About Watermark PDF
A watermark tells anyone holding a document what status it has before they read a line: a draft that shouldn’t be quoted, a copy that isn’t the signed original, a file meant for one audience only. This tool writes the text you type onto every page of your PDF, either once in the middle of the page or repeated in a tiled pattern that covers it from edge to edge.
You control the look. Out of the box the text is gray, 48 points high, 20% opaque and running diagonally at 45 degrees, which is easy to spot without making the page hard to read. Opacity ranges from 10% to 60%, the color can be gray, red, blue or black, and the angle can be diagonal or horizontal.
The text becomes part of each page’s content instead of sitting in a separate comment or annotation layer. That has two practical effects. The watermark prints along with the page, and a viewer’s option to hide comments won’t make it disappear. And the rest of the page isn’t re-rendered: the original text underneath stays selectable and searchable, images keep their quality, and the file barely grows. Latin text is set in Helvetica Bold, one of the standard fonts every PDF reader supplies, and text in other alphabets embeds only the few characters you typed.
How to use Watermark PDF
- Open your documentDrag the PDF onto the tool or pick it from your files. A password-protected file has to go through Unlock PDF before it can be stamped, which means knowing its password.
- Type the text and style itEnter the wording, for example DRAFT or INTERNAL USE ONLY. Then set the font size, opacity, angle and color, and choose between a single centered stamp and a tiled pattern.
- Download the stamped PDFApply the watermark and save the result. Scroll through a few pages, and print a test sheet if the copy is going on paper, because pale gray can come out lighter on some printers.
When people use it
Circulating a draft contract
Stamp DRAFT diagonally across each page before sending terms out for comment, so nobody mistakes a working version for the final agreement or signs the wrong file.
Sending a scan of an ID or bank statement
When a landlord or employer asks for proof, a tiled line such as FOR RENTAL APPLICATION ONLY across the scan makes the copy awkward to reuse for anything else if it gets forwarded.
Marking classroom or sample copies
Teachers and offices handing out reading material can mark it COPY or SAMPLE in light gray, which keeps the master file visibly distinct from everything that was distributed.
Picking settings people can still read through
- Single or tiled. One centered stamp is enough for a status label such as DRAFT. Tiling repeats the text across the whole page, which suits scans of personal documents because the mark can’t simply be cropped off one corner.
- Opacity. Stay around 10–20% for pages someone has to read in full. Use 30–60% for proofs and samples where the mark should dominate.
- Color. Gray is the neutral choice and red signals urgency. On a black-and-white printer every color turns into a shade of gray, so judge the result by its opacity, not its hue.
- Length and size. A long phrase at 48 points can look cramped, especially on the diagonal of a small page. If it does, shorten the wording or lower the font size.
Which languages the watermark text can be in
English and the other Western European languages, digits and everyday punctuation are drawn in Helvetica Bold, a font built into the PDF format, so nothing is embedded. Letters beyond that set, such as Polish, Turkish or Vietnamese accents, Greek and Cyrillic, switch to Roboto Bold, and Chinese and Japanese characters to Droid Sans Fallback. Both fonts are Apache-2.0 licensed, and only the characters in your watermark are embedded, which adds a few kilobytes to the file. The Chinese and Japanese font is a download of about 4 MB that your browser fetches only when the text needs it. Mixed wording such as 机密 DRAFT works too, each part in the right font.
Korean Hangul, Arabic, Hebrew, scripts that need shaping such as Hindi or Thai, and emoji are not supported. Instead of printing empty boxes, the tool names the characters it can’t draw so you can change the wording. Short words in capitals tend to stay legible even at low opacity.
A label, not a lock
A watermark is not a security feature. Anyone with a PDF editor can delete or cover text that was added to a page, and the stamp does nothing to stop copying, printing or forwarding. If the aim is to control who can open the file, add a password with Protect PDF as well.
To make the mark harder to strip out, you can turn the stamped pages into pictures with PDF to JPG and rebuild them with JPG to PDF. The watermark then becomes part of each image, at the cost of selectable text and a bigger file, and it is still not impossible to edit.
Adding a watermark also modifies the file, so any digital signature it carried will no longer validate; stamp documents before they are signed. The stamping is done by code running in this tab, and neither the PDF nor the text you type is sent anywhere. See how to verify that yourself.