Here is a painting of how the Cologne cathedral looked shortly after its completion: http://www.altertuemliches.at/files/langl_dom_352613_01_kl_0.jpg http://www

Here is a painting of how the Cologne cathedral looked shortly after its completion: http://www.altertuemliches.at/files/langl_dom_352613_01_kl_0.jpg http://www.altertuemliches.at/files/langl_dom_352613_01_kl_0... During the WWII bombings, the cathedral was damaged at the front, which was repaired only recently. The original color can also be seen there: http://in0.bilderbuch-koeln.de/bilder/k%C3%B6ln_altstadt_nord_dom_nordturm_ehemalige_stelle_der_domplombe_l%C3%BCrbke_anicursor_643b37061_600x450xcr.jpeg http://in0.bilderbuch-koeln.de/bilder/k%C3%B6ln_altstadt_nor... As you can see, the repaired area is already blackening again. AFAIK, this is inevitable with this kind of stone.