[obsoquasi]

Hi, wchutt, thanks for the hint, I actually already have this book and checked it again if it contains a solution. It's an awesome book for lighting, but it doesn't answer my question though. Imagine the shadow pattern that conventional window blinds make on the wall in the morning hours, I am looking for that kind of distinctly sharp shadow patterns. Conventional strobe bulbs are already to large to act as a point source at close range.