The contribution of binocular vision to gloss perception has been suggested in the literature [1][2]. A simple assumption is that binocular disparity plays a role in gloss perception. Nevertheless, everyone can verify that his ability to judge the gloss of a surface is maintained by closing an eye.

We have conducted a psychophysical experiment to quantify the visual perception of gloss, in binocular and in monocular vision. Ten black coated papers [3], presenting a range of specular gloss [4] from 1 to 90 were evaluated using a pair comparison method and a maximum likelihood difference scaling [5]. Six observers completed the experiment.

Results show that the mode of vision modifies the sensation of gloss only on very glossy samples (ie: specular gloss at 60° higher than 70 gu). We speculate that the influence of binocular vision in gloss perception depends upon the strategy used by the observer to carry out his judgment.

_ Observers who present results similar in binocular and monocular vision, possibly judge gloss only according to the luminance reflected by the sample in the specular direction.

_ Observers for which the gloss sensitivity increases in the binocular case, probably based their judgment of gloss on the distinctness of image (DOI), and profit from keys provided by the different views taken by each eye.

We have also noticed that the benefit from binocular vision increases as the interpupillary distance of observers decreases. Could the interpupillary distance be involved in the strategy chosen by observers to realize gloss appraisals?