Add Watermark
Stamp a transparent text watermark across your PDF pages
Real Transparency
PDF ExtGState alpha — not just light gray
Any Angle
0–360° rotation for diagonal or straight
Custom Color
Any RGB hex color for the watermark text
Page Selection
Apply to all, odd, even, or a range
Stamp a custom text watermark — like "CONFIDENTIAL" or "DRAFT" — across every page (or selected pages) of a PDF, with full control over opacity, angle, color, and size.
How It Works
How Add Watermark to PDF Works
The tool uses a custom FPDI subclass that adds true transparency support to the underlying FPDF engine via the PDF specification's ExtGState mechanism, since transparent text isn't something the base library supports out of the box.
Each selected page is imported as a template, and the watermark text is drawn on top at your chosen rotation angle using a rotated text-matrix transform, calculated so the text is visually centered on the page regardless of the angle chosen.
You control the opacity (5–100%), font size, hex color, rotation angle, and which pages receive the watermark (all, specific numbers, ranges, or odd/even) — the text is rendered as real vector text, not a flattened image, so it stays sharp at any zoom level.
Worked Example
See It In Action
A draft contract PDF watermarked with "DRAFT — NOT FOR DISTRIBUTION" at 25% opacity, a 45° diagonal angle, and light gray color produces a version where the watermark is clearly visible across every page but doesn't obscure the underlying text.
FAQ
Frequently Asked Questions
Can I apply the watermark to only some pages?
Yes — use the page-selection field to target specific numbers, ranges like "1-3", or "odd"/"even", instead of watermarking every page.
Is the watermark a flattened image or real text?
Real vector text drawn directly onto the page, with true alpha transparency — it stays crisp when zoomed in and doesn't add the file-size overhead of an image-based watermark.
Can I control how see-through the watermark is?
Yes — opacity is adjustable from 5% (barely visible) to 100% (fully solid), letting you balance visibility against readability of the underlying content.
What colors and angles can I use?
Any hex color and any rotation angle from 0–360°; the diagonal 45° angle is a common default for "CONFIDENTIAL"-style stamps, but straight horizontal watermarks work too.
