How to add a do not copy watermark to a pdf
- Step 1Open the watermark tool and load the file — Drop the restricted document into pdf-watermark. One file per run.
- Step 2Set the text to DO NOT COPY — Change the default
CONFIDENTIALtoDO NOT COPY(or a stronger phrase likeDO NOT COPY OR DISTRIBUTE). Longer text auto-scales to fit the page. - Step 3Choose a prominent opacity — For a deterrent that's hard to ignore, 0.20–0.25 works well — more visible than a subtle confidential marking. The field accepts 0.05–1.0 in 0.05 steps.
- Step 4Set the font size — Default 60 pt gives a large central warning. Leave it and let the tool auto-shrink longer phrases to fit, or raise it toward the 200 pt max for a single short phrase you want dominant.
- Step 5Apply to every page — Run the tool —
DO NOT COPYis drawn diagonally and centred on all pages. No page can be left unmarked, which is what you want for copy deterrence. - Step 6Add real restrictions, then distribute — For enforcement, follow with pdf-permission-setter to set an owner password and disable copy/print. Then distribute the marked, restricted copy and keep the clean original.
Deterrent vs. enforcement — which tool does what
A watermark sets intent; permissions enforce it. Use both for real copy deterrence. Verified against the implementations.
| Goal | Tool | What it actually does |
|---|---|---|
| Visible 'DO NOT COPY' warning | pdf-watermark (this tool) | Draws the diagonal grey warning on every page |
| Block copy/paste of text | pdf-permission-setter | Sets an owner password and disables the copy permission |
| Block printing | pdf-permission-setter | Disables the print permission via owner password |
| Require a password to open | pdf-password-protect | Encrypts the file so it can't be opened without the password |
| Remove hidden metadata before sharing | pdf-metadata-scrubber | Strips author/producer and other metadata |
The watermark tool's controls
Three inputs; colour, angle, font, and page coverage are fixed. Real values from the UI and engine.
| Property | Control | Range / value |
|---|---|---|
| Text | Text input | Any string (default CONFIDENTIAL) |
| Opacity | Number input | 0.05 – 1.0, step 0.05 (default 0.15) |
| Font size | Number input | 12 – 200 pt (default 60) |
| Colour | Fixed | Mid-grey — no red option |
| Angle | Fixed | -45° diagonal, centred |
| Pages | Fixed | All pages |
Input limits by tier
One file per run. Limits on input size and pages. Real configuration values.
| Tier | Max file size | Max pages |
|---|---|---|
| Free | 2 MB | 50 |
| Pro | 50 MB | 500 |
| Pro + Media | 500 MB | 2,000 |
| Developer | 2 GB | 10,000 |
| Enterprise | Unlimited | Unlimited |
Cookbook
Copy-deterrence setups. Each lists the three inputs and notes where to add real enforcement.
Standard DO NOT COPY on a price list
A prominent warning so a forwarded or photocopied price sheet clearly shows the restriction.
text: DO NOT COPY opacity: 0.22 fontSize: 60 → bold diagonal warning on every page; visible in a screenshot or photocopy of the pricing.
Exam paper marking
For assessment papers, a strong central warning discourages sharing of the questions.
text: DO NOT COPY — EXAM MATERIAL opacity: 0.20 fontSize: 54 → longer phrase auto-scales to fit; clear across every question page.
Deter copy AND block it (chained)
The watermark sets intent; the permission setter enforces it. Run both for real deterrence.
Step 1 — pdf-watermark: text: DO NOT COPY opacity: 0.22 fontSize: 60 Step 2 — pdf-permission-setter: owner password + disable copy + disable print → visible warning backed by enforced restrictions.
Per-recipient copy marking for leak tracing
Identify each issued copy in the watermark so a leaked page points to a recipient.
text: DO NOT COPY — Issued to R. Patel opacity: 0.18 fontSize: 48 → run once per recipient with their name; a leaked screenshot is attributable.
Strong single-phrase warning
When the document is short and the warning should dominate the page.
text: DO NOT COPY opacity: 0.30 fontSize: 90 → large, prominent diagonal warning for cover sheets or single-page proprietary templates.
Edge cases and what actually happens
You expect DO NOT COPY in red
Grey onlyThe watermark colour is fixed mid-grey — there's no red. For an alarm-red warning, make a single-page red DO NOT COPY graphic and overlay it with pdf-stamp, which composites a stamp PDF onto every page.
The watermark doesn't actually stop copying
By designA watermark is a visual deterrent, not enforcement — text can still be selected and copied, and the page can be screenshotted. To genuinely block copy and print, set permissions with pdf-permission-setter, or require a password to open via pdf-password-protect.
