The viewing angle relates to the angle, beneath which the contrast is better than 10:1. These are normally values of 160° to 178°. These values do not provide any information about what enormous differences in contrast may result within the viewing angle. The contrasts should not change significantly for users with a perpendicular view and a slightly side-on view. It must not make a difference whether the viewer is looking at the middle of the image or the edge of the image. How much the contrast stability varies with different LCD technologies is best checked using a measurement diagram or by a direct visual comparison. The more stable the contrast in the user's viewing frustum, the better the image rendering.