It took 3 coats to cover and I used a 2 to 1 ratio 2 parts paint to one part calcium carbonate. (domesticimperfection.com)
I made chalk paint by mixing 2 parts Valspar signature paint in Ultra White, 1 part calcium carbonate, and just a little bit of water to thin the paint a little because the mixture was pretty thick at first. (thepaintedhinge.com)
By creating a database of all possible chemical formulations, the MIT research team found 1.5 parts calcium to every 1 part silica to be the «magical ratio,» according to Pellenq. (scientificamerican.com)