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Thread: Digital Negatives with PDN+Piezography K7

  1. #21

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    Re: Digital Negatives with PDN+Piezography K7

    Ok this is how I see it.

    What Mr Cone is doing is offering an inkset that works well for digital negatives, that has a lot of value. He also offers curves to go with the inkset. So if you use his curves as he suggests with PDN you will have a nice smooth grain free print with a minimal photoshop adjustment curve. Essentially what he offers is an optimal colour to be used in the PDN system.

    You cant tamper with his QTR curve directly, you must linearise it for your process using PDN.

    However a lot of people have got used to directly using QTR at some level or other and would prefer to use QTR directly to linearise their process. Theoretically this should produce the cleanest print. This is the approach favoured by Ron Reeder. Sandy King has a QTR curve available for the 3800 and the Carbon transfer process.

    There is apparently no gain in resolution in using Cone ink over Epson ink, using QTR. QTR out resolves the Epson driver, so there is a gain to be had using PDN with QTR. The Cone ink set is probably less grainy. If one wants to bypass PDN and use the Cone ink set one must start from scratch in constructing your curve. Apparently someone is producing a spreadsheet that can do this for you.

    If Mr Cone made his curves human readable we would have a starting point and one could quickly make a curve that would work without a photoshop adjustment curve, it may not be up to Mr Cones high standards but may meet your requirements. Making his curves directly alterable cuts Mr Nelsons snout out of the trough but one must still purchase Mr Cones excelent inkset. Of course nobody is stopping you starting from scratch and making your own curve using the Cone inkset.

    I may have the wrong end of the stick somewhere or betrayed my ignorance, so shoot it down if you like. I have no axe to grind. From my point of view following Mr Cones system requires the purchase of QTR, PDN and software, Mr Cones inkset, Photoshop in addition to an Epson printer. The direct approach requires purchase of QTR, an Epson printer and possibly the Cone inkset.

    Time v Money

  2. #22
    Clay
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    Re: Digital Negatives with PDN+Piezography K7

    Yes, it does, and thank you for your in-depth reply.

    I am a long time user of QTR for all my digital negatives (and positives for polymer gravure), so I am pretty familiar with the guts of the system. To paraphrase your reply, what you are supplying to the user is a set of .quad files, which are basically a set of input/output transform functions for each ink in the printer. I have used those files at one time or another for making nice graphs of the curves and so forth.

    So anyway, if I understand the key distinction of your curves, it is in the fact that you have your own proprietary method of smoothly adjusting the transitions between inks as various output densities are called for by the input file's target ink percentage. You have longer 'tails' on the curves to ensure that at every input gray percent, you are in effect using a set of inks that maximizes the total ink coverage in the dither pattern for that particular density.

    And if you know the exposure scale of your print process, all you need to do is choose the desired density range from one of your profiles, and then print with it. And tweaking of the image file is done to mimic any desired process specific 'looks' that you may be trying to achieve.

    Is that more or less right?

    Anyway, this looks very interesting. Thanks again for hopping in here and volunteering the information.
    Quote Originally Posted by joncone@cone-editions.com View Post
    Hi Clay,

    Does that answer your question?

    Jon

  3. #23

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    Re: Digital Negatives with PDN+Piezography K7

    Yes! That is the theory (that QTR linearized to the print will produce the cleanest print).

    That is also the applecart that I may appear to be upsetting, but I am not. I am simply enhancing it by offering a level of QTR linearization that is not achievable in a make-it-from-scratch approach or alter-someone-elses-starting-point approach using the QTR Curve Tool.

    There are some observations that you made that are incorrect, but they are irrelevant because you were trying to compare a new approach to an older approach.

    Jon

    Quote Originally Posted by mdm View Post
    Ok this is how I see it.

    What Mr Cone is doing is offering an inkset that works well for digital negatives, that has a lot of value. He also offers curves to go with the inkset. So if you use his curves as he suggests with PDN you will have a nice smooth grain free print with a minimal photoshop adjustment curve. Essentially what he offers is an optimal colour to be used in the PDN system.

    You cant tamper with his QTR curve directly, you must linearise it for your process using PDN.

    However a lot of people have got used to directly using QTR at some level or other and would prefer to use QTR directly to linearise their process. Theoretically this should produce the cleanest print. This is the approach favoured by Ron Reeder. Sandy King has a QTR curve available for the 3800 and the Carbon transfer process.

    There is apparently no gain in resolution in using Cone ink over Epson ink, using QTR. QTR out resolves the Epson driver, so there is a gain to be had using PDN with QTR. The Cone ink set is probably less grainy. If one wants to bypass PDN and use the Cone ink set one must start from scratch in constructing your curve. Apparently someone is producing a spreadsheet that can do this for you.

    If Mr Cone made his curves human readable we would have a starting point and one could quickly make a curve that would work without a photoshop adjustment curve, it may not be up to Mr Cones high standards but may meet your requirements. Making his curves directly alterable cuts Mr Nelsons snout out of the trough but one must still purchase Mr Cones excelent inkset. Of course nobody is stopping you starting from scratch and making your own curve using the Cone inkset.

