A grey-scale psychophysical experiment was carried out for evaluating colour differences using printed colour patches. In total, 446 pairs of printed samples were prepared surrounding 17 colour centers recommended by the CIE with an average dE?ab,10* of 3 units. Each pair was assessed 27 times by nine observers. The visual results were used to test some selected more advanced colour-difference formulae and uniform colour spaces. The results showed that CIELAB and OSA performed the worst, and the advanced formulae and spaces gave quite satisfactory performance such as CIEDE2000, CIE94, DIN99d, CAM02-UCS, and OSA-GP-Eu. The colour discrimination ellipses were used to compare with those of the earlier studies. The results showed that they agreed well with each other. (c) 2011 Wiley Periodicals, Inc. Col Res Appl, 2012