| Popis: |
In the literature, inductive brightness depression has been described by several authors. They have made use of different configurations of the stimulating fields. Using a haploscopic brightness-matching technique experiments were performed to establish the influence of the luminances and of the configurations of the stimulating fields. Four configurations were tested and compared, one of which had not previously been studied. Two conclusions can be drawn: 1. The configuration in which the test field is completely enclosed by a ring-shaped inducing field results in contrast effects impairing the brightness judgment. Brightness-matching becomes ambiguous in cases where effects such as opposite contrasts occur, when there is a wide separation between the two fields which have to be matched. 2. The amount of the inductive effect is greatly influenced by the extent to which the inducing field encloses the test field. To evaluate inductive brightness depression as it is influenced by retinal distance between test patch and inducing field, for example, it is important to choose a configuration which entails the symmetry of test patch and inducing field and in which the largest possible boundary between test and comparison patch occurs. |
