Thanks for the reply, Wolfsong.
i'm not very familiar with "tinting" but from what you say i understand that you can have some objects(eg. buildings) with same texture but different colouring/shading. interesting. but how does it work? does the editor randomly selects a colour for a object, or the objects have predefined colours to them that are mixed with one(or more) channels from the texture?
the green channel seems to be a grayscale version of the texture...
i want to know more about this.