The color scheme for the playing surface is predominantly black.

Paint the whole surface black. put it on nice and thick and get it into the crevices.

A note about what paint to use. Any kind of a cheap acrylic or arts and crafts paint is quite sufficient for this. Do not use spray paint. Most spray paints have a chemical in them that will melt the foam.

If you really want to use a spray paint for this step you can use something called Krylon H2O paint. It is latex based and will not melt the foam. But it can be tricky to find. I have seen it in hardware stores.

If you have any question about the paint you should simply do a test painting on a small spare piece of the foam.

Once it is painted set it aside and let the black paint dry completely. Put a fan on it to speed it up if desired.

Now let's Dry Brush it

Dab some white paint onto a soft brush then dab most of that white paint off the brush onto a rag. The brush now has just a little bit of white on it.

Then lightly and with quick motions brush over the surface of the dungeon. Only a little bit of paint gets onto the surface. And none of it goes into the cracks we cut. It is quite ok for it to be very iight. You can simply go over it multiple times until you get it the shade that you want.

And you can use different colors like grey.

Once you are satified with how it looks set it aside to fully dry. It won't take long.

Let's Seal it for durability and so the colors don't fade.

You can use any type of white glue including Elmer's glue or PVA glue (white glue). Mix it 50/50 with water.

Or you can use Mod Podge Gloss for a really good seal.

Both the white glue and the mod podge will dry clear.

Either way brush on a nice liberal and thick coat being sure to get into the cracks.

This next picture shows it completely dried. It is sealed, durable and strong. It also has a little bit of shine to it. If you don't want the shine you can use Mod Podge Matte.

Let's continue and make the walls of the dungeon