Switch to English Language Passer en langue française Omschakelen naar Nederlandse Taal Wechseln Sie zu deutschen Sprache Passa alla lingua italiana
Members: 70,708   Posts: 1,548,568   Online: 1112
      
Page 3 of 8 FirstFirst 12345678 LastLast
Results 21 to 30 of 80
  1. #21

    Join Date
    Dec 2002
    Shooter
    Large Format
    Posts
    6,242
    Mike...very well stated...and I concur completely...But then look at how boring this site would be if we didn't discuss all of the assorted and sundry reasons why we can't get shadow detail in our prints, or why we can't get photographs that exhibit any meaningful tonal range, or what developer is the latest and greatest thing on the block, what paper is the greatest thing since sliced bread, or why Bergger BPF doesn't live up to it's advertised claims, or why we need to burn and dodge to distraction, or why my dog hates me, or my wife won't talk to me any longer. Hell, I would miss all the entertainment if everyone suddenly did the work to find the answers for themselves.

  2. #22

    Join Date
    Mar 2003
    Location
    Greenville, SC
    Shooter
    Large Format
    Posts
    4,813
    Images
    5
    BTW, why is this discussion in the Alternative Photography forum?

    Should it not be under B&W or Exposure?

    Sandy

  3. #23

    Join Date
    Jul 2003
    Location
    Texas
    Shooter
    Multi Format
    Posts
    3,576
    Images
    27
    Quote Originally Posted by sanking
    BTW, why is this discussion in the Alternative Photography forum?

    Should it not be under B&W or Exposure?

    Sandy
    Sandy, may not have been the best place for this...but I ask here since the prints from the negatives are intended for alternative process (Ziatypes,
    plt/pld prints). Sean if you feel it needs to be moved, by all means feel free to move it.

    Mike, what a great response...really never know quite how to respond to the 'reactive' responses to zone system or BTZS questions but feel quite like you that the whole thing is more scientific than not.

    The purpose of the post is two fold - first wanted to understand what all those numbers/abbreviations are that I see discussed here - you know the 1.30 vs 0.12 and CI vs DR vs etc. In other words, my intent is to understand that if I used film X, exposed at Y and develop using developer A then I can expect the negative to look like P...which might be the kind of negative that I would use to print a Ziatype, on the other hand if the intended print is to be made on VC silver paper, I might want to make an adjustment to exposure or development or some other variable.

    If this seems like a lot of trouble to some, and it may be - but I ENJOY THIS PART OF THE PROCESS, just as much. If it's not your thing that is OK, just skip over these types of post. Since I have not found what works for me (or maybe I haven't realized it yet), asking those members here that are willing to share what they know is useful. Will I chose the zone system, BTZS, a combination of the two, or something else? Heck, I don't know yet..what I intend to use is what I find works for me, something that will help me enjoy making photographs and consistently produce the type of negatives that will allow me to print what ever type I choose.

    Thanks to all that have responded, it's the input from everyone that is important...how we choose to use it is up to us.
    Mike C

    Rambles

  4. #24
    smieglitz's Avatar
    Join Date
    Oct 2002
    Location
    Kalamazoo, Michigan, USA
    Shooter
    Large Format
    Posts
    1,864
    Images
    97
    Quote Originally Posted by smieglitz
    Get ye some standard graph paper and scale the vertical axis for density in 0.10 intervals. For the horizontal axis have a spacing interval of one stop (zone) equal to 0.30 density units. From the same graph paper make a ruler scaled identically as the vertical axis. Make an index mark at the edge of origin of the scale and mark it "A". Go to the 0.20 value and make another mark labelled "B" at the edge. At a value of 2.20 make a mark "C". (I'm relating this from memory but the last value is 2.20 IIRC. Check this in the Kodak or Ilford literature or perhaps someone else could confirm?)
    I'm back at work, it is Monday (hooray ???) and I'm able to check these numbers. In the 1987 version of Kodak Professional Black-and-White Films (publication F-5) on page 19 there is a description on how to determine CI. The figures for the CI ruler I quoted last week are in fact correct.

