There's going to be a presentation of my photos taken in Berlin and Potsdam on our second visit there of last year, the one in October, and it is going to be done by beamer ... is there anything I need to observe? In how far will the presented images differ from my screen (i.e. the way I see them and like them)? I hear they are darker? And beamers cannot produce true black? What is there to know and how do I have to treat my images beforehand?