Ink on paper → transparent PNG, under 20 KB
White paper in. Transparent PNG out.
Upload a photo of ink on white paper; the browser thresholds to pure black-and-white then maps white to transparency. The result is a transparent PNG under 20 KB that sits cleanly on any form — no Photoshop, no upload, no white box around the strokes.
- 100% client-side
- Nothing is uploaded
- No account
- Canvas / WebAssembly on your device
Loading compressor…
The four-step transparent pipeline
- Shoot right. Black gel pen on plain white paper (not ruled), daylight, no shadow, fill ~60% of the frame. Colour ink or ballpoint blue photographs poorly — black photographs to a clean bitmap.
- Threshold. The tool turns the grey photo into pure black/white. Move the slider until strokes are solid and paper grain vanishes — around 120–160 works for most daylight photos.
- White → alpha. Pure white becomes transparency; black stays opaque. The checkerboard preview is what the portal sees — if you still see a white rectangle, the threshold is too high.
- Cap to 20 KB. The PNG is quantized and cropped to the strokes; a typical 700×260 px signature lands at 8–18 KB. If you need 10–20 KB band, set the floor; the tool pads with zero visual cost.
Why signatures get rejected (and why PNG vs JPG matters)
| Rejection | Actual cause | Fix |
|---|---|---|
| “White box around signature” | Opaque white background instead of transparent | Threshold correctly; download transparent PNG, not JPG |
| “File too large” above 20–30 KB | Colour photo + no crop | Crop to strokes, threshold, quantize — colour photos are 3× larger |
| “Blurred / pixelated” | Small source + upscaling, or JPG re-encode | Shoot close (60% frame), output PNG — JPG fuzzies ink edges |
| “Invalid format” | Uploading JPG where transparent PNG expected | Check notification: photo fields want JPG, signature fields often want PNG |
Do not upload a passport photo as your signature, or vice versa — validators check aspect ratio (signature ≈ 3.5×1.5 cm, 140×60 px) and reject a square crop.
Which KB and pixels for which exam
| Exam / portal | Signature size |
|---|---|
| SSC family | 4×2 cm, 10–20 KB JPG/PNG |
| IBPS / RBI / SBI | 140×60 px / 160×60 px, ≤30 KB |
| RRB | 3.5×1.5 cm, ≤100 KB |
| NEET / JEE | 3.5×1.5 cm, ≤30 KB |
| UPSC | 3.5×1.5 cm, ≤300 KB (generous) |
When the notification publishes a band like 10–20 KB, set both Maximum and Minimum so the file lands inside it. A 7 KB PNG fails a 10 KB floor just as a 25 KB one fails a 20 KB ceiling.
Frequently asked questions
How do I make a transparent signature PNG?
Shoot black ink on white paper, upload here, drag the threshold until paper grain vanishes and strokes stay solid, then download the transparent PNG. The checkerboard preview is what the portal sees.
Why is my signature rejected as “white box”?
You uploaded an opaque JPG or a PNG whose white was not mapped to transparency. A correct signature shows a checkerboard behind the strokes in the preview — no white rectangle.
What pen and paper photograph best?
Black gel pen on plain white (unruled) paper in daylight, no shadow, filling ~60% of the frame. Blue ballpoint and ruled paper photograph to noisy greys that threshold poorly.
What KB and pixels for SSC and IBPS signatures?
SSC: 4×2 cm, 10–20 KB. IBPS/RBI: 140×60 px, ≤30 KB; SBI: 160×60 px, ≤30 KB; RRB: ≤100 KB; NEET/JEE: 3.5×1.5 cm, ≤30 KB. Always check your notification.
Is my signature uploaded?
No. Thresholding, alpha mapping and PNG quantization all run in this tab with Canvas/WebAssembly. Nothing is uploaded or stored.