Signature size in KB — the two ranges portals actually print

Signature uploads fail more often than photographs, and for a boring reason: the rule has a floor as well as a ceiling, and most tools only respect the ceiling. Ink on white paper compresses so efficiently that a neat crop lands at five or six kilobytes, comfortably under a ten-kilobyte minimum, and the portal returns an error that sounds like nonsense until you understand it.

Two ranges cover almost every Indian form. Ten to twenty kilobytes is the banking and commission standard: the Institute of Banking Personnel Selection prints it alongside a one-hundred-and-forty-by-sixty pixel box, and the Staff Selection Commission prints the same kilobyte range with a six-by-two centimetre box instead of pixels. Ten to one hundred kilobytes is the National Testing Agency range used across the medical, engineering and university entrance tests, which is far easier to satisfy.

Pages for other numbers — five, twenty-five, thirty, forty, fifty, sixty kilobytes — were removed. They existed on the strength of search demand rather than any published rule, and they now forward to the signature tool with the number filled in, which is what a visitor wanted anyway.

There is one exception worth knowing about. The Staff Selection Commission captures your photograph live inside its application module and asks you to upload only the signature, so for those forms the signature file is the single image you have to prepare correctly.

The advice that prevents most retakes is physical rather than digital. Sign inside a drawn rectangle with roughly the proportions your form wants, using a black or dark blue medium-tip pen. Photograph the paper flat in daylight so the box fills the frame. Then trim the margin, clean the background to white, and only after that worry about the kilobyte window. Doing it in the reverse order produces a thin, grey, tiny signature that fills the portal's box with almost nothing.