A color display includes multiple composite pixels, each composite pixel including sub-pixels of more than one color type. Sub-pixels of at least one of the color types are provided with differing luminance capability in different composite pixels. Each composite pixel may include red, green and blue sub-pixels having different luminance capability in different composite pixels. The differing luminance capability may be achieved by providing sub-pixels of at least one of the color types of differing relative area. An image data processing unit (IDPU) receives input image data of a standard format, and modifies the input image data into output image data for display to account for a discrepancy between the luminance capability based on the differing luminance capability or differing size of each sub-pixel, and a luminance capability as expected based on the input image data. The IPDU then outputs the output image data to control the composite pixels.