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PDF添加水印

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最大文件大小：100MB

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    Free PDF Watermark Tool Online

    Professional PDF watermark tool supporting text and image watermarks with advanced customization options. Add watermarks to PDF documents instantly using WebAssembly local processing - no file uploads required, completely free and secure.

    Key Features

    Dual Watermark Types

    • Text Watermarks: Custom text with font size (12-120px), color selection, and rotation control (-180° to 180°)
    • Image Watermarks: Upload JPG/PNG logos or stamps (max 5MB), scalable from 10%-200%
    • Layout Options: Center placement for logos, tiled patterns for security marking

    Customization Controls

    • Opacity Settings: Adjustable transparency from 10%-100%
    • Page Management: Apply to all pages or specific ranges ("1-3,5,7-10")
    • Real-time Preview: Instant watermark effect display
    • Color Picker: Full RGB spectrum support for text watermarks

    Privacy & Performance

    • Local Processing: WebAssembly technology - files never uploaded to servers
    • Fast Speed: Process 10-20 pages per second with no server delays
    • File Support: Handle PDF documents up to 100MB

    How to Use

    1. Upload PDF: Drag and drop or click to select your PDF document
    2. Select Type: Choose text watermark (custom text) or image watermark (logo/stamp)
    3. Customize: Configure position, size, opacity, rotation, and layout mode
    4. Process: Click "Add Watermark" to apply and download the watermarked PDF

    Use Cases

    • Business: Corporate branding, proposal marking, copyright notices
    • Security: Confidential marking, draft notation, internal use labels
      Legal: Document protection, ownership attribution, version control

    Technical Specifications

    • Performance: WebAssembly native processing with 100% quality preservation
    • Compatibility: Chrome 88+, Firefox 85+, Safari 14+, Edge 88+ support
    • Requirements: 2GB RAM minimum, modern CPU, network only for initial load
    • Output: Standard PDF format compatible with all readers

    Frequently Asked Questions

    Q: Is this PDF watermark tool free?
    A: Yes, completely free with no hidden costs or registration required. Add unlimited watermarks to your PDFs.
    Q: Are my files secure?
    A: Absolutely. All processing happens locally in your browser - no files are uploaded to any server.
    Q: Can I watermark specific pages?
    A: Yes, apply watermarks to all pages or custom ranges like "1-3,5,7-10".
    Q: What's the optimal watermark opacity?
    A: Use 20-40% transparency for subtle marking that doesn't interfere with document readability.