With the release of high‐brightness and high‐chromatic OLED displays, color characteristics have become different from existing displays. The saturation of each pixel increases, and the luminance range widens, resulting in an H‐K effect that looks brighter than the actual luminance. This is a phenomenon that looks bright due to high purity and cannot be measured. In this paper, we intend to quantify the color characteristics of OLEDs using perceptual lightness predicted by color appearance model (CAM16) and measured luminance values. A new model to predict the H‐K effect was suggested as ‘Color Strength’ using the perceptual lightness and luminance. As a result, the values of QD OLED, W OLED, and LCD were compared by calculating the Color Strength.