How do I prepare concrete walls before applying water-dispersion paint?

Question

I had a concrete wall painted with white water-dispersion paint. Every here and there the old paint was chipped and dark gray bare concrete could be seen.

I got a can of white water-dispersion paint and coloured it into light-green tone. The instructions on the paint say "prime the surface, then apply two layers of paint". That's what I did exactly. The wall looks great now except that the dark gray concrete can be seen through the paint layer (yes, not only the surface is not flat, but also dark gray concrete can be identified through two layers of paint) - looks like the paint doesn't block light that much. The parts of the wall where the old paint wasn't chipped look just great.

How should I have prepared the wall so that those dark gray regions of concrete were not visible through new paint?

Answer 1

More coats of primer might have done the trick. Paints have different levels of coverage/opacity.

If you wanted to even out the texture, that is harder; maybe some sort of skim coat over the entire wall, to unify it? Or pre-paint/joint compound/etc. over just the areas that were chipped.

I don't know whether you can add additional layers over your existing paint; the can may give more info about overcoats.