Pt/Pd Highlights come paper white

Discussion in 'Hand Coated Wet Prints' started by Minas Stratigos, Jul 19, 2018.

  1. Minas Stratigos

    Minas Stratigos Subscriber

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    Seeking the expert advise of the forum members once more regarding my paper white highlights.

    Original image attatched along with the image of two prints. Top print is 6 mins single coat, Bottom print is double coated (all coats same mix), 8mins 32secs (half stop increase in exposure since the first image obviously needed more exposure). My base exposure is 6 mins, this is the time used to develop my curve.

    The original image highlights were shifted a bit down to RGB 235 before printing the negative on pictorico ultra premium with my curve applied on EpsonP600. FO is 7drops C is 5 drops Pt 2drosm and Pd 10 drops, ammonium citrate developer. What can possibly be the error, its not the first time i get such paper white highlights but i havent managed to fix them, any suggestions?

    Should I just keep my highlights below a certain RGB value not to blow them ( i have no idea what this value can be)

    Your help is always appreciated.

    Minas
     

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    Last edited: Jul 19, 2018
  2. jeffreyg

    jeffreyg Subscriber

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    Minas,

    What you see on your monitor and print with ink is a different medium than pt/pd. My experience is to make a bracketed test print then make a print at what appears to be the best exposure time and then to go from there. When making a negative on Pictorico as opposed to enlarging a negative on to duplicating film I can go back to the computer and make changes if necessary and print a new negative. I have had times when printing several copies in pt/pt to have different results using the same mix and exposure time. I can't explain it. Several years ago I printed a limited edition for another photographer. He couldn't get why doing the exact same thing would give slightly different results. I had made 32 almost identical prints for him to select 14.
    I just accept that's the way it is at least for me despite carefully measuring each drop and even having used pipettes calibrated to 1/10th of a ml.

    http://www.jeffreyglasser.com/
     
  3. nmp

    nmp Member

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    Was the correction curve (or gradient layer) tailored on these particular set of conditions (including chemistry, development, exposure and ink/printer/paper)? It looks like the curve is not steep enough at the highlight end of the range. You should not have to bring down your white point in your highlights in the original image in order to stop them from blowing out if the correction is right (that will make your image look duller.)

    Do you print a step wedge together with the image? If you do, you can see where the problem is. I always incorporate a 21step wedge on the side of all my images. A good way to keep track of the process and tweak the curve if need be.

    :Niranjan.
     
  4. Dan Pavel

    Dan Pavel Member

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    To my eyes even the 8 mins. 32 secs. exposure doesn't have strong enough blacks when compared with the original image, even the outside-image zones look well exposed. And the highlights are a bit burned in comparison with the original, as well. That's a sign that a further increase in the exposure time may be needed. After you get the correct blacks you'll see if a modification of the correction curve is needed or not.
     
  5. OP
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    Minas Stratigos

    Minas Stratigos Subscriber

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    I totally understand that monitor and print are two different things, I guess I need to amend the negative and try again. In the meantime, i am gonna try the Na2 method (chemicals arrive soon) and see the differences there as well. Thanks a lot for your reply :smile:
     
  6. OP
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    Minas Stratigos

    Minas Stratigos Subscriber

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    There is a slight difference in the mix, used a drop less restrainer when made the curve. The curve was made for 6mins exposure (my base time). Also the curve was never used for double coating.
     
  7. OP
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    Minas Stratigos

    Minas Stratigos Subscriber

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    Its an option to expose more i guess, 9m 30s or 12 minutes. My step tests though showed that above 6 mins i do not get significant increase in Dmax
     
  8. nmp

    nmp Member

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    I measured the Dmax (on the peripheral area) in the 2nd print at RGB of around 20 which pretty damn good...considering the scan/photo of the print is representing the levels correctly. Inside the image, the shadows do look slightly lighter as Dan mentioned which could be the problem of the correction curve as well. I would suggest to re-do the curve once you are absolutely certain of the process (you can use the old curve as a start-up curve and combine the two as discussed in a thread on Digital Negatives forum recently.)

    Sometime ago I played around making a flow chart of the a generic alternative process using digital negative for my own understanding so I don't go in circles. It is still work-in-progress. See if it is useful. Comments/questions are welcome.

