Add CONFIDENTIAL Watermark to PDF

CONFIDENTIAL is conventionally rendered in a warning colour — typically red — precisely because it needs to register faster than a neutral grey watermark would, at a glance and even in a stack of other documents or a quick skim through a folder. The lower opacity here, slightly under the DRAFT preset's default, compensates for the fact that a saturated red reads as more visually assertive than plain grey text at the same transparency level, so the two presets are tuned to land at roughly the same felt intensity on the page despite using different colours.

As with any watermark applied this way, it is worth repeating that this is a labelling convention understood by anyone who reads it, not an access restriction — a document that genuinely must not be opened by unauthorised people needs encryption or a password on top of this, not instead of it.

A document marked confidential often passes through several hands before it settles — reviewed, forwarded to a second party, printed for a meeting, attached to a follow-up email — and at each of those points, someone new is deciding how carefully to handle it. A watermark stamped on every page means that decision is informed the same way regardless of which point in that chain someone encounters the file, rather than depending on whoever forwarded it last remembering to mention its sensitivity.