    Now, I'm trying to see where the conversation got sidetracked into one of BTZS rather than CI. As I do, I'm looking at Davis' 1981 version of BTZS and trying to see how CI fits into his system. It would appear to me that Davis is actually defining density range and subject brightness range on the basis of Ilford's G-bar rather than Kodak's CI, and that these two determinants might yield different values for DR and SBR. For example, the graphs on page 35 (under the "Curve Gradient Measurements" heading) would appear to indicate greater SBR and DR when using CI vs G-bar assuming those graphs are scaled the same. Is this correct?

    If so, couldn't I just take all my CI curves and convert them to the simpler G-bar measurement and then determine SBR and DR ala Davis? Then, I'd at least be on the same page as the rest of you perhaps.

    Conversely, I'm wondering if the Kodak system might actually represent the standard way of expressing SBR and DR? Or, has the Ilford/Davis method become the standard amongst photographers? I'm wondering because last year if y'all recall, I was at my wits end trying to determine what various authors meant by the term "density range" in relation to their film exposures needed for alternative process printing in various media.

    Joe

  5. #25

    Join Date
    Apr 2005
    Shooter
    35mm RF
    Posts
    295
    Quote Originally Posted by smieglitz
    I'm back at work, it is Monday (hooray ???) and I'm able to check these numbers. In the 1987 version of Kodak Professional Black-and-White Films (publication F-5) on page 19 there is a description on how to determine CI. The figures for the CI ruler I quoted last week are in fact correct.

    Now, I'm trying to see where the conversation got sidetracked into one of BTZS rather than CI. As I do, I'm looking at Davis' 1981 version of BTZS and trying to see how CI fits into his system. It would appear to me that Davis is actually defining density range and subject brightness range on the basis of Ilford's G-bar rather than Kodak's CI, and that these two determinants might yield different values for DR and SBR. For example, the graphs on page 35 (under the "Curve Gradient Measurements" heading) would appear to indicate greater SBR and DR when using CI vs G-bar assuming those graphs are scaled the same. Is this correct?

    If so, couldn't I just take all my CI curves and convert them to the simpler G-bar measurement and then determine SBR and DR ala Davis? Then, I'd at least be on the same page as the rest of you perhaps.

    Conversely, I'm wondering if the Kodak system might actually represent the standard way of expressing SBR and DR? Or, has the Ilford/Davis method become the standard amongst photographers? I'm wondering because last year if y'all recall, I was at my wits end trying to determine what various authors meant by the term "density range" in relation to their film exposures needed for alternative process printing in various media.

    Joe

    From what I've read on the subject, the two systems (Kodak and Ilford) are not in complete agreement. Kodak claims that negatives developed to the same CI will print on the same grade of paper, not that they will look the same when so printed. The reference points on the Kodak system are closer together. The high density point is lower in the Kodak system.

  6. #26
    smieglitz's Avatar
    Join Date
    Oct 2002
    Location
    Kalamazoo, Michigan, USA
    Shooter
    Large Format
    Posts
    1,864
    Images
    97
    Quote Originally Posted by Ornello Pederzoli II
    ...The reference points on the Kodak system are closer together. The high density point is lower in the Kodak system.
    I think you have that backwards. According to Davis' methods, the Kodak numbers are higher for both DR and SBR (seederivation on the characteristic curve below). The calculations do appear to yield similar numbers for G-bar and CI though.
    Attached Thumbnails Attached Thumbnails CIvsGbar.jpg  

  7. #27
    mikepry's Avatar
    Join Date
    Mar 2003
    Location
    Salem, Wi (By Milwaukee)
    Shooter
    8x10 Format
    Posts
    413
    Images
    40
    "The purpose of the post is two fold - first wanted to understand what all those numbers/abbreviations are that I see discussed here - you know the 1.30 vs 0.12 and CI vs DR vs etc. In other words, my intent is to understand that if I used film X, exposed at Y and develop using developer A then I can expect the negative to look like P...which might be the kind of negative that I would use to print a Ziatype, on the other hand if the intended print is to be made on VC silver paper, I might want to make an adjustment to exposure or development or some other variable."

