InDesign Server Scripting Question: Export Black and White PDF

[Alexandria5E9E]

I am adding color images to an idml file like this:

var docArray = [
  "idml template name",
];

for (x = 0; x < docArray.length; x++) {

  // Open IDML file
  var idmlDocName = "folderName/" + docArray[x] + ".idml";
  try {
    var idmlDoc = app.open(idmlDocName);

  // Modify idml
    var myStories = idmlDoc.stories.everyItem().getElements();
  for (i = 0; i < myStories.length; i++) {
    var myTextFrames = myStories[i].textContainers;
    for (j = 0; j < myTextFrames.length; j++) {

      switch(myTextFrames[j].contents) {
        case "FLS_IMG_TAG;1;1;1":
          myTextFrames[j].place(File("folderName/imgName.jpg"));
          myTextFrames[j].fit(FitOptions.CONTENT_TO_FRAME);
          myTextFrames[j].fit(FitOptions.PROPORTIONALLY);
          myTextFrames[j].fit(FitOptions.CENTER_CONTENT);
          break;
      }
    }
  }

  //Export the document as PDF (fill in a valid file path).
  var pdfDocName = "folderName/" + docArray[x] + " - edited.pdf";
  idmlDoc.exportFile(ExportFormat.pdfType, new File(pdfDocName));

  } catch (error) {
    alert(error + " docName: " + docArray[x]);
  }
}

The images are in color and I want to programatically change them to black and white. Is it possible to do that before or after exporting to PDF?

[Laubender]

You could do one thing:

Via bridgeTalk you could open PhotoShop, open the images in PhotoShop, convert and save it to grayscale.

Update the links in your InDesign document. Then export to PDF.

See documentation in the JavaScript Tools Guide CC.pdf, chapter:

5 Interapplication Communication with Scripts

Pages 166 to 193

Especially pages 179 pp

BridgeTalk Class

BridgeTalk message object

Also see into the DOM documentation for PhotoShop.

Regards,
Uwe Laubender

( ACP )

[Alexandria5E9E]

BridgeTalk is a new concept for me. I'll take a look but I think changing the colorspace looks pretty straight forward.

[Alexandria5E9E]

I found the answer after a little more digging.

  app.pdfExportPreferences.pdfColorSpace = PDFColorSpace.CMYK;
    if (pdfDocName.indexOf("BW") !== -1) { //true
    app.pdfExportPreferences.pdfColorSpace = PDFColorSpace.GRAY;
  }

[Laubender]

But wouldn't that convert all elements on a page to grayscale?

( Thought, you would like to do this for placed images only. )

FWIW: You can get better quality if you include PhotoShop into the workflow.

But this will require image contents evaluation like statistics on individual gradation and so forth.

PhotoShop is able to do that.

If you want convert all pages you could also look into an Acrobat Pro DC workflow.

Regards,
Uwe Laubender

( ACP )

[Laubender]

"I found the answer after a little more digging."

That's by far not the whole picture. You also need a decent color management setting for your document, a loaded *.csf file where all the conversion paramenters are stored before you open your IDML files.

Regards,
Uwe Laubender

( ACP )

[rob day]

If you are trying to convert the entire PDF to grayscale, you would have to also include a gray destination profile. The PDFColorSpace property refers to the Output>Color Conversion setting in the UI, which is a bit confusing. So this exports a PDF/X-4 with a conversion to Dot Gain 20%

var f = new Folder(Folder.desktop)
var doc = app.documents.item(0);
var thePath = f + "/" +  doc.name + ".pdf";
var preset=app.pdfExportPresets.itemByName("[PDF/X-4:2008]");

//PDF Export Prefs
with(app.pdfExportPreferences){
    pageRange = PageRange.ALL_PAGES;
    pdfColorSpace = PDFColorSpace.GRAY;
    pdfDestinationProfile = "Dot Gain 20%";
    pdfXProfile:"Dot Gain 20%";
}

doc.exportFile(ExportFormat.pdfType, File(thePath));