How to scan or photograph a signature for an online form

Sign on the right paper, in the right ink

Use plain white unruled paper. Ruled paper leaves lines in the crop, and coloured paper turns into a grey or tinted background once compressed.

Use black ink unless your notification says otherwise. Black produces the strongest contrast against white, which both looks correct and compresses smallest. Blue ink is a frequent rejection reason, because many notifications specify black explicitly.

Sign in the middle of the sheet with plenty of margin. Do not sign near an edge or a fold.

If you have a scanner

Scan at 200 to 300 dots per inch. Higher resolution gains nothing here — a signature has few details worth preserving, and a larger file is harder to bring under 10 KB.

Use the colour or greyscale setting if a black-and-white setting makes the stroke look broken or jagged. A clean greyscale scan compresses better than a harsh two-tone one.

If your scanner has a document feeder, use the flatbed instead. The feeder can skew the paper, and a skewed signature looks wrong.

Check the output before you continue. If the paper is grey rather than white, adjust the brightness or exposure and scan again.

If you only have a phone

Lay the paper flat on a plain surface and photograph it from directly above, not at an angle. A photo taken at an angle changes the height-to-width proportion of the signature and can look visibly skewed.

Watch your own shadow. Position yourself so that neither your body nor the phone casts a shadow across the paper — this is the single most common cause of a grey background.

Use daylight from a window rather than a flash. Flash produces a bright spot in the middle of the sheet and a shadow around it.

Hold the phone steady and take several frames. Slight motion blur is common and invisible on a small screen.

Crop tightly, then resize

Cropping is the most valuable step and the one most often skipped. A scan of a whole A4 sheet with a small signature on it wastes most of its file size on blank paper.

Crop to just outside the stroke, leaving a small even border on all four sides — roughly ten per cent of the signature width. Do not crop so tightly that the stroke touches the edge of the image, which looks clipped and is sometimes rejected.

Only then set the pixel dimensions if your notification states them, and afterwards compress to meet the size ceiling.

What to check before uploading

• The signature is handwritten, not a typed name in a script font.
• It is in the ink colour the notification specifies.
• The background is white, not grey, not cream, not shadowed.
• The whole signature is in frame, including the tail of the last stroke.
• It is in focus from start to finish — check the final flourish, which is where blur usually shows first.
• The pixel dimensions match the requirement, if one is stated.
• The file is under the size ceiling with a little margin.
• It matches the signature you will use on any printed copy you have to send.

Questions people ask