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  • 1.  G7 Calibration for two different color spaces

    Posted 12-23-2023 08:00 PM

    I am using one calibration curve for our regular shop work - GRACoL 2013 is the CRPC - but am needing to do another one for SWOP #3 2013. Reason being is some of the photos are really dark and we are wanting to go to a "lighter" color space to see if that can help. We do color correction for these dark images to help. Seeing how I have not done one for SWOP #3 2013 is there something different that I need to use for a calibration chart? I use the P2P51 for our GRACoL 2013 but I do not believe it will work for the SWOP. Any help on the matter would be nice.

    Jason



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    Jason Wright
    Prepress Manager / G7 Color Professional
    Slate Group
    Lubbock TX
    (800) 794-5594
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  • 2.  RE: G7 Calibration for two different color spaces

    Posted 12-24-2023 08:05 AM
    Jason -

    The P2P51 chart is used for all G7 Curve calibrations, whether CRPC6 (GRACoL 2013) CRPC 5 (SWOP3) or CRPC3(Uncoated) et al. It all comes down to the paper you are using, and ink densities printed thereon. The curve will be different for each paper/ink type, but still may not achieve the results you desire. G7 is not a Color Management system. There are multiple workflow options you could apply, such as GCR, (G7 curves do 0% GCR) to achieve the results you may be looking for.

    I'd love to discuss offline with you. I'm familiar with your shop and its history, being a Lubbock native myself and an ex Copy Craft employee in the 90s. Tell DonD I said Hi.

    Kyle Hargrove

    kyle@...

    512-431-9838

    G7 Expert – Fiery Cutsheet Expert

    ECG - PrintWide ICC – CxF/X-4 Consultant

     

     




    Original Message


  • 3.  RE: G7 Calibration for two different color spaces

    Posted 12-24-2023 05:17 PM

    Jason,

    I'm hearing two separate things here.

    One is that you'd like to profile Grade 3 paper on an open web press. The second is that you have images that are too dark.

    To solve the dark image issue, assuming you want to apply the same curve to all images on all pages. You could build a photoshop action and do them in batches, this approach would only work on raster files like TIFFs or JPGs. If the documents are PDF, you could use something like Callas PDF ToolBox.

    I hope this helps

    Regards

    Alvaro



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    Alvaro Rodriguez
    Color Management Specialist
    Xeikon, a Division of Flint Group
    Elgin IL
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    Original Message


  • 4.  RE: G7 Calibration for two different color spaces

    Posted 12-26-2023 09:25 AM

    Hi Alvaro,

    Thanks you for your response. Guess I should have been more clear in my OP. The images that come through are dark for they are cows and not the best images for print. Plus, they are in a PDF so I am using Acrobat to open the image in Photoshop and run my script on it. I have a few scripts that I use but sometimes there is not enough data (photo with the sun on their backs) to draw out so they are flat. 

    That being said we tried running to SWOP 3 to see if that would help along with our line screen at 175ppi on coated. It seemed to help a little considering the white point coming through the images has increased due to the drop in ppi. We are trying what we can to help but we all know it comes down to the document supplied. 



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    Jason Wright
    Prepress Manager / G7 Color Professional
    Slate Group
    Lubbock TX
    (800) 794-5594
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    Original Message


  • 5.  RE: G7 Calibration for two different color spaces

    Posted 01-16-2024 06:41 AM

    Transitioning from GRACoL 2013 to SWOP #3 2013 for color correction? Opt for a SWOP-specific calibration chart. Refer to SWOP #3 2013 documentation or seek professional advice for accurate results on darker images.



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    Chitra Mishra
    Software Developer
    IBM
    Los Angeles CA
    (859) 675-2585
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    Original Message


  • 6.  RE: G7 Calibration for two different color spaces

    Posted 12-27-2023 02:14 AM

    Hi Jason,

    You need a special "cow" profile; these can be obtained at your local university extension service. Alright, not really. You've received some intelligent comments. What I would say is similar: You have two distinct but overlapping issues: One is the calibration of the press, which is a simple 1D curve adjustment that can lighten and gray-balance results, and the other is that images should, ideally, be optimized for the specific output condition, even though the press is calibrated. If the images are already printing well on coated stock they can be converted, separately in Photoshop, or in situ in a PDF using, yes, Callas PDF Toolbox, or its OEM little brother in the Convert Colors tool Acrobat's preflighting, or an industrial-strength color server such as ColorLogic ZePrA, which handles a huge variety of color management tasks with a high degree of automation (Disclosure: I sell this stuff). The critical point in my view is that a different print condition may involve more than just a darkening of single colors but changes in overprinting behavior as well, and to extract the best possible results it's a good idea to have that calibrated  press/paper/screening combination characterized in the form of an ICC profile (off-the-shelf or custom) and convert your jobs though a device link employing that profile as its destination, in suitable software. This way you can safely convert vector objects as well.



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    Mike Strickler
    MSP Graphic Services
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    Original Message