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braidedwire
Inspiring
February 15, 2018
Answered

Can i set dpi for line art/vectors when exporting to PDF/X-1a?

  • February 15, 2018
  • 4 replies
  • 2796 views

Ok, this might be confusing. What i came across recently was technical specs for printing by one of printing studios. They require 2400 dpi for line art.

Is there any way to set the exact dpi for line art when exporting indesign project to PDF/X-1a? When setting compression options and image resolution you can choose the right option for color images, grayscale images and monochrome images. The only option i can see during the export is small square to tick that says: compress text and line art.

    This topic has been closed for replies.
    Correct answer braidedwire

    Ok i seem to understand now. Thanks everyone.

    In most cases PPI going as high as 2000 or more refers to bitmap/monochrome images. So i'm guessing the printing studio made a mistake. It clearly says in their specs: 350 dpi for photographs and 2400 dpi for vectors. I thought that since during offset print any vector object will eventually be transferred to real world dimension they were referring to that and that there's a way to force the pdf export to set it.

    BTW just out of curiosity: what does the tick box with compress line art under monochrome image options refer to?

    PDF/X-1a:2001 seems to be the standard in my country and the safest way to go without any surprises.

    4 replies

    B
    braidedwireAuthorCorrect answer
    Inspiring
    February 18, 2018

    Ok i seem to understand now. Thanks everyone.

    In most cases PPI going as high as 2000 or more refers to bitmap/monochrome images. So i'm guessing the printing studio made a mistake. It clearly says in their specs: 350 dpi for photographs and 2400 dpi for vectors. I thought that since during offset print any vector object will eventually be transferred to real world dimension they were referring to that and that there's a way to force the pdf export to set it.

    BTW just out of curiosity: what does the tick box with compress line art under monochrome image options refer to?

    PDF/X-1a:2001 seems to be the standard in my country and the safest way to go without any surprises.

    Derek Cross
    Community Expert
    Derek CrossCommunity Expert
    Community Expert
    February 18, 2018

    There’s no resolution in vector images.

    Re choice of PDF, PDF/X-4 is the favoured choice for commercial litho in most situations.

    rob day
    Community Expert
    rob dayCommunity Expert
    Community Expert
    February 18, 2018

    Last time I checked most major online printers still suggest or require  PDF/X-1a or PDF/X-3—Blurb, Ingram, Moo, Vista. I have yet to find an online printer that requests X4.

    Mike Witherell
    Community Expert
    Mike WitherellCommunity Expert
    Community Expert
    February 15, 2018

    Why this job limitation? Why not a PDFX4?

    Mike Witherell
    rob day
    Community Expert
    rob dayCommunity Expert
    Community Expert
    February 15, 2018

    Is there any way to set the exact dpi for line art when exporting indesign project to PDF/X-1a? When setting compression options and image resolution you can choose the right option for color images, grayscale images and monochrome images.

    Since vectors don't have resolution, I think it's a pretty safe bet they are referring to line art as 1-bit images, (Image>Mode>Bitmap in Photoshop).

    I agree with Uwe that 2400ppi for 1-bit images seems excessive, but if you want to meet the requirement, you would have to make sure any placed 1-bit image (listed as Black and White in the Links panel) has an Effective res of at least 2400. You would also have to change the default Monochrome Compression setting to 2400ppi

    L
    Community Expert
    LaubenderCommunity Expert
    Community Expert
    February 15, 2018

    Hi,

    this might be confusing? This is confusing! And makes no sense at all for vector graphics.
    Unless you want to render vector graphics to pixels with e.g. PhotoShop or by using transparency reduction.

    Line art is a different thing. That could mean images with highest possible contrast. Like 1bit black & white images. You refer to them as monochrome images. For this kind it makes a bit more sense to use an effective resolution of 2400 ppi ( pixels per inch—not dpi that stands for dots per inch and is used for the smallest imaging dot on e.g. a printing plate ). But this value seems to be a bit exaggerated. Effective 1200 ppi would be enough in 99.999 % of all cases, I think.

    Note: You can read out the value of effective ppi for an image from your Links panel in InDesign.

    Important: Your monochrome images have to have this effective resolution before you do an export. You will not upsample anything when you export to PDF. Also do not try to upsample monochrome images with PhotoShop. That will not better quality.

    Regards,
    Uwe

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