Signature to JPGTurn a signature photo into a clean JPG

A phone photo of a signature is mostly paper: grey, often with a shadow, sometimes tilted. The converter first decides which pixels are ink by comparing each one with the brightness and spread of its own neighbourhood (a Sauvola threshold), so a shadow that darkens one corner is still read as paper. The direction the ink runs in gives the angle the paper was held at; the picture is turned back by it, up to 20°.

It then crops to the ink with a small margin, ignoring isolated specks, turns every paper pixel white and sets the ink to solid black, blue or the pen's own colour. The edge of each stroke keeps its soft anti-aliased ramp, so curves are not stair-stepped. The result is fitted into the box the form asks for, padded with white, and the JPEG quality is searched until the file is inside the KB range. A very clean signature can come out under a portal's minimum even at the highest quality; the row then says so rather than padding the file with junk bytes.

1. 1Sign on plain white paper with a dark pen and photograph it in daylight, filling most of the frame.
2. 2Drop the photo here. The clean-up is already on: check the result on the stage and in the 400% view.
3. 3Adjust the ink threshold if faint strokes vanish or shadow survives; choose black or blue ink.
4. 4The SSC signature preset (10–20 KB, 4.0 × 2.0 cm at 200 DPI) is selected; pick your own form's preset in the Form panel, then press Download JPG.

The Form panel shows the clean-up at 400% so the stroke edges can be checked, and the angle it straightened by. After the file is written, the checklist reads the JPG itself: format, extension, size in KB, pixel box, DPI label and a portal-safe file name. If the portal also wants your photograph, add it to the same queue — each file can use its own preset.