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  1. #41

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    Sean, I also read what Ctein had to say which was that transparencies were approximately 20% sharper with the condenser head but the others B&W and color negatives were the same sharpness in Photo Tech magazine articles.

    A following issue had a reader question Ctein if he had conducted his test with negatives optimized in exposure and development for each system. Ctein said he had NOT conducted such tests and speculated that there could be a difference with such changes.

    I too wonder about the coated condensers. I believe that the flare level is so low from the Durst enlarger with condensers that it is below being perceptable.

    Still I would certainly love to have the coated T condensers.

  2. #42

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    Claire,

    Thanks for the description of the transformer.

    Tey use the transformer dial to adjust the voltage, which will reduce the output to the lamp. That can be used to lengthen the printing time, except that the different output levels will have different filtration requirements due to the red shift that occurs when dimming the lamp.

    Anyone have one of these transfrormers laying around in need of a good home? I'll put one together for my own purposes if one doesn't show up anytime soon.

    The one enlarger also came with an interesting multicontrast filter kit for the head. It has 8 metal sleeves in tracks that work similar to waterhouse stops, but each one has a particular grade of multicontrast filter. The filters are old an need to be replaced, and only having 8 filter choices is not ideal, but it may be a useful device. I'm going to work with it a little and see if it makes sense to use it for printing. I often use split filter printing, and this would make that approach easy to do, as the change from one grade to another would be very simple. That product also appears to be made in the US by Durst USA.


    ---Michael
    www.mutmansky.com
    B&W photography in Silver, Palladium, and gum bichromate.

  3. #43

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    Claire et al.

    I don't have the coated condensors. I spoke with Jensen sometime ago in regard to UV transmission of the regular Durst condensors and he did say that they were largely transparent to UVA with a loss of perhaps 1/3 stop. This may not address their performance when used with a point light source however.

    I recognize that the opal lamps are semi diffuse and with the improvement I have seen over a pure diffusion light source, I would be very prone to move to a pure point light source at some point.

    Do you have the conversion that Jensen has for their replacement lamp? I wonder because their transformer for that lamp also has voltage adjustment.
    If that is the case, Jensen told me that the transformer output voltage for their lamp was 82 volts with a 1200 watt lamp.

  4. #44
    skahde's Avatar
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    Quote Originally Posted by Donald Miller
    I spoke with Jensen sometime ago in regard to UV transmission of the regular Durst condensors and he did say that they were largely transparent to UVA with a loss of perhaps 1/3 stop. This may not address their performance when used with a point light source however.
    The opacity of a set of condensers to a given wavelength is a fixed value as it is determined by choice of material (including coatings) and thickness alone. It's the color temperature of the light source which may be the variable to watch out for here. If it is a small halogen lamp it usually will burn at higher temperature and put out more UV than an opal lamp.

  5. #45

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    Donald good luck with a point light source. It is a very demanding light source with which to work. The system I have while easily centered etc still is extremely demanding of cleanliness and negative defects.

    It is true that my work is mainly 35mm and the magnification (typically 6.5x) is such that extremely small dust motes are rendered with clarity and are much helped with oil immersion. The converse, if using a 5x7, is the magnification is much reduced but the area to be kept cleaned is 20x more and it may well be as much of a head ache. I am inclinded to think that anyone regularly using a point light source for enlarging would be well advised to have a closed off negative loanding/printing station that is a high air pressure are and is fed with air that is cleaned thru filtration by a laminar flow.

    But, Don I guess you will have to find out for yourself.

  6. #46

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    One further point from my experience. I have both a 50mm Apo Rodagon N and a 63mm N El NIkkor. The difference between wide open and optimum aperture is just as visble with point light source as with regular condenser or diffusion enlarging. The improvement in either case is substantial and is easily seen.

  7. #47

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    Hi, there is someone that have the Durst Laborator 138s enlarger's instructions manual?
    Regards
    Francesco

  8. #48
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    Quote Originally Posted by ciccioder View Post
    Hi, there is someone that have the Durst Laborator 138s enlarger's instructions manual?
    Regards
    Francesco
    http://www.durst-pro-usa.com/resources.php

    Scroll down about 2/3s of the page for both the manual and the catalog.
    Browse this whole page and others on the site. There are many useful resources.

    John Powers
    "If you want to be famous, you must do something more badly than anybody in the entire world." Miroslav Tichı

  9. #49

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    Really, thanks, but i thought that the web site was not functioning.....but they still sell???? Do you know???
    regards
    Francesco

  10. #50
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    Sorry. I just go there for the information. It is a different address than the last time I was there and what seems like quite a bit more information. One would assume that if they put that much effort into the site they are trying to sell, but I have no personal experience. My 138 came second hand and modified to 8x10 Aristo cold light.

    John
    "If you want to be famous, you must do something more badly than anybody in the entire world." Miroslav Tichı

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