tilting easel during printing equates to rear swing and tilt

Discussion in 'Enlarging' started by frank, Dec 8, 2003.

  1. frank

    frank Subscriber

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    Driving home from work today I was thinking about photography, like I usually do, particularly about my printing session the previous Sunday afternoon. I used the trick of tilting the paper easel on 2 of the 12 prints I made in order to render a portion of the image relatively smaller. (In one case it was a child's feet in the lower portion of the frame which were sticking forward as he was sitting on a bench swing. The other print was a group shot with a largish woman on the end, that will, I'm sure, like her image better that way.) I conceptually made the connection between tilting the easel during printing with rear swings and tilts (that I don't have on my 4by5 Speed Graphic) during the exposure of the negative. Am I correct in the assumption that each gives the same result and that the movements of rear swing and tilt on the camera can be duplicated by tilting the printing easel?
     
  2. David A. Goldfarb

    David A. Goldfarb Moderator Staff Member Moderator

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    Exactly! If you have an enlarger with a tilting lens stage, you can also compensate for the easel tilt to render the whole neg in focus using the Scheimpflug principle, so you don't have to stop the enlarging lens down as far.
     
  3. Thomassauerwein

    Thomassauerwein Member

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    I do this all the time It works for stretching and compressing element along the edges really well. Also if you want to throw things out of focus while maintaining a sharp point of interest. It's a cool trick.
     
  4. Thilo Schmid

    Thilo Schmid Member

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    Well, it is not exactly the same. The problem is, that while taking a picture, you render a three-dimensional space on a two dimensional film image. Objects that are closer to your camera will be "distorted" different from objects that are farer away. While enlarging, all "picture points" receive the same transformation. So on a WA Image, you may either correct the foreground (e.g. a tree) or the background (e.g. a building).
     
  5. Ed Sukach

    Ed Sukach Member

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    I've been "chewing" on this for some time, now. I'll agree that the so called "brick trick", tilting the enlarging easel to modify ... It's not exactly "distortion", more accurately, "perspective"... is not *quite* the same - but just how "quite", I'm not sure.

    I once used this "tilting" to correct (11) rolls of 35mm film - photographs of artwork - paintings - taken by someone who did not have a clue about positioning the camera at a right angle to the center of the work. Took a bit of sweat ... but it was successful.

    The main problem is in focusing. I usually use a grain focuser in the enlarger... but here, it is necessary to use a lot of estimation ... and the smallest enlarging lens apertures.

    Certainly, a useful "tool".
     
  6. frank

    frank Subscriber

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    Thilo,
    Interesting point you make about the difference between the recording of a 3-d world versus the projection of a flat negative.
    I'm still thinking that the result is exactly the same though because the 3 dimensionality of the real world during picture-taking versus the 2-D of a negative during printing only has an effect if the camera lens is moved. That movement would cause spacial relationships of objects in the real world to change, whereas during printing, shifting the negative would only change the framing, not the spacial relationships of the objects already on the negative. I stand and wait to be corrected however as I have been wrong about a few things before!
    By the way, I was born in southern Germany.
     
  7. Thomassauerwein

    Thomassauerwein Member

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    This is an easy little trick I use it almost every print and even keep track in my notes as to what direction. Theirs another variation also. By stacking under the paper in the easel shims you can reduce the size of certian componants within the image. You guys can teckno talk this simple thing to death but it works easly and well.
     
  8. Ed Sukach

    Ed Sukach Member

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    It's got to be about as "low tech" as it gets. I've used JOBO bottle caps, a container of X-acto blades, bona fide *bricks*, film reels - anything to get the easel to tilt as I want it.
     
  9. frank

    frank Subscriber

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    Okay, another drive home (30min.) and some more thinking about this and Thilo's post, and now I can see that with a wide angle lens on the camera, rear swing and tilt will produce a different effect than tilting the easel during printing, but only because of the differnce in focal length of the lens on the camera and on the enlarger. If the lenses are the same, then I think the effect, achieved either with rear swing/tilt or easel tilting, would be exactly the same. The only advantage I can see to doing it in-camera would be that if you're making contact prints, it could not be done during the printing stage.
    That was an enjoyable mental exercise, and now I don't need to worry about the lack of rear movements on my Speed Graphic.

    (Thomass, yes I know it works easily. What was new to me was equating easel tilting with rear camera movement.)
     
