Add to ORKGTo determine the relative importance of colorfulness, brightness, contrast and sharpness on perceived image quality, we needed the just noticeable difference in chromaticity, black level, white level and contour rendering. Therefore, we performed a subjective experiment to measure these just noticeable differences with natural image content instead of with homogeneously colored patches. The results indicate that when using natural image content the just noticeable differences are considerably higher than what is reported in literature for homogeneously colored patches