Standard target faces, which are made in different sizes, are generally of five colours: gold, red, blue, black and white.
Each coloured circle is divided by a central line, this format is used by both G.N.A.S. and F.I.T.A. Depending on the type of round being shot the colours can have different scoring values.
These are shown in the diagrams below:
Below are a couple of resources which go into further detail about how to score: