A psychophysical study of the Fuchs phenomenon.

The Fuchs phenomenon (ie the perception of transparency when the object seen through transparency lies on a homogeneous background, and does not jut out from under the transparent layer) has been studied by the numerical-rating method in two experiments, with the use of achromatic colours. The results of the first experiment show that the degree of transparency depends on the difference in colour between the object and the background. The results of the second experiment suggest that the processes producing the phenomenon are different in nature from the processes producing the kind of transparency most frequently studied in which the object juts out from under the transparent layer.