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Thread: Placement

  1. #11
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    Quote Originally Posted by Stephen Benskin View Post
    Those examples appear to be more about exposure technique than exposure placement on the film curve.
    Ok so I chewed on this thought most of the morning and I don't see the point you are trying to make.

    The technique doesn't really matter, spot, incident, sunny 16, all simply provide a reference point.

    From whatever reference point we have, with an understanding what it has just told us, we need to decide where we want to place that tone or those tones on the curve.
    Mark Barendt, Ignacio, CO

    "We do not see things the way they are. We see things the way we are." Anaïs Nin

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    Quote Originally Posted by markbarendt View Post
    Ok so I chewed on this thought most of the morning and I don't see the point you are trying to make.

    The technique doesn't really matter, spot, incident, sunny 16, all simply provide a reference point.

    From whatever reference point we have, with an understanding what it has just told us, we need to decide where we want to place that tone or those tones on the curve.
    In the case of spot lighting the exposure with the reflectance meter where the reading is taken and then the indicated exposure is reduced should produce the same exposure indication as a straight incident meter reading taken on stage. I was trying to point out that those examples aren't so much about a difference in exposure placement but simply interpreting the meter reading.

    I've only had a chance to glance at page 32. My first impression is there are a few caveats that need to be address with Dunn's statement. Also, being in the motion picture and color section should raise a flag. There are differences in what defines acceptable conditions between motion picture, transparency, color negative, and black and white negative.

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    Also see in the monochrome section page 15, at least in the 3rd Ed. "exposure requirements"

    I agree that there are caveats to consider. The caveats though seem to be based on the limits of the materials and what we decide is most important in a scene.

    His thought seems not about tossing important detail, more about using a smaller safety factor and even using the curve of the toe to as he puts it, compensate. Precise exposure with little if any extra detail in the negative "below" what we plan to print when we drop the camera shutter.
    Mark Barendt, Ignacio, CO

    "We do not see things the way they are. We see things the way we are." Anaïs Nin

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    What Dunn was discussing was a very specific set of circumstances and not a general concept. It was about how to handle a scene where the luminance range was greater than normal. He presented a number of approaches. Dunn’s argument for not reducing the development of the negative was that it compresses the tonal values too much causing the print to appear dull. He proposed normal development of the negative even for greater than normal luminance ranges.

    This left a couple of options to control the higher negative density range printing when printing on a normal grade of paper. One was to use printing techniques such as burning, dodging, and masking. The other was to print for the highlights and midtones at the expense of the shadows. “…it is in such cases almost invariably at the expense of the shadows, especially when the latter are small.”

    Personally, I use all three methods. While I agree that smaller areas can be printed without concern for detail, the question is always how small? It all depends on the intent of the photograph. Documentary and photojournalism are more concerned about the moment than detail in the shadows. With large format landscape photography, tone reproduction plays a greater role.

    Then there is the creative intent. The parameters in the psychophysical judging that lead to the definition of an excellent print for tone reproduction theory was for the image to produce in the viewers mind the impression of how closely it portrays the original scene. This means that print quality is based on the literal impression of a scene. If a photographer decides to deviate for creative reasons from this, it is no longer applicable to apply those concepts in judging the quality of the print. As the psychophysical determination of print quality is the basis for film speed, this also applies to the concept of “correct” or appropriate film speed and exposure.

    There is also the complex concept of the two aspects of tone reproduction: objective and subjective tone reproduction.

    But where Dunn and I disagree is that I want the shadow detail on the negative to give me a choice to use it or not, where as Dunn feels that if it isn’t going to be used, “there is no point at all in exposing the negative for the shadows and thus forcing the required highlights far up into the very dense part of the negative characteristic.”

    I’m not sure why the reference to page 10 as it is just an explanation of the basic concepts of exposure theory. You should check out Appendix B for a more detail explanation.

    Don't let the examples of the affects of flare on the film curve fool you. Combining the film curve and the affects of flare on the same curve is more for convenience and can be conceptually misleading as to how flare works. Flare doesn't change the shape of the film curve. It just changes where the exposure will fall on the curve.

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    You have obviously put a lot of thought into this, thank you for taking the time to do this. Your thoughts are helping me.

