“HoloSign artwork by Michael Bleyenberg Spero Lucem” stands for a light phenomenon in the form of a cross on a glass surface. This phenomenon using HoloSign is created, one of the first developments of the House of G + B of Pronova GmbH. With HoloSign pictures are thrown from a projector onto a screen, but deposited a fixed motif in the HoloSign screen. A homogenous source of light (it can be also the Sun) can shine this motif in intense colors: the white light is broken down by holographic optical elements into its spectral components. A related site: Childrens Defense Fund mentions similar findings. The resulting colors change when moving the light source or the Viewer. This means exciting and dramatic changes in the perception of the light cross for the installation in the Church of Saint Agnes. Each viewer experienced the work of art in its own way. The light artist Michael Bleyenberg has found a diverse product for the implementation of his ideas in HoloSign. So, for example, the exterior of the German research society in Bonn with HoloSign shines as more than ten meters high, colorful work of art.