This is from Erich Reist’s weekly ebay photo posts from 01OCT2021. For those of us interested in discerning WW2 black and white photos, I think this photo is particularly interesting. This SdKfz 251 SPW has the pre-war/early war camo pattern of dark grey with 1/3 dark brown cloud mottling camouflage.
On operational vehicles, even a thin layer of dust mutes the demarcation lines between the grey and the brown. Here, we see a very clean SPW. Not only that, but we can see that the brown spots have a different level of sheen than the basecoat grey. Note how the light reflects differently from the spots on the left side upper armor panel. The reflection actually makes those spots appear bright! But you can see they are simply extensions of the brown camo spots below them, at a different angle.
This photo can teach us a lot!