how to use a grain focuser?

Discussion in 'Darkroom Equipment' started by stradibarrius, Feb 13, 2009.

  1. stradibarrius

    stradibarrius Member

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    I know the grain focuser is to finely focus the enlarger before printing, but how do I use it?

    Sorry for such a novice question but I am.
     
  2. optique

    optique Member

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    Good question, because using the focuser on 4x5 negs going to 8x10 size, I can not see grain. Are my eyes bad?

    Otherwise, I use the focuser on finely detailed elements, like tree branches, or person's hair, to focus.

    Tri-x in Diafine if that matters.
    Steve.
     
  3. Christopher Walrath

    Christopher Walrath Member

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    You place the neg in the carrier and into the enlarger. Place the easel on the baseboard and then the focuser onto it so that you have the focuser the proper distance from the surface of the easel where the paper will be. Turn on the light and focus. Then mark your focus , turn the enlarger off, place your paper and then get to it.
     
  4. pentaxuser

    pentaxuser Subscriber

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    With the Paterson grain focuser you simply focus the black line in the focuser by moving the moveable part of the focuser. Do this under the enlarger light at full aperture without a neg. There's a screw which enables the correct adjustment to be set.This adjusts the focuser for your eyesight. Put the neg into the carrier then the rest is done by the bellows adjuster on the enlarger to get the neg's grain in sharp focus. Do this also at full aperture. I'd take it beyond what you think is the sharpest grain focus and then move the bellows back into focus. Once you have done this on a couple of negs, it becomes second nature to do it correctly.

    Finally adjust the lens aperture to expose the paper at a reasonable number of seconds, say between 5-10 secs. Unless your eyes are perfect a grain focuser gets your print into focus much better. Try focussing by eye then use the grain focuser. Unless you have an exceptional talent for focussing by eye I guarantee that the grain focuser will pull the grain into focus to an extent that the naked eye will fail to do.

    pentaxuser

    pentaxuser
     
  5. Martin Aislabie

    Martin Aislabie Subscriber

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    Steve, it depends on what sort of grain magnifier you have.

    When I moved up to 5x4 I was using a Paterson Focus Finder - it worked fine on 35mm & 6x6.
    However on 5x4 there was no grain to see at 10x8 or even 12x16.
    However, if you moved the magnifier around the print you can find details/edges/something to use to help you find focus.

    After a while of doing this I got really fed up with it, so I crumbled and bought a Peak Focus Finder - and the grain has returned even on 5x4 - but they are expensive.

    If you can manage with your standard focus finder and edge/detail/something to focus on then stick with it and save your money.

    It might be worth keeping an eye on E-Bay - they do occasionally show up.

    Martin
     
  6. stradibarrius

    stradibarrius Member

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    My question is even more basic...the grain focuser looks like a small microscope with a mirror. If you look through the ocular you see the mirror so how do you see the grain in the negative?
     
  7. Christopher Walrath

    Christopher Walrath Member

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    The image projected by the enlarger appears in the mirror and you then adjust your enlarger lens bellows until you have the focus down in the grain focuser eyepiece.
     
  8. stradibarrius

    stradibarrius Member

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    That's what I was looking for!!
     
  9. johnnywalker

    johnnywalker Subscriber

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    I've been using one for a while now and it works fine, but one thing I'm curious about. The grain (at least that's what I hope I'm focusing on) is almost wormy looking, which is not what I expected. I'm sure it's the grain, because I can see the details are at their sharpest when the little "worms" are at their sharpest.
    For 35mm I focus on top of the paper using the red safe light filter on the enlarger. For the 4x5 I use a throw-away piece of paper and no safelight. Once it's focused I change paper (remembering to turn the enlarger light off, of course).
     
