The origins of Watchmen

The Comedian, whose murder launches the story, started out with a military-style uniform, but evolved into a fearsome leather-clad figure, complete with leather mask Photograph: PR

The Comedian's evolution continued towards the form seen here (left). Early designs for Rorschach (far right) included a full-body suit, which was quickly discarded. Dr Manhattan (second from right) was originally imagined as changing colour with energy level from blue to red or white hot Photograph: PR

This early character sketch for Rorschach shows how he rapidly found his iconic form Photograph: PR

Rorschach's face changes every time he appears, so Gibbons used a selection of ink blobs made by hand to ensure variety and randomness Photograph: PR

This preliminary group shot was coloured as a guide for colourist John Higgins Photograph: PR

Some early cover designs, such as this sketch of the cover for the final instalment, survived through the development of all 12 issues Photograph: PR

Nite Owl took his name from a character Dave Gibbons created when he was about 14, though Alan Moore insisted on the "American" spelling Photograph: PR

An early pencil sketch of Dr Manhattan, the only character with genuine super-powers Photograph: PR

Early sketches for Dr Manhattan featured the most minimal of costume designs. Eventually the costume was dispensed with completely Photograph: PR

Pencil sketches (left) and final colours (right) for issue one, page 20 featuring Dr Manhattan Photograph: PR

Panels from the second chapter of the story, Absent Friends Photograph: PR

The first edition of Watchmen in France was cheaply produced and full of mistakes in translation. This is the cover for the third French edition Photograph: PR