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  • ink pigment

    Hi

    Somebody, know Why?
    Magenta is out to the range
    Is it a problem relative of Ink ? or Is it a problem the machine?

    Thank you

  • #2
    Originally posted by xmoles View Post
    Hi

    Somebody, know Why?
    Magenta is out to the range
    Is it a problem relative of Ink ? or Is it a problem the machine?

    Thank you
    What printing process? Offset? What halftone screening? (Compared to your target)
    Last edited by gordo; 06-22-2018, 08:54 AM.

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    • #3
      It appears the substrate you are using is more blue than the reference. It shifts your entire gamut in the -b* direction. Don't know if that's the definite answer for your question, though.

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      • #4
        Hi

        Yes, offset printing process, round dot to 175 lpi
        I have doubts about the substrate,,, maybe

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        • #5
          Looks like your solid magenta is out of target. Seems like there's problem with pigment

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          • #6
            I agree with Schnitzel, the paper white (PW) of your sample seems to be too bluish compared to the reference/standard paper white. Our eyes see the paper is really "white"... but translated to instruments they see blue... Check for the value of delta b* of the paper white. Probably the paper has a high amount of OBAs. Remember that paper is the 5th color my friend!

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            • #7
              Originally posted by Ferran View Post
              I agree with Schnitzel, the paper white (PW) of your sample seems to be too bluish compared to the reference/standard paper white. Our eyes see the paper is really "white"... but translated to instruments they see blue... Check for the value of delta b* of the paper white. Probably the paper has a high amount of OBAs. Remember that paper is the 5th color my friend!
              Do OBA's affect solid's as well? Not for the eye of course, but for measuring device? Look again at the data. Cyan and Yellow Solids are not affected. Only Magenta.
              Last edited by cementary; 06-25-2018, 11:07 AM.

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              • #8
                Originally posted by cementary View Post

                Do OBA's affect solid's as well?
                Yes (but not as much) because the inks are relatively transparent (so they can filter light). The screened areas are more affected since there is more uninked paper. (http://the-print-guide.blogspot.com/...agents-in.html)

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                • #9
                  Originally posted by gordo View Post

                  Yes (but not as much) because the inks are relatively transparent (so they can filter light
                  IMHO, most pigments filter uv part. Except some yellow and transparent (ie "no color")
                  I don't question screened areas. That's why industry came to m1 after all

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                  • #10
                    Like Ferran already remarked: your substrate is to bluish compared to the reference. What reference are you using in the chart? Fogra 39?
                    The new ISO standards (ISO12647-2:2013) are taking the trend to use more optical brighteners into account.
                    So if you are using Fogra51 instead of Fogra39, maybe your will be within specs.
                    But still: when you look to the chart, the 100% magenta color is also to bluish, and at this point magenta is covering the paper so the whiteners have less influence at this point. Possibly your solid magenta is also out of specs... This is almost certainly caused by the pigments in your magenta ink, but maybe you can get within specs by choosing another density. Print a color blend from density 1.0 up to 1.7 (from left to right), and measure all solid magenta densities from left to right until you find a magenta spot (measured in Lab color with an i1Pro for example) that is within range (DeltaE<3) from the target (ISO) magenta Lab color.
                    Don't forget to use black backing.
                    Attached Files

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                    • #11
                      ps. About my poste above (I can't add text):
                      This is the press sheet I use for finding the right density. Where the triangles are narrow, the densities are the highest.

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