A method for operating a light-emitting device includes operating, at least for some pixels, a selected subpixel of a pixel and at least one further subpixel of the pixel configured to emit light of a different color to display a pure color corresponding to a dominant wavelength of the selected subpixel and providing, at least for some pixels, a correction matrix associated with the pixel for adjusting brightness of the subpixels of the pixel, wherein the correction matrix is provided by determining, at least for some pixels, a brightness of each subpixel of the pixel necessary to emit light of a given color, determining, at least for some pixels, a dominant wavelength (λr, λg, λb) of each subpixel, plotting dominant wavelengths (λr, λg, λb) of each subpixel in a CIE-XY color space and forming color triangles, and determining inner triangles of the color triangles in pairs.