Pictorico workflow to RA4

Discussion in 'Digital Negatives' started by peoplemerge, Mar 3, 2018.

  1. peoplemerge

    peoplemerge Subscriber

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    I've been thrilled with the results I've had printing medium and large format negatives to RA4, and I've had fun printing transparencies with RA-RT. The results I've seen from my Epson R2000 I find acceptable and I think I can sell but lack the excitement and magic I get from Ektar or Portra in medium / large format printed to Endura Premiere. As can be expected, I've encountered a few scenarios specific to the art reproduction subjects I'm working on where I need make a print that I can sell but to do so, I want to manipulate the image in photoshop. I can produce digital images of an usable size by drum scanning on a newly-acquired Howtek 4500 or photo stitching digital camera files, so I'm going to experiment with the photrio contact print to RA4.

    Before you say forget it, let me state I'm theoretically aware of the vast research Kodak and friends have applied in chemistry and color science in going simply from negative print film to color paper, so I can experience the magic with a minimum of fuss. I know I'm missing out on the system solution. I did various searches on this forum and the interwebs and haven't seen much come up.

    As an alternative, I considered the local lab who can produce a lightjet print, and though I'm skeptical it can do better than a pictorico workflow given it's an 8-bit process (good color is a big deal to artists and collectors), I plan to include it in a head-to-head test. In terms of cost per page, it's roughly 10x more due to their labor costs, and drive time / store hours makes it no more convenient than printing RA4 in trays at home.

    Armed with an grasp of the essentials of BTZS, I've experimented in the past with pictorico and color separation alt processes. What I not sure about are the mechanics of how to actually produce the negative, so I thought I'd ask for feedback here on how I think it can work.

    Setup
    =====
    1. Create a step wedge chart with 21 levels of black, magenta, yellow, and cyan.
    2. Print on pictorico
    3. Measure steps on densitometer (for reference, might be optional)
    4. Load empty frame in enlarger to use as orange mask, load Endura Premiere, place the pictorico negative on endura, cover with glass, use starting points from past printing sessions on the respective paper (around 0/55/45 Endura, 0/45/58 Crystal Archive) print RA4. Adjust time and colors until I get a print with a full range of values.
    5. Measure steps on densitometer
    6. Create transfer function in photoshop specific to that paper, taking note of the time and color balance.

    Production Workflow
    ================
    1. Load the image in photoshop and adjust until it looks good on screen. It's important to me that this process be relatively true to screen at this stage, so I can make all of the adjustments here, and don't need to make adjustments later, for example, once the image is inverted to negative in photoshop, or in the enlarger
    2. Create new layer to invert the image
    3. Create a new layer to apply the transfer function
    4. Print to pictorico
    5. Print to RA4. I'm sure it'll come out perfect the first time. Yeah right.

    Questions:

    Anyone done this?

    Any major factors I've left out?

    Would you expect the dynamic range of the R2000 is sufficient for a fine print? Setup step 4 should determine if this process simply won't work.

    You may notice I don't provide much detail in setup step #6 - I could use some help here.

    Should I try to include the orange mask in the step tablet calculation instead of ? Any starting points of people may have used?

    Dan Burkholder's "Making Digital Negatives for Contact Printing" describes using a transfer function, but I don't see that in Photoshop CC. Links appreciated.

    In production step 3, I'm not super clear on how the reversal should be done. Simple Invert Image? Again, links appreciated.
     
  2. Bob Carnie

    Bob Carnie Subscriber

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    I would be interested in seeing your results... the pictorico I use is for separation negatives for tri colour, I am a bit fuzzy on how RA4 dye coupler paper is going to react.... post your first print.
     
  3. nmp

    nmp Member

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    Never done this nor thought of ever doing it, so take it for what it's worth.

    A couple of points.

    Regarding the transfer function, Dan Burkholder's method (or others' similar ones) is primarily aimed to calibrate a single monochromatic print like the platinum/palladium or salt print etc. with the use of a correction curve. (Each process has unique correction curve based on individual circumstances of paper, chemistry, printer, inks, negative material etc. So as such there is no universal transfer function that you will find in Photoshop CC.) You are dealing with a multi-color process so a single transfer function probably wouldn't work. The closest thing in the alternative process world would be the tricolor gum process or the carbon process. In those cases, one has to do separations for each color, apply appropriate correction curves and make a digital negative for each color and then contact-print them individually, successively building up a stack of pigmented layers in registration to each other. In essence, your proposed method does something similar but the printing is done in one shot. You can likewise do a similar sequence except that the exposures are done one by one on the paper using registration pins followed by a single wet-process. Alternatively, you can make a single negative incorporating all colors applying one combined transfer curve and contact-print in one exposure. Either way, I am not at all clear how transfer functions created from pure colors would apply to combined values. In other words, by calibrating the axes of the gamut, how do the points within the gamut replicate the input image values.

    There may be an another way. Consider your whole process after the final digital image is made (including inversion, flipping, R2000 printing on transparency, contact exposure on Endura, RA-4 wet processing, drying) to be a black box or virtual inkjet printer. Then you can do an equivalent icc profile for this whole process using any number of hardware/software combos like the Colormunki Photo, for example. You have to start with making a digital negative of the appropriate profile target without any color management (very important!) by use of something like Adobe Color Printing Utility (ACPU.) Do Endura/RA-4 process with this negative using whatever final baseline process is arrived at. Use the outcome to build the icc profile. Then you would go back to your image and print the final negative the same way as before except with addition of the icc profile as a first step (using Convert to Profile function.) If you do not want to get into doing this yourself, you can also make use of one of those custom profile makers who can make an icc profile for you. They normally work with inkjet prints so I am not sure how they will deal with a wet-processed print.

    Good luck!

    :Niranjan.
     
    Last edited: Mar 5, 2018
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