Abstract
In achromatic transparency, Beck and Ivry (1988) have found that color scission may be imperfect, i.e., observers may report that the color of the background seen through the transparent region differs from the color of the background seen directly. The present study tested whether the probability of occurrence of imperfect scission predicts the extent of perceived transparency. Experimental stimuli consisted of a bicolored rectangle with a transparent square placed on the center of the rectangle. Let P and Q be the luminances of the left and right halves of the transparent region and let A and B be the luminances of the left and right halves of the rectangle outside the square, respectively. Four values were used for each of these luminances. Of all possible combinations, those that satisfied the relation A < P < Q < B were used for the experimental stimuli. Subjects had the task to report whether the colors seen through the transparent region on the left and right halves of the background were equal or differed from the colors seen directly on the left and right halves of the background, respectively. Subjects also rated the extent of transparency of the transparent square on a 1–99 scale. All subject showed imperfect scission. It has been found that the extent of transparency was equal to the product of a proportionality constant multiplied by the arithmetic mean of the proportion of reports that scission was imperfect in the left and in the right parts of the transparent square.
Special thanks to Prof. Masin for his important suggestions