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How to calculate M-Score respresenting Uniformity within a Press Sheet?

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  • 1.  How to calculate M-Score respresenting Uniformity within a Press Sheet?

    Posted 08-03-2020 04:18 AM

    The M-score came from Idealliance digital press certification.
    But I do not make it clear how to calculate it? Anyone know more details about it? Thanks in advance.

    "The press sheets described above will be measured using colorimetry and the measuring geometry and configuration as stipulated in this document. The M-Score procedure is used as a pass/fail criterion for this test.

    The M-Score is based on ISO 15311. The M-Score computes a single value, scaled from 0 (poor reproduction) to 100 (perfect reproduction), which correlates well with the perception of print variations for a uniform tinted test form printed on digital press systems. The following procedure is used to calculate the M-Score."

     



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    Mike Yao
    BrandQ Expert
    G7 Expert
    Fujifilm (China)
    Shenzhen
    86-15012558115
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  • 2.  RE: How to calculate M-Score respresenting Uniformity within a Press Sheet?

    Posted 08-04-2020 09:42 AM
    Hi Mike
    If you are working with digital printing I recommend this document.
    Cover

    The PDF-file can be downloaded from the Fogra homepage free of charge. The contractual partner shall be entitled to pass the work on to its business partners in unaltered form and to point the download website www.fogra.org.


    Even there you will find teschart that will be useful to you

    KG…

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    Fernando Fernandez Lugo G7 Expert
    Fernando Fernandez Consulting Services
    Guadalajara
    +523331302863
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  • 3.  RE: How to calculate M-Score respresenting Uniformity within a Press Sheet?

    Posted 08-04-2020 09:46 AM
    Edited by Jinkai Qian 08-04-2020 09:56 AM
    Hello Mike,

    I don't have the ISO 15311 at the moment but the description of calculating the M-score from your screenshots provided a pretty good idea for the computation.
    My understanding is you need to average the CIE L*a*b* value across the columns ( 46 columns) and rows (64 rows), then sum up the dE for the columns and the rows and multiply by 10 to get dE_short_line and dE_long_line respectively. Next is to get the dE_short&long by averaging the above dE_short_line and dE_long_line to get ready for the final M score computation.

    Feel free to reach out to my email for any discussion.

    Best Regards,
    Jinkai Qian

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    Jinkai Qian
    Techkon USA
    Danvers
    (978) 777-1854
    jqian@...
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  • 4.  RE: How to calculate M-Score respresenting Uniformity within a Press Sheet?
    Best Answer

    Posted 08-04-2020 10:09 AM

    Hi Mike –

     

    I have developed an Excel spreadsheet to calculate M score along with a visualization chart of the readings showing areas where dE00 varies the most. This was part of a total G7 Digital Press Report to calculate all the metrics of the qualification criteria.

    I'd be happy to share it with you with the caveat that you may need to adjust the links slightly, depending on the CGATS measurement file header format.

     

     

    Kyle Hargrove
    Product Manager | Digital Printing Technologies

    IDEAlliance G7 Expert

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    CGS ORIS | AMERICAS

    Email kyle.hargrove@... Web www.cgsusa.com

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  • 5.  RE: How to calculate M-Score respresenting Uniformity within a Press Sheet?

    Posted 08-05-2020 08:13 AM
    Hi Kyle,
    Thanks a lot ! The excel looks wonderful ! It is exactly what I need!



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    Leilei Yao BrandQ Exp
    G7 Expert
    Fujifilm (China) Investment Co., LTD
    Shenzhen
    86-15012558115
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  • 6.  RE: How to calculate M-Score respresenting Uniformity within a Press Sheet?

    Posted 08-05-2020 09:16 AM
    Nice work Kyle.

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    Cory Sawatzki
    VP of Purchasing
    AlphaGraphics, Inc.
    Denver
    (469) 879-5546
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