Duplicate and copy specific pages in a PDF document offline.
If you copy a 10MB photograph on your hard drive, it takes up 20MB of space. But PDFs are designed as relational databases. If you duplicate a 10MB page in a PDF, the final file size will barely increase at all. Why?
Every page in a PDF is defined by an Object ID (for example, 4 0 R).
When this tool "duplicates" a page, it does not physically copy the heavy graphics, vectors, or text streams embedded inside that page object. Instead, it simply takes the Object ID of the original page and inserts it a second time into the document's central /Kids array (which lists the page order).
When a PDF viewer opens the file, it reads the array of instructions: "Show Object 4, then show Object 5, then show Object 4 again."
The viewer renders the exact same binary data twice on screen without needing to store that data twice on disk. This makes duplicating pages inside a PDF a nearly instantaneous, zero-cost operation.
If you duplicate a 5MB page inside a PDF, how much will the overall file size increase?
