Sign before you send: the right fax method

Handwritten signature: careful scanning

Print the page and sign it first. Then scan using black-and-white mode — often marked "text" or "document" — instead of color or grayscale. This setting keeps output to pure black and pure white, matching how the fax will reproduce it, so what you see on screen is exactly what arrives.

A flatbed scanner is still the gold standard. With a smartphone, place the page on a dark, uniform background, light it head-on without shadows, and use the "document scan" function, which straightens the page and sharpens the contrast. Then check the signature by zooming into the PDF: a dotted line? Increase the contrast or redo the signature with a steadier hand.

Drawing your signature in a PDF

Nearly every PDF viewer and mobile app has a built-in signing feature: draw your signature once, it gets saved automatically, and you can drop it anywhere. Perfect for sending from your phone, no printer needed.

Two things to watch out for. Draw your signature quite large in the input window, then scale it down once placed — a tiny drawing often ends up as three disjointed segments. Then export the file as a standard (flattened) PDF before sending: the signature must be part of the page, not left as an annotation that software could ignore.

Fax does not carry the electronic signature

European eIDAS regulation defines three tiers. Simple electronic signature covers any process linking data to a signatory — a ticked box, a pasted image. Advanced signature must uniquely identify the signatory and reveal any subsequent tampering. Qualified signature additionally requires a dedicated certificate and a qualified creation device; European regulation gives it the same standing as a handwritten signature. The Belgian electronic identity card can produce this higher level.

All these guarantees rely on the file's cryptography: document fingerprint, certificate, and sometimes a timestamp. Fax, by contrast, only transmits a rasterized image of the page. Take a PDF signed electronically and then faxed: it arrives as a plain copy, and the recipient at best sees a “signed by…” panel, with no way to verify anything.

The recipient requests an advanced, or even qualified, signature? Use whichever delivery method they indicate — eBox, portal, email — to transmit the signed document. Fax remains relevant for documents where a signed copy is sufficient.

When the paper original is required

Some documents always require the original: notarized deeds, certain contracts, documents the administration demands “as an original” on its forms. In those cases, a fax can announce the file or, if the recipient accepts it, start the clock — but the original must then be sent by post or handed over in person. Each organization keeps its own list: read their instructions or ask them.

On a multi-page document, initial every page in the same spot — bottom right, for example — and number them “page 2 of 5.” The initials prove the signatory saw every page; the numbering helps the recipient verify nothing is missing. Keep the signed original together with the receipt or transmission report.

A signature that holds up at 204 × 196 dpi

• At fine resolution, a fax page has roughly 8 dots per millimetre: a very fine stroke can slip between two dots and vanish.
• Prefer signing with a felt-tip pen or a medium-point pen, black ink; light blue and pencil don’t survive the black-and-white filter well.
• Keep the area clear: a stamp, a halftone background, or a line of text cutting across it will blur the stroke.
• Give it a normal size — at least two lines of text; a tiny signature ends up as a smudge.
• Before sending, open the PDF at 100% zoom, in black and white: the preview faithfully shows what the recipient will print.

The cover sheet states who is writing, for whom, and how many pages follow: the recipient immediately knows which file to attach the signed document to. Generate your cover sheet, free of charge