Citadel Runelord Brass Base paint is designed to give a smooth, solid dark brass color over an undercoat and for that reason this will almost always be the first paint you use on a miniature. Shake the dark brass paint before using (you can make this easier by adding an agitator ball).
The dark brass paint can be a bit thick sometimes and then you just add a few drops of water to your pallet. You really don't need a lot of water. Something to watch out for is to make sure you don't apply too much paint so that you don't start hiding details.
Another important functionality of this dark brass paint is that it not only covers the underlayer, but also covers other colors. So if you later miss something about this color, you can easily paint over it with this Runelord Brass base paint.
The color of Citadel Runelord brass (21-55) is similar to: Old Citadel Brazen Brass; Vallejo Game Color Brassy Brass (72058); Vallejo Model Color Brass (70801); Reaper Master Tarnished Brass 2 (9198); Coat D'arms Brass (131); Scale75 Viking Gold.