Enlarger alignment for each neg carrier?

Discussion in 'Darkroom Equipment' started by mikeb_z5, Dec 27, 2004.

  1. mikeb_z5

    mikeb_z5 Member

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    Hi,

    Tonight I aligned my d6 enlarger (neg stage and lensboard) for the first time with a laser alignment tool. I inserted the piece of glass that came with it in a 4x5 glassless neg carrier and aligned without problem. Did the same for lensboard, no problem.

    Then I got to thinking(always dangerous) and inserted my new used 4x5 glass carrier and rechecked alignment. I was surprised to find that alignment had changed about 1/8" on the target somehow.

    Is this normal? How much error in alignment would call for an adjustment?

    Thanks for your replies,

    Mike
     
  2. David A. Goldfarb

    David A. Goldfarb Moderator Staff Member Moderator

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    Blansky has said that he aligns every print by shimming the easel, if I remember correctly.

    Zig-Align makes an easel alignment tool, which might be a bit easier than shimming.
     
  3. wfwhitaker

    wfwhitaker Member

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    1/8" variation on the target doesn't sound like a lot. Depends upon how high the enlarger head is set (what would otherwise amount to magnification). Possibly the glass in the carrier is providing its own reflection and may not be completely plane parallel. The question is whether or not the negative itself is orthogonal to the optical axis. But again, 1/8" doesn't sound like a lot....

    Can you tell a difference between prints made with the two different carriers, but with the same negative and same magnification?
     
  4. Bob Carnie

    Bob Carnie Subscriber

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    Hi Mike
    I only use the same kind of glass carriers for my printing, on a very odd occasion will I use the plates without glass.
    I never thought to check if there was a difference between the two.
    I would check the bottom of the negative carriers, glassless and glass, to see if there are any differences.
    For example on omega carriers there is a small alignment plate held down with four small screws. I have found that if one of these screws comes off the pressure is different when sitting in the negative carrier stage.
    I would align your enlarger each time you change carriers as this alignment tool is quick to use, I know this solution is a bit of a pain. but other than different pressure from the bottom of the negative carrier I do not know what could be giving you this difference. 1/8 of an inch spread over a 20x24 will give you soft edges.
     
  5. blansky

    blansky Subscriber

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    As David said I align every print. I got the idea from Les because I was too stupid to think of it myself.

    My setup is a Zone VI enlarger and I usually print 16x20 and 20x24. I usually print with the lens wide open because of the enlargment times needed.

    I have a homemade table that allows the "shelf" that the easel sits on to go from about 2-3 different heights. When I built it I was pretty anal about getting everything level ( on each level) but after I got the laser alignment tool I found that I was always out of alignment.

    So rather than fight the thing, I just align every print which takes about ten seconds. I then shim under the vacuum easel with those little wood shims that you can get at a hardware store.

    If I was enlarging at a better f stop, this may not be necessary but until the LED enlarger head gets here that's the procedure.


    Michael
     
  6. Les McLean

    Les McLean Subscriber

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  7. mikeb_z5

    mikeb_z5 Member

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    Thanks for your replies!

    Initially I was getting a dual reflection. I solved that by inserting a piece of paper between the glassless carrier and the condenser. Between the glass sandwich on the glass carrier.

    I haven't printed larger than 11 x 14 yet so I set the alignment a the mid point between 5x7 and 11x14. After I was done I ran the head up and down the column and could not see any difference in alignment.

    Checking alignment was quick with this device though so maybe I will just do a quick check and shim if necessary.

    Thanks again,

    Mike
     
  8. mikeb_z5

    mikeb_z5 Member

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    I might add That when I first set this enlarger up 2 months ago I leveled it with a bubble level. The laser proved it to be off the target by 1 1/2" (lol). I can't wait to start printing tonight and see the difference it makes :smile:

    Mike
     
  9. rbarker

    rbarker Member

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    Les - I'm curious. Assuming the two laser reflections are coming from the two surfaces of the bottom glass, wouldn't the dimmer reflection represent the top surface upon which the negative is resting? If so, wouldn't that be the better reflection to use?
     
  10. Les McLean

    Les McLean Subscriber

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    Interesting observation Ralph, I have to say that I did not think of that as the reason for the two reflections, I assumed that the weaker of the two was bounced from the opal glass cover on the lamp housing. I think Mike's post would support that theory and I intend to do the same as he did when I next print. I do know that my enlarger is always perfectly in alignment for I sometimes work with the lens wideopen and still have pin sharp grain across the whole of the image.
     
  11. oriecat

    oriecat Member

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    Does anyone have an alignment for dummies link or reference, because I'm not following any of this... :sad:
     
  12. blansky

    blansky Subscriber

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    Usually every enlarger needs alignment. The manual describes how to do it. One needs to align the negative carrier support as well as the enlarger head in relationship to the baseboard.

    If you use an f stop somewhere in the middle (f8, f11) you may never have a problem but if you enlarge wider open, then the depth of field won't cover your butt.

    The tools that we are talking about is a Versalab Laser Alignment tool which shoots a laser light up off a mirror type surface on the lens or negative holder and bounces the light back down to the baseboard. By making adjustments you align everything.

    Many people here have made home made devices for very little money that work great. Check the archives here or photonet and you'll find tons of info.