    Quote Originally Posted by Stephen Benskin View Post
    What Dunn was discussing was a very specific set of circumstances and not a general concept. It was about how to handle a scene where the luminance range was greater than normal. He presented a number of approaches. Dunn’s argument for not reducing the development of the negative was that it compresses the tonal values too much causing the print to appear dull. He proposed normal development of the negative even for greater than normal luminance ranges.
    The way I read his lead-in to this concept he is talking about everything except: "medium and low range subjects which are to be reproduced, via negatives, on to black and white paper prints or transparencies (lantern slides)".

    To me that statement seems to define the special circumstance, rather than the norm, given that he goes on to say: "It has been found by experience, however, that while the shadow detail method is theoretically best for the particular type of work just mentioned, this is by no means the case for practically all other types of work."

    I do agree that he is talking about a long scale subject specifically and I heartily agree with the thought that trying to straight print too long a scene scale results in dull prints.

    Quote Originally Posted by Stephen Benskin View Post
    This left a couple of options to control the higher negative density range printing when printing on a normal grade of paper. One was to use printing techniques such as burning, dodging, and masking. The other was to print for the highlights and midtones at the expense of the shadows. “…it is in such cases almost invariably at the expense of the shadows, especially when the latter are small.”
    I apologize for focusing on the concept of letting the shadows go earlier in the thread, as I said I'm still trying to really wrap my head around this. I was describing the result rather than the reason.

    Actually his statement "or (b), if - as is usually the case- the main interest is only at one end of the scale, to print for that end only and ignore the other end entirely." is the statement that most interests me. This idea can be applied regardless of where the interest may be on the exposure scale.

    Placement of my main subject has always been my intuitive priority. In general though metering methods are not taught from that perspective.

    For example with incident metering we are first taught to use the reading displayed, this is a dumbed down technical version of Dunn & Wakefield's concept, it works well for many, but it lacks the real thought that Dunn & Wakefield imply regarding the relative importance of different parts of the scene.

    Quote Originally Posted by Stephen Benskin View Post
    Personally, I use all three methods. While I agree that smaller areas can be printed without concern for detail, the question is always how small? It all depends on the intent of the photograph. Documentary and photojournalism are more concerned about the moment than detail in the shadows. With large format landscape photography, tone reproduction plays a greater role.
    I agree completely and see no conflict with the book there.

    Quote Originally Posted by Stephen Benskin View Post
    Then there is the creative intent. The parameters in the psychophysical judging that lead to the definition of an excellent print for tone reproduction theory was for the image to produce in the viewers mind the impression of how closely it portrays the original scene. This means that print quality is based on the literal impression of a scene. If a photographer decides to deviate for creative reasons from this, it is no longer applicable to apply those concepts in judging the quality of the print. As the psychophysical determination of print quality is the basis for film speed, this also applies to the concept of “correct” or appropriate film speed and exposure.
    One of the points made by Dunn & Wakefield really leapt out for me. It is about the time the viewer has to consider a given frame.

    "But in viewing motion pictures the upper and middle tone areas - and particularly the human face - claim so much attention by virtue of motion (and sound where applicable) that the scene has normally changed before there is time for the shadows to be critically examined at all." page 33

    If that "motion" doesn't describe the world we live in and the way photos are viewed today, I don't know what does.

    Dunn & Wakefield seem here simply to concede to the norm of what people expect first.

    My thought here actually falls at least partly outside the exposure question, in composition. If I catch the eye with the brightest spots where do I take them from there. Could be to smaller details rather than darker shadows.

    In any case the shadows seem generally to hold only a supporting role

    Quote Originally Posted by Stephen Benskin View Post
    There is also the complex concept of the two aspects of tone reproduction: objective and subjective tone reproduction.
    I do think that is part of what I'm trying to grapple with.

    Quote Originally Posted by Stephen Benskin View Post
    But where Dunn and I disagree is that I want the shadow detail on the negative to give me a choice to use it or not, where as Dunn feels that if it isn’t going to be used, “there is no point at all in exposing the negative for the shadows and thus forcing the required highlights far up into the very dense part of the negative characteristic.”
    I see this as an artistic/technical style choice. Do I want to do that work with the camera or the enlarger?

