Signature cropper
Trims the paper away, cleans the background to white, and lands under the KB limit your form demands.
Exam and recruitment portals ask for a scanned signature, on white paper, in black or blue ink, under a strict size limit — often 10 or 20 KB. A phone photo of a signed sheet is none of those things: it is a 3 MB image, mostly empty paper, with grey shadows.
This tool finds the ink, crops to it, forces the paper to pure white, and compresses to your target.
How to use it
- Sign on plain white paper in black or blue ink, then photograph or scan it.
- Drop it in. The ink is detected and the surrounding paper trimmed automatically.
- Pick your size limit and process.
Getting a clean scan
- Plain white unlined paper. Ruled lines get detected as ink and widen the crop.
- Black or blue ink, with a pen that produces a solid line. Pencil and fine gel pens scan faintly.
- Sign larger than usual. A big signature holds detail after it is scaled down.
- Even light, no shadow. Photographing indoors under a ceiling light usually casts your own shadow across the page — sit near a window instead.
- Shoot straight down, parallel to the paper, so the signature is not skewed.
What each option does
Trim empty paper scans for pixels darker than the paper and crops to their bounding box with a small margin. This alone typically removes 80% of the file.
Clean background to pure white pushes every near-white pixel to exact white. Uniform white compresses to almost nothing, so this both looks better and shrinks the file substantially.
Darken the ink forces the darkest pixels to solid black. Useful for a faint scan, though it can thicken a delicate signature — leave it off unless you need it.
Grayscale discards colour information. On a black-ink signature that data is pure waste, and removing it makes a meaningful difference at a 10 KB target.
Typical portal requirements
- Signature — 10 to 20 KB, JPEG, commonly 140 × 60 px minimum
- Photograph — 20 to 50 KB, JPEG, 3.5 × 4.5 cm
- Thumb impression — 20 to 50 KB
Some portals also set a minimum pixel size, so do not reduce the output width further than necessary. Use the passport photo maker for the photograph half of the same application.
Questions
What size should a signature be for an online form?
Most Indian exam portals want a JPEG between 10 and 20 KB, often with a minimum of about 140 × 60 pixels. Check your specific portal — requirements vary.
The auto-trim cropped too much or too little.
It follows the darkest pixels. Ruled lines, smudges or a shadow across the page will widen the crop. Re-scan on plain white paper in even light, or switch the trim option off.
Can I use a photo instead of a scan?
Yes. Shoot straight down in even natural light. The background cleanup handles ordinary paper tone well.
Should I use grayscale?
For black or blue ink, yes — it cuts file size noticeably with no visible difference.
Why does my signature look thin after processing?
Downscaling thins fine lines. Sign larger, or turn on Darken the ink.
Is my signature uploaded?
No. It is processed entirely in your browser and never transmitted.