  10. Thilo Schmid

    Thilo Schmid Member

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    Frank,
    shift and tilt are totally different things. While it does not matter whether you shift the negative carrier, the front or the back standards of your camera, tilting the camera front or back standards or the easel are three different things. The focal length of the enlarger lens does not matter. Enlarging is a simple projection of a two dimensional source on a two dimensional target and is totally independent of the focal length of the el-lens. El-lenses do have different focal lengths in order to archive different image circles without the need of distorting WA lens designs.
     
  11. Thilo Schmid

    Thilo Schmid Member

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    Thomas,
    here is no doubt about the effect. The question was whether tilting the easel really equals tilting the film plane of the camera. Nor does anybody doubt that using a softening filter on either the camera lens or the el-lens will yield a softer image. But the effect is not exactly the same in both cases. While the difference is a matter of taste or artifical expression in the latter case, you may get in serious trouble if you need to correct the perspective of e.g. a shot of an architecutral model afterwards.
     
  12. David A. Goldfarb

    David A. Goldfarb Moderator Staff Member Moderator

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    I agree that there is a subtle difference between using rear tilt/swing and tilting the easel (or its digital equivalent of using perspective transformation in Photoshop), but I don't think that the difference is in the rendering of the relative size and shape of objects in the frame. Either method can be used to correct convergence in one plane in the image.

    Rear tilt/swing or easel tilt alone will not correct a complex composition with multiple planes at multiple distances, which is best corrected with rise/fall of either standard on the camera, and post-processing methods will have no effect on the plane of focus in the image.

    The advantage of applying rear tilt/swing in the camera over doing it after the fact is that it can be done without the loss of image quality that would result from varying the enlargement factor across the frame, and without the need for cropping the trapezoidal image that results. Doing it in the camera also eliminates the need for stopping down the enlarging lens to compensate for the easel tilt on enlargers that lack a tilting lens stage.

    That said, the kinds of corrections usually applied in the darkroom are typically small, and for small corrections, easel tilt is quite effective.
     
  13. Ed Sukach

    Ed Sukach Member

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    Thinking about this, I remembered an article in the dear, departed ... and severely lamented Camera and Darkroom, expressly about easel tilting and its comparison to view camera tilts, swings, rise, fall ... and other esoteric "jiggling". The tiltle of the articel WAS "The Brick Trick".

    Simple easel tilting is effective to a point; the correction of *all* errors that would, more or less, be corrected by T,S & R,F are not possible by this method... but *significant* improvements in "falling down" buildings, for example, can be realized.

    I remember an "architectural" photograph, with pronounced convergence of vertical lines, as the camera was *much* below the center. They then corrected in camera and took another image. They took the first "converging" image and tried to correct to the same degree by easel tilting.

    The result: Almost! All vertical lines in the in-camera corrected image were perpendicular and nearly parallel.
    One (1) dormer on the roof of the tilted image was not, but the overall improvement was well worth the effort.

    I *miss* Camera and Darkroom.
     
  14. frank

    frank Subscriber

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    Thanks everyone for your input. I understand now that the 2 things are almost the same.
     
  15. pierre

    pierre Member

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    The effect is identical, as far as I can tell. I used to take architectural photos with my 35mm camera back in the 70's, and I corrected the perspective by simply tilting the easel. It works very well, if it's just a matter of correcting converging lines. All you have to do is to use a smaller aperture so that the whole picture remains in focus. I uploaded a scan of a 1975 print I made this way in the Technical gallery (Old office building).
     
  16. cesarb

    cesarb Subscriber

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    This topic brought to my mind an ancient reading and - yes, I found it! - at "Enlarging" - C.I. Jacobson and L.A. Mannheim, Focal Press, 22th ed, where they extensively cover correcting parallel lines with enlarger movements. Some clever equations show that real distortion can come into the scene if specific relationship among camera and enlarger lens focal lenght, angle of tilts and magnification are not considered. Perspective and proportion control can be thought as diferent subjects and precisely calculated to include even Scheimpflug's law.
    Obviously, it's really quite, quite technical. Almost boring...
     
  17. MikeK

    MikeK Member

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  18. SteveGangi

    SteveGangi Member

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    I have done the same thing, using this to "straighten out" buildings. My "secret recipe" was to use books of different thicknesses, so I could have some control over the amount of tilt. That, and a piece of graph paper which was a guide for knowing when it was right.