PDF Watermark
Add text watermark to all pages of a PDF. Customize text, opacity, rotation, color.
What is a PDF watermark?
A watermark is a recognizable image or text overlaid on a document, typically used to indicate ownership, status (DRAFT, CONFIDENTIAL), authenticity, or to discourage unauthorized reproduction. PDF watermarks are essential for: legal documents (CONFIDENTIAL, ATTORNEY-CLIENT PRIVILEGED), drafts not for distribution (DRAFT, WORK IN PROGRESS), trial versions (SAMPLE, TRIAL), branded reports (company name), and security-sensitive materials. A watermark doesn’t prevent copying or printing but it does make unauthorized distribution obvious and traceable. This tool adds text watermarks (not images) with customizable opacity, rotation, color, and size – useful for most common watermarking needs.
How to use this tool
- Upload your PDF — Tool reads the file and prepares for watermarking.
- Enter watermark text — Single word or short phrase. ‘CONFIDENTIAL’, ‘DRAFT’, ‘Sample’, or your company name.
- Adjust opacity — 0-100%. Default 20% is barely visible but clearly present. 100% = fully opaque (blocks content underneath).
- Set font size — 10-200 pixels. Default 72pt makes large diagonal text. Smaller for less obtrusive watermarks.
- Choose rotation — -45° (default diagonal) is classic watermark angle. -90° (vertical), 0° (horizontal), 45° (diagonal opposite).
- Pick color — Default gray (#888) is professional. Red for warnings (CONFIDENTIAL), other colors for branding.
- Click ‘Add watermark’ — Watermarked PDF downloads. Watermark appears on every page in the center.
Watermark technical details
The tool uses pdf-lib’s drawText() with specific styling parameters:
- Position: Center of each page (page width and height / 2, minus half the text width)
- Color: Custom hex color converted to RGB (0-1 range)
- Opacity: Alpha channel of the text (0 = fully transparent, 1 = fully opaque)
- Rotation: Applied as PDF degrees rotation around text center
- Font: Helvetica Bold (built-in standard PDF font)
The watermark is drawn AFTER any existing content – it appears on top. The watermark is part of the PDF, not a removable annotation – users can’t simply turn it off. However, advanced PDF tools could remove it.
Examples
- CONFIDENTIAL contract: Text=’CONFIDENTIAL’, red color, 15% opacity, diagonal rotation
- DRAFT proposal: Text=’DRAFT’, gray, 25% opacity, diagonal
- Sample product manual: Text=’SAMPLE – DO NOT REPRINT’, red, 20%, diagonal
- Company branded reports: Text=’Company Name’, subtle gray (10%), horizontal at bottom
- Trial software documentation: Text=’TRIAL VERSION’, gray, 20%, diagonal
- Photographer’s preview: Text=’© 2026 Studio Name’, white with shadow, large diagonal
Tips & best practices
- 20-25% opacity is professional – visible but doesn’t obscure content. Avoid 100% which makes document unreadable
- -45° rotation is classic diagonal watermark – traditional and instantly recognizable
- For maximum impact use red color and the word ‘CONFIDENTIAL’ or ‘PRIVATE’
- For minimum impact (e.g. company branding), use light gray (#cccccc) at 10% opacity
- Large text (72pt+) is more authoritative; small text (24pt) is more discreet
- Watermark cannot prevent screenshots or copy-paste – it’s a deterrent and tracking mechanism, not a security measure
- Test watermark visibility by printing one page first – some watermarks look fine on screen but disappear on paper
Limitations & notes
This tool adds text watermarks only – not image watermarks. For image watermarks (logos), use a desktop PDF editor like Adobe Acrobat. The watermark is centered on each page – can’t position it elsewhere (use Page Numbers tool for header/footer text instead). Watermarks added by this tool can be removed by advanced PDF editing software – true security requires encryption + DRM, not watermarks alone.
Frequently Asked Questions
Will the watermark appear on every page?
Yes – the watermark is applied to all pages of the PDF in one operation. Each page gets the same watermark in the same position.
Can the watermark be removed?
By advanced users, yes – Adobe Acrobat Pro and similar tools can remove watermarks. By regular users, no – it requires specialized software. Watermarks deter casual misuse, not determined attackers.
Will the watermark obscure my content?
Depends on opacity. At 100% it completely covers content behind it. At 20-25% (recommended) it’s clearly present but content remains fully readable underneath. Always test before distributing.
Can I use a logo as a watermark?
Not with this tool – it’s text-only. For image/logo watermarks, use Adobe Acrobat Pro, Foxit PhantomPDF, or similar desktop tools that support image watermarking.
How long is the maximum watermark text?
Short single phrases work best. ‘CONFIDENTIAL’ (12 chars) or ‘COMPANY NAME’ (12 chars). Longer text reduces visibility. Multiple words separated by space work too: ‘STRICTLY CONFIDENTIAL’, ‘WORK IN PROGRESS’.
Does watermark make my PDF larger?
Slightly – typically 1-3 KB total added (one font embedded for text rendering, plus the text strings). For most documents this is negligible.
Can I choose color and position?
Color: yes, any hex color via color picker. Position: fixed at page center with rotation – can’t move to corner or specific coordinates. For positioned text, use the Page Numbers tool with custom text.