PDFScanner Automation
As it turns out, the cause of the problem was trivial. I simply used the wrong type of (formatted) quotation marks in tell application "PDFScanner". After removing the formatting, everything worked like a charm. This workflow saved me quite some time:



on run {input}

    tell application "PDFScanner"
        repeat with PDF in input
            deskew PDF
            rasterize PDF
            ocr PDF to PDF
        end repeat
    end tell

    return input
end run