No Contrast on this armor!
I used this Jack of Clubs How to Paint Raven Guard video as a basis. https://www.youtube.com/watch?v=wLF7buMfyLQ
I ended up going through 4 or 5 test models of "hmm could use more/stronger highlights" until I was happy. In the end the highlights look way too strong right after airbrushing (had a small panic attack after highlighting 15 guys this way), but the wash at the end brings everything way down.
1. airbrush prime Vallejo Surface Primer Black
2. airbrush base Vallejo Game Air Black (in case I have to do any touch-ups)
3. large airbrush highlights of Vallejo Game Air Sombre Grey
4. smaller airbrush highlights of Vallejo Model Air Light Blue RLM65
5. edge highlight Vallejo Model Air Light Blue RLM65 (they don't make a non-air Light Blue RLM65)
6. heavy wash of 100% The Army Painter Dark Tone (this really helps to tone down the highlights and smooth the transitions)
That's it! There is a little bit of skill involved in the airbrush highlights and the edge highlighting, but it's mostly just technique/recipe!