Add a watermark to PDF

How to Watermark PDF

1. Choose a PDF, or drop it on the box above.
2. Type your text (CONFIDENTIAL is filled in for you), then pick a layout, a colour and how see-through it should be.
3. Check the preview of page 1. It changes as you change the settings.
4. Press Add watermark, then Download. You get a new file ending in “-watermarked”; your original is not changed.

What you can set

The watermark goes on every page, sized to each page’s width, so landscape pages and mixed page sizes look right too. You choose:

• Text: up to 60 characters. Short words such as CONFIDENTIAL, DRAFT, COPY or your company name read best.
• Layout: “Across the middle” puts one large line at an angle through the centre of the page. “Straight” puts it level across the middle. “Repeated” fills the page with smaller slanted copies in staggered rows, which is harder to cut out of a screenshot.
• Colour: red, grey, blue or black.
• See-through: a slider from 10 to 90, starting at 25. A higher setting gives a stronger mark; a lower one lets more of the page show through.
• Put it behind the page content: draws the watermark under the text and pictures instead of on top of them.

Watermarks in Arabic and other languages

English and other text in Latin letters is written into the page as real PDF text, so it stays sharp at any zoom.

Arabic letters must join and run right to left, and the fonts built into PDF readers can’t do that. So for Arabic, and for other scripts such as Hindi or Urdu, your browser draws the text and the tool places it on each page as a high-resolution see-through picture. The letters join correctly and the words keep their order. The one difference is that this kind of watermark is a picture, so it can’t be selected or searched as text. Text that mixes Arabic and English is drawn the same way.

On top or behind: which to choose

On top, the default, shows on every kind of page, including scans and photos. Behind looks neater on typed documents: the words stay fully dark and the watermark sits in the background like printed paper.

Many files exported from Word and similar programs paint a plain white background first. The tool clears that white layer so a watermark behind it can show. It can’t see through a scanned page or a page with a solid coloured background, though: there a watermark behind the content stays hidden. The preview shows page 1 only, so if your file mixes scanned and typed pages, keep the watermark on top.

What a watermark does, and what it doesn’t

A watermark tells every reader what the document is: a draft, a copy, confidential, or yours. It is not a lock. Someone with a PDF editor may still be able to remove it, especially an English one stored as text, which can also turn up when the page text is copied or searched.

To make it much harder to remove, open the watermarked file in Flatten PDF and choose “Everything — pages become pictures”. The page and the watermark become one picture, but the text can no longer be selected. To stop people opening the file at all, use Protect PDF. To hide a detail for good, use Redact PDF.

A PDF with a password, or with limits set by its owner, is refused until you remove them with Unlock PDF and the right password. A digitally signed PDF needs a tick first, because adding a watermark makes the signature show as invalid.

Everything happens in your browser: your file is never uploaded to any server. You can check: once your file is open, turn on airplane mode — the tool still works.

Questions

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