The side of the patient’s dental arches closest to the film is recorded in focus while the side closest to the x-ray source is blurred out of focus (Figure 19). The x-ray source has a vertical slit aperture and directs the x-ray beam in a lingual to labial direction through the structures. Panoramic machines vary in style but operate according to the principles outlined above. Some models allow the patient to sit-down and while in others the patient stands. The resulting image is uniformly magnified (due to the long object-receptor distance) with some premolar contact overlapping. However, this technique produces reasonably good overall representations of the teeth and surrounding anatomical structures.