Someone edits the watermark out
PossibleThe warning is drawn into the page content, so it survives normal viewing and printing, but a user with PDF-editing software can remove drawn content. Pair the marking with enforced permissions for protection that doesn't rely on the watermark staying intact.
Only the answer pages of an exam should be marked
Not supportedThere's no page-range option — every page is marked. To mark a subset, extract those pages with pdf-extract-pages, watermark them, and reassemble with pdf-merge.
Long warning phrase
PreservedDO NOT COPY OR REDISTRIBUTE and similar long phrases are auto-scaled — the font shrinks (to a 16 pt floor) so the warning spans about 72% of the page diagonal and fits, centred, on every page.
The file is already permission-restricted
SupportedThe tool opens PDFs with encryption ignored, so it can usually watermark a restricted file. The saved output is un-restricted, so re-apply permissions with pdf-permission-setter after watermarking.
Free-tier file over 2 MB or 50 pages
RejectedFree tier caps input at 2 MB and 50 pages. A large multi-page exam bank or catalogue may exceed it — upgrade to Pro (50 MB / 500 pages) or split it first with pdf-split-fixed.
Recipient retypes the content instead of copying
Out of scopeNo watermark or permission setting stops someone retyping or photographing content. The watermark deters casual copying and establishes intent; for genuinely sensitive material, control distribution and combine marking with pdf-permission-setter.
Marking appears faint over a dense table
Raise opacityA 0.15 grey can disappear into a dense price table. Push the opacity to 0.22–0.30 so the DO NOT COPY warning reads clearly over the data, accepting it'll be more prominent on sparser pages.
Frequently asked questions
Does a DO NOT COPY watermark prevent digital copying?
No — it's a visual deterrent, not technical protection. Text can still be selected and copied, and pages can be screenshotted. To actually block copying and printing, set permissions with pdf-permission-setter, which uses an owner password to disable those actions. Best practice is to use both: the watermark for the visible warning, permissions for enforcement.
Can I make the DO NOT COPY watermark red?
No. The watermark is always mid-grey; there's no colour control. For a red warning, create a single-page red DO NOT COPY graphic and overlay it on every page with pdf-stamp. This tool produces a consistent grey diagonal text marking only.
How do I actually stop people copying the content?
Layer the pdf-permission-setter on top of the watermark: it sets an owner password and lets you disable copy and print. For the strongest control, also encrypt with pdf-password-protect so the file can't be opened at all without a password. The watermark states intent; these tools enforce it.
Will the warning appear on every page?
Yes — the watermark is applied to all pages with no page-range option, so every page of a price list, exam, or template carries the warning. That's deliberate for copy deterrence: there's no unmarked page to copy cleanly.
Can I track who received each copy?
Put a recipient identifier directly in the watermark text — e.g. DO NOT COPY — Issued to R. Patel — and run the tool once per recipient. There's no automated mail-merge, but a distinct text string per export makes a leaked page traceable to the recipient it was issued to.
What opacity is best for a DO NOT COPY warning?
0.20–0.25 — more prominent than a subtle confidential marking, because the point is to be noticed. Over dense tables you can push to 0.30. The field accepts 0.05–1.0 in 0.05 steps; the default 0.15 is on the subtle side for a copy warning.
Can recipients remove the watermark?
The warning is drawn into the page content, so it survives normal viewing, printing, and copying. It's not unremovable, though — capable PDF-editing software can strip drawn content. That's exactly why you should pair it with enforced permissions via pdf-permission-setter rather than relying on the watermark alone.
Can I watermark several documents at once?
The tool processes one PDF per run — it isn't a batch tool. Run each document individually. Processing is local and quick, so marking a set of files in sequence is fast.
Does the document get uploaded?
No. Watermarking runs entirely in your browser — the file is loaded, marked, and saved locally and never reaches a server. That keeps proprietary pricing, exams, and templates on your own machine.
Can I watermark just the first page as a warning sheet?
Not directly — the warning goes on every page. For a single-page warning, you could extract page 1 with pdf-extract-pages, watermark it, and merge it back with pdf-merge. For copy deterrence, though, marking every page is the stronger choice.
What's the maximum file I can mark on the free tier?
2 MB and 50 pages on Free. Pro raises that to 50 MB / 500 pages, Pro + Media to 500 MB / 2,000 pages, and Developer to 2 GB / 10,000 pages. Enterprise is unlimited. Split large exam banks with pdf-split-fixed if needed.
Is red really the most effective colour for this?
Red is conventional for warnings, but this tool can't produce it — the marking is grey. In practice, a grey DO NOT COPY at 0.22–0.25 opacity is plenty visible. If red is genuinely required, build a red graphic and apply it with pdf-stamp instead.
Privacy first
All PDF processing runs locally in your browser using PDF-lib and pdf.js. No file is ever uploaded — only metadata counters are saved for signed-in dashboard stats.