The video gives an introduction to the so-called Köhlering of a light microscope, i.e. the adjustment of optimal contrast and brightness according to the method developed by August Köhler, which can be carried out for most light microscopes in this or a similar form. The process is demonstrated using a plant specimen as an example, but the focus is on the technical/optical details of setting the microscope. The video is aimed at students in the first semesters who want to prepare for microscopy practicals.