The purpose of this study is to make clear the relation between the physical condition of the visual task and the visibility when the task is covered with a uniform veiling reflection. The main results obtained in this paper are ; 1. The Visibility of such a task can be prescribed by the following two factors, "apparent background luminance" and "apparent luminance contrast" which account for the additional luminance caused by the reflection. 2. The evaluation of readability of the task above the visual threshold correspond to the "VEL ; visual ease level" which is presented by Sato et al.. This means VEL is an available index in the case that the task is covered with some veiling reflection. 3. The threshold of readability of sentences and that of Landolt ring coincide well with each other.
