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I am converting pdf's to other formats and i would like to have the end output pdf/jpg/png etc to have the same effect as when one selects the simulate overprinting option in the adobe acrobat reader.

I went through a similar question at Ghostscript - don't show objects with overprint set

The device pdfwrite doesn't work with the option -dSimulateOverprint=true.

EDIT 2 Sample input file can be found here

The input pdf file has layers and I am trying to convert it to a pdf for the client who will be able to see the underlying layer, without clicking on simluateoverprint option in tools menu of a adobe pdf pro application.

A newbie trying to get some help.

Binoy Cherian
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1 Answers1

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Fundamentally, as I said over on the question you posted before, you can't. There are two reasons;

Firstly (fore rendering devices) overprint is only defined for CMYK space, so the only way to get overprinted output is to use a CMYK device. You can simulate the effects of spot colours being overprinted by setting -dSimulateOverprint (which is in nay case the default value). You cannot represent overprint at all on any device which is not basically CMYK.

For high level output devices, such as pdfwrite, it doesn't (normally) render anything. So you can't 'simulate overprinting' on these devices. Either the output has overprint operations, or it does not. Whether the output does is solely dependent on whether the input does. If the input has overprint, then the output will have overprint. Its up to the rendering engine which consumes the PDF file how to render overprinted content.

KenS
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  • Thank you for your input. The input pdf which I am using for the test has colors, cmyk along with pantone 279C, white, cutter. I was hoping to get a final pdf which is a combination of all these. If I don't select the overprint option, I get a blue layer on top of my orginal image. I don't want to select overprint each time to get to see the real content. Could you suggest something to meet this requirement. – Binoy Cherian Sep 14 '18 at 10:04
  • I don't understnad your requirement. You already have a PDF file whose content is 'a combination of all of these'. If you don't like the way overprint works, then don;t use it. If you want a preview where there is no overprint, render to an RGB image, all the spots and so on will be rendered in their alternate space, then converted to RGB and rendered. Since the device is RGB, there will be no overpinting. But it seems likely I don't understand what it is you want. In the absence of an example to look at, its hard to make suggestions. Whatever it is, though, pdfwrite won't do it. – KenS Sep 14 '18 at 11:02
  • Thank you for your comment. There is a blue layer on top of the main image in my pdf which kinda vanishes when I click on simulate overprinting on a adobe acrobat reader. And so when I convert the pdf to every other format, I get this blue layer instead of the image underneath. The team that created this pdf said the blue layer helps in printing. I know it's all vague and apologies, the doc is not shareable. – Binoy Cherian Sep 14 '18 at 14:11
  • I don't see blue layer when I use tiffsep to generate different tiffs. I could attach some images if you would like. – Binoy Cherian Sep 14 '18 at 15:12
  • Images don't help, I can't experiment with a picture. Fundamentally what you describe is the way that this is specified to work. Ghostscript doesn't have a means to 'emulate' overprinting in a non-CMYK device, and even if it did, like Acrobat you would have to turn that feature on. The pdfwrite device goes to great lengths to maintain as much of the content of the input as it can, so it cannot and will not every have this feature. Your best bet is to use Ghostscritp to render to a CMYK image and look at that, or use Acrobat. – KenS Sep 15 '18 at 07:57
  • I took some time to get the file, it is available at https://ufile.io/6m8ow – Binoy Cherian Oct 09 '18 at 14:09
  • So I still don't understand what you hope to achieve. Your PDF file has overprinted content. If you open that in a PDF viewer it will generally be creating RGB (for screen display) so it won't apply the overprinting with the result that much of the content is obscured. Actobat has a means to simulate CMYK overprinting on RGB, so you can preview it. Ghostscript can do this too, when rendering to CMYK output, so you could render to a CMYK TIFF file and open that for a preview. The pdfwrite device will preserve overprinting, so it will produce an identical appearing PDF file. – KenS Oct 10 '18 at 15:29
  • Actually, your problem is worse than that, your file involves /Separation colour space which are overprinted, and that will only work with Ghostscript when you produce separations. If you render to the tiffsep device it will produce a composite file in addition to all the separations, and that will be a true representation of the overprinted output. That is your only solution with Ghostscript though. – KenS Oct 10 '18 at 15:36
  • Then do you think, the composite tiff -> pdf sounds good in my case. In the end the clients need to get a pdf with data similar to the composite tiff – Binoy Cherian Oct 10 '18 at 15:44
  • Well you could use ImageMagick to convert the composite TIFF into a PDF file, then delete all the files. – KenS Oct 10 '18 at 18:06