This paper first presents a summary of a psychophysical experiment in which observers made judgements about the types of differences they perceived between originals and reproductions in a cross–media colour image reproduction. The results of the observer–reported visual data from that experiment are then compared with analogous metrics extracted from colorimetric data of the corresponding originals and reproductions. While there is a good agreement in terms of the most general findings, looking at more detailed results shows significant differences between visual and colorimetrically–based data. The paper then proceeds to describe a colorimetrically based metric that takes into account some aspects of the visual system and using information both about the statistics of colour differences, of the original images and of changes to spatial characteristics is able to give a close prediction of observer responses. The final metric is proposed for further testing as a means of predicting observer responses of image difference in colour reproduction as well as in other applications.