This study focused on suggesting an intelligible index for evaluating gloss degrees of printed images.Psychophysical evaluation of image-clarity was performed for various kinds of paper surfaces. Additionally, cluster analysis was performed for classifying the evaluated values. As results, we found that image-clarity on a printed image and paper can be classified into 4 main categories, and quantitatively clarified that 3 main kinds of paper can be the intelligible index to describe gloss degrees of printed image . Furthermore, extent , in which observers cannot recognize differences of image-clarity, has been shown, and this result is expected to be a useful guide for determining conditions of printers from gloss quality point of view.