    Michael
     
  13. Bob Carnie

    Bob Carnie Subscriber

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    Hi Michael

    It is my understanding that closing down a process lens for enlarging does not produce any ""Depth of Field" issues.
    Enlarging process lenses are made to be flat field and you may only see a slight depth of focus.
    Closing down the lens should not give you better sharpness .
    Apo lenses are made to work wide open or closed down with the sweet spot two stops from wide open on any lens. they are dramatically different than camera lenses.
    I think this needs clarification as taking the logic that depth of field will pull a negative into focus , workers would start using f32 f22 .
    Could someone help me on this issue as I have heard this before on previous threads and to my knowlege this is not the case.
     
  14. Nick Zentena

    Nick Zentena Member

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    Shorter process lenses [up to 600mm?] are designed to be used at F/22. Longer ones at F/32. The real short ones [105mm?] might be designed for use at F/16. The lenses are at thier best at the designed F/stop.

    Isn't it two issues? Depth of field and depth of focus. The negative is on one side of the lens the paper the other.
     
  15. Ed Sukach

    Ed Sukach Member

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    Lenses are lenses. Depth of Field/Focus is not directly related to "Flatness of Field".
    Using a smaller f/stop *will* increase Depth of Field/ Focus.
    Try tilting the easel in enlarging to correct perspective. Stopping down is virtually necessary.
    "Apo" is a shortening of "Apochromatic" ... supposedly additional care is taken to reduce chromatic abberation - a.k.a. "color fringing"" - But I don't know --- Certainly some of the non-Apos are very good as well. Possibly, "APO=Higher Price".

    Yeh, yeh... "Best" aperture is usually designed to be in the center of the aperture range .... but that is probably as over-critical as you can get. I haven't yet seen an enlarging lens that was materially - or even noticeably worse at the extremes of the range.
    If they were as "bad" as some believe, they would not be fitted with adjustable f/stops.
     
  16. Bob Carnie

    Bob Carnie Subscriber

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    Hi Ed

    I think I must disagree,
    I am sure that the design of lenses for enlargers are not built with depth of field in mind. The are designed to be focused sharp along a flat field which is the enlarger easal.
    I have never corrected un - sharp edges of a print by closing down, alignment of the lensboard negative stage and easal is the only way that I am aware of getting sharp edge to edge.
    As well try putting a lith negative of very small sharp type into your enlarger and project , and then start wide open , middle f stop, and very closed down.
    adjust the density so that each print equal.
    You * will * find that some of the prints are much sharper and ledgible to read.
    In my past , I did a lot of multiple exposing of images and type onto photographic paper and film and I know that selection of apeture for the type was critical.
    This may be a simple test to do and I think that it does indicate some fstops on an *enlarging lens * are better than others.
    This simple test can also answer the debate whether you should have white walls or black walls surrounding ones enlarger.
    Granted when we did these test we were making 8ft murals and the room we worked in was large. We found the type to be sharper with black on the walls not white.
     
  17. blansky

    blansky Subscriber

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    I'm not all that technical. My experience of depth of field/focus is really just anecdotal and I find that printing wide open is not optimal but in my case necessary, for now.

    In my work optimal sharpness is not as necessary as someone doing scenics for example. I try for very sharp eyes (portraits) and the rest is not a huge concern, especially falloff etc.

    Michael
     
  18. Ed Sukach

    Ed Sukach Member

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    I'll try to answer, item by item. Hopefully I'll get the format right..

    The idea of a "flat field" is a primary concern. Even though there are "primary design criteria", there are also "secondaries" ... and those characteristics that are inherently "there". Every "flat field" lens will have a finite depth of field or depth of focus. Example: Mount an enlarging lens onto the lensboard and use it as a taking lens. You will see that everything focuses in much the same way as a taking lens - there will be no razor thin "plane" where everything "snaps in" and then "snaps out".

    ??? Depends on WHY the edges are "unsharp." If sharpness isn't there in the negative, there is little hope for improvement. If there is an amount of misalignment - Stopping down most certainly will increase apparent sharpness. Try tilting the easel -- something I've done to correct perspective. One focuses near the center, and then stops down to gain a suitable amount of "sharp".

    True ... there is an "optimum" aperture for all photographic lenses - part of the design criteria. Has little to do with alignment, though.
    I will, though, take exception to your use of the word "much". With my lenses, Rodenstock, Schneider, Omega, Elgeet(!) - what the heck is on that old Federal ? - It cannot be described as "much". At least not much-- and I have done a fair amount of lens testing (Optical Quality Assurance Specialist - in a previous life) in my opinion.

    Come to think of the "Elgeet" lens -- that is on an old DeJur enlarger I got as a gift. It needs to be rewired ... the electric cord accompanying it disintegrated with time. It has a tilting negative carrier, used for perspective control, and a much neater way to do it than film cans, bricks, sundry other items under the easel to obtain the necessary amount of tilt.

    I guess one could characterize the use of that carrier as, "Aesthetically Adjustable Misalignment".
     
  19. Ole

    Ole Moderator Staff Member Moderator

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    During a long printing session I first checked the focus over the entire printing area.

    I then printed the first (5x7") negative using a glass carrier, put a second (13x18cm) negative in a glassless carrier, printed that, next a 4x5" negative in another glassless carrier, and finished with a 9x12cm negative in a second glass carrier.

    Never once did I adjust focus or realign the enlarger, I merely swapped paper sizes. All prints were sharp from corner to corner.

    BTW, I used the same 180mm Rodagon lens too. And the enlarger is a Durst L138S.