Time to paint. First coat will be a heavy drybrush. I use all Testors acrylic paints. The base is Battle Ship Grey, but any dark grey will work.
Foam core will warp when it gets wet and allowed to air dry, acrylic paints are water based. I use a heat gun (a hair dryer will work too). It speeds up the drying time & it prevents warping. Next layer is a heavy black wash (25% black paint to 75% water)
Make sure your wash gets down in your embossed cracks & crevases. Again use your heat gun. Make sure the wash is completely dry before proceeding. Then a light drybrush of olive drab.
Then a very light drybrush of light grey
Thin out your black wash by 50% and give it another light coat, there again getting it in all the cracks. I sprayed mine down with Testors Dull Coat to seal the paint and to minimize reflection. Add figures & photograph!
Hope this helps! It actually took more time to write up this how-to than it did to make the wall. Dave
__________________
"It ain't about how hard you hit, but how hard you can get hit, how much you can take and keep moving forward - thats how winning is done!" Rocky Balboa