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• • October 31, 2013 at 4:32 am #66042
    Anonymous

    Inactive

    Hi there,

    If I draw a squiggly wiggly line in black, then put a box over it with 20% Black fill and set it to overprint, it doesn’t do a damn thing. All the other colours will overprint fine, but if you add even 1% black to the mix, the overprint stops working. This seems to work the same with any colour – a magenta box will not overprint a magenta line etc.

    Now I get it that I can’t lay down 120% Black onto my paper, but I would have thought that ID would show my 20% black box overprinting the rest of the image, and I could imagine that my line would still be 100 K.

    Is the only option to lay the line down on top of the grey box and overprint it the other way round? My current layer structure would not make that easy.

  • October 31, 2013 at 6:55 am #66043
    David Blatner

    Keymaster

    That’s not how overprint works. You perhaps want multiply. Please see: https://creativepro.com/indesigns-onscreen-untruths-overprinting-or-multiplying-spot-colors.php

  • October 31, 2013 at 8:14 am #66045
    Anonymous

    Inactive

    Thanks David, but I’ve got no spot colours anywhere near this document, just process colours that I want to overprint each other. Not even gradients.

    I’m not suggesting it’s anything but my ignorance to blame, but I can’t get to the bottom of it.

    Try it on my file:
    https://www.dropbox.com/s/umz9sxkak50tgz8/Overprint.indd

  • October 31, 2013 at 8:17 am #66046
    Anonymous

    Inactive

    I should say that I first suggested using using multipy when this problem came up in the studio, but everyone else shouted me down: ‘no, no that’s not how multiply works’. So if it is multiply then that would be doubly great.

  • October 31, 2013 at 8:25 am #66047
    David Blatner

    Keymaster

    The point is that 20% of any color ink on top of 50% of the same color ink (whether spot or process) = 20%, whether you have overprinting on or off. However, setting it to Multiply gives you 70% (more or less).

  • October 31, 2013 at 8:40 am #66048
    Anonymous

    Inactive

    Well it’s gratifying to be right – so the answer is that overprinting will not add up the amount of the same colour underneath to give 70%. Is there a real-world reason why it’s set up like that? Presumably InDesign could interptret the colours that way if it wanted to. Is it to stop people trying to lay down more than 100% of ink in one place?

  • October 31, 2013 at 9:14 am #66050
    David Blatner

    Keymaster

    Yes, you can bask in the glory of being right! :)

    This is the model that PostScript started with back in the 1980s, so that’s the way it has “always” worked. It’s called an “opaque imaging model.” In other words, ink is always considered opaque, and the top-most “ink” wins.

  • October 31, 2013 at 9:17 am #66051
    Anonymous

    Inactive

    Thanks David, I will print out A4s of my smug face and leave them on everyone’s desk

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