Maybe you should refer him to this thread, it mentions and shows pictures of more than just black and white paint. Not only are the blues white with blue spots, the shades of blue can be light and dark and everything in between, just like a solid blue. The spots are pigment holes, so whatever the white color is hiding shows the spot color. I imagine we will be seeing buff spots soon. I know someone on this thread even mentioned lavender spots (though they might be hard to tell the difference from a light splash). I personally have black with white, blue with white, and red with white paints. All three pictured below:
The only paint "rule" if you can call it that - is the color should be the entire length of the feather.
The only paint "rule" if you can call it that - is the color should be the entire length of the feather.