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mariog69599891
Known Participant
July 27, 2017
Question

Monchrome images in exported PDF seems like CMYK?

  • July 27, 2017
  • 5 replies
  • 3000 views

It seems like InDesign is reformatting my images when I don't want it to, during PDF export.

I have a simple InDesign document.  I place an 8-bit grayscale TIF file, and a monochrome (B&W) TIF file on a single page.

I export this to a [PDF/X-1a:2001] file, with the following change:

     Output - Color - Color Conversion = No Color Conversion

I then open the exported file with Acrobat DC, and select Tools / Export / Image / TIFF ( Export All Images )

Using Photoshop CC, I open the two TIF files that were exported.

The 8-bit grayscale image is still an 8-bit grayscale image.

However, the monochrome image is now a CMYK image.

Since InDesign's Export feature specifically contains Compression options for Monochrome images, why am I getting a CMYK in exported out of the generated PDF file?

Or most importantly, how can I export my InDesign file so that I'm sure the monochrome image remains monochrome (1-bit B&W) in the PDF it creates?

Thanks in advance

    This topic has been closed for replies.

    5 replies

    rob day
    Community Expert
    rob dayCommunity Expert
    Community Expert
    July 28, 2017

    Or most importantly, how can I export my InDesign file so that I'm sure the monochrome image remains monochrome (1-bit B&W) in the PDF it creates?

    When you place a 1-bit image the monochrome pixels always get assigned a color, which is by default the CMYK [Black] swatch. If you direct select the image you can assign any CMYK, RGB, Lab, or Spot color.

    If you export the page with No Color Conversion Acrobat defines the 1-bit image as an ImageMask filled with whatever Color Space and Color Values you chose over in ID. You can use AcrobatPro's Output Preview>Preview>Object Inspector to see the image info. The Separation preview only tells you how the image's color will output given the chosen Simulation profile, and not anything about the image itself.

    Here the selected 1-bit image is filled with a Pantone Color:

    And here's the same image with a 100|0|100|0 CMYK fill

    Derek Cross
    Community Expert
    Derek CrossCommunity Expert
    Community Expert
    July 28, 2017

    Are you trying to produce a PDF for commercial litho printing? If so, follow Bob's advice.

    By  "monochrome" do you mean bitmap?

    vinny38
    vinny38
    Legend
    July 28, 2017

    +1 for both answers above.

    First, I would definitely check PDF using Acrobat Output Preview.

    Now, is there any chance you applied a color to your bitmap image?

    See example below: I "accidentally" selected the image using direct selection tool and applied "Registration".

    Looks black but obviously if I check my PDF, my black is in fact 100/100/100/100...

    You might want to check that too...

    Danny Whitehead.
    Danny Whitehead.
    Legend
    July 28, 2017

    I'm not sure I'd trust an image exported from Acrobat as evidence of a conversion happening in InDesign's PDF export.

    In Acrobat, bring up Output Preview (Print Production > Output Preview). Hover over the image. Does it show anything on the C, M or Y separations?

      BobLevine
      Community Expert
      BobLevineCommunity Expert
      Community Expert
      July 27, 2017

      Why are you using X/1-a?

      Use X/4 and don’t change anything.

      M
      mariog69599891Author
      Known Participant
      July 28, 2017

      Thanks, but I am using it because the client specified it as a requirement.  I can ask them to change it, but I would only do so after I can confirm that the same thing doesn't happen in that format.

      rob day
      Community Expert
      rob dayCommunity Expert
      Community Expert
      July 28, 2017

      I export this to a [PDF/X-1a:2001] file, with the following change:

           Output - Color - Color Conversion = No Color Conversion....

      Thanks, but I am using it because the client specified it as a requirement.

      If you set the Color Conversion to No Color Conversion the PDF is no longer a PDF/X-1a—the Standard dropdown will change to None. If your client really needs PDF/X-1a you have to set the Color Conversion to CMYK, which is an X-1a requirement.

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