Switch to English Language Passer en langue française Omschakelen naar Nederlandse Taal Wechseln Sie zu deutschen Sprache Passa alla lingua italiana
Members: 71,928   Posts: 1,585,192   Online: 725
      
Page 11 of 19 FirstFirst ... 567891011121314151617 ... LastLast
Results 101 to 110 of 182
  1. #101
    markbarendt's Avatar
    Join Date
    May 2008
    Location
    Beaverton, OR, USA
    Shooter
    Multi Format
    Posts
    5,796
    Blog Entries
    3
    Images
    19
    Quote Originally Posted by DREW WILEY View Post
    The direction the curves goes depends on which side of the Greenwich Meridian you're own, so whether
    it's more convenient to look left or right. The shape of the curve is straightest near the equator, but is
    curved by the coreolis force the closer you get to the poles.
    I haven't factored in our friends in the Southern Hemisphere either.
    Mark Barendt, Beaverton, OR

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

  2. #102
    Photo Engineer's Avatar
    Join Date
    Apr 2005
    Location
    Rochester, NY
    Shooter
    Multi Format
    Posts
    23,553
    Images
    65
    Quote Originally Posted by Stephen Benskin View Post
    Ron, the Haist curve examples are only film curves and not tone reproduction diagrams. Different uses. And yes the print goes from left to right in decreasing density or at least did. I believe the convention is changing in stand a lone paper curves, and the convention is a left to right increasing density for the paper curve when used in tone reproduction diagrams.
    Stephen, the "Y" axis shows the range of density from the negative curve that you will get in a print. Given that the print will reproduce values from 0.2 to 2.2 on average, this instantly shows you the print image range and the negative range it covers.

    If the silver criterion is adhered to, and it is in B&W, then you do not need 4 part diagrams to interpret what Haist shows. And, remember that there are several pages of tutorial along with those diagrams. Along with that, you have Mees. He too shows only the negative curve, and superimposed on that is the range of acceptable and unacceptable prints. They both show that you can derive everything in B&W from the simple film curve.

    PE

  3. #103
    Stephen Benskin's Avatar
    Join Date
    Jan 2005
    Location
    Los Angeles
    Shooter
    4x5 Format
    Posts
    1,222
    Quote Originally Posted by Photo Engineer View Post
    Stephen, the "Y" axis shows the range of density from the negative curve that you will get in a print. Given that the print will reproduce values from 0.2 to 2.2 on average, this instantly shows you the print image range and the negative range it covers.

    If the silver criterion is adhered to, and it is in B&W, then you do not need 4 part diagrams to interpret what Haist shows. And, remember that there are several pages of tutorial along with those diagrams. Along with that, you have Mees. He too shows only the negative curve, and superimposed on that is the range of acceptable and unacceptable prints. They both show that you can derive everything in B&W from the simple film curve.
    Tone Reproduction diagrams were used by Jones. Hell Jones invented it and Jones is God. They are also in Theory of the Photographic Process and every book that discusses tone reproduction theory, and they do provide information a single curve doesn't. They also show the full process at a glance. I've seen so much confusion because people only use film curves and because you can't derived everything from just the film curve. Tone Reproduction diagrams show how everything interacts. Ron, it's just a tool which I find incredibly useful.
    Last edited by Stephen Benskin; 04-19-2013 at 02:43 PM. Click to view previous post history.

  4. #104

    Join Date
    Feb 2010
    Location
    Montreal, Canada
    Shooter
    Multi Format
    Posts
    5,104
    Quote Originally Posted by Photo Engineer View Post
    Stephen, the "Y" axis shows the range of density from the negative curve that you will get in a print. Given that the print will reproduce values from 0.2 to 2.2 on average, this instantly shows you the print image range and the negative range it covers.

    If the silver criterion is adhered to, and it is in B&W, then you do not need 4 part diagrams to interpret what Haist shows. And, remember that there are several pages of tutorial along with those diagrams. Along with that, you have Mees. He too shows only the negative curve, and superimposed on that is the range of acceptable and unacceptable prints. They both show that you can derive everything in B&W from the simple film curve.

    PE
    But the Jones and Dorst diagrams show the transitions from scene luminances to negative densities to print densities. That's the whole point. Just because you meter something doesn't mean it will end up being where you think it will.

    Using just a film curve, you have to make quite a few assumptions which may or may not be right. You also have to more or less assume the paper curve is a mirror image of the film curve, which of course it is not. The diagrams show the system from end to end.

