Based largely on JuanHidalgo Miniatures 'Eavy Contrast video, this is how I painted the main armour and trim colours of this Alpha Legion Chaos Space Marine. I haven't covered the scale effect on this leg here, for this I would recommend checking out his full video. It really is excellent.

Blue/Green Armour

1. Basecoat the miniature in Vallejo Metal Color Duraluminum . You could use Leadbelcher if you are in a pure GW mood.
2. Shade the inside of all armour panels that will be coloured with Black Templar , you may want to get the deep recesses too. Make these lines nice and thin.
3. Glaze the higher parts of the panels and any raised portions with a brighter silver (like Vallejo Metal Color White Aluminum .
4. Paint all of the panels with a 1:1 mix of Akhelian Green and Contrast Medium . Avoid the armor trim where possible.
5. Edge highlight all of theblue armour with your lighter silver. I used Vallejo Metal Color White Aluminum again.
6. Glaze the lower portions of the coloured panels with Warp Lightning , thinned with Contrast Medium . I would recommend recess shading relevant parts with this mix too.

Silver Trim

1. Neaten up the trim of the armour with Vallejo Metal Color Duraluminum again.
2. Wash all of the armor with Nuln Oil and Lahmian Medium mixed 1:1.
3. Once dry, pop some more of the Nuln Oil and Lahmian Medium into deeper recesses or places you want more shadow.
4. Selectively edge highlight the extreme edges and high points with Vallejo Metal Color White Aluminum .