Levels approximating 33 percent and 100 percent of the display luminance should be used for brightness coding.
Additional Information:
The intensities used should not be less than 6 ft-L (20 cd/mē). Intensity coding should not be used for displays with a maximum display luminance of less than 18 ft-L (60 cd/mē) or more than 29 ft-L (100 cd/mē).