Research on large color difference evaluation using printed samples

A grey-scale psychophysical experiment was carried out for evaluating color differences using printed color patches. In total, 100 pairs of printed samples were prepared with an average ΔE*
ab
of 13.8 units. Each pair was assessed 60 times by a panel of 20 normal color vision observers. The visual results were used to test the existing color-difference formulae. The results showed that all formulae gave quite satisfactory performance except OSA-Ep-Gu, which is the formula for calculating the magnitude of small-medium color difference. The optimized k
L
values were used to compare with the medium color difference (MCD) of the earlier studies. The results showed that they agreed well with each other.