Perceptual transparency

Although he was not the first author to study the phenomenon of transparency illusion, the Gestalt psychologist Metelli was probably the one who made the major contribution to the problem.

Although physically correct in a number of situations, the filter model never gained a significant role in the prediction of perceptual transparency.

In spite of being much more complicated than the episcotister model, it doesn’t lead to significant improvements in predictions about the occurrence of the illusion.

Masin and Fukuda (1993) proposed as alternative conditions for transparency to (i) and (ii) the ordinal condition p Є (a, q) [or q Є (p, b)], that was shown to agree better than episcotister model with transparency-judgements performed by naïve subjects in a yes-no task (Masin 1997).

According to the model, transparency illusion would be generated by coherent convergence and translation in colour space.

However, also in colour space, evidence was found in which the perceptual appearance does not reflect the physical model.

For instance, D'Zmura et al. (1997) showed that equiluminant convergence and translation in colour space can elicit an impression of transparency, even if no episcotister nor physical filter can generate this stimulus configuration.

Chen and D'Zmura (1998) showed deviations from the predictions of convergence model when the transparent regions have complementary hues.