How can I add watermarks to PDF documents in batch on my win 11?

The following are two efficient batch processing methods for adding watermark to PDF to meet the needs of custom position, transparency and size:

Method 1: Use professional tool PDF-XChnge Editor (Windows platform)
Core functions:

• Support batch adding watermark to PDF, and can import hundreds of documents at the same time;
• Customize watermark type (image/text), adjust transparency (0-100%), rotation angle, and level (cover or under the content);

Precisely set the position (center/fill/specify coordinates), and support automatic scaling of watermarks according to page size.

Operation process:
Open the software → click "Batch Processing" → Add files → Select the "Add Watermark" function → Configure parameters and execute with one click.

Method 2: Use Ghostfcript command line tool (cross-platform)
Technical advantages:

• Free and open source, batch adding watermark to PDF through code, suitable for technical users;
• Scripts can be written to loop through all PDFs in a folder, and the watermark position is precisely controlled by coordinates;
• Adjusting transparency requires image processing (such as reducing the opacity of logo images in advance).

Sample command:

ghostsffcript -dBATCH -dNOPAUSE -sDEVICE=pdfwrite -sWatermarkFile=logo.png -o output.pdf input.pdf

The watermark position needs to be set with parameters (such as -dWatermarkX=100 -dWatermarkY=200).

Both solutions can achieve efficient batch processing. The former is suitable for visual operations, and the latter is suitable for automation needs. You can quickly complete the add watermark to PDF task by selecting according to the scenario.