Thank you for your comments.

I would've thought that getting paint to stick to chalk would be the devil's business? 
You're right, chalk is not as easy material to work with. It is difficult to glue, (because of the dust loose). It is also hard to paint, because it absorbs too much paint.
Perhaps once the base coat has soaked in you get a better foundation?
Yes, the base coat mkes paint work easier. I will use hairspray with my next walls. I imagine that will prevent loss of dust, and will be easier to glue and paint it.
Cheers.