CAVEAT - Yes, I KNOW brick colour varies by location!
Anyway...
I have some resin brick walls - some of 7 courses, some of 9, respectively approx. 15mm and 20mm in height, so the bricks are about 2mm height. The bricks are regular - not like a dry stone wall On top there are capstones. This makes them very approximately 1:30 scale.
What should I paint them? I want the most generic I can, as they will have to be good for North of England, downwards, through to Western France, possibly WW2 Italy. As they have capstones we could be looking at a soft clay, with a harder clay on the capstones.
Cheers.
Whitewashed. Completely location & era agnostic.
Prime bricks black.
Drybrush to pick out the bricks with German camo medium brown Vallejo 826
When dry lightly drybrush the bricks with Dark yellow Vallejo 978 (or a sandy colour)
When dry Very light drybrush with ivory.
This will give you a very generic brick finish. You could also use a Brick red instead of the brown, but this gives a more European look.
Coping stones in contrasting colour like grey. Again drybrush from a dark to light grey
Coat d'arms- brick highlighted over cream base coat
Then the odd one a different hue or parr colour
Cap stones black or terracotta orflat stone, depends on taste.
One thing that is very often forgotten/overlooked when painting things like brick walls or walls in general (especially plaster ones - even in desert or hot climates), is that when it rains (& it can do quite hard in the north African deserts especially) the soil/mud at the base of the wall very often splashed upwards (to a height of circa 2 feet). So the bottom of your brick wall would be a lot dirtier than the top part. Just saying.
I'd always go for red-bricks, as bricks are very transportable, often over very great distances.
Just a couple of thoughts.
Cheers
Mark