In a method of processing data of a display apparatus, red, green and blue data are gamut mapped as red, green, blue and white data. The red, green, blue and white data are reconstructed by means of subpixel rendering to generate metameric sets dot pixels composed for example of one such dot pixel having red and green color components and another such dot pixel having blue and white color components such that when the metameric set dot pixels is lit up it produces a white colored region on the display apparatus and when un-lit it appears as contrastingly dark colored region on the display apparatus. By selectively forcing one metameric set of dot pixels to be un-lit, the method allows an immediately adjacent metameric set of dot pixels to be lit-up as a contrasting white region on the display apparatus.