I have been on a steep learning curve [re-newed learning, I might add..time dims the skills, y'know]....having to paint my son's latest fetish, Games Workshops LOTR soldiers..plastic and whitemetal.
GW have some excellent painting manuals, and their paints are excellent quality, being acrylics especially formulated for this wargaming lark.
They suggest painting a base coat of either black or white....depending on how bright the finished scheme needs to be....
their 'chaos black' is the most usual..not only providing a base coat, but also getting into all those nooks and crannogs that abound ....just in case one misses a bit with one's top coats?
Humbrol car spray is also useful.....I'd basecoat first, followed by the top coats..which will be variable?
I've also tried some matchpot-type paints, sold as 'emulsion'......bought for pennies years ago, I have used Wiko's black flat emulsion....this is variable....but as a black, it has a subtle grey tint....somewhat akin to washed and dried coal.
I take it, emulsion, being water-soluble, is a type of acrylic? am I right there?