Tri-X is a black and white photographic film produced by the Eastman Kodak Company.

[1] The combination of hand-held cameras and high-speed Tri-X film was transformative for photojournalism[2] and for cinema.

[3] Introduced around 1940, in sheets rated at ASA daylight 200 and tungsten 160, it was one of Kodak's first high-speed (for the time) black and white films.

Tri-X 400 is usually rated at ISO 400 when processed in standard developers and remains among the fastest black and white films today.

In 2007[citation needed], Tri-X was extensively re-engineered, receiving the new designation 400TX in place of TX or TX400, and became finer-grained.