Does the "PS version" in the printing industry refer to film similar to traditional photography technology or negative film formed after taking pictures with film?

The PS version before printing (unused) is similar to film, and the PS version after printing is similar to negative film. But this is different. PS plate is an indispensable material in offset printing. Ink is transferred through the graphic pattern on it, and then transferred to paper or other substrate through blanket to form a specific pattern. In the past, film printing was used for printing, but now CTP direct plate-making technology is used, that is, plate-making is carried out directly by computer, and there is no need to dry the film.