Da Vinci’s manuscript page with his self-portrait before and (below) after it was whitened. (Reuters)

Perugia, March 1: Italian researchers believe they have unearthed a previously unknown self-portrait by Leonardo da Vinci, drawn when the artist was a young man.

The faint pencil sketch has emerged after being hidden for 500 years in one of the Renaissance genius’s most famous manuscripts, the “Codex on the Flight of Birds”.

An Italian scientific journalist studying the document noticed the faint outline of a human nose hidden underneath lines of ink handwriting.

It is thought that da Vinci first made the drawing, then later reused the same paper to write the codex.

The journalist, Piero Angela, enlisted the help of art historians, Carabinieri police forensic experts and graphic artists to tease out more details from the ghostly image.

Over months of micro-pixel work, graphic designers “removed” the text by making it white instead of black, revealing the drawing beneath. What emerged was the face of a young to middle-aged man with long hair, a short beard and a pensive gaze.

Angela was struck by similarities to a famous self-portrait of da Vinci, made when the artist was an old man.