How do I export single pages to duplicated spreads as a pdf

Hi @jdg789456123 I was thinking along the same lines as @Luke Jennings3. I've written a quick script that does (I think) what you describe. See if it helps.

- Mark

/**
 * @file Double Place Active Document.js
 *
 * Imports the active document into a new document,
 * placing each page twice per spread.
 * 
 * Note: does not alter the active Document.
 *
 * @author m1b
 * @version 2025-04-16
 * @discussion https://community.adobe.com/t5/indesign-discussions/how-do-i-export-single-pages-to-duplicated-spreads-as-a-pdf/m-p/15269931
 */
function main() {

    if (0 === app.documents.length)
        return alert('Please open a document and try again.');

    var doc = app.activeDocument;

    if (!doc.saved)
        return alert('Please save document and try again.');

    // set up a new doc, based on the active one
    var doubleDoc = app.open(doc.fullName, true, OpenOptions.OPEN_COPY);

    doubleDoc.documentPreferences.properties = {
        allowPageShuffle: false,
        createPrimaryTextFrame: false,
        preserveLayoutWhenShuffling: true,
        facingPages: false,
    };

    // with none of the original pages
    doubleDoc.spreads.add(LocationOptions.AT_END, doubleDoc, { appliedMaster: null });
    doubleDoc.pages.itemByRange(0, -2).remove();

    // and only one layer
    while (doubleDoc.layers.length > 1)
        doubleDoc.layers[-1].remove();

    var layer = doubleDoc.layers[0];
    layer.visible = true;
    layer.locked = false;

    app.importedPageAttributes.importedPageCrop = ImportedPageCropOptions.CROP_CONTENT;

    var placingEachPage = true,
        docSpreadCounter = 0,
        imageSpreadCounter = 0,
        firstImagePageNumber = 1,
        spread,
        firstPage,
        secondPage,
        placedItem;

    while (placingEachPage) {

        app.importedPageAttributes.pageNumber = imageSpreadCounter + 1; // 1-based

        spread = doubleDoc.spreads[-1];
        firstPage = spread.pages[0];
        placedItem = firstPage.place(/* file */doc.fullName, /*placePoint*/undefined, /*destinationLayer*/layer, /*showingOptions*/false, /*autoflowing*/false, {})[0];

        if (
            imageSpreadCounter > 0
            && placedItem.pdfAttributes.pageNumber == firstImagePageNumber
        ) {
            // no more pages to import, so it gave us the first one again
            // which we don't want, so clean up and we're finished placing pages
            placedItem.parent.remove();
            spread.remove();
            break;
        };

        docSpreadCounter++;
        imageSpreadCounter++;

        // add a second page to the spread, and duplicate the first page to it
        spread.allowPageShuffle = false;
        secondPage = doubleDoc.pages.add(LocationOptions.AT_END, spread, { appliedMaster: null });
        placedItem.duplicate(secondPage);

        // get ready for the next spread
        doubleDoc.spreads.add({ appliedMaster: null });

    }

};
app.doScript(main, ScriptLanguage.JAVASCRIPT, undefined, UndoModes.ENTIRE_SCRIPT, 'Double Place Document');

Edit 2025-04-16: fixed bug didn't handle facing pages correctly.

@jdg789456123

Can't check your file, but i think I understand what you need.

If you want to do it in the InDesign, you'll need: 

1) export your original document as single page  PDFs, 

2) create 17x11 INDD document, 

3) use ImageCatalog script twice - with an extra shift / left margin for the 2nd run to place 2nd copy of the pages.

I am not sure if this can be done natively. Maybe a script would be needed for this. Something similiar done using an Acrobat script is discussed in the post linked below

https://community.adobe.com/t5/acrobat-discussions/script-to-duplicate-certain-pdf-page-between-each-pages/td-p/14824618

-Manan