Sharpness issues

Discussion in 'Enlarging' started by J Pellegrino, Feb 25, 2005.

  1. J Pellegrino

    J Pellegrino Member

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    I've recently started enlarging Xpan negatives (24 x 65mm), and at first I was using a cut and filed-out regular glassless 35mm negative carrier, and experiencing a lack of sharpness because the carrier just could not hold such a large negative flat.

    So I am now using an anti-Newton glass 6x9 carrier, but I swear that overall, the prints are just not as sharp as before. I look at this anti-Newton glass, and it is like shower-door glass...surely this is having an effect, if not in sharpness, then it must be diffusing and lowering the contrast of prints? Is this an inescapable tradeoff?

    Also...would Ilford FB Warmtone paper be less sharp than their regular "cold-tone" Multigrade IV? Or is it my imagination?

    Thanks, JP
     
  2. eric

    eric Member

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    That's an odd analogy. I've used a glass 8x10 carrier on a Beseler 8x10 enlarger for 6x17. Very sharp prints. Does it really look like cheapo glass?
     
  3. J Pellegrino

    J Pellegrino Member

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    I wouldn't say "cheap." (Certainly the thing cost enough!) It is an authentic Beseler 6x9 carrier. But the bottom glass looks like it was sandblasted, or "pebbly." Hard to describe. Never having seen anti-Newton glass before, I assume this is what it is supposed to look like.
     
  4. Bob F.

    Bob F. Member

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    Almost... it should look like that, but it should be on top of the negative, not underneath it. Sometimes (I read) it's OK, sometimes not - on my L1200, it's not a good idea... Try plain glass on the bottom and see if you get an improvement.

    Cheers, Bob.
     
  5. eric

    eric Member

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    It's been so long since I've used it I can't remember which side the "pebbly" part was. Can you make a print by turning the neg carrir upside down?

    I am in the middle of filing my 6x9 carrier (no glass) and I noticed my 6x9 negs are bowing. I'll probably just scotch tape some sections of it to keep it flat on the edges.
     
  6. Eric Rose

    Eric Rose Subscriber

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    My glass carrier for my Omega has that funny shower door look too. The prints however are razor sharp. I have glass carriers for 6x6, 6x7 and 4x5. I never print without them. Except for 35mm of course.
     
  7. Tom Stanworth

    Tom Stanworth Member

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    Anti newton bit should go on top (against the smooth base of the film) and the clear glass on the bottom (against the emulsion, which not being as glossy smooth, tends not to cause newton rings). My Devere anti newton glass is very subtle, certainly not pebbly, but upon close inspection has a slight disruption to the surface on one side. Even with such a subtle surface I would not dream of using it under the neg!

    Tom
     
  8. eric

    eric Member

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    Maybe you guys should just start printing in the shower :smile:
     
  9. Bruce Osgood

    Bruce Osgood Membership Council Council

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    My Omega 4X5 glass carrier has two pieces of glass that I wouldn't call shower door look, but they have a 'blurring' quality. One rests the neg and the other covers on top. Additional pieces of glass are of the blur type except one which is clear. It is beveled on the ends like the blurry glass.

    The prints, while not razor sharp are sharp, I've attributed this to the taking lens. I'm wondering now if perhaps a clear glass should be on the bottom? Or the other way around?

    Any ideas?
     
  10. Claire Senft

    Claire Senft Member

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    look carefully

    After placing the anti newton glass on top and making a print you get newton rings then you have the glass upside down. Some anti newton glass is hard to be sure you have it right side up.
     
  11. Bruce Osgood

    Bruce Osgood Membership Council Council

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    Claire,
    Are you saying only one sheet of anti newton glass in required? On the top correct side up. And on the bottom what is used, clear glass or anti newton?
     
  12. Ronald Moravec

    Ronald Moravec Member

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    The AN glass goes on top only. The rings form between the base side of the neg and the smooth glass.

    You maybe can fabracate a top glass carrier with no glass on the bottom. Lots of enlargers are made this way. I just installed a AN glass from a slide mount into the top of my 35mm Omega carrier. I left the bottom open.
     
  13. Bruce Osgood

    Bruce Osgood Membership Council Council

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    BINGO!
    I just replaced the lower AN with the clear and immedieatly I can see a difference on the easel. The grain focuser works better also.

    Thank you Ronald.
     
  14. Bob Carnie

    Bob Carnie Subscriber

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    The anti newton glass is on top , you can use clear glass on bottom or as Roman says you can use a regular bottom carrier and glass on top.
    I think as the enlarger heats up the negative bows towards the heat. therefore glass on top is good.
    Personally I prefer glass on top AN and Regular bottom
    As well and I find this to be quite critical and will pass these gems of info free of charge to this community. Usually its$9.99 video at Kmart

    when using glass carriers for mf printing or 35mm I have a strick set up proceedure as follows.

    1. approx center the negative in glass carrier, emulsion down
    2. raise the enlarger height to the correct printing height
    3.In my case make sure proper condensor placement is in.
    4. put in the proper lens
    5. place the easal into position and take neg carrier out of enlarger
    6. turn on enlarger and position the easel dead center to the circle of light
    7. put glass carrier set up back into the enlarger.
    very important ladies and gents.
    8. make sure image is centered into the easal blades, if not move the NEGATIVE not the easel.
    9. when you are happy that the easel , lens , negative, condensors, and light are in a vertical path.(tape the negative to the bottom glass)
    10.Important step> I use black masking tape on the underside of the glass carrier to mask out the raw light going around the mf negative(some enlargers have swing in blades for this purpose)

    I use a light table for set up, I have qtips handy , canned air, lens brush , anti static cloth , negative cleaner.
    Keeping the humidity down is good to control dust.

    If I am not sure of the enlarger alignment I will check after everything is sized and correct if needed and then start printing.

    Sorry for the long post but I think the above is critical for edge to edge sharpness and this is the technique I use.