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Watermark PDF

Add a text or image watermark to PDF pages, centred or tiled, with opacity, angle, colour and page range controls.

Overview

Adds a text or image watermark to a PDF, centred on each page or tiled across it. Set the text size, colour, opacity and angle, or use a PNG or JPG logo sized as a share of the page width, and apply it to all pages or a range. The watermark is drawn in your browser, so the document is not uploaded.

How It Works

Drop a PDF and choose Text or Image, then Centered or Tiled. For text, type up to 200 characters, set a font size from 12 to 200 pt and pick a colour. For an image, choose a PNG or JPG of up to 20 MB and set its width from 5 to 100 percent of the page. Opacity runs from 5 to 100 percent and the angle from -90 to 90 degrees, in steps of 5. Enter a page range or leave it blank for every page. The preview shows the first page with an approximate watermark before you download.

Step-by-Step Usage Guide

  1. Drop the PDF you want to watermark.
  2. Choose a text or image watermark and a centred or tiled layout.
  3. Type the text or choose a PNG or JPG logo, then set size and colour.
  4. Adjust opacity and angle, and enter a page range if needed.
  5. Check the preview and download the watermarked PDF.

Technical Specifications & Standards

The watermark is added on top of the existing page content with pdf-lib, using real PDF transparency, so the original text underneath stays selectable and nothing is re-rendered. Text watermarks use Helvetica Bold, a standard PDF font that covers Latin characters only; if you type characters it cannot draw, such as Chinese, Arabic or emoji, the tool lists them and suggests an image watermark instead. Images are checked by their file bytes rather than the extension, and transparent areas of a PNG stay transparent. Tiled mode repeats the mark in an offset brick pattern that reaches past the edges, so rotated tiles still cover the corners, and the count is capped so a small mark cannot slow the file down. Centring and angles are worked out against the page as it is displayed, so pages with a /Rotate value get the same diagonal as the others. A watermark added this way is a separate layer of content, so a determined person with a PDF editor can remove it; it deters casual reuse rather than providing security.

Targeted Use Cases

  • Stamping DRAFT or CONFIDENTIAL diagonally across every page of a document.
  • Adding a company logo faintly behind the content of a proposal.
  • Tiling a recipient's name across a shared report to discourage forwarding.
  • Marking sample pages of an ebook or course handout before publishing them.

Notes & Gotchas

  • Keep opacity between 10 and 30 percent so the page stays readable.
  • Use a PNG with a transparent background for logos, since a JPG always has a solid rectangle.
  • Choose an image watermark for non-Latin text, because the built-in font cannot draw it.

Frequently Asked Questions

How do I add a watermark to a PDF for free?

Drop the file, type your watermark text or choose a logo, adjust opacity and angle, and download. Only your own watermark is added to the pages, and processing happens on your device.

Can I watermark only certain pages?

Yes. Type the pages in the range field, such as 1-5 or 2, 4, 6, and only those pages get the watermark.

Why can I not use my language in a text watermark?

Text is drawn with Helvetica Bold, which only includes Latin characters. Make an image of your text and use the Image option instead.

Can someone remove the watermark?

Yes, with enough effort. The watermark is a separate layer of page content that a PDF editor can delete. It discourages casual copying but is not protection against a determined person.

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