For the audience this is aimed at I would have thought acrylics would be an option. Also not sure about paint brands, are you working with those brands?
I'm not working with any paint brand at the moment.
The reason for using real paint brands is that the app relies on the RGB encoded paint colors. Each branch has different names of similar paints and even paints with the same name have different RGB values. Thus, letting users to choose predefined paints looks like a solution.
I will add acrylic paints in the future. Didn't want to delay the launch of the app.