Transition between color contrast and assimilation by perceived size manipulation

The purpose of the present research is to show that color contrast can be also achieved by manipulation of perceived size and to generalize the idea that perceived size is more fundamental to color contrast and assimilation than retinal size of images. In the experiment we assessed color appearance of grating for three color combinations with four stripe widths from 4.6 to 18.6 min. at three vergence angles. Assimilative/contrastive color shift occurred when the vergence was larger/smaller and stripe appeared narrower/wider. Since both of stripe width of retinal image and subject's vergence affect perception of stripe width, we analyzed the size and direction of color shift in terms of perceived width. It was shown all color shifts were attributed to change in perceived width, which suggests perceived dimension is more fundamental then retinal dimension in color perception.