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  17. jp80874

    jp80874 Subscriber

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    Not quite right. Michael Mutmansky, an engineer, designed and built the conversion unit, used it with negatives from his 8x10 RH Phillips, changed formats and sold the enlarger to me.

    If you would be very specific about what view of the negative carrier you would like and if I can figure out my wife's digital camera again, which neither of us have used for a year, I could post something.

    John Powers
     
  18. resummerfield

    resummerfield Subscriber

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    Curt, I thought your carrier would be glass and I was curious as to how you positioned and operated it. I’ve never seen or even heard of a Zipper carrier, so thanks for sharing this.

    The only glassless carriers for large format that I’ve seen required small holes to be punched in the corners of the negative, and used small springs to apply tension.

    John, a picture isn’t really necessary. I was just interested if your carrier was glass or glassless, and how it was positioned within the housing.
     
  19. jp80874

    jp80874 Subscriber

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    It is glass, one sheet anti newton, one sheet clear with two nylon twist hold downs and two nylon stops. The little drawer on the front in the picture pulls out and there is the negative carrier about an inch under the cold light diffuser. It is cut out of 1/4" plywood and painted flat black. The plywood is mounted at right angles to the drawer front and slides on rails.

    Because the cold light fluctuates wildly I followed Michael Mutmansky's suggestion to buy the RH Designs Stop Clock Vario with the probe in the cold light. All exposures are predictable now. Unsolicited plug.

    John Powers
     
  20. Curt

    Curt Subscriber

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    Because my enlarger is a 5x7 I can put the negative carrier on or near the enlarger plate support. With an 8x10 head it would be higher up. I need to make a head with negative drawer for 5x7 and a head for 8x10 that uses the same light source, two heads. I'm going to use the three bulb/filter units RGB I have from an older colorhead. My plan is to have them on switches or dimmers. By doing it this way I won't need to spend very much money.
     
  21. ic-racer

    ic-racer Member

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  22. Curt

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    When Glenn converted a 138 to 8X10 he mentioned completely removing the built in masking system, is this necessary, I like having it in there, it's designed extremely well? Also it dawned on me that an 8X10 negative could only be placed in landscape position with the masking system as the opening is 5X7. It isn't a problem for me to have the negative placed in one orientation but it might bother others.

    On converted models with the negative plane located at a greater distance from the mounting plate of the enlarger which is just above the masking blades, are there any problems focusing a 35mm negative, I haven't worked out any specifications for this. What I am getting at is can the 8x10 head with its height accommodate all formats or would a lower support riser be needed for smaller formats. I hope this make sense. I am planning on putting it into the place were I have my Beseler 45 in the darkroom. I don't need two or three enlargers as I have an Omega enlarger too that I bring in sometimes. I want to be a one enlarger user and with the NuArc unit I have to simplify the equipment.
     
  23. ic-racer

    ic-racer Member

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  24. Curt

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    No, I have a complete enlarger minus the head and that one is in the VI, it isn't the one for me. Now that I have this machine called a NuArc I have plenty of time to figure out the head for the Durst 5x7 while I learn Carbon Transfer. I do have a shop and if properly motivated and provided with some good weather I might just come up with a really neat diffused color head of my own to use with VC black and white photo paper.
     
  25. ic-racer

    ic-racer Member

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  26. ic-racer

    ic-racer Member

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    There is one on e-bay now: # 290397026951

    (I'm not affiliated in any way with that item, etc...)