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Thread: Halftone angle correction in Fiery?

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  1. #1
    GarethO is offline Senior Fiery Forum Contributor GarethO is on a distinguished path
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    Default Halftone angle correction in Fiery?

    I have been noticing issues with print quality and ran a series of tests.

    The issue turned out to be with the halftone pattern applied in the RIP.

    We are running a Canon C6000 Imagepress with an A1100 server.

    The gradation adjustment prints printed straight out of the machine do not have a pattern or any issues, so I know it is not the printer at fault.

    The issue arises when the pattern is applied in the RIP.

    The worst and most obvious issue, is that there is magenta in the yellow channel.

    The lesser, but still serious issue is that the yellow and magenta channels seem to use the same angle. The red and blue channels are also at the same angle.

    (here is a scan of the pattern)

    How do I remove the magenta from the yellow channel, what angles should the RIP be applying and how do I adjust to those angles?
    Last edited by GarethO; 10-01-2014 at 11:08 AM.

  2. #2
    shmegenke is offline Fiery Forum Expert Contributor shmegenke is on a distinguished path
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    If you have the Graphic Arts Package on this system, you should be able go into the color setup via CWS and make the changes via "Halftone Simulation" then select the screen via the driver or job properties in CWS.
    See screenshot below.

    For the Magenta in Yellow channel problem, where did that color chart come from?

    If you send a CMYK job with only 100% yellow do you still see the problem?



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  3. #3
    GarethO is offline Senior Fiery Forum Contributor GarethO is on a distinguished path
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    Thanks for your reply. No we do not have the graphic arts package. It would be nice, but an expense we don't really need. Surely I don't need an add-on to get a correct halftone?


    That pattern was printed via PS test page in Command Workstation. But I get the same results printing CMYK targets sent to the Fiery.

  4. #4
    oxident is offline Fiery Forum Expert Contributor oxident is on a distinguished path
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    Even I'm absolutely not familiar with Canon this looks like a huge problem. 50% yellow should definitely not contain any magenta.

    Maybe there's a problem with the color workflow setting in general or the output profile in specific. Did you make any changes within color setup?
    What kind of output and simulation profile do you use?
    IC-306 v3.01 FS100 Pro / KM C6000, IC-308 v2.1 FS150 Pro / KM C71hc / SD-513, IC-414 / KM C754
    CWS 5.8 SP2, Windows 10 x64

  5. #5
    GarethO is offline Senior Fiery Forum Contributor GarethO is on a distinguished path
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    So I changed the output profile and so far it doesn't make a difference.


    I did manage to get the halftone a bit better by changing the diffusion to high res / high res.


    The issue with the colour (magenta in yellow) seems to be completely at the RIP end. When I print via the driver, turn colourwise off or to none and make acrobat control colour the colours are amazing compared to the RIP output.


    I will look into this further.

  6. #6
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    Please list out your current color settings on the Fiery. The CMYK Simulation profile can also affect this - for example if you are using SWOP coated, it will almost certainly contaminate the yellows, in order to compensate that the yellow toner is much brighter than the yellow ink defined in SWOP coated profile.

    If you are not trying to simulate any other CMYK device, but simply want to take advantage of the full gamut of your printer, try printing with CMYK Simulation: None.

    Regards,
    Greta.

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