This is my take on the Betrayers of Pain colour scheme featured in White Dwarf 332/333. I decided to go for a rusted silver trim rather than purple.

The main colours for this scheme are a sickly green and rusted iron.

General Information:

My general method is to lay down all the base colours for the model, then do all the shading in the recesses before moving on to the highlights.

I don't own an airbrush, so the recipe will mainly consist of brush on paints.

Priming:

I find the metallic sprays from GW tend to be a little on the transparent side, so an initial undercoat of grey helps.

1. Prime the model lightly with Mechanicus Standard Grey
2. Prime over that with a coat of Leadbelcher

Silver (Armour Trim):

I generally start with the armour trim so that any time I get paint on another piece its easy to cover later.

1. Drybrush over the model lightly with Leadbelcher to even out the colour.
2. Shade the recesses and around any rivets with Athonian Camoshade
3. Add rust around rivets and on lower surfaces with Skrag Brown thinned 1:1 with Lahmian Medium
4. Highlight fine points and sharp edges with Stormhost Silver

Green (Armour Panels):

1. Base the areas with Deathworld Forest
2. Shade the recesses with Athonian Camoshade
3. Highlight the edges with Nurgling Green
4. Highlight fine points and sharp edges with Ogryn Camo

Black (Details - Armour Ribbing, Cables):

1. Base with Abaddon Black
2. Highlight the edges with Eshin Grey
3. Highlight sharp edges and fine points with Dawnstone

Beige (Details - Belts, Wraps):

1. Base with Zandri Dust
2. Shade the recesses with Agrax Earthshade
3. Highlight the edges with Ushabti Bone

Brown (Details - Leather Pouches):

1. Base with Rhinox Hide
2. Shade the recesses with Agrax Earthshade
3. Roughly highlight the edges with Skrag Brown
4. Add a finer highlight of Ushabti Bone allowing for some Skrag Brown to show through

Red (Details - Lenses):

1. Base with Mephiston Red
2. Shade the recesses with Agrax Earthshade
3. Layer the middle with Wild Rider Red
4. Add points of Fire Dragon Bright