Thank you both.
Actually the metal technique is very simple, although I experimented it for the first time on this piece. When your HU 85 layer is starting to dry - let's say, half an hour after painting - put an used well dried brush into your bottle of graphite powder, then brush the armour with it, roughly, without paying attention to details and the amount of powder. The powder in excess with not adhere and only a very thin coat will remain on the surface of the armour. The wetter your base coat, the shinier the armour.
Be careful and prepare your painting schedule well, or the powder will pollute the surrounding areas, including the base and most important, your fingers.
After complete drying (I suggest 24 hrs minimum in order for the thinners not to interfere between each other), you may repesent the shadows (juncions between the plates mainly) with controlled washes of blue black.