    I may have the wrong end of the stick somewhere or betrayed my ignorance, so shoot it down if you like. I have no axe to grind. From my point of view following Mr Cones system requires the purchase of QTR, PDN and software, Mr Cones inkset, Photoshop in addition to an Epson printer. The direct approach requires purchase of QTR, an Epson printer and possibly the Cone inkset.

    Time v Money

  4. #24

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    Re: Digital Negatives with PDN+Piezography K7

    Clay,

    I think you hit it!

    My problem in communicating is that I have been designing QTR curves on a regular basis for so many years that I probably suppose everyone else understands the basics of it and then can understand what it is new that I bring to it. Further, because I am using these new things as a matter of fact, I forget that they are not in the more universal understanding of QTR or the understanding of its practice.

    There really is so much you can do with QTR if you are willing to take control of the curves design outside of it. Because QTR reads .quad files which are easily created in spreadsheets - one can actually take an abstract approach to digital printmaking with it - or produce a mathematically controlled curve making approach utilizing macros - or whatever one can imagine.

    Jon



    Quote Originally Posted by clay harmon View Post
    Yes, it does, and thank you for your in-depth reply.

    I am a long time user of QTR for all my digital negatives (and positives for polymer gravure), so I am pretty familiar with the guts of the system. To paraphrase your reply, what you are supplying to the user is a set of .quad files, which are basically a set of input/output transform functions for each ink in the printer. I have used those files at one time or another for making nice graphs of the curves and so forth.

    So anyway, if I understand the key distinction of your curves, it is in the fact that you have your own proprietary method of smoothly adjusting the transitions between inks as various output densities are called for by the input file's target ink percentage. You have longer 'tails' on the curves to ensure that at every input gray percent, you are in effect using a set of inks that maximizes the total ink coverage in the dither pattern for that particular density.

    And if you know the exposure scale of your print process, all you need to do is choose the desired density range from one of your profiles, and then print with it. And tweaking of the image file is done to mimic any desired process specific 'looks' that you may be trying to achieve.

    Is that more or less right?

    Anyway, this looks very interesting. Thanks again for hopping in here and volunteering the information.

  5. #25

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    Re: Digital Negatives with PDN+Piezography K7

    I believe it will be a considerable service to the community if Jon makes available QTR profiles to users of K7 Piezograpahy that will print with perfect linearity on Pictorico at the needed DR for the process, whether that be log 1.5, 2.5 or 3.0. In my own case, were he to be able to provide me with a profile that would print with linearity on Pictorico with my Epson 7600 with a DR of around 2.5 I would be almost home free since the carbon transfer process that I use is quite linear. So very little tweaking with .acv curve would be necessary, or as I understand it, Jon would offer a service to linearize the profile for a specific process?

    In any event, the theoretical advantages of an all gray ink set for making digital negatives are obvious. Whether or not there is a real improvement with alternative processes over a color ink set depends, of course, on the process. As Jon points out in an earlier message, the paper itself of some processes hides the dithering.

    Sandy
    For discussion and information about carbon transfer please visit the carbon group at groups.io
    [url]https://groups.io/g/carbon

  6. #26

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    Re: Digital Negatives with PDN+Piezography K7

    Quote Originally Posted by sanking View Post
    I believe it will be a considerable service to the community if Jon makes available QTR profiles to users of K7 Piezograpahy that will print with perfect linearity on Pictorico at the needed DR for the process, whether that be log 1.5, 2.5 or 3.0. In my own case, were he to be able to provide me with a profile that would print with linearity on Pictorico with my Epson 7600 with a DR of around 2.5 I would be almost home free since the carbon transfer process that I use is quite linear. So very little tweaking with .acv curve would be necessary, or as I understand it, Jon would offer a service to linearize the profile for a specific process?

    In any event, the theoretical advantages of an all gray ink set for making digital negatives are obvious. Whether or not there is a real improvement with alternative processes over a color ink set depends, of course, on the process. As Jon points out in an earlier message, the paper itself of some processes hides the dithering.

    Sandy

    Sandy,

    I owe you that curve, and said I would make it if we found a working 7600 in our studio with enough good heads to afford me up to five shades of gray. We have!

    I am going to go out and work with Don Messec in a few weeks to linearize his photopolymer process. I am interested in working again with gravure and bought an Amergraph. But, I have not used any non-toxic approaches to gravure. I used to print for photographers using the copper aquatint photogravure method (Talbot's dust grain gravure). I want to start that back up again but need to be non-toxic. I especially want to print my own work again in etching ink.

    Are you by chance in or near Santa Fe? I am wondering if the system I make for Don could be applicable to you. I do not know if these new photopolymer plates have sensitivity similar to dicromate sensitized carbon tissue.

    You need a DR of 2.50. Typically though I recall that carbon tissue when sensitized required about 0.28 to 0.34 for base density. Would 0.10 to 2.60 work as well for you as 0.30 to 2.80? It would have an effect on what shades of ink I choose to make your curve.

