the center of the screen, the rest as black. The light output is measured just in this center area. Limitations with CRT video projectors result in them producing greater brightness when just a fraction of the image content is at peak brightness. For example, the Sony VPH-G70Q CRT video projector produces 1200 "peak" lumens but just 200 ANSI lumens. Color light output Brightness (white light output) measures the total amount of light projected in lumens. The color brightness specification Color Light Output measures red, green, and blue each on a nine-point grid, using the same approach as that used to measure brightness. SI photometric units See also André Blondel Brightness Luminous efficacy Lux Nit (unit) Notes References External links International Lighting Vocabulary 2nd Edition (online searchable version of international standard CIE S 017:2020 Units of luminous flux SI derived units