    Personally I'm with Dunn on this.

    For me, I prefer making those decisions at the camera and I can't remember a single shot where I got the main interest right and said to myself, "darn it I wish there was more shadow detail."

    Don't get me wrong, I'm not averse to using the latitude of a film to get a shot, or to make shooting easier/faster, or to avoid underexposure where there is something in the shadows I want but I'm not fishing for more ways to interpret a scene in the darkroom.

    Quote Originally Posted by Stephen Benskin View Post
    I’m not sure why the reference to page 10 as it is just an explanation of the basic concepts of exposure theory. You should check out Appendix B for a more detail explanation.
    Page 15 actually, and I'm working through the appendix.

    I have made an observation about myself with regard to calibration of late.

    As I gain experience and my darkroom skills grow the people at Ilford and Kodak and Fuji and Sekonic all look smarter and smarter.

    Quote Originally Posted by Stephen Benskin View Post
    Don't let the examples of the affects of flare on the film curve fool you. Combining the film curve and the affects of flare on the same curve is more for convenience and can be conceptually misleading as to how flare works. Flare doesn't change the shape of the film curve. It just changes where the exposure will fall on the curve.
    The point I remember Dunn & Wakefield making was essentially that flare has the effect of extending the toe making it tough to run away from.

    The windmill diagrams you provided earlier seem to bear this out too. The +1 diagram shows a more pronounced/longer curve toe in the reproduction quadrant.
    Mark Barendt, Ignacio, CO

    "We do not see things the way they are. We see things the way we are." Anaïs Nin

  6. #16
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    Quote Originally Posted by markbarendt View Post
    The point I remember Dunn & Wakefield making was essentially that flare has the effect of extending the toe making it tough to run away from.

    The windmill diagrams you provided earlier seem to bear this out too. The +1 diagram shows a more pronounced/longer curve toe in the reproduction quadrant.
    This might sound like nitpicking but I believe it presents an important conceptual distinction. Flare doesn't change the film curve. How can it? The illuminance range from the subject striking the film has the lower tones compressed by flare producing the equivalent effect of extending the toe. You can see how that works in Quadrant I, Camera Image / Flare Curve in the examples I attached (which are from a program I wrote).

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    That is a fair distinction.
    Mark Barendt, Ignacio, CO

    "We do not see things the way they are. We see things the way we are." Anaïs Nin

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    So what have I learned so far.

    Still muddling through Dunn & Wakefield's Exposure Manual.

    The following are my impressions and extrapolations. It appears to me that there are three basic ways to peg an exposure to a film curve and by extension to a print; shadow point, main light key tone (highlight), and middle tone pegging.

    -------

    The shadow point method (normally measured via spot metering) appears to be a pure attempt to maximize the quality of the print by using a minimum but safe amount of exposure on film and quite regularly zone system ideas.

    There is debate on how much buffer is important here to maintain a safe/workable exposure. This seems to me mostly a personal EI decision, a matter of calibrating the system to fit our own needs. This may be one reason we get such widely varying views on what EI is best for any given film.

    This method in general protects shadow detail nicely, minimizes grain, keeps shutter speed faster, ..., and when combined with a contrast adjustment to film development or paper grade also protects highlight detail and with experience makes for easy printing.

    On the downside, mid-tones though will typically "fall where they may" because both ends of the scale that surround them are fixed in separate decisions. Unless burning and dodging are also employed, the brightness of faces for example, may vary considerably from what we might prefer.

    For landscape shots this method makes great sense, for portraits and other subjects, not so much, at least for me.

    ------------

    The highlight key tone method picks the main light as the basis for exposure; typically a white card, a gray card, a piece of paper, the palm of a hand, anything that has a known off-set from white is measured in full frontal light. Flat face incident meter readings taken when pointed at the main source light provide essentially the same setting for the camera.

    This is a measurement of incident light without regard to the camera's point of view.

    This method has the advantages of placing subjects very specifically on the curve and of protecting highlight detail for the final print.

    What struck me in Dunn & Wakefield was where this highlight pegging was important, color and movie work.

    And why, because the highlights are what catches our attention first and because of the importance of the human face and with movies the speed at which each frame is viewed, there is simply not enough time to explore the shadows and faces constantly changing brightness is disconcerting.

