Best Practices When Signing on Paper

Use a smooth black or dark blue ink pen on clean, unlined white paper. Avoid ruled notebook paper, as grid lines interfere with digital thresholding.

Write at your natural scale. Making the signature overly small makes it harder for your phone camera to capture clean stroke edges.

Capturing the Shot with Your Phone

Place the paper near a window or daylight source so light falls evenly across the surface. Angle your phone directly parallel to the paper to prevent perspective distortion.

Keep your hands or phone from casting a harsh shadow directly over the handwriting.

Removing Shadows and Whitening the Paper

Digital signature tools use brightness thresholding to separate ink from paper. Any pixel brighter than the threshold turns pure white (#FFFFFF), eliminating grey casts.

Ink pixels darker than the threshold are darkened to pure black or deep blue, creating razor-sharp stroke definition.

Framing Tight Margins and Exporting

Crop tightly around the signature, leaving a small, balanced margin of white space around the outermost pen strokes.

Because the background is pure solid white, file compression is extremely efficient, easily keeping the exported file under 20 KB.