The present study proposes metrics predicting level of vividness and preferred-vividness that are one of the important image-quality attributes for colour laser printers. Vividness is a term representing chromaticness of colours and also has been adopted as one of the colour adjectives in ISCC-NBS colour naming and PCCS systems. It is conceptually similar to chroma. According to ISO 20462-2, triplet comparison method, which is a new psychophysical method that involves the simultaneous scaling of three test stimuli, was performed. As a result, an interval scale for vividness was established and it was modelled as a function of mean C*_ab and L* of primary colours, e.g. CMYRGB. Pearson correlation between the metric prediction and corresponding subjective data was about 0.96. Both preferred-vividness and vividness metrics were based upon chroma and lightness but contribution of lightness is a lot higher for the former (∼ 40%) than for the latter (∼ 10%). Consequently, our vividness metric confirms earlier findings published by Nayatani in 2005.