The steadiness (English: image steadiness, French: fixité d'image) is a term used in film technology and a measure of the picture quality, so how quiet the screen looks. A good image position is characterized by a high degree of accuracy of registration of successive individual images . If the image is poorly positioned, the moving image trembles, wobbles or dances.
The quality of the image is checked in still settings .
The image status of a film presentation is influenced by various components:
- the enlargement factor for the projection (partly determined by the image size of the film format )
- the manufacturing tolerances of the film (film width and perforation )
- the play of the transport gripper and the locking pins of the film camera
- the selected copying process (intermittent or continuous)
- the film drive of the film projector , or the film guide during film scanning .
The subtotal error film and camera is z. B. determined by the accuracy of how the transport holes of the film fit together with the camera mechanics. Normal film is transported with a group of four pairs of holes per stroke.
The aim is to minimize all individual errors and the partial sum errors so that the total image stability error on the cinema projector is in the range of a hundredth of a millimeter.