Jake Gyllenhaal wears a Timex Model 84

In a fluorescent-lit San Francisco Chronicle newsroom, a file box marked NIXON on the desk between them, Robert Graysmith leans against a colleague's workstation with a paper coffee cup while crime reporter Paul Avery talks. Jake Gyllenhaal plays Graysmith in David Fincher's Zodiac (2007), and the real Graysmith was exactly what the film shows, a political cartoonist at the Chronicle who grew obsessed with the unsolved Zodiac killings and eventually wrote the books the movie draws from. On his left wrist sits a modest gold-toned dress watch on a steel expanding bracelet, time-only, the unshowy piece a salaried newspaper artist would actually own.

It is a Timex Electric Model 84, and the Model 84 is not a mechanical watch at all; it is one of Timex's electric watches, where a battery drives the balance wheel through a moving coil, a design Timex introduced in 1965. The form matches what is on Graysmith's wrist, a gold-finished cushion case with a steel back, a light gold dial with plain markers enlarged into squares at twelve, three, six and nine, on a steel expanding band with a wide dark center. It is the watch of a man whose budget and ego both run small.

Timex turns out to run all through the real case. Graysmith's own account notes that two of the Zodiac's victims, David Faraday and Paul Stine, wore Timex watches, and that the killer of Cheri Jo Bates left a broken Timex behind. There is even a second timepiece in the film, on the prime suspect: Arthur Leigh Allen, played by John Carroll Lynch, wears a vintage Zodiac Sea Wolf dive watch, so a movie called Zodiac quite literally puts a Zodiac on the man the investigators most want to be guilty. The dial of Graysmith's Timex is too small to read on screen, so the call rests on the watch's shape, but it is plainly there on the right wrist in the right scene, and it looks the part.