Re-Focusing W/Grain Focuser - Necessary Or Neurosis?

Discussion in 'Enlarging' started by DF, Aug 4, 2017.

  1. DF

    DF Member

    Messages:
    227
    Joined:
    Nov 10, 2012
    After the whole slew of test strips are in and I decide to go with whatever seconds/enlarger lens opening for the 1st print, I again check the grain in the focuser and notice there needs an adjustment at times and sometimes not. Is it heat from the lamp on the negative the cause - and is it temporary? Should you wait for a cool-down - then check again?
     
  2. mrosenlof

    mrosenlof Subscriber

    Messages:
    111
    Joined:
    Feb 25, 2010
    Location:
    Colorado
    Shooter:
    Multi Format
    I use a grain focuser for every negative I print. But I don't adjust after the initial focus. Lamp heat can certainly affect how much "bow" you have in the neg, but I haven't felt to re-check focus after a test strip, or print. I'm using glassless neg carriers. I was once very fussy about lens sharpness. I'm less so these days, but still care, and don't think I'm making unsharp prints. whatever all that means :smile:
     
  3. Theo Sulphate

    Theo Sulphate Subscriber

    Messages:
    3,419
    Joined:
    Jul 3, 2014
    Location:
    1984
    Shooter:
    Multi Format
    Maybe I'm neurotic, but I re-check the focus.
     
  4. ac12

    ac12 Member

    Messages:
    667
    Joined:
    Apr 27, 2010
    Location:
    SF Bay Area (SFO), USA
    Shooter:
    Multi Format
    Actually you should study the situation.
    You WANT the print focused.
    So you need to determine how much it is going out of focus and what time frame.
    Is the film bowing after 10 sec or 15 sec or ?
    And is this for ALL films or just certain films?
    Maybe you have to preheat the film before making your print.
    In the extreme, maybe you need to switch to a glass negative carrier.
     
  5. Patrick Robert James

    Patrick Robert James Subscriber

    Messages:
    1,080
    Joined:
    Jul 31, 2012
    Shooter:
    Med. Format Pan
    If you don't have a glass negative carrier then yes, you probably need to refocus after the negative absorbs some heat from the lamp. Do yourself a favor and get a glass negative carrier! Life is too short to deal with accidentally unsharp prints.
     
  6. RalphLambrecht

    RalphLambrecht Subscriber

    Messages:
    9,359
    Joined:
    Sep 19, 2003
    Location:
    K,Germany
    Shooter:
    Medium Format
    sharpness is a bourgeois concept.
     
  7. juan

    juan Subscriber

    Messages:
    1,845
    Joined:
    May 7, 2003
    Location:
    St. Simons I
    Shooter:
    Multi Format
    With an incandescent head, the negative will pop. I've never seen a cold light do it. Don't know about leds.
    Why wouldn't you want to recheck focus just before exposure anyway? Unless you agree with Ralph.
     
  8. bdial

    bdial Subscriber

    Messages:
    5,940
    Joined:
    Jan 2, 2005
    Location:
    North East U.S.
    Shooter:
    Multi Format
    If you check and notice a need to adjust, then yes, you need to check.
    There are various things that could cause it though, any possibility the focus or head is creeping out of position, for example?
     
  9. Alan9940

    Alan9940 Member

    Messages:
    654
    Joined:
    Jun 17, 2006
    Shooter:
    Multi Format
    Probably unnecessary, but I always do one final last check of focus with a grain magnifier just before making a final print.
     
  10. MattKing

    MattKing Subscriber

    Messages:
    20,153
    Joined:
    Apr 24, 2005
    Location:
    Delta, BC, Canada
    Shooter:
    Multi Format
    A check of focus isn't necessarily the same as re-focusing. And you can do the check at the aperture chosen for exposure. So there isn't a big reason not to check.
     
  11. tedr1

    tedr1 Member

    Messages:
    595
    Joined:
    Feb 3, 2016
    Location:
    50 miles from NYC USA
    Shooter:
    Multi Format
    The points made above are good, I'll add one.
    A lot depends on the aperture setting of the lens, this changes the depth of field at the negative in just the same way that it is changed by the aperture of the camera taking lens. Using the lens wide open gives the brightest image for focusing and the most shallow depth of field, this combination is good for making focus adjustments, provided nothing changes. If the negative bows after focusing the focus adjustment is now incorrect and needs to be redone. Using the lens stopped down gives a more dim image however depth of focus is greater, best focus may be more difficult to locate precisely. In this situation the effect on sharpness of the negative bow after focusing is less due to the greater depth of field.
    Many enlarging lenses are designed to be used closed down two stops or so.
    If it seems negative bow is occurring a good idea is to make tests, prints aren't needed; let the negative and negative carrier cool, set the lens wide open, turn on the lamp and focus immediately, then with the lamp on watch the sharpness of focus while things heat up. If there is a change due to negative bow then refocusing is needed.
     
