Originally, I hadn't planned on publishing a step-by-step guide to my painting process for the tombs, but I took plenty of photos as I was painting the smaller tomb, so here we go...
I paint using a mix of colors from the following brands, in the description each is marked as follows: Citadel (GW), Formula P3 (P3), Army Painter (AP), Vallejo (V), and Liquitex Burnt Umber Transparent Ink (brown ink).
Priming and Base Spray
Once everything was assembled and the foam coated with a couple layers of Mod Podge to protect it, I sprayed it with black primer (either Duplicolor Sandable Primer, or Bright Touch Primer are my recommendations, depending on availability). After the primer, I gave the whole thing a dusting of brown (Model Masters Light Earth) and then hit the stone areas with some grey (Bright Touch grey primer).
Painting the Stone
The stone was drybrushed with a mix of AP Uniform Grey and P3 Bastion Grey. Anywhere that it got too light, or filled in the cracks, I used some GW Nuln Oil to apply shading.
Then, I washed a few individual stones with GW Agrax Earthshade, and applied some patches of P3 Ordic Olive to add a bit of mossy green weathering. Then I hit everything with a final drybrush of AP Uniform Grey lightened with some AP Brainmatter Beige.
Basecoating the Dirt
I touched up the dirt, giving special attention to the areas around and between the stones, with a mix of P3 Battlefield Brown, brown ink, and a little P3 Gun Corps Brown. I used fine brushes in the tight corners and larger brushes to blend out the brown on the open areas of ground.
Finishing the Rocks and Dirt
I washed the rocks with a mix of GW Agrax Earthshade and P3 Bastion Grey. I wanted to give them a grey-brown hue so they would stand out from the dirt but not be as grey as the stonework. Then, I drybrushed the earth with a mix of GW XV-88 Brown and P3 Gun Corps Brown. This was followed by a drybrushing of GW Screaming Skull darkened with a touch of Gun Corps Brown over the dirt and rocks, and finally a slight drybrush of straight Screaming Skull over everything, including the edges of the stonework.
Painting the Metal
To paint the metal, I first basecoated it all with black, mixed with a touch of P3 Pig Iron to give it a very dark metallic hue, like black wrought iron. Over this, I liberally washed patches of P3 Bloodstone, brown ink, and orange in different combinations to crate a rusted appearance. I finished off the metal by hitting the edges with straight Pig Iron in a few places.
I also applied some rust streaks on the stonework with P3 Bloodstone and brown ink. I painted the rust as a vertical line, following the contour of the stones, and feathered out the bottom of the streak with a dry brush.
Painting the Bones
I basecoated the bones with a mix of GW XV-88, brown ink, and a tiny bit of GW Screaming Skull.
Then, I overbrushed the bones with Screaming Skull, taking care on the smaller pieces not to get any paint on the stones.
The bones were then shaded with a mix of brown ink and GW Agrax Earthshade, thinned with GW Lahmian Medium.
Once the shade was dry, I finished it up with a drybrush of Screaming Skull, and a little AP Brainmatter Beige for the final highlights.
The last bit of painting was on the bags– These were simply basecoated, shaded, and highlighted with the same browns I used for everything else.
And that's it! I'm using this same process on the larger tomb, but it is taking much, much... much... longer. I'll tackle the flock, grass, and vines on everything once the large tomb is painted.