Abstract: A method for compensating for the non-uniform color appearance of a color display is disclosed. Since there are variations of the chromaticity coordinates for each primary of every pixel in a display, the color appearance is not uniform. From the distribution of the chromaticity coordinates of the original primaries, we can choose a set of virtual primaries so that the chromaticity coordinates of each virtual primary can be produced by the original primaries in every pixel. The virtual primaries are used as the primaries of the display in stead of the original primaries. Because the chromaticity coordinates of the virtual primaries are the same for all pixels, the color appearance can be made to be uniform. This method is called the virtual primary method. LED displays are taken as an example to show this method.