Ink Coverage

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This topic contains 10 replies, has 5 voices, and was last updated by  David Morgan 1 week, 3 days ago.

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  • #69518

    Barry Monks
    Member

    I export from InDesign to PDF using the Daily Mail’s AMNO-FLEXO-NEWSPAPER color profile but Acrobat shows excessive ink coverage and I have to convert again in that. What’s going on?

  • #69522

    Opo One
    Member

    I have no knowledge of the colour profile you are mentioning but simply attaching a colour profile is not going to change the ink weight within a file. We adjust ink weight manually before sending ads.

  • #69560

    Barry Monks
    Member

    The correct ink weight appears to be included in the profile when converted in Acrobat. So why can’t InDesign do this?

  • #69561

    David Blatner
    Keymaster

    If you have, for example, a CMYK image that has the incorrect ink coverage (like 400% cmyk ink in one area), and you place that in InDesign, then InDesign will simply pass that CMYK value through into the PDF. That is what the “Convert to Destination (Preserve Numbers)” feature does. If you need to cross-render to a different cmyk (so that all your cmyk images get converted) it is trickier but possible.

    Have you tried the Ink Limit feature in InDesign’s Separations Preview panel?

  • #69609

    Barry Monks
    Member

    Thanks, David. The Ink Limit preview certainly shows the areas of excess. But how do I reduce them within InDesign without re-profiling individual images? It seems to me that overall Ink Coverage is [or should be] part of the profile; If I export with no color conversion then convert in Acrobat then it’s fine.

  • #69610

    Eugene Tyson
    Member

    I’d adjust the ink limit in the problematic individual images in photoshop.

  • #69612

    Barry Monks
    Member

    Thanks,Eugene; but I use the same images in many different publications each of which has it’s own prescribed PDF Job Options and colour profiles. I can’t create and then tailor each image individually for all these. If Acrobat can fix it at a stroke, why can’t InDesign?

  • #69614

    David Blatner
    Keymaster

    Acrobat can do all kinds of things that InDesign cannot. However, in this case: what do you think Acrobat is doing? If there is 350% CMYK coverage in a CMYK image, the only solution you have is to cross-render that to a different CMYK.

    HOWEVER, the real solution here is much simpler: You should be using RGB images in InDesign, not CMYK. Especially if you are planning on using the same image in more than one publication (with different printing needs), RGB is the choice of experts. Then you never have to worry about ink limits because the RGB image is always converted to the proper profile when you create your PDF.

  • #88417

    David Morgan
    Member

    I have experimented with the RGB workflow and I’m finding that Indesign can convert RGB images on the fly to their target CMYK profile and the total of the CMYK values are within the ink weight limit. However, Indesign doesn’t convert placed CMYK images which may be over ink weight to the target profile. Also, and this is quite surprising – Indesign doesn’t reduce the ink weight of its native objects that may have a CMYK value with high ink weight to the target ink weight.

    Lastly, if you have an image placed with a gradient multiplying over the top (to darken an area for example), Indesign will not take into account the ink weight limit when it creates the PDF. So an RGB image with a darkening vignette over the top may result in a CMYK PDF with too high an ink weight.

    Is there any way around this? Otherwise I will have to go back to creating a composite version of that image in Photoshop instead of doing quick image adjustments in Indesign.

    • #88419

      David Blatner
      Keymaster

      David, you are correct that InDesign does not, by default, push CMYK through its color management system to “cross-render” it to the new CMYK. That is on purpose, as most CMYK images are already targeted to a particular output and shouldn’t be messed with. (For example, if I spec 50% cyan in a CMYK image, I don’t want InDesign messing with that… I want it to just pass that 50% through.)

      However, you can force cmyk images to be color managed in a couple of ways. You’d have to tell InDesign to honor its embedded profile in Object > Image Color Settings (or on import). And you can also turn off the “Preserve Numbers” feature when creating your PDF. Again, most people should not have to do this, but it can be helpful in certain circumstances.

      I talk about this in more detail in my Lynda.com course on color management in InDesign.

      By the way, another option might be to export your INDD file as an RGB PDF and then rasterize that by opening it in Photoshop and doing the conversion to CMYK there (if you have to have CMYK). But of course, then you’ll lose vector art.

  • #90077

    David Morgan
    Member

    Hi David, I’ve created an AppleScript for dealing with the situations that I mentioned. We use an assortment of ink weighted CMYK images but we are beginning to use RGB images more and more in our workflow knowing that they are more versatile and can be converted on-the-fly to CMYK when we make the PDFs. The problem I mentioned is that sometimes we use transparency effects in Indesign and often have darkening vignettes over the top of images. We do this to make reversed out text more readable for example.

    As mentioned, these areas can become over ink weight in the final CMYK PDF.

    So anyway, you run this script after you have selected some objects that may cause the above problem. It will copy the selection, create an RGB PSD and save it in the nominated folder. Then it deletes the selected items on the Indesign page and replaces them with the RGB PSD placed as an image. Now the Indesign file is ready to be converted to a CMYK PDF without any risk of those items going over ink weight.

    The script is here: http://www.drscripto.com/?p=668
    I’d love to get feedback on this, there could be other reasons why people might like to convert Indesign objects into Photoshop documents!

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