I once received a contract draft with no watermark — forwarded twice, it reached a client who assumed it was final. Awkward calls followed. A diagonal DRAFT at 25% opacity would have prevented the entire incident for zero cost. Watermarks are status communication baked into pixels: draft, confidential, sample, do-not-copy. This guide covers wording, opacity math, placement strategy and the readability line you must not cross.
Part of the PDF workflow guide. Stamp in PDF watermark; prepare the file with PDF merge first if needed.
Wording: DRAFT, CONFIDENTIAL, SAMPLE, DO NOT COPY
| Stamp | Meaning | Use for |
|---|---|---|
| DRAFT | Not final, feedback welcome | Reviews, iterations |
| CONFIDENTIAL | Restricted circulation | Contracts, HR, finance |
| SAMPLE | Example, not deliverable | Portfolios, demos |
| DO NOT COPY | Distribution ban | Pre-release, exams |
Rotate phrases per audience and version (DRAFT v2, DRAFT v3) so stale copies self-identify. Archive unwatermarked masters separately — watermarks deter casual sharing, not determined extraction.
Opacity and placement that stay readable
| Opacity | Placement | Readability | Use |
|---|---|---|---|
| 20% gray | Center diagonal | High | Draft review |
| 25% gray | Center diagonal | High | Confidential (recommended) |
| 30% gray | Corners | Very high | Near-final samples |
| 80–100% black | Center | Low — avoid | Nothing (obscures) |
The reference recipe: DRAFT, 48pt, 25% slate, center-diagonal. At 100% zoom, body text reads cleanly underneath; at thumbnail scale, the stamp dominates — exactly the dual behavior you want. Test-print one page before wide circulation: screens forgive density that paper punishes.
Text stays selectable (and what watermarks can't do)
Overlay vectors render independently of content, so underlying characters remain selectable and copyable — watermarking is a social signal, not DRM. It will not stop screenshots (nothing does), survive aggressive redaction expectations, or work on image-only scans beyond visual deterrence. For true restriction, combine stamping with password permissions; for true secrecy, don't distribute. Keep version histories: contract-draft.pdf vs contract-draft-watermarked.pdf, masters never overwritten.
General guidance only. Watermarks communicate status — for legal protection, consult counsel about notices and registrations.