Tips for a good signature scan
- Sign with a dark pen on plain white paper, large and with space around it.
- Photograph or scan in bright, even light and hold the camera straight above the paper.
- Turn on Clean background to whiten the paper and darken the ink. The result is greyscale.
- Crop close to the signature, using the box locked to your target shape, so it stays readable at small pixel sizes.
What Clean background does
It measures the darkest ink and the paper brightness in your picture, then pushes the paper to white and the ink darker. This hides grey shadows and paper texture, and usually makes the file smaller too.
The result is greyscale. Turn it off if you need to keep the original ink colour.
KB, pixels and DPI explained
- Pixels are the width and height of the picture. More pixels means more detail and a bigger file.
- KB is the size of the file on disk. At a fixed pixel size it depends mostly on JPEG quality and how busy the picture is.
- DPI only converts centimetres to pixels. A 3.5 × 4.5 cm photo at 200 DPI is about 276 × 354 pixels. The file itself does not change with DPI.
When a form asks for centimetres, pick cm or mm above and set the DPI the form mentions. If it does not mention one, 200 DPI is a common choice, but check the notice.
Questions
Is my photo uploaded anywhere?
No. The image is processed in your browser and the page blocks network requests, so it never leaves your device.
Does it remove EXIF and GPS data?
Yes. The output is re-encoded from pixels, so camera details and location data from the original are not included.
How does it reach your signature KB range?
It sets the exact pixel size, then searches JPEG quality for the highest value that stays under your maximum. If the file ends up below your minimum, it adds invisible comment bytes to the JPEG so the size reaches it.
What if the file is still too big?
Lower the pixel dimensions, crop tighter, or raise the maximum if your form allows it. The tool shows the smallest size it could reach and suggests smaller dimensions.
What size should a signature be?
It depends on the form. 3.5 × 1.5 cm and 10 to 20 KB are common starting points here, but read your official notice and edit the fields to match.