Sensitivity of Achromatic Color Considering Visual Attention

This study investigated thresholds for perceiving color and lightness differences in digital environments using psychophysical methods, particularly, focusing on achromatic gray against RGB primaries. As a result of the experiment, perception thresholds were derived by dividing it into JND (just noticeable difference) and JAD (just acceptable difference). For chromaticity, the study proposes JND Δu′v′ = 0.001 and JAD Δu′v′ = 0.002. For lightness, the acceptable threshold aligns with Weber fraction principles at Log(ΔL/L) = −2. This study also demonstrated the influence of luminance, hue, and presentation methods on perception thresholds. In particular, expanding the attention area in the presentation methods affects the perception of the sensitivity of color and lightness difference. These findings highlight the importance of visual attention in evaluating color differences and suggest: For sensitive evaluations, adopt low luminance conditions and side-by-side presentation methods for red and green primaries.