Electroacoustic music, performed using only loud-speakers, does not give anything to see on stage, as there is no musician. However, if looking at the composers' writings, it appears that the visual aspect is often brought to light. This is especially true for François Bayle, who always claimed his interest for plastic arts. The analysis of the composer's writings, as well as the titles of his pieces, show three constants related to vision. These are the notions of shade and light, completed by the more general idea of transparency. A phenomenological approach makes clear that musical characteristics, such as intensity, pitch or evenemential density, are linked to each of the three previous notions. More than a secondary element, visual imagination permits to describe precise musical and poetic situations.