Plaka yellow?
You expect me to share my secret recipe? Oh, go on then as it is very simple but dont call me names for using craft paints.
Base coat of Inscribe Golden Yellow shaded with Burnt Umber watercolour, Inscribe Sunlight and then same with a little, you guessed it, Inscribe "Snow" added for the last highlights. All over a white undercoat but they have the pigment to cover over black.
In fact as I think about it these yellow ones are almost entirely Inscribe colours despite the dozens of Foundry, CdA, Vallejo etc. in my paint racks.
http://www.fredaldous.co.uk/shop-online/inscribe-59ml-acrylic-paint.htmIts basically the same as I used on this chap sometime ago

Svennn