One of the most popular black and white films

Tri-X was released in 35mm and 120 formats in 1954. Tri-X 400 is usually rated at ISO 400 when processed in standard developers and remains among the fastest black and white films today. Push processing Tri-X to a higher "exposure index" of EI 800 in a standard developer yields very good results, while further pushing to EI 1600 requires more sophisticated processing.