In an earlier article the authors related visually-scaled large colour differences to Delta E* values calculated using four colour-difference formulae. All four metrics yielded linear regressions from plots of visual colour difference against Delta E*, and Delta E-94* gave the best linear fit, but the correlations were rather low. In an effort to clarify matters, the previous investigation is expanded to include data not hitherto examined. The link between visual colour difference and Delta E* colour metrics is further explored in terms of a power law relationship over a wide range of lightness, hue, and chroma variations within CIELAB colour space. it is shown that power-law fits are superior to linear regressions in all cases, although correlations over lar ge regions of the colour space are not very high. Parti- tioning of the experimental results to give reduced data sets in smaller regions is shown to improve correlations markedly using power-law fits. Conclusions are drawn concerning the uniformity of CIELAB space in the context of both linear and power-law behavior. (C) 2000 John Wiley & Sons, Inc.