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  1. #51

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    my 2 cents worth..go take a workshop at Peter's Valley this summer with Tillman Crane...the best investment in Platinum printing you will ever make!
    best,peter
    website down for maintenance!

  2. #52

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    Loris, I'd like to say sorry first for the questions I'm going to ask. Is "Average tool" in PS? I can't figure out which one it is. Also I don't understand how to use the levels or treshold tools to assess merging. Why not eyedropper to read K values and make comparison?

  3. #53

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    Hi sudek. It's under Filters -> Blur -> Average. Treshold or Levels is easier to see if there's any merging step or to see which one is the darkest step - all at the same time. Do as I say (average each step - paying attention to not include the numbers and to keep the selection area always in a single step, desaturate and put a treshold or levels layer on top of the image) then fiddle a little bit and you'll instantly realize what I'm talking about.

    Regards,
    Loris.

  4. #54

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    Loris,thanks much for the detailed instruction. I scanned the 31 step tablet exposed for 40 minutes and did exactly what you've taught.When the treshold value was 43,I got step 2 and 4 turn to black simultaneously,while at the treshold value of 45,step 3,5,6 turn to black simultaneously.Is it abnormal?

  5. #55

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    Hi Sudek, if there are more than one steps turning black with a single RGB step adjustment, then you can safely assume they're in fact merged steps, "if and only if" there aren't too obviously distinct to your naked eyes - "in natural viewing conditions". Send me (privately) the RAW scan of your step tablet print. (All of the step tablet under OHP material would be better, if you have one.)

    Don't know what's going on when you further increase the blackpoint but if you don't get further merging steps we can assume that you have dmax (a convincing black) under step 5.

    Can you read the number of step 5? (Makes sense only if tthe number also was under OHP.) If you can't read / differentiate the number, it can be considered dmax.

    Regards,
    Loris.

    P.S. BTW, do the assesment always at 100% magnification.
    Last edited by Loris Medici; 03-06-2014 at 09:08 AM. Click to view previous post history. Reason: Added P.S.

  6. #56

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    May I ask if the glass you are using has UV blockers? Could that affect not getting a full black?

  7. #57

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    The problem is due to the fact that the process has self-masking and bronzing / solarization (when grossly overexposed). This two phenomena may lead to not being able to have any merging steps in the step tablet prints. If you're only looking for merging steps to find the dmax, that may lead you to confusion - just like sudek's case. It's simple actually; look not for merging steps (if you have them it's allright), just grossly overexpose and look for the darkest step.

  8. #58

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    Loris,as it seemed somewhat strange to me when I saw step 2 and 4 merged without step 3, I decided to expose for the same time to check if the result is consistent.So I exposed for 35 mins and 40 mins again,but I made new developer solution this time(I use Sodium Citrate as deveoper).And it was so astonishing......so the developer that can be used forever is only KO? It made such a big defference. On the strip exposed for 40 mins,all the steps from 2 to 8 turn into black simultaneously,which means overexposure too much,right? For the 21 step tablet exposed for 35 mins,step 4 turns to black first,followed by step 3 and 5 simultaneously,and then step 2,and later on step 6. Could step 4 be consider Dmax then? According to the calculation method you mensioned above,I should decrease exposure by approximately 2 stops,right? For a 35 minutes exposure that means about 9 minutes?

    P.S. Sorry that I forgot to have all of the step tablet under OHP,covering it on the part without numbers as usual.Should I send all the RAW scans or just the newest scans? Please let me know.Many thanks !!

    Peter,the suggesion is not very realistic to me,thank you though.
    Thomnola,I have switched glasses before and it doesn't seem to be the problem.Thanks a lot!

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  9. #59

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    Hi sudek, can't comment about the developer; there isn't any developer in the process variant I use myself. (It's pop pd...)

    As for the the evaluation; step 8 (on the 31-step tablet / 40:00 minutes test print) is dmax. Since the evaluation was made with the test film + OHP, your actual dmax is at (virtual) step 9. (You count the step tablet as 1/3 stop...) You need step 1 to be dmax, therefore you have to decrease exposure by 9 - 1 = 8 steps. With the 31-step tablet each step is 1/3 stop. Therefore, you have to decrease your exposure by 8 steps = 8 * 1/3 = 2 2/3 stops, that makes: 40 / (2^(2 2/3)) ~= 6,30 ~= 6:18 - practically 6:20. (Remember, to decrease you divide, to increase you multiply...) Seems like a pretty typical exposure time with your exposure unit and OHP...

    Regards,
    Loris.

  10. #60

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    BTW, I don't see any patch beyond 8. Do you have a visual confirmation that step 9 is not dmax?



 

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