PDF Duplex Merger

This tool helps you efficiently digitize double-sided documents using a simple scanner with an automatic feeder without a duplex unit. It merges your scanned front and back pages into a correctly ordered PDF.

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Scanning Workflow

1. Scan All Front Sides (Odd Pages)

   • Place the entire stack in your scanner’s automatic feeder with page 1 facing up.
   • Scan all front sides. The resulting PDF will contain pages in this order: 1, 3, 5, 7, ...

2. Flip the Stack and Scan All Back Sides (Even Pages)

   • Flip the stack so that the back sides are now facing up, keeping the page order.
   • Scan again. The resulting PDF will contain the back sides in reverse order: last page, next-to-last, ..., 2.

3. Result

   • You will have two PDFs:
     • Fronts: All odd pages, starting with page 1.
     • Backs: All even pages, starting with the last page and ending with page 2.

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How to Use

1. Add Two PDF Files

   • Drag and drop both PDFs (fronts and backs) into the program window
     or
     use the "Add Files" button to select them.

2. Start Merging

   • Double-click the file in the list that contains the front pages.
     The tool will automatically detect which file contains the back pages.

3. Result

   • The two PDFs will be merged so that the pages are correctly interleaved:
     1, 2, 3, 4, 5, 6, ...

4. Output Filename and Location

   • The merged PDF will be named Fronts_Backs.pdf (using your actual filenames)
     and saved in the same folder as the front pages file.

🛠 Requirements

• Python 3
• PyPDF2
• tkinterdnd2 (for drag & drop support)
• Tkinter (included with standard Python installations)

Install dependencies

pip install -r requirements.txt