Sign before you send: the right fax method
Handwritten, drawn, electronic: the steps, and what comes out of the other machine.
For sending a signed document: write the original in bold ink, then scan using black and white, or insert a hand-drawn signature into the PDF. In any scenario, the other party only obtains a picture of your signature rather than a legally verifiable electronic signature. If the physical paper copy is mandated, faxing cannot take its place.
Four key points
A fax carries only a monochrome image: the signature is reduced to a drawing, with no certificate and no timestamp.
Whether advanced or qualified under eIDAS, a signature loses all verification power the moment it is printed or faxed.
Initial every page and paginate as "1/4, 2/4…": the recipient can see immediately if a sheet is missing.
At fax resolution (204 × 196 dpi), a line that is too fine breaks apart: use a medium pen tip and prefer black ink.
Three signing methods, three results for the recipient
Much hinges on the recipient's requirements and the tools available to you. The middle column shows what the recipient's machine will output.
| Method | Procedure | What the recipient receives | Best suited for |
|---|---|---|---|
| Handwritten, then scanned | Print the document, sign it in ink, and scan it as a black-and-white PDF. | A reproduction of the original signature, generally the most legible. | Administrative forms, cancellation letters, standard powers of attorney. |
| Drawn into the PDF | Draw the signature with your finger or a stylus in a PDF reader, or insert an image file. | A signature image, visually identical to the previous method. | Everyday sending, without a printer or scanner on hand. |
| Electronic, eIDAS level | Apply a certified signature using the Belgian electronic identity card or a dedicated service. | Only the visual rendering: the certificate and the integrity check remain in the source file. | Transmitting the file by electronic means, never by fax. |
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
Certain paperwork always demands the original: authentications by a notary, specific contracts, and files that an administration requires “as an original” on its forms. In those situations, a fax may notify the recipient of the file or, if accepted by the recipient, begin the countdown — but the original still needs to be transmitted by mail or delivered in person. Every institution maintains its own list: review their guidance or contact them directly.
With a multi-page document, mark each page in the same location — for instance, bottom right — and label them “page 2 of 5.” The initials show that the signatory examined every page; the numbering assists the recipient in confirming that nothing is missing. Keep the signed original alongside 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.
- Make it normal size, at least a couple of text rows; if the signature stays very small, it ends up as a blurred blot.
- Before sending, open the PDF at 100% zoom, in black and white: the preview faithfully shows what the recipient will print.
The cover page identifies sender, recipient and how many pages come after, so the person receiving it knows at once which file the signed document belongs to. Generate your cover sheet, free of charge
Signature and fax: frequently asked questions
- Touchscreen signature or inked and scanned: is one worth more?
- Once faxed, both arrive as an image: no technique can tell them apart. It’s up to the recipient, or the rule governing their file, to decide whether a signed copy is sufficient.
- Can a PDF signed with the electronic identity card be sent by fax?
- Yes, though faxing strips away the electronic signature itself; what remains is merely its on-page appearance. If verification needs to be possible, send the recipient the original PDF via a digital channel.
- Does the cover sheet need to be signed?
- Generally, no: the cover sheet describes the shipment. Signatures and initials go on the document pages, not on the cover sheet.
Fax in everyday life
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