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  1. #111

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    I see this happening too. I always recheck the focus for each print. I know that in my case the negative isn't popping. It just doesn't get anywhere near hot enough with the dichro head on one enlarger. The heat absorbing glass on the my other, condenser enlarger does a good job of preventing the negative stage from getting too warm too. What does happen is that the enlarger head will creep down the column just a little bit if I forget to lock it in place.
    Frank Schifano

  2. #112
    Steve Smith's Avatar
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    A reply from Tohkai

    I have receiverd a reply from Mike Suzuki at Tohkai, manufacturer of the Peak focuser:

    At first, it is not necessary for you to place a piece of paper under the focuser, but at the same time this is not compensated for in the desing. Because we conshider that the differnce from the thickness of a paper is the tolerance. In face, we have never heard from our customers about any inconvenience from that tolerance.

    At the same time, we often hear that some users put a plate as thin as a paper under the focuser when using it. However we do not prepare such a plate formally, because every user has different papers from many companies, it means it depends on his condition.
    I think the bit about the tolerance is interesting. What he is effectively saying is that although it is designed to be x in length, it could end up being x + or - the paper thickness as a manufacturing tolerance. This means that using a piece of paper would make some product better and others worse but equally not using a piece of paper would make some worse and some better depending upon which end of the tolerance band they were manufactured to.

    The other manufacturers will also have the same tolerance issues.

    I think then that the concensus of opinion is that these devices are designed such that the plane of focus is on the base and if you want to put a piece of paper under it you can but it doesn't really make any difference.

    I think we need to concentrate our efforts where things actually do make a difference such as the flatness of the negative and the alignment of the negative carrier and lens carrier.


    Steve.
    Last edited by Steve Smith; 05-10-2010 at 02:17 AM. Click to view previous post history.

  3. #113

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    Quote Originally Posted by Steve Smith View Post

    I think we need to concentrate our efforts where things actually do make a difference such as the flatness of the negative and the alignment of the negative carrier and lens carrier.


    Steve.
    A good point, and in my experience different film stocks exhibit varying degrees of flatness in the negative carrier.

    Tom

  4. #114
    RalphLambrecht's Avatar
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    Steve

    Thanks for the effort. I'm glad it's official now.
    Regards

    Ralph W. Lambrecht
    www.darkroomagic.comrorrlambrec@ymail.com[/URL]
    www.waybeyondmonochrome.com

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