Image line
The image line is the unexposed area between the phase images on a film strip. It is at the same height for every image format and is used as a reference when threading the film into the copier and film projector ; it also determines the point at which film cuts are made. With narrow film 8 mm film , Super 8 , it is very narrow, here the individual images almost collide and the splices are clearly visible. Even with 16 mm film, the image line width is not sufficient to accommodate a wet glue point. In the case of a dry adhesive, however, the transparent adhesive tape covers two entire images and the line of the image is retained. On the other hand, with normal film , Academy format , it is 3 mm wide, so that the wet glue areas are invisible.
In film copies of the frame line is often falsely attributed to the 16: 9 - format bar equated. This, however, is optional and has the task of covering that which does not belong to the picture. As a rule, it is black, and annoyingly sometimes white (copier error) so that, among other things, the image format can be correctly determined. Quality copies have double-exposed image lines, blackened through to accommodate footer titles.
In the USA , the full-screen window is very popular, which only creates a narrow line of images. The picture window mask in the cinema projector limits the film image to the desired aspect ratio . With television, however, almost the entire picture (normal picture, 4: 3 or 16: 9) is shown, which means that some microphones are visible and the composition of the picture may suffer.
In the cinema
The condition in the cinema is also referred to as “image line” or offset when it becomes visible - that is, when the presenter has made one to three perforation holes wrong after a film tear or when linking the individual acts .
This can be temporarily corrected using the height adjustment device or the picture window in the projector (in many cinemas it can also be remotely controlled from the hall). Since the offset would occur again at the next performance, the splice should be corrected beforehand.