How to Scan a Clean Signature With Your Phone

What you need

• Plain white paper with no lines. Lined or squared paper leaves marks that are hard to remove.
• A black or dark blue pen with a medium tip. Gel and felt-tip pens give a more even line than ballpoints, which can skip.
• Good, even light — a window during the day is ideal.

Taking the photo

1. Sign a little larger than usual, in the middle of the page. Larger signatures keep more detail when they are shrunk to a small size later.
2. Put the paper on a flat surface. Hold the phone directly above it, parallel to the paper, so the signature isn't stretched.
3. Turn the flash off. Flash creates a bright spot and dark corners; natural light is more even.
4. Make sure your own shadow, or the phone's, doesn't fall across the paper. Moving slightly to one side usually fixes this.
5. Tap the screen on the signature to focus, then take the photo. Take two or three and keep the sharpest.

Cleaning and resizing it

Even a good photo has grey paper, uneven light and lots of empty space around the ink. Open the Signature Resizer and choose your photo. With “Clean background” on, it measures the paper's brightness, turns it pure white and slightly darkens the ink. “Crop to the signature” removes the empty paper, and the signature is centred inside the exact width and height you enter.

What size does your form want?

There is no single standard — each portal sets its own rules, so always read the form's instructions. Look for three things: the width and height in pixels, the maximum file size in KB, and the file format. Signatures are usually requested in a wide shape (several times wider than tall) and a small file size, often 10–50KB, as a JPG.

• If the form gives exact pixels, type them into the width and height boxes.
• If it only gives a file size, choose a wide shape such as 300×80 or 400×150 pixels and the matching KB limit.
• Choose JPG unless the form asks for PNG. JPG files are much smaller for the same size.

If the result looks wrong

• Faint or broken lines usually mean the photo was too dark or blurry. Retake it in brighter light.
• Grey speckles mean the paper wasn't evenly lit. Move away from shadows, or try a whiter sheet.
• If your pen is very light, switch off “Clean background”, which may treat faint ink as paper.

Keep your signature safe

A signature image can be misused. Upload it only to official portals you trust, don't post it on social media, and delete copies you don't need. ZIYNU's Signature Resizer works entirely in your browser, so the image never reaches our servers.

Common questions

Can I draw my signature with my finger instead?

If the form only needs an image, a drawn signature may be accepted, but it usually looks quite different from your handwritten one. Banks, universities and government offices may compare it with the signature on your existing records, so a photo of your normal pen signature is the safer choice.

Black or blue ink?

Use whatever the form asks for. If it doesn't say, both work — what matters is that the ink is dark and the lines are solid, so the signature survives being shrunk to a small image.

Why was my signature image rejected?

• The pixel size doesn't match what the form asked for.
• The file is over the KB limit, or in a format the form doesn't accept (for example PNG instead of JPG).
• There's too much empty paper around the ink, so the signature appears tiny once the form displays it.
• The lines are too faint to read after resizing.