Abstract: An indicator according to the present invention is used to indicate the presence or absence of a photo sensitive material in a film holder. The indicator comprises a pivotal indicator element and a actuating element. The pivotal indicator element has a pivot at its one end and is mounted on the surface of the film holder near its exposing window. The actuating element is adapted to be moved interlockingly with the pivot upon the insertion of the photo sensitive material and is provided facing a photo sensitive material receiving channel.

Abstract: A film holder which is disclosed herein includes a inner frame defining a photo-sensitive plate insert slot between a partition plate, and outer frames each defining a dark slide insert groove between said inner frame. In this film holder, a plurality of stopper springs are formed on the peripheral sides of a body which is comprised of the partition plate and the inner frame. A plurality of hooks are formed on each the outer frames which are overlaid on the body to define the dark slide insert slot. These stopper springs and hooks are in the corresponding relationship, respectively, so that they are engaged with each other to lock the body and outer frames together in an overlaid relationship.

Abstract: Dark slides are insertable in a film holder. Each dark slide has engaging portions formed at its opposite ends of the upper edge of the dark slide. Sliding members are provided for sliding movement along the upper edge of the dark slide. Each sliding member has a locking portion at one end. A spring is provided for biasing the slide member to cause the sliding member to resiliently lock the dark slide.