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Thread: New Color Carbon Printing Service business... A new trend ?

  1. #41

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    Re: New Color Carbon Printing Service business... A new trend ?

    If stitching used then a Phase is not necessary, any consumer DSLR can deliver a gigapixel image in that way...

  2. #42
    Drew Wiley
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    Re: New Color Carbon Printing Service business... A new trend ?

    Phase One is quite common in commercial stdio settings, esp w repurposed Sinar P film cameras. But I should keep my mouth shut about stitching, cause going out making sequential sheet film color seps in the field is analogous. And I'm calibrated to do that once I stumble on something suited to a particular pigment set. The problem of long-term bonding in layered carbons is due not only to the inevitable exp/contraction stresses w dissimilar pretty paper, but due to the way certain mineral ingredients or contaminants are charged and affect the cross-linking of gelatin. There's plenty of research about gelatin cross-linking in the medical field, but none about gum arabic, and casein is another story too. Even strongly mechanically-bonded layers like quad Fresson are showing fine cracks. But I don't want to cry wolf without doing my own tests first.

  3. #43
    bob carnie's Avatar
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    Re: New Color Carbon Printing Service business... A new trend ?

    Quote Originally Posted by Drew Wiley View Post
    Phase One is quite common in commercial stdio settings, esp w repurposed Sinar P film cameras. But I should keep my mouth shut about stitching, cause going out making sequential sheet film color seps in the field is analogous. And I'm calibrated to do that once I stumble on something suited to a particular pigment set. The problem of long-term bonding in layered carbons is due not only to the inevitable exp/contraction stresses w dissimilar pretty paper, but due to the way certain mineral ingredients or contaminants are charged and affect the cross-linking of gelatin. There's plenty of research about gelatin cross-linking in the medical field, but none about gum arabic, and casein is another story too. Even strongly mechanically-bonded layers like quad Fresson are showing fine cracks. But I don't want to cry wolf without doing my own tests first.
    I wish I understood what you just said there...

  4. #44
    Drew Wiley
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    Re: New Color Carbon Printing Service business... A new trend ?

    Just another important parameter for zeroing in on an ideal process pigment set, which art stores can't help you with.

  5. #45
    Drew Wiley
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    Re: New Color Carbon Printing Service business... A new trend ?

    If different layers of a pigmented sandwich develop over time different degree of brittleness vs plasticity, of course cracks, blisters, and maybe even delamination are inevitable. Dissimilar electrical properties in the respective color pigments can lead to this. I'm oversimplifying the problem, but hinting why even very permanent pigments have issues - and esp natural oxides, chromium greens (common in older pigment prints), cadmium colorants, etc. Anything metal-family.

  6. #46
    Drew Wiley
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    Re: New Color Carbon Printing Service business... A new trend ?

    You harden gelatin to begin with using a chromium salt and UV energy. Analogously, certain pigments or contaminants are capable of cross-linking gelatin and making it brittle at a much slower rate. Again, not an ideal explanation, but good enough perhaps. What this means is that truly permanent color prints are probably impossible, though it is probably realistic to achieve results much more permanent than inkjet etc. But this is not something accelerated-aging tests are likely to predict well, and are probably poorly studied in photo R&D, which is mainly concerned with organic dyes. Even color Carbro really had pre-press ad use as it's priority.

  7. #47

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    Re: New Color Carbon Printing Service business... A new trend ?

    For color carbon, I'm exploring classic pigments, here in page 8 there is a list, we may want AA or A permanency grade, and we may want transparency for the outer layers, the innermost can be opaque...

    For the brittleness probles, I speculate, perhaps it can be evaluated by hardening the gelatin to the maximum possible in a post treatment, this is sensitizing+UV burning again, or using Formaldehyde as a hardener, or perhaps this would make the gelatin layers stable, as all the gelatin transformations would be made in the finishings of the process.

    Another factor is gelatin bloom grade, it can be as low as 30, perhaps the inner layer can 300 and the outer layer can be 30, to make outer layer elastic...

    Perhaps another way would be using thinner layers...

  8. #48
    bob carnie's Avatar
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    Re: New Color Carbon Printing Service business... A new trend ?

    Drew you bring up some very interesting points... When I look at my prints multiple layers I see how each layer lends with each other, they do NOT appear to be layered like a tissue on top of each other.. This consideration was brought to my attention by Mark Osterman regarding some vintage Carbon Transfer Prints.

    I am quite surprised you brought this up as I am sure this is not normal discussion you and Bigfoot have around the campfire... I look forward to discussing this further with you.. I am impressed.

    Bob

  9. #49
    bob carnie's Avatar
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    Re: New Color Carbon Printing Service business... A new trend ?

    I would love to be able to know that the gum layers are actually bonding with each other and not creating a Layer as you point out... The properties of Gum Arabic are the issue me thinks as the pigment IMO are inert ground stone.

  10. #50
    Drew Wiley
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    Re: New Color Carbon Printing Service business... A new trend ?

    This whole suite of issues has never, to my knowledge, been adequately addressed in photograhic literature per se. Certain "classic " pigments have not only theoretical but observable issues over time in relation to gelatin. That why other categories of pigments must be looked at. Classic pigments are also way behind the curve of actual current R&D in other applications (and I certainly don't mean inkjet!). But "ground stone" is not the answer either. It's generally got diaelectric properties, and I don't have any idea if gum arabic is analogous to gelatin in this respect. But truly permanent ground stone isn't anything you could afford. I know where tiny samples can be obtained at higher cost per ounce than gold. But printers need something industrially available at reasonable cost and absolute batch to batch pure consistency, at least in terms of process colors. Stay tuned (maybe for quite awhile if my tile man gets available and I'm buried under remodeling).

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