The plaster got a basic coat of wall paint. I made a mix of yellow and brown for the area around the drainage channel. For the rest of the layout I added black to this mix and painted all visible surfaces.
When the paint was dry, I started ballasting the track. A while ago I ordered a sample package of ballast at
Koemo Modellbahnschotter. It consists of six 40 ml bags of different ballast colours. I made a test with every single single type. For this layout I have mixed all colours. The uncoloured types stood out pretty obviously. To blend them in I added a small amount of “dirt” and rust weathering powders. That worked well so I the games could begin. After applying the glue, the ballast looked much darker.