I would like to know what color brown to paint the ground in a diorama. The location can be from Europe to Russia. Thanks for help.

Hi shreed,
I'm using acrylic burnt umber for base color, after that when ground is dry oils - mix of raw umber and burnr siena, even sometimes adding some grey. Few posts below You can see my dio in progress post. Hope it helps.

Depends what type of ground your diorama will represent. There's everything from desert to rain-forest in the area you mentioned, so you need to be exact with where the dio will take place. Saying that, your base colour is only there to cover the basic material used to build the base, so that when you add on all the grass, dirt, mud, rocks, and general detritus, you won't see some bright blue or white or whatever showing through the small gaps.

If you're going with a temperate, forested area, any medium to dark brown colour will do. Dapple on a little green too if there will be copious amounts of green ground cover added on later. Dryer areas or deserts will need light browns and tans, or even some reddish brown if the area dictates it.