    The transitions are the parts people don't get. They compartmentalize exposure, the negative and the print. They spend time tuning their negative processing without thinking enough about how the paper "sees" the negative. I've seen a lot of evidence of this on APUG.

    For example how many people calibrating their negatives to a paper grade even really realize the local contrast implications of the negative shoulder coinciding with the paper toe (and vice versa)?

  5. #105
    Photo Engineer's Avatar
    Join Date
    Apr 2005
    Location
    Rochester, NY
    Shooter
    Multi Format
    Posts
    23,553
    Images
    65
    Then what I suggest is just too complex for you.

    But, if you have metered an object, you can then read its density on the negative and from the curve set as done by Haist, you can then get the range of densities that the print will have. If you then place that on the curve by Mees, you will see if your print falls within the range of acceptable prints.

    By using varying contrasts, you can take the print curves and see in what way the entire gamut can be adjusted, and you can pick out the proper contrast.

    After a few tries with this, it becomes almost second nature.

    But, for color, I use the 4 part diagrams for my color work. We called them Silver Criterion curves and go by a paper written by W. T. Hanson in the 30s or 40s. No one ever mentioned Jones or Dorst in our work. So, they either came after the Hanson paper, or they were copied by Kodak in the very early years.

    PE

  6. #106
    Stephen Benskin's Avatar
    Join Date
    Jan 2005
    Location
    Los Angeles
    Shooter
    4x5 Format
    Posts
    1,222
    In The Theory of the Photographic Process 3rd edition, Chapter 22 The Theory of Tone Reproduction, top of page 466, "A tone-reproduction diagram of the type developed by L.A. Jones is a convenient means of showing the relation between the objective tone reproduction curve and the characteristic curves for the photographic materials and equipment used to make the photograph. The paper reference for this is L.A. Jones, J. Franklin Inst. 190,39 (1920).

    Now for that reproduction curve with fine detail superimposed.

    Click image for larger version. 

Name:	Fine detail reproduction curve.jpg 
Views:	13 
Size:	439.4 KB 
ID:	67480

    And a fun diagram showing the effects of changes of paper grades.

    Click image for larger version. 

Name:	Grade Changes.jpg 
Views:	10 
Size:	727.8 KB 
ID:	67481

    And an insane diagram showing the effects of masking.

    Click image for larger version. 

Name:	Unsharp Mask.jpg 
Views:	16 
Size:	914.1 KB 
ID:	67483

  7. #107

    Join Date
    Feb 2010
    Location
    Montreal, Canada
    Shooter
    Multi Format
    Posts
    5,104
    I like that masking diagram.

  8. #108
    Stephen Benskin's Avatar
    Join Date
    Jan 2005
    Location
    Los Angeles
    Shooter
    4x5 Format
    Posts
    1,222
    Applied Photographic Theory by Paul Kowaliski, Chapter 1 Tone Reproduction,

    "The graphical method invented by Jones, already mentioned in several instances, allows a determination of objective and subjective tone reproduction with full consideration of all the empirical relationships between the various parameters described in the preceding chapters (see also p. 3). These relationships depend so much on the influence of different factors that they cannot be expressed analytically, and apparently minor variations in curve shape correspond in the visual evaluation of the final result to quite important differences. Thanks to Jones' simple graphical method it is possible to obtain complete information on the reproduction of tones by a given system. The basic idea underlying this method is to employ the axis of ordinates of a first graph—in which for instance the luminance scale of the original subject has been transformed by the first parameter of the system, the flare light in the camera—as the axis of abscissas of a second graph which gives the transformation due to a second parameter, for instance the sensitometric characteristic of the negative, etc. Taking into account all operations intervening during the process of photographic reproduction, it is possible to construct the tone reproduction curve with precision, so that not only any given system can be evaluated, but also all parameters, and especially the exposure and processing conditions can be chosen for optimum results."

    In The Encyclopedia of Photography, under the entry "Jones Diagram" it says "See Quadrant Diagram."

    The Manual of Photography: Photographic and Digital Imaging, Chapter 15 Sensitometry, page 237, "It has been found valuable to employ graphical methods to study the problems of tone reproduction, one very useful method being the so-called quadrant diagram originated by L.A. Jones. This enables practical problems in tone reproduction to be studied, and solved scientifically."

    Controls in Black and White Photography, 2nd Edition, Chapter 8, The Relationship Between Original Scene and Final Print,page 241, "The first method depicting these transitions is that introduced by Jones in 1920."

