I wrote this up a few weeks ago on another forum, hopefully this will help:
First step here is a a total cote of flat black. Except I use satin black, don\'t tell anybody. Because I do so much terrain, I use black paint by the quart, not the pot. It\'s much cheaper. I had mine made up from the mis-tint paint at the hardware store, only cost me $2.
2nd is a heavy drybrush of grey. Again, since I use so much, I mix it up myself. I use cheap acrylics from the craft store, this was mix of black and tapioca.
3rd is just a lighter cote, mixed from the same mix, with a bit more white, to catch highlights.
4th is straight white, only on corners, and the edges of the stone, to bring out highlights. It keeps all of the grey from running together.
5th is a light drybrushing of goblin green from the pot. You have to go light with this step, because it is very easy to overdo. It gives a nice slimy or fungus feel. It\'s not like fresh cut stone, but weathered.
6th, I do a light brushing of a dirty brown around the base. Normally I do this after it is in place on the hardboard, but skipped ahead for this tutorial. This step is to indicate that the building is part of the base around it, it collects dirt, and mud splatter from traffic, instead of simply being stone on a table.
7th and last, I\'ll go to any windows, or anywhere that water would run on the stone, and using my finger, smudge black in one move straight down. I\'ll do this again later on the roof, or on various parts of the building, to break up the color, and indicate mold and wear.
If I\'m doing something elvish, or Gondorian, I\'ll start with a grey base, and work my way up to white, essentially skipping the 4th step. I\'ll still do the others though. You can do it with brownish greys and yellows too for desert style sandstone. Really any combo you want, just build the color up gradually, and don\'t forget about weathering, that\'s what sets it off.
The painting, on such a large surface, actually goes quite quickly. It can take weeks to build a building out of foam, but just a couple of hours for paint. As fast as it dries is as fast as you can go. I\'ll commonly do step right after step, because when I get back to the side I started on, the paint is already dry.