    I personally made a leap of logic here in relation to a series or tryptic that is meant to be hung/seen together. Continuity becomes quite important.

    Shadow point exposure settings will render faces/scenes at very different brightness levels from frame to frame as the camera moves from full front lighting through random points in the gamut of possibilities to full back lighting. These images may stand very nicely alone but may clash when hung together.

    For this key tone/main light method Dunn & Wakefield essentially postulate that the typical center of interest normally resides at the higher end of the scale so when a key tone is fixed from frame to frame it is typically only the expendable (my word) shadow detail that is lost.

    Since my favorite subjects are people, this method struck a cord as I was reading.

    This key tone method also, for me, has the huge advantage of "set it and forget it" for a given situation. Subjects simply fall normally in relation to the main light, whatever that may be. Those in full sun look like they are in full sun, those in open shade look like they are in open shade, etcetera...

    The very real risk with this method is in the underexposure of something important.

    This underexposure risk is another driver that I can see for people making personal EI choices especially with high latitude negative films for shooting at 1/2 box speed.

    This is also very much the situation toy & disposable camera shooters find themselves in. Essentially toy camera shooters choose the film/camera/process based on the main light we expect and we let everything else just fall where it may.

    This method is easy for camera work but may require some extra effort at the enlarger.

    ---------

    The third method is based on mid-tone pegging. The middle way as Dunn & Wakefield call it.

    It is a compensated key tone method that adds consideration for the view the camera has.

    Readings for this method are normally made; using a flat face incident meter by duplexing, measuring pointed directly at the main source and measuring pointing toward the camera then finding the logarithmic average, or by using a single hemispherical incident meter reading.

    This method gives precedence to the middle tones, "excess" low and high tones are simply left to fall where they may, even if that means they are lost.

    This method of metering caught my attention because a) most of my important subjects are in the middle, and b) the decisions about where I want to place my main subject (compensation) are easy (normal, light, or dark), c) it is how I learned incident metering. I didn't really understand the difference between main light pegging/incident metering and compensated incident metering until studying this book.

    This compensated method has the advantage of placing the main (key tone) subject very specifically and little risk of underexposure.

    It also has, the very minor in my mind, disadvantage/necessity of having to set exposure for every shot and the slight risk of losing detail at both ends in a high contrast situation.

    The extra effort at the camera is generally rewarded at the enlarger, prints from this compensated method should, if we use the technique consistently, require very little adjustment from the "normal" settings we might use. Theoretically we should be able to use standardized enlarger settings and get very predictable results.
    Last edited by markbarendt; 06-04-2011 at 02:13 PM. Click to view previous post history.
    Mark Barendt, Ignacio, CO

    "We do not see things the way they are. We see things the way we are." Anaïs Nin

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    "Readings for this method are normally made; using a flat face incident meter by duplexing, measuring pointed directly at the main source and measuring pointing toward the subject then finding the logarithmic average, or by using a single hemispherical incident meter reading."

    Mark, could you expand on the technique? I think you are saying a flat face measurement of the source illumination is logarithmically averaged with a flat face measurement with the flat face pointed at the subject,
    or,
    a single hemispherical domed measurement with the dome pointed at the subject (opposite of the typical incident measurement with the dome pointed back at the camera). Do I understand you correctly?
    -Fred

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    Quote Originally Posted by Fred Aspen View Post
    "Readings for this method are normally made; using a flat face incident meter by duplexing, measuring pointed directly at the main source and measuring pointing toward the subject then finding the logarithmic average, or by using a single hemispherical incident meter reading."
    Mark, could you expand on the technique? I think you are saying a flat face measurement of the source illumination is logarithmically averaged with a flat face measurement with the flat face pointed at the subject,
    or,
    a single hemispherical domed measurement with the dome pointed at the subject (opposite of the typical incident measurement with the dome pointed back at the camera). Do I understand you correctly?
    Nope.

    Oops, fixed.

    Thanks for the proof read!

    One reading pointed directly to the source light, one directly toward the camera, then logarithmic average.
    Mark Barendt, Ignacio, CO

    "We do not see things the way they are. We see things the way we are." Anaïs Nin

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