    Exposure Manual
    , 4th Edition, J.F Dunn & G.L. Wakefield, Chapter 1, page 20,

    "For the benefit of those interested in pursuing this mater further, however, it should be mentioned that the "windmill" diagrams illustrates an extremely valuable aid to the study of tone reproduction problems generally, and this method has been used by a number of workers for some years in order to obtain a much fuller story of tone reproduction than can be included here - for example to determine the influence of such important additional factors as the subjective viewing of the original scene and the final print under various lighting conditions, the effect of flare in the camera, the influence of illuminant size, film graininess and flare in the enlarger. All this was very adequately summarized by Loyd Jones in the Sixteenth Hurter & Driffield Memorial Lecture to the Royal Photographic Society in 1949, entitled Recent Developments in the Theory and Practice of Tone Reproduction, and readers who wish to study this interesting branch of the subject can hardly do better than refer to this accordingly."

    From a paper by Jones in The Photographic Journal based on his Hurter & Driffield Memorial lecture. "Since that time the contributions of the theory and practice of tone reproduction have been many and varied. Much of this material has been summarized and analyzed by Dr Mees in his book The Theory of the Photographic Process, published in 1942. It is the intention of the present paper to pick up the story at approximately the point where it was left by Dr Mees in that publication... The general over-all theory of photographic tone reproduction has been discussed many times before and it is felt, therefore, that a greater contribution to this problem can be made only by dealing with it in a rather detailed fashion. To do this, the solution of an elaborated tone reproduction diagram, illustrated by a quantitative example, will be carried through."

    An example from the paper.

    Click image for larger version. 

Name:	Jones Objective Diagram.jpg 
Views:	11 
Size:	614.3 KB 
ID:	67484
    Last edited by Stephen Benskin; 04-19-2013 at 10:01 PM. Click to view previous post history.

  9. #109
    Photo Engineer's Avatar
    Join Date
    Apr 2005
    Location
    Rochester, NY
    Shooter
    Multi Format
    Posts
    23,553
    Images
    65
    Excellent series of references Stephen. The problem is that they are overly complex for the average person. We used them under a different name, but then we were trying to design a new film or paper. The APUG members are just trying to get a good picture, and that is why Mess and Haist simplified things. That is all I am trying to get across.

    Those charts, attributed to Jones, were frequent items in my daily work during product design. In fact, we went into far more detail than any of these ever did. And, there were lots of internal papers on this related to silver tone and dye sets. Silver tone affects the linearity of the curve that translates a film image into a print image and the results are quite interesting but again beyond the scope of this forum.

    PE

  10. #110
    Stephen Benskin's Avatar
    Join Date
    Jan 2005
    Location
    Los Angeles
    Shooter
    4x5 Format
    Posts
    1,222
    Quote Originally Posted by Photo Engineer View Post
    Excellent series of references Stephen. The problem is that they are overly complex for the average person. We used them under a different name, but then we were trying to design a new film or paper. The APUG members are just trying to get a good picture, and that is why Mess and Haist simplified things. That is all I am trying to get across.

    Those charts, attributed to Jones, were frequent items in my daily work during product design. In fact, we went into far more detail than any of these ever did. And, there were lots of internal papers on this related to silver tone and dye sets. Silver tone affects the linearity of the curve that translates a film image into a print image and the results are quite interesting but again beyond the scope of this forum.
    Generally I use the tone reproduction diagrams for illustration purposes. A picture is worth a thousand words kind of thing. If you read through all those quotes, you should have noticed that many emphasized the problem solving ability of the diagrams. A film curve just shows the response of the film to exposure and development. The tone reproduction diagram puts the curves to work. I don't expect people to plot their own. It's impractical to plot them by hand. That's a big advantage of my program. It does all the tedious work for me. Unfortunately the program isn't ready for prime time, buy I believe BTZS has a program that does a two quad curve if anyone wants to pursue it.

    You might feel it's too technical. That's your opinion, but who are you to make this judgement for others? I believe I shouldn't have to tailor the information the lowest common denominator. Some people might be interested in what I have to say. I don't know about you, but I go for extremely long periods of time where nothing catches my interest on these forums. There are a number of experienced photographers here who probably also crave something beyond the endless string of mundane photo 101 type questions. For those less advanced, I like to think I'm potentially exposing them to new concepts. Isn't it better to encourage a challenging discourse.



 

APUG PARTNERS EQUALLY FUNDING OUR COMMUNITY:



Contact Us  |  Support Us!  |  Advertise  |  Site Terms  |  Archive  —   Search  |  Mobile Device Access  |  RSS  |  Facebook  |  Linkedin