6.3.2-4 Off-Centerline Viewing Angle

The determination of the acceptability of off-centerline viewing should take into account both the spatial distortion of the image and the effect of the viewing angle upon screen characteristics such as brightness and color rendition.

Additional Information:
Individual viewers in a fixed location should be no more than 10 degrees off the centerline. For multiple viewers, it indicates a preferred limit of 20 degrees and an acceptable limit of 30 degrees off the centerline. This guideline addresses spatial distortion of the displayed image due to the viewing angle. However, off-centerline viewing of large-screen display devices may also result in (1) loss of general brightness for high-gain screens, and (2) loss of color rendition in projection-type devices due to the angles of reflection of the separate projection elements. Loss of general brightness for high-gain screens is usually not a problem until off-centerline viewing exceeds 25 degrees for beaded screens and 30 degrees for high-gain metallic screens. These effects may further reduce perceived resolution by reducing the effectiveness of color codes and image contrast. Thus, the combined effects of off-centerline viewing upon image distortion and screen characteristics should be considered.