The workshop · Number, watermark
How it works : Number, watermark
Positions are systematic, never picked with the mouse: that is what makes it possible without displaying the page, and so without carrying a rendering engine. The tool shows you BEFORE the act what will be written on each page, and it names the pages whose display angle is going to tip everything sideways.
Two jobs that turn up at the last minute: a dissertation due in whose pages are not numbered, and a document about to circulate that needs “draft” or “confidential” written on it large enough that nobody can miss it. Both happen here, on your device.
The technical choice behind this tool is the same one as behind form filling, and it is written rather than hidden: positions are SYSTEMATIC. Six spots for a page number, two for a watermark, and no free placement with the mouse. Placing something with the mouse would mean displaying the page, so carrying a 1.72 megabyte rendering engine. A systematic position, on the other hand, is computed from the page's dimensions, and that is exactly what a page number needs.
The tool shows you BEFORE acting what will be written on each page, and it flags the pages whose display angle is not upright: on those, the number will follow the page's angle and end up on its side. We say so rather than letting you find out, and the “Reorder and rotate pages” tool in the same corner can straighten all of that first.
How it works
- Drop your PDF in. The tool counts its pages and tells you which ones are not upright.
- Set the numbering (format, position, starting number, pages to skip) and, if you want one, the watermark text.
- Read the written preview: it tells you page by page what will be laid down. Then click, and the file arrives.
Formats accepted
PDFs only. The text is written with one of the format's fourteen standard fonts, which limits the available character set: see the limits just below.
PDF document
Pages are not redrawn: the number and the watermark are ADDED on top of the existing content. No image is recompressed.
Its limits
Six positions for a number, two for a watermark, and nothing by mouse
Placing something with the mouse would mean DISPLAYING the page, so carrying a PDF rendering engine, and the only serious one weighs 1.72 megabytes minified. We will not do that for one tool. A systematic position is computed from the page's dimensions, it is reproducible, and it is what a page number asks for anyway.
Fourteen fonts, and a Western European character set
Writing text into a PDF takes an embedded font. Without an extra font engine, only the format's fourteen standard fonts exist, and they only carry the Windows-1252 set: Western European languages, the euro sign, typographic quotes. A character outside that set (Cyrillic, Greek, Arabic, Chinese) cannot be written, and the library would replace it with a question mark WITHOUT SAYING A WORD. So the tool checks your watermark before the act and names every character that is a problem.
On a page that is not upright, the number follows the page's angle
A PDF stores a display angle per page, and what we write is laid down in the page's frame, not your screen's. On a page lying on its side, the number will therefore appear sideways. We do not compensate for that angle blind: we would rather NAME the pages involved before the act and send you to the “Reorder and rotate pages” tool in the same corner, which straightens them losslessly.
The watermark goes ON TOP of the content, never behind
A watermark written on top is a watermark nobody can miss, which is the whole point of a “draft” or a “confidential”. Putting it behind the content would mean rewriting the drawing order of every page, with a real risk of breaking documents built in unusual ways. The opacity setting is there so the text underneath stays readable.
A watermark is not protection
It stops nobody from copying the text, cropping the pages or covering the watermark over. It is there to SIGNAL a state (draft, copy, confidential), not to forbid anything. To stop a document being opened, you need a password, and the “Password protect a PDF” tool in the same corner really does that.
80 MB
The document is opened entirely in memory, and its numbered version lives beside it. That is the honest limit of one tab on a modest device.
A password protected PDF will not open here
It has to be unlocked first, which takes its password. The “Password protect a PDF” tool in the same corner knows how.
Questions about this tool
Is my document sent anywhere?
No, and you can check it in thirty seconds. Open the inspector with the F12 key, the “Network” tab, clear the list, then drop the document in and lay your numbers down. Not one line appears. Cut your connection and do it again: the tool works the same.
Why can I not put the number where I want?
Because it would mean showing you the page. Displaying a PDF page takes a rendering engine, and the only serious one weighs 1.72 megabytes minified: it would be downloaded by every visitor to the site, for a single tool. We preferred six systematic positions, computed from each page's dimensions, which covers what a page number is actually for. It is the same decision as for form filling, and it is written on the “Our method” page.
My pages lie on their side and the number appears sideways.
That is the case the tool flags for you before the act. A PDF stores a display angle per page, and what we write is laid down in the page's frame, not your screen's. Straighten your document first with the “Reorder and rotate pages” tool in the same corner: rotation there is a simple change of angle, so lossless and with no recompression. Then come back and number it.
Does the watermark stop my document being copied?
No, and you must not believe it does. A watermark signals a state: draft, copy, confidential. It prevents neither copying the text, nor cropping the pages, nor covering it over. If what you need is to stop the document being opened, you need a password, and the “Password protect a PDF” tool in the same corner really does that, in AES-256.
Can I number from a different figure?
Yes, and it is built for two common cases: a document that continues another one, and a document whose cover must not count. The “number of the first numbered page” setting fixes the starting point, and the “pages at the start to leave unnumbered” setting leaves the cover bare. The total shown in the formats with a total counts numbered pages, not the file's pages: that is what a reader expects.
Why is my watermark in Russian or Chinese refused?
Because writing text into a PDF takes a font, and without an extra font engine only the format's fourteen standard fonts exist. They carry the Windows-1252 set, which is to say Western European languages. The library we use would replace the other characters with a question mark without saying so: the tool therefore names them before the act rather than handing you back a damaged document.
Does this make my file heavier?
Barely. A page number is a handful of bytes per page, and the watermark is the same text repeated. Helvetica is one of the fourteen standard fonts: it is not embedded in the file, only named, because every PDF reader has it. So the file you get weighs a few hundred bytes more, not a few megabytes.
Positions are systematic, never picked with the mouse: that is what makes it possible without displaying the page, and so without carrying a rendering engine. The tool shows you BEFORE the act what will be written on each page, and it names the pages whose display angle is going to tip everything sideways.
VerifyThe proof, step by stepThe network inspector check, explained one gesture at a time, with screenshots.
The cornerThe PDF cornerMerge, split, sign, fill, slim down. A PDF should never have to travel to a stranger to be cut in two.