[ChrisMAg2]

Since they are "buildings", they are (if ever) camouflaged with paints used for construction. These colors/ paints do not follow the RLM coloring standard (these are for a/c only), but the RAL (which is a general industrial standard) code for colors. Ofcourse this is also a matter of availaility. And especially later in the war, they used everything available.

And for occupied territory they would usually source the local market for anything equivalent/ compatible (Material and hue). If you would want to know the brand names for the (german) suppliers, you can assume the existing companies now, already existed then too.