    I can linearize film remotely if the film for some reason were not linear and you print it with the film master curve that I provide. But if the alt process goes through film, you need a process to linearize the alt proc such as PDN or yourself and PS. Because my profiler works in 16bit and a gray curve has 256 points rather than the 16 of QTR - the measurement from the media being profiled must be the media. If I make a curve for film, I need to receive measurements from the film or I introduce mathematical anomalies - as would be the case with your taking them off the alt proc.

    If I visited you on site and built a master curve for your process from scratch - I would build it measuring the results off your final print and design it in response to your process rather than the film. It is much more difficult. Then I would make a master curve that I could re-linearize remotely. But the gain is not worth the work when you use PDN and my film based curve - or as you say, making a small adjustment in PS to a curve. I documented a specific process curve making project here: Getting very long in the shadow.

    The film and PDN is just as effective with my profiler and easier in the end for us both.

    But, the gain in being able to meet you, working together to see if there is some synergy we can produce to make the process better, and your ending up with a master curve that we could relinearize for you through email might be worth it. You could then send me 256 measurements or 101 (which is as low as I go) depending upon the resolution of fidelity that your process requires. You may even be able to use CreateICC to linearize it.

    Food for thought....

    Jon

  7. #27

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    Re: Digital Negatives with PDN+Piezography K7

    Jon,

    Carbon transfer and photopolymer don't have a lot in common. More in common with copper plate gravure in that both start with carbon tissue, but in fact relatively little in common since we need a negative for carbon and a positive for photogravure.

    Carbon is actually quite flexible in terms of the density range that can be used, but for various reasons I have settled on a DR of about 2.5. I don't know the source for your comment that a base density of 0.28 to .34 is needed for carbon tissue but it is not true in my case when working with digital negatives. A base density of 0.10 works just fine for me so all I need is a a profile that will print a linear step wedge on Pictorico with a base density of the substrate and a DR of 2.5, so if the base density of the substrate is 0.10 I would need a Dmax of 2.6.

    I am quite familiar with PDN and would have no problem creating a curve with Curve Calculator II to correct for any lack of linearity caused by the carbon process. But again, this would be a very small correction since carbon is one of the most linear of all photographic processes.

    So whenever you have the time just send me a profile for the 7600 that will print on Pictorico with a DR of about 2.5, and we can go from there based on the actual results I get with the profile. Do remember that I would like the profile made for the regular Shade 2 and Shade 4 inks, not the diluted inks.


    Sandy
    For discussion and information about carbon transfer please visit the carbon group at groups.io
    [url]https://groups.io/g/carbon

  8. #28

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    Re: Digital Negatives with PDN+Piezography K7

    May I ask you for a step wedge printed with your log 3 DR curve on something smaller than 8x10 so that I can see how it prints with my carbon tissue. I am happy to cover some minimal shipping and pictorico etc. I do not like your method of truncating the tones in a file to control how it prints but since carbon transfer should cope with the full density range, perhaps only minor adjustments are required.

    I use a 2880 which is supported with your curves and could consider purchasing your inkset if the results prove satisfactory and your shipping charges are reasonable. I have some pictures I want to print very badly and would like to do so with the best negative possible and my QTR curve is grainier than I would like. I am also very short of time. Dont print much colour anyway.

    Of course I am willing to share the results.

  9. #29

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    Re: Digital Negatives with PDN+Piezography K7

    David,

    I am going to make a QTR carbon tissue curve for Sandy King that will contain a 2.5DR and work with my regular shades (if I can). This is what you need without truncating data from your image file.

    At 2.5DR I (most likely) can eliminate 100% black ink from the recipe and bring it to the quality of the curves I have now which completely eliminates dither dots. Grain is what you may be referring to dither dots. If Sandy OKs the curve, I will mail you a test strip. If there is interest, I will then create it for the newer printers.

    Jon


    Quote Originally Posted by mdm View Post
    May I ask you for a step wedge printed with your log 3 DR curve on something smaller than 8x10 so that I can see how it prints with my carbon tissue. I am happy to cover some minimal shipping and pictorico etc. I do not like your method of truncating the tones in a file to control how it prints but since carbon transfer should cope with the full density range, perhaps only minor adjustments are required.

    I use a 2880 which is supported with your curves and could consider purchasing your inkset if the results prove satisfactory and your shipping charges are reasonable. I have some pictures I want to print very badly and would like to do so with the best negative possible and my QTR curve is grainier than I would like. I am also very short of time. Dont print much colour anyway.

    Of course I am willing to share the results.

  10. #30

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    Re: Digital Negatives with PDN+Piezography K7

    I am ok with the log 3 curve. Sandys curves print with 3% Ammonium Dichromate. I can use a different % Dichromate to print with different contrast. I dont want anything special, all I want to see is if I can make the standard curve work. If I cant then I will truncate it as you recommend.
    Having thought about it a little, the PDN 101 step tablet would be ideal, it has those little squares at the corners which are useful for understanding the relief you can achieve as well as the resolution. I have converted mine to a tiff. I can then compare my curve with yours. Mine is dodgy so there is no risk for you there. It is important to me that I pay something reasonable for it, I am not after free stuff.

    You are free to decline too, but it seems that it would be a good idea for you to offer wedges printed with your curve and inkset, just as you offer sample prints.

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