PURPOSE: To detect rapidly and accurately the positions of images to be printed without damaging a film before printing by developing an imagewise exposed film having a photographically transparent layer and by magnetically recording the positions of images to be printed with a magnetic head.

CONSTITUTION: Plural films each having a photographically transparent magnetic layer are joined together at a joining section 1 after photographing. The resulting film is continuously developed, fixed, washed, and dried in a processing section 2, and it is rolled up. The film is continuously sent to a detecting section 3, where it is stopped when an edge of each image is detected, and the position of the image is recorded on the suitable part of the film with a magnetic head. An image requiring no printing is passed without recording the position. The film is rolled up again, each recorded position is read with a magnetic head to stop the film, and printing is carried out with a printer 4. Thus, the positions of the images to be printed can be detected rapidly and accurately without damaging the film, and printing can be carried out.