How do I make my signature 300×80 and under 60 KB, with a clean white background?

You signed on a white sheet, took a photo with your phone, and the result is a grey page with a shadow in one corner and a signature in the middle. The form wants 300 × 80 pixels and no more than 60 KB. The size is actually the easy part. Getting a signature that looks clean in that long, thin strip is where most people struggle.

What the form asks for

Neither source we read gives a minimum size for the signature, only a maximum. If your circular also sets a minimum, open More options and type it in Smallest size.

Why a photographed signature looks grey

A phone camera does not know the paper is meant to be white. Under a room light it records the paper as light grey, often darker at one edge, and your hand or the phone itself adds a shadow. On your phone screen it looks fine. Shrunk to 80 pixels tall and placed on a white web form, it looks like a dirty grey box.

The grey also makes the file heavier. In our tests, the same 300 × 80 signature at the highest quality was about 16.7 KB on grey paper and 5.3 KB once the paper was made white. Both are far under 60 KB, which tells you something useful: at 300 × 80, the file size is almost never what goes wrong. The look is.

The shape: a long, thin strip

300 × 80 is nearly four times as wide as it is tall. Most signatures are not that wide, so something has to give:

• Stretching it to fill the strip makes it look squashed and fat.
• Cropping it to fill the strip cuts off letters.
• Adding white edges on the sides keeps the signature exactly as you wrote it. On white paper the edges are invisible.

Resize Image does the third. It first trims away the empty paper around your ink, then adds white to the sides (or top and bottom) until the picture is exactly 300 × 80.

Before you take the photo

• Use plain white paper with no lines. Lines from a notebook page may stay after the clean-up.
• Use a dark pen. A thin, light ballpoint line can get very faint at 80 pixels tall.
• Sign at your normal size or a little larger. A tiny signature loses detail when it is shrunk.
• Take the photo in daylight, with the phone held flat and directly above the paper, so its shadow does not fall on the page.
• Fill most of the screen with the signature, leaving some paper around it.

Step by step

1. Open Resize Image and choose your signature photo. It stays on your phone or computer. It is not uploaded.
2. Under Picture, choose Signature. Background switches to White by itself: the paper goes white and the ink goes darker. Type 60 in the File size box, then 300 in Width and 80 in Height. JPG is already the format.
3. Look at the clean-up in the preview. If the paper is still grey or shadowed, choose White, fully. If thin parts of the signature start to vanish, go back to White, or choose Original to switch the clean-up off. Under More options, Ink lets you keep the ink's own colour or choose Make the ink black.
4. Trim to the signature (under More options) is on, so empty paper is cut away with a small white margin left around the ink. The result is then fitted into 300 × 80 without stretching.
5. Tap Actual size to check every stroke is there and make sure every line in the list has a tick. Tap Resize picture and download signature.jpg.

Why the portal rejected your signature

• Wrong pixel size. It is under 60 KB but not exactly 300 × 80. Some apps shrink the file without changing the pixels.
• Not really a JPG. A screenshot of a signature is usually a PNG. Renaming it does not change it. The tool always saves a real JPG.
• Sideways. Photographed with the phone turned, it can arrive on its side. The tool turns it the right way up using the note the phone stores in the photo. If it is sideways in your gallery too, rotate it there first.
• Over 60 KB. Almost always a photo that was never resized. At 300 × 80 a signature is a small file.
• Grey or shadowed paper, faint ink, a squashed signature. The upload box may take these, but anyone who reads your application sees a poor signature. Choose Signature so the paper is made white, and check it at actual size.

What the tool cannot do

• It cannot fix a signature that is broken, smudged or cut off in the photo. Sign again and take a new photo.
• The clean-up is made for plain paper. Printed lines, a stamp or writing behind the signature may not go away.
• It does not draw a signature for you. It works with a photo or scan of your real one.

Some exam forms ask for the opposite problem: a signature of at least 10 KB and at most 20 KB. A clean signature is often smaller than that minimum. Signature Resize handles that: when the signature on its own comes out under the minimum, it adds blank data inside the JPG to reach it, without changing the picture, and tells you it has done so.

For the photo that goes with this signature, see the 300×300 Teletalk photo guide.