  12. oldtimermetoo

    oldtimermetoo Subscriber

    Messages:
    758
    Joined:
    Jul 28, 2014
    Location:
    Shreveport,
    Shooter:
    Multi Format
    Theo, I am with you but I do have a question. Why should anyone care whether I do because it is necessary or because I am neurotic? What I do in my own darkroom is my business and no one else's and I am certainly not going to feel "guilty" if I recheck the grain one time or one hundred times. Not upset or anything, just don't think it is important........Regards!
     
  13. Sirius Glass

    Sirius Glass Subscriber

    Messages:
    23,433
    Joined:
    Jan 18, 2007
    Location:
    Southern California
    Shooter:
    Multi Format
    Once I was introduced to a grain focuser at Kodak, I have used one every time ever since.
     
  14. Frank53

    Frank53 Subscriber

    Messages:
    212
    Joined:
    May 18, 2013
    Location:
    Netherlands
    Shooter:
    Multi Format
    If this bothers you, you better switch to glass negative holders. If the negative bows, it means it is not flat anymore, so you can refocus the middle and than the sides will be out of focus. Imo the only solution is keeping the negative flat, not refocussing. I switched to glass after I noticed the same problem and my prints look really sharp now.
    Regards,
    Frank
     
  15. OP
    OP
    DF

    DF Member

    Messages:
    227
    Joined:
    Nov 10, 2012
    Just how heated up can a negative get so it renders the image differently then if it were cool?
     
  16. kwm

    kwm Member

    Messages:
    24
    Joined:
    Jul 6, 2009
    Shooter:
    Medium Format
    With my Durst enlarger I`m still using the small Paterson grainfinder, that I started with in the mid-seventies. Never tryed to get one of those overpriced finders. Making prints is just a hobby, no rocket-science ...
     
  17. MattKing

    MattKing Subscriber

    Messages:
    20,153
    Joined:
    Apr 24, 2005
    Location:
    Delta, BC, Canada
    Shooter:
    Multi Format
    When negatives get warm, they pop and curl.
    Which means parts of them can go out of focus.
    If you wish to maximize the benefit of depth of focus at the negative, you may need to adjust the enlarger's actual point of focus.
     
  18. Nodda Duma

    Nodda Duma Subscriber

    Messages:
    1,029
    Joined:
    Jan 22, 2013
    Location:
    Brookline, NH
    Shooter:
    Multi Format
    One of the many great concepts the bourgeoisie have gifted to the world. :D
     
  19. tim_walls

    tim_walls Subscriber

    Messages:
    1,117
    Joined:
    Sep 6, 2006
    Location:
    Bucuresti, R
    Shooter:
    35mm
    Life is even shorter when it comes to dealing with bloody dust, though...

    Having used both, I prefer glassless. But that may be because my "darkroom" is shambolic, and it's taken enough effort to conquer light without making it a cleanroom too...
     
  20. Sirius Glass

    Sirius Glass Subscriber

    Messages:
    23,433
    Joined:
    Jan 18, 2007
    Location:
    Southern California
    Shooter:
    Multi Format
    I will stick with dirty dust, not bloody dust.
     
  21. RalphLambrecht

    RalphLambrecht Subscriber

    Messages:
    9,359
    Joined:
    Sep 19, 2003
    Location:
    K,Germany
    Shooter:
    Medium Format
    well said!
     
  22. RichardJack

    RichardJack Subscriber

    Messages:
    288
    Joined:
    Sep 14, 2011
    Location:
    Long Island, NY
    Shooter:
    Multi Format
    The answer depends on your vision. If your near sighted and don't have a problem getting close to the projected image you might not benefit from the focuser. If you do use a focuser place it on top of a waste piece of enlarging paper of the same thickness.
     
  23. chip j

    chip j Subscriber

    Messages:
    1,424
    Joined:
    Oct 26, 2012
    Location:
    NE Ohio
    Shooter:
    35mm
    Get a Leica enlarger, any model--only one glass surface to touch the neg & keep it FLAT!!