By my engagement at the RWTH University of Aachen I have the task to documentate all wall areas of the historic town hall: in- and outside. One special part of this are eleven historistical wall-paintings called the Rethel-frescoes and made in the 19th century. They are named in memory to one of their artist: Alfred Rethel (AR). Four other are done by Johann C. Bollenrath (JB) und the last two ones are made by Albert Baur (AB). The in-scale documentation was necessary for a general restauration of the artwork.