    That's it....kinda. With the BTZS you START with the paper. Don Miller has written about this in the past and like him, that is what attracted me to the whole process. All the other systems leave the paper more or less out of the whole process. With BTZS you make the exposure and then and only then you decide what printing process you will use. Once decided, you develop your neg for that exposure scale (of the paper) and voila. A negative tailored for your preffered paper for that particular image. I might suggest getting the BTZS Lite along with the BTZS book as it has a nice metering section in it that goes into the incident way of working. Good luck and if you have any questions there are a few of us here familiar with the system that will be more than happy to help out.
    Last edited by mikepry; 04-04-2005 at 05:45 PM. Click to view previous post history.
    "EVERY film and paper is good .......... for something"
    Phil Davis

  8. #28

    Join Date
    Apr 2005
    Shooter
    35mm RF
    Posts
    295
    Quote Originally Posted by smieglitz
    I think you have that backwards. According to Davis' methods, the Kodak numbers are higher for both DR and SBR (seederivation on the characteristic curve below). The calculations do appear to yield similar numbers for G-bar and CI though.
    I don't have my reference materials handy, so you could well be right. They do differ, however, and neither has anything to do with ZS. Both CI and G-bar measure the amount of development it takes to yield a certain slope based on a measured exposure intensity, such as you would have in a control strip.

  9. #29

    Join Date
    Apr 2005
    Shooter
    35mm RF
    Posts
    295
    Quote Originally Posted by mikepry
    "The purpose of the post is two fold - first wanted to understand what all those numbers/abbreviations are that I see discussed here - you know the 1.30 vs 0.12 and CI vs DR vs etc. In other words, my intent is to understand that if I used film X, exposed at Y and develop using developer A then I can expect the negative to look like P...which might be the kind of negative that I would use to print a Ziatype, on the other hand if the intended print is to be made on VC silver paper, I might want to make an adjustment to exposure or development or some other variable."

    That's it....kinda. With the BTZS you START with the paper. Don Miller has written about this in the past and like him, that is what attracted me to the whole process. All the other systems leave the paper more or less out of the whole process. With BTZS you make the exposure and then and only then you decide what printing process you will use. Once decided, you develop your neg for that density range (of the paper) and voila. A negative tailored for your preffered paper for that particular image. I might suggest getting the BTZS Lite along with the BTZS book as it has a nice metering section in it that goes into the incident way of working. Good luck and if you have any questions there are a few of us here familiar with the system that will be more than happy to help out.

    The density range is just that: it has nothing to do with CI or G-Bar.

  10. #30

    Join Date
    Mar 2003
    Location
    Greenville, SC
    Shooter
    Large Format
    Posts
    4,813
    Images
    5
    Quote Originally Posted by smieglitz
    I think you have that backwards. According to Davis' methods, the Kodak numbers are higher for both DR and SBR (seederivation on the characteristic curve below). The calculations do appear to yield similar numbers for G-bar and CI though.
    How did you make the determination that the Kodak numbers are higher for both DR and SBR? When I compared the calculations with real plots for the two methods the DR and SBR were identical. The only practical difference between the two is that the Ilford G-Bar methos suggests a slightly higher EFS than Kodak's CI. This might, depending on the paper curve of the process, result in some differnce in the printing characteristics of the negative. But for all practical purposes the difference between G-Bar and CI is irrevelant.

    BTW, my reference is the 3rd edition of Beyond the Zone System and on page 29 Davis explains how Average Gradient, or G-Bar and CI (Contrast Index) are determined. It is same as one finds in Kodak and Ilford literature.

    Sandy King

Page 3 of 8 FirstFirst 12345678 LastLast


 

APUG PARTNERS EQUALLY FUNDING OUR COMMUNITY:



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