    :Niranjan.

    Edit: I modified the chart a bit...
     

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    Last edited: Jul 19, 2018
  9. NedL

    NedL Subscriber

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    I'm enjoying looking at this and thinking about it. There are obvious analogues if you produce your negatives in a camera. There are various ways this directed graph can be organized ...
     
  10. nmp

    nmp Member

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    I tried to make the simplest possible chart to get started. There are obviously some nuances/details that can be added or the chart organized differently. Can also be adapted for in-camera negatives. It can also be individually tailored for a particular process like the Pt/Pd.

    Feel free to add/modify/suggest in any way you like...

    :Niranjan.

    Add: May be we should have a new thread if this discussion was going into a greater depth.
     
    Last edited: Jul 19, 2018
  11. OP
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    Minas Stratigos

    Minas Stratigos Subscriber

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    To be honest, this flowchart is very familiar to me as it is pretty much the way i do things... I guess i will wait next week that Na2 arrives and start all over... Learning curve ;-)
     
  12. nmp

    nmp Member

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    Yeah, nothing earth shattering about it...

    By the way, did you get yourself a P600 after all?
     
  13. OP
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    Minas Stratigos

    Minas Stratigos Subscriber

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    I managed to borrow a brand new P600 from a friend :smile:
     
  14. OP
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    Minas Stratigos

    Minas Stratigos Subscriber

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    Considering advise, I had my curve re-done for this specific mix i use now. Not a major change in curve i used before by the way. I made a few more prints adding a step wedge, please see attatched and let me know your thoughts.

    There is an obvious coating issue (I need to get used to my new brush, you can see brushing marks). The step wedge looks ok, there is difference in shade from 0% to 5% and 10%, maybe an issue with the midtones? I do attatch the curve I used as well for your reference.

    Any comment is always welcome

    thanks!
     

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    Last edited: Jul 22, 2018
  15. nmp

    nmp Member

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    A couple of things:

    1) This print looks much "cooler" than your previous ones. Is it real or something happened on digitization?

    2) The step wedge shows all the 5% gradations with no breaks (good.) I made some very rough measurements (not very precise but probably in the ballpark) which suggest that the print might be brighter than the original. The correction curve I arrived at from the step wedge looks like this:

    CC.jpg


    As you can see it is slightly below the theoretical line. Again the measurements are from a low-res jpeg so take it for what it's worth. Of course, this may not represent truly your process as your brushing problem may have contributed to the discrepancy. So your original correction curve may still be right.

    Other than that, your print looks like it has the full range of tones. What is it that you don't like about it?

    :Niranjan.
     
  16. OP
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    Minas Stratigos

    Minas Stratigos Subscriber

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    First i would like to thank you for you time to work on the curve, you have been so helpful in this journey :smile:

    This image looks cooler as it is scanned the previous were photos and obviously the ambient light made them warmer.

    I guess i have to measure as well and see the correction but yes you are right, the image looks quite brighter than the original, in the church the original is much darker.

    Finally, I would like to see deeper/richer blacks and better tone distribution, this is what i am missing, apart from the coating issue i face at the moment
     
  17. jeffreyg

    jeffreyg Subscriber

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    I haven't noticed any mention of humidity. From your location I assume you are working under low humidity conditions. Relative humidity can influence tonality. I live in a high humidity location but my house and darkroom are air conditioned so I pre-humidify my paper by coating with distilled water and waiting until it is almost dry before coating. I find that has helped the coating process. You may be doing that but I didn't see it mentioned.

    http://www.jeffreyglasser.com/
     
  18. OP
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    Minas Stratigos

    Minas Stratigos Subscriber

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    Thanks Jeff, i print in a storage and the humidity was 63% during the print, i dont humidify the paper more than what is in the room.
     
  19. nmp

    nmp Member

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    You are quite welcome. Not much effort on my part.

    Regarding the deeper blacks and the overall print look, the reality is because the greater than 0 of Dmax and less than 255 of Dmin, the print can not match visually what you see on the monitor even if you have perfect linearity with the correction curve. To counter that I usually add some contrast to the original image prior to the correction curve so the final print looks perceptually similar to the image on screen.

    :Niranjan.
     
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