<title>Appearance match between hardcopy and softcopy using lightness rescaling with black point adaptation</title>

Abstract

When we view a softcopy image on a CRT display, typical CRT white point color temperature is 9300K and standard ambient light is 5000K. In this case, the black on the CRT screen is lightened and the chromaticity of the black is far from the achromatic axis because of the reflection of ambient light on the CRT displays. Also, when viewing hardcopy in the same environment as a CRT monitor, the chromaticity of the printer black is far from the achromatic axis. If such a printer were the source device and CRT monitor the destination device, dark printer colors cannot be reproduced on the destination device because, for dark colors, the gamut of the destination is smaller than the gamut of the source. Thus, lightness compensation is needed to reproduce dark colors on destination device. Three methods were considered:(1) Simple lightness compression method, (2) Complete black point adaptation method that consists of mapping to the CRT black, (3) Incomplete black point adaptation method that is a compromise between method (1) and (2). Visual experiments were performed to investigate these methods. The results indicated that the appropriate black point adaptation ratio is located between softcopy and hardcopy black points.

Reproducing room appearance on displays

“…The color appearance model, CIECAM02, was recommended by the International Commission on Illumination (CIE) to predict the appearance of colors under different viewing conditions and to help achieve accurate cross‐media color reproduction. In order to achieve a better model performance under a wide range of viewing conditions, it is required to set the correct viewing parameters in the model for different applications such as the values of the luminance factor of the background, the luminance of the adapting field, the background, and the surround, which includes a dark surround, a dim surround, and the so‐called average surround. Hence, several experiments have been conducted to verify the model, to extend the model, and to derive new scales for specific applications.…”