The word "photoptosis" is Greek, meaning roughly „incidence of light“. In the Prélude, this process refers to the changes of color occurring by the way the light comes in: here in the field of tone colors in the broadest sense. The inspiration behind this composition was the monochrome wall areas of the foyer at the Musiktheater im Revier, Gelsenkirchen decorated by Yves Klein. Bernd Alois Zimmermann. But, there is one unknown sharp which has 3 lines (2 that is going up/down and 1 going right.) In this unknown sharp, it says that this sharp will be "a microtone higher" (which is understandable since I like microtonal music as well).