the Marines have scriptures and Black Templars iconography
freehnad painted on various parts of their armor
The 'dingy' white look on the shoulder pads was achieved
1) A basecoat of Bleached Bone over a Black undercoat.
2) Skull White layered on until an even coat is acheived.
3) Wash of Gryphonne Sepia.
4) Re-apply Skull White, leaving the shading visible in
You could techinically skip step 1, but it's a lot harder
to get an even tone with straight white over a black undercoat.
At this point, the models are good to go.