Could you show me how to paint a realistic armoured character?
Painting armour is all about light and how it reflects off the metal plates. When you look at characters in polished, shining armour, those highlights are all reflections of the environment around them. If the surface is buffed to a mirror sheen, it’s basically like taking an actual mirror and bending it around the wearer. Sky, trees, the person pointing the camera and anything else around can all be found in the reflections. It is for this reason, though, that light doesn’t fall across polished metal the same way that it does on most surfaces.
If you place a lamp above a mannequin in cotton robes, the portions of the cloth that face the light will be the brightest. With a polished helmet, however, the brightest point won’t be on top, but at the exact point where the light reflects off the steel and back towards your eyes.
Imagine shooting an imaginary laser or anti-gravity billiard ball off the helmet to hit the lamp. You wouldn’t want to graze the top, because then if would just glance off at almost the same angle and end up far behind the armour. Shoot it straight forward, and it’ll bounce back towards you. Aim between the top and the straightforward position, though, and you’ll have an angle the bounces right up towards the light. That’s the spot where the lamps’s reflection will be, and where you should place the highlight. The colour, shape and intensity of the reflection will all match the light source if it’s standard silver plate mail.
If you imagine the armour as a collection of bent mirrors attached to each other, you'll have a good starting point.
Increasing the intensity of the highlights, shadows and sharp edges will make the armour appear more polished. Lowering the contrast makes it seem dull.