Document robustness laboratory

How far does your watermark resist?

Add one or more images or PDFs, create a watermark mention or run an automatic removal test, then compare and export results locally.

Processed locally in your browser The document, mask, fingerprint and result are not sent to the After Algorithm analysis API.

Official public-service reference

Need a simple visible mention on a document?

Open FiligraneFacile if you only need to add a visible mention, without running tests or comparison tools.

Open FiligraneFacile ↗

After Algorithm and Filigrane Lab are independent from FiligraneFacile and beta.gouv.fr. This link is provided as an official reference resource.

Filigrane Lab

What do you want to do?

Choose your goal. Technical controls remain available, but the automatic path comes first.

Add your documents

Drop one or more files, or click to select them

JPEG · PNG · WebP · multi-page PDF

2.4.2 release: multipage PDFs are supported when every page is a full-page JPEG image. Vector or mixed PDFs are explicitly rejected rather than partially analysed.

The file stays on this device during the test.

Ready. Add one or more files to begin.

Test the watermark

Start with automatic detection. Review the proposed mask before reconstruction.

Watermarked source

Guided mode

Automatic test

The browser looks for distributed colours and patterns that may match a watermark. The result is a suggestion to review, not proof.

Automatic removal scope

Advanced manual controls

Use these tools only when automatic detection misses part of the mark or selects too much content.

Sample a colour

Click the button, then click directly on the watermark. The colour and mask are applied immediately.

Colour tolerance 28

Brush size Brush size 24 px

Reference original (optional)

Add the unwatermarked version only if you have it. It is used to measure reconstruction, never to reconstruct the document.

Local creation

Add or strengthen a watermark

Keep it simple: write the mention, choose a mode, then preview before applying the watermark.

Watermark mention

Recipient (optional) Date (optional)

Creation mode

Automatic watermark preparation

The Lab proposes a dual-colour pattern, a local signature and a readable structure you can still adjust.

Identity and local code

The Lab adds a local signature and export code so you keep an internal trace. This remains informative and is not cryptographic proof.

Identity · After Algorithm

Identity Local code

Reset and new test

These actions clear the mask or the current work. They are separated from ordinary controls to avoid accidental clicks.

Blue team

Strengthen the watermark

A visible watermark can deter misuse but is not an integrity proof. To increase removal cost:

Personalise the mark with purpose, recipient and date when relevant.
Avoid a perfectly periodic pattern and slightly vary position, density or opacity.
Cross informative zones without making the document unreadable.
Combine visible marking with an integrity mechanism or digital signature when authenticity must be verified.
Test several document families: flat colours, text, photography, logos and fine detail.