Hopefully very simple questions regarding 21 step tablet + paper

Discussion in 'B&W: Film, Paper, Chemistry' started by sun of sand, Aug 17, 2009.

  1. sun of sand

    sun of sand Member

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    Are you exposing to get good deep density on step 5 or 7 in order to stretch tones out into the denser highlight steps -like say 14-21

    Do you expose min time max black through the "rebate" area of the tablet
    if not
    why not

    I see the contact printing of tablet along with negative
    -min time max black-


    I did it both ways on several papers using an amidol developer
    Some papers give less dense blacks letting me see more steps clearly down to step 2/3 etc
    some give an extre step or two in the highlights

    I've read Azo gives "17 steps" or whatever
    I'm seeing more like 12
    actually less steps than other papers -esp in denser blacks but does give more highlights



    Are there a few simple rules as to how to expose properly and judge paper to paper
    Does paper contrast come into play
    Does it come into play using wrong paper grade for negative -as in using grade 4 paper for a very contrasty neg vice versa
    Dmin/Dmax all that

    Or is it OK to expose for random time and just count steps
    Is it JUST steps produced or is there more to it
     
  2. fschifano

    fschifano Member

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    To determine the contrast range of the paper, you'll want to expose it so that you have a few steps at one end of the range completely black and a few steps at the other completely white. The range the difference between the last fully black step and the last step to show the slightest hint of tone compared to paper white. The 21 step tablet is divided into 1/2 stop intervals. Divide the difference by 2 and you have the number of stops, to the nearest 1/2 stop, of range you can get from the paper. There is also a 31 step wedge which gives a little more precision because it divides the range into 1/3 stop intervals.
     
  3. sun of sand

    sun of sand Member

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    You've answered my most needed so thanks

    I'll do that and rework my thoughts
    it's one step forward and 2 back as I needlessly rethink things for some reason once I've learned something new
    Inviting problems
     
  4. dancqu

    dancqu Member

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    At Least Two undifferentiated Blacks

    That many maximum blacks assures you that
    your exposer has produced the very deepest
    of blacks.

    As contrast goes up the number of gray bars
    will decrease; and visa versa. Six or fewer
    any you've contrasty paper, nine and
    more, soft paper. Dan
     
  5. L Gebhardt

    L Gebhardt Subscriber

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    From my own observations as long as you have two steps with the same density at either end you are good. As long as you do this the progression of steps between white and black should be about the same (about because the step wedge has steps and isn't continuous). Generally you would want to keep the exposure time about what you would use in printing to avoid reciprocity issues.

    It sounds like you are not sure why you are doing this test. What are you trying to accomplish?

    I can guess you are comparing Azo to another paper. If so, you can determine relative speed as well as contrast differences between them by exposing/developing them both the same. Then you will know if the new paper is more or less contrasty, and whether is faster/slower. You may need a different paper grade to match you old negatives, or to use different development.
     
  6. sun of sand

    sun of sand Member

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    I think I have the idea down
    not too difficult to understand what its showing you
    just didn't -and probably still don't quite know why- 2 max blacks are needed
    It does just seem like assurance
    But I'll do it that way and maybe at some point it will register why you should do it this way
    Not a big bother

    Contrast range -if thats the correct term- doesn't seem to vary all that much paper to paper
    ?
    The contrast # of the paper corresponds to the range it carries/gives so that info seems given

    I think I'm doing this test just to see for myself
    as well as see if there are noticable gradation differences
    You can tell smoothness of a papers gradation this way, right?
    Visualize a papers toe/shoulder? A developers effect on the paper
    Probably use these little test strips for toners/times experiments

    I just try to pick something new up and run with it for as long as I can
    Photography shares time with many other things and hobbies so I figure this is perhaps more for when I get a bit older/devote even more time to it
     
  7. reellis67

    reellis67 Subscriber

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    That's it exactly. With only one black you cannot be certain that that black is as black as it gets. Having two blacks (or pure whites) ensures that indeed you have reached that end of the range because you can see that there is no difference in the last step and the second to the last step...

    - Randy
     
  8. pgomena

    pgomena Member

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    I try to match the middle step (#11) to an 18% gray card. I visually compare the two through a Zone VI brand viewing filter so as to eliminate color from the equation.

    Peter Gomena
     
  9. dancqu

    dancqu Member

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    For same Grade papers the the step count may be
    expected to be the same. Grade 2 papers should show
    7 or 8 steps. The number on the package though and
    the measured contrast of the paper can disagree.

    I tested four papers, the no longer Arista Classic,
    Kentmere Bromide, Emaks, and Slavich; all glossy
    Grade 2. The first three tested within the 7-8 range
    while the later was clearly a Grade 3, 6 steps.

    The developer was Beer's 1, an Ansco 120 equal.
    Tested in Beer's 7, a higher contrast mix, all papers
    increased in contrast by at least a step. The Slavich
    was an easy Grade 4.

    The change in contrast with change in developer
    was not uniform. Beer's is one contrast control
    developer worth using. Adams' Ansco 130 is
    another. Edwal may still market a contrast
    control developer. Dan