This study aims to investigate factors affecting the appearance of print on both opaque and transparent substrates. In particular it looks at factors from five categories: the digital input, the printing system, the print, the illumination under which the print is viewed and the viewing environment in which it is viewed. The key method underlying the work described here relies on identifying a range of factors in these categories and having alternative states for each factor, e.g., the substrate factor can be ‘plain paper’, ‘glossy paper’ or ‘newsprint’. A reference state is then defined for each factor and alternative states are compared with the reference one factor at a time. The comparison is in terms of color differences between patches of a test chart obtained in the reference and an alternative state. The results for factors are then viewed both individually and by grouping all factors of a given category together. Finally the results indicate the magnitude of the change that can be expected due to a given factor or category and this makes it possible to order factors in terms of the magnitude of visual difference they can cause when altered. Having such an ordered list is then of use both in improving printing systems and in dealing with customer service queries.