PDF Watermark
PDF Watermark applies customizable text overlays to each page of your PDF directly in your browser. This client-side tool ensures your documents are watermarked without uploading any files, preserving privacy.
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PDF Watermark lets you add text watermarks to PDF documents entirely within your browser, using the pdf-lib library for client-side processing. It supports precise placement with six positions, including a 45-degree diagonal rotation, and customizable font sizes from 12 to 120 points, opacity levels between 5% and 100%, and RGB color selection. Since all processing happens locally, no data leaves your device, ensuring maximum privacy. This tool complements related utilities like Protect PDF for securing files and Add Page Numbers PDF for enhancing document navigation.
How to Use PDF Watermark
- Upload your PDF file into the tool interface.
- Enter the watermark text you want to apply.
- Choose the watermark position: center, diagonal, or any of the four corners.
- Adjust the font size (12-120pt), opacity (5-100%), and set the RGB color values.
- Apply the watermark and download the watermarked PDF; all operations run in your browser without uploading files.
How It Works
The tool utilizes pdf-lib, a client-side JavaScript library, to manipulate PDF content. It embeds the standard Helvetica font from StandardFonts, avoiding the need for external font loading. The watermark text is drawn on each PDF page using the page.drawText() method. Positioning options include placing text at the center, at a 45-degree diagonal using degrees() rotation, or any corner. The watermark is rendered as an overlay, ensuring it appears on top of existing content without altering the underlying PDF structure.
Example
Input: PDF with 3 pages, watermark text "Confidential", position: diagonal, font size: 48pt, opacity: 50%, color: RGB(255,0,0)
Output: The resulting PDF shows "Confidential" diagonally across every page in semi-transparent red Helvetica, with the watermark overlaying existing text and images.When to Use PDF Watermark
- Developers needing to mark PDF documents with copyright or draft status directly in web applications.
- Designers adding branding watermarks to sample PDFs without altering the source files.
- SEO specialists protecting content by embedding visible watermarks to prevent unauthorized reuse.
- Students watermarking academic papers or presentations to indicate ownership or confidentiality.
For additional PDF enhancements, consider Protect PDF to encrypt your documents or Add Page Numbers PDF to insert page numbers. You can also combine multiple PDFs before watermarking using Merge PDF.
Frequently Asked Questions
Does PDF Watermark upload my PDFs to a server?
No, PDF Watermark processes all PDFs entirely in your browser using pdf-lib. This client-side operation means your files never leave your device, ensuring complete privacy and security.
What font is used for the watermark text?
The tool uses the Helvetica font embedded via pdf-lib's StandardFonts. This avoids external font loading and guarantees consistent rendering across different systems.
Can I control the opacity and color of the watermark?
Yes, you can set the watermark opacity anywhere from 5% to 100% and specify the RGB color values precisely, allowing for subtle or prominent watermarks as needed.
How is the diagonal watermark applied technically?
The diagonal watermark uses the degrees(45) rotation method from pdf-lib to rotate the text 45 degrees. This transformation is applied during page.drawText() rendering on each page.
Is the watermark an overlay or underlay?
The watermark text is drawn as an overlay on top of the existing PDF content, ensuring it is visible without modifying or removing any underlying elements.