How to watermark a PDF — and what a watermark does and does not do
A watermark answers two questions before anyone reads the first line: whose document is this, and what state is it in? DRAFT across a proposal stops it being mistaken for the final version; CONFIDENTIAL on a report reminds every reader how to treat it; a logo on a portfolio says who made it. This guide explains how to add a text or picture watermark with Watermark PDF without uploading anything, which settings make it readable rather than intrusive, and — because the word promises more than it delivers — what a watermark actually protects.
A watermark is a label, not a lock
Start with the honest part. A watermark is drawn on top of the page like any other content. Viewers show it, printers print it, and a PDF editor can remove it in a few clicks, just as it could remove a paragraph. It does not prevent copying and it does not prove authorship in any technical sense. What it does is set expectations for every person who opens the file, including the ones who forward it: a page marked DRAFT is read as a draft, and a page marked CONFIDENTIAL is harder to share by accident.
If the content must stay private, the tool for that is a password, not a stamp. Watermark first, then encrypt the result with Protect PDF: the mark travels with every copy anyone with the password makes, and the password keeps everyone else out. If you need to prove a document is yours, keep the original and its sources; a watermark on a copy shows intent, not evidence.
Adding a text watermark
- Open Watermark PDF and add the file, or up to 20 files that should carry the same mark. Each row shows the page count and a preview.
- Leave Watermark on Text and type the words: CONFIDENTIAL, DRAFT, SAMPLE, DO NOT COPY, your name, your website. Keep it short — a watermark is read at a glance, not studied.
- Pick a colour. Mid-grey is the classic choice because it reads on white paper and on screen without competing with the text; red says urgency, and a brand colour suits a logo-style name.
- Choose Size (Small, Medium or Large — a share of the page, so one setting fits A4, Letter and phone scans alike), Opacity (30 % is the usual balance between visible and readable) and Angle (Diagonal for the classic across-the-page stamp, Horizontal for a header or footer line).
- Place it with the position grid — the centre for the traditional stamp, a corner for a discreet mark — or press Tile to repeat it across the whole page, which is the choice for proofs and samples.
- Under Pages, keep All, or choose Odd, Even or Custom to mark only some pages. Click Watermark, check the preview of the first page, and download.
Everything happens in your browser. The file and the text never leave your device, and the original file on disk is not modified; the result is a new file named after the original with -watermarked added.
Logos and pictures
Switch Watermark to Image to stamp a logo, a signature or any picture. A PNG with a transparent background gives the cleanest result: only the logo itself is drawn, with no white box around it. JPG, WebP, HEIC, SVG and the other formats the site opens work too; a JPG naturally brings its white or coloured background with it, so lower the opacity or use it in a corner.
Size is a share of the page width — Small for a corner mark, Large for a half-page emblem — and opacity, angle, position and tiling work exactly as for text. The picture is stored once in the file however many pages carry it, so a 300-page document with a logo on every page grows by the size of one logo, not three hundred.
Non-English text, and other things people ask
PDF's built-in fonts cover Latin letters with accents, digits and common symbols, so most watermarks are written as real text that stays crisp at any zoom. Text with other characters — Turkish İ, ğ and ş, Cyrillic, Greek, Chinese, Japanese, Korean, Arabic, emoji — would print as question marks in those fonts, so Watermark PDF draws it with your browser's own fonts at high resolution and embeds it once as a transparent picture instead. It looks exactly as you typed it; the row says when this was done.
- Behind the content? Not here. The mark is drawn on top, which is the only way to add to a PDF without rewriting every page. At 30 % opacity the text underneath stays fully readable, which is how most Confidential and Draft stamps are made.
- Only some pages? Yes: Odd, Even, or a list such as 1-3, 7. The same list applies to every file in the batch; a file that has none of those pages is reported rather than copied unchanged.
- Existing watermarks? They are not detected or removed. If a document already carries one, choose a different position or the opposite angle.
- What changes in the file? Only the pages you chose gain the mark. Bookmarks, links, annotations, editable form fields and metadata are kept, because pages are stamped in place rather than copied. Encrypted PDFs must be unlocked first; signed documents and XFA forms are refused.
Choosing settings that work
A good watermark is noticed and then ignored. Grey, 30 % opacity, Medium, Diagonal, centred: that is the setting that reads as professional on almost any document, and it is the default. Go darker or larger when the document will be photographed or scanned and the mark has to survive a poor copy; go lighter and smaller for something people will read for an hour. Tile a proof or a sample so that no crop of the page is free of the mark. Use a corner for a name or a website that should identify without interrupting.
Then look at the result. The preview on the row shows the real first page; open the downloaded file and page through it before sending. If the mark sits on a figure or a signature line, move it with the grid; if it is too loud, lower the opacity and run again. The original is untouched, so there is nothing to undo.