  10. Brickbird

    Brickbird Subscriber

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    I was going to ad...Use an old piece of paper to put the focuser on and do not focus on the easel. Paper is thicker than film grain so have some in there for the test focus then put your real paper in after not touching the enlarger bellows.....also, focus at your desired f-stop if possible. Grain that is sharp at the widest aperture is not sharp at smaller apertures. It may be minimal but it is not the same. It does make a difference if you are shooting 120 film and going up to a 16x16 or 16x20 print size. Or do the reverse and focus a neg at f16 or f22 and get the grain tack sharp then open up to the widest aperture and check the grain. It will be different.
     
    Last edited by a moderator: Feb 13, 2009
  11. Anscojohn

    Anscojohn Subscriber

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    Depends upon the type of grain focuser. The ones which have a reference line are meant to be operated using the parallax method, not "when the grain looks sharp." I know the old Bausch and Lomb worked that way. I think the Scoponet does (have not used my Scoponet in quite some time and I just don't remember.)
    Positioned as folks have noted above, you focus until the grain looks sharp, whilst you are looking through the center of the focus finder. Then you tilt the head back and forth slightly. If the grain moves in relation to the reference line, you are not quite in focus. Refine focus until there is no displacement when the parallax changes.
     
  12. dancqu

    dancqu Member

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    So for 35mm a color is used for which the paper is not
    sensitive and is at the opposite end of the spectrum for
    which the paper is sensitive, blue, and for VC, green as
    well. Well the lens may or may not be all that well
    corrected. That is, blue and also the green may
    focus at other than the red focus.

    Enlarging lenses are for the most part achromates, two
    color corrected. Actually blue is the supplied filter color
    of the more expensive grain focusers. Paper sensitivity
    extends well into the very deep blue and even the
    ultraviolet. That goes for Graded and even more
    so for VC.

    I don't bother with grain focusing. I don't need a forty,
    sixty, eighty, or more diameter enlargement to know
    if my image is in focus. I rely on close viewing with
    reading glasses, both eyes open. Focus with lens
    wide open then stop down. I the image looks
    sharp wide open it's got to be even sharper
    stopped down. Dan
     
  13. Christopher Walrath

    Christopher Walrath Member

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    Too true, Dan. I also read somewhere that (as long as you pretty much use the same thickness paper) you could take a piece of your printing paper and affix it to the bottom of your focuser so that you would have the focuser the proper distance above the easel.
     
  14. Steve Smith

    Steve Smith Member

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    This comes up quite often. However, Gene Nocon, a much better printer than I will ever be, suggests not using paper on the easel. He also advocates the use of a blue filter so that you see the same wavelength of light that the paper is sensitive to.

    This is in his book "Photographic Printing" well worth getting a copy if you can find one.

    However, Amazon lists it new here: http://www.amazon.co.uk/Photographic-Printing-Gene-Nocon/dp/1852270152 for £184 which seems a trifle excessive!

    I bought mine for a few pounds at a charity shop.



    Steve.
     
    Last edited by a moderator: Feb 16, 2009
  15. Steve Smith

    Steve Smith Member

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    See my post above.

    It is my opinion that the grain focuser manufacturers have already taken the paper thickness into account.


    Steve.
     
  16. pentaxuser

    pentaxuser Subscriber

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    Wow a £184! I have read the book and it's OK but on this basis a new Tim Rudman or Les McLean book must be worth a four figure sum!:D

    Seriously though, I think it must be due to its being out of print and seen as the original book on f-stop printing a collector's item maybe. Gene mentions the blue filter giving a sharper focus and in the book produces a before and after print to prove the point. It might be the limitation of print reproduction in a book but I looked at both prints long and hard and couldn't distinguish between them.

    Others who have written on the subject and are well regarded in the printing game have expressed similar doubts but "you pays your money etc"

    pentaxuser
     
  17. Steve Smith

    Steve Smith Member

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    I will let mine go for a mere £160 if anyone is interested!!!


    Steve.
     
  18. RJS

    RJS Member

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    The Hocus Focus, distributed by Jobo is extremely inexpensive, simple to use and seems as if it can't be terribly accurate. Testing against my Peak magnifier I can't find a difference in the focus point. It flies in the face of reason that something so simple and inexpensive should be so good.