First some very basic grammar : your question should be about a person who PAINTS walls. Third person 's' - I paint, you paint, he paints... I'm sure you learnt this in one of your very first English lessons, so it doesn't look good if you forget it. Now for the answer. A person who paints walls is a painter. If you want to distinguish between this and an artist who paints pictures, you could call him a 'painter and decorator'. This makes it clear what his profession is.

You're correct, we call them both painters. If we need to clarify, we would say a "house painter". For a fine arts painter, we would clarify as "artist".

Painter and decorator. And the two words go together. For example, a decorating company may have a sign on the side of their van saying, "FRED SMITH and SON, PAINTERS and DECORATORS." If I only had time to say ONE word, it's a 50:50 split. "He's a painter." "They're decorators." If you say, "he's a painter," context will usually tell you if you're talking decorating, or Picasso.

Hi, I'm Italian but I know what you are talking about. The non-artistic work is "Painter" as well, but according to the context, you might need to specify if Artistic painter ("Artist"), or Interior painter. However, since Interior Painters don't use just "white" but are often asked for decorative coats, it isn't that true that "there's a huge gap" with the artistic work and this difference might be useful only for fiscal purposes -- as a properly artistic work might fall within a different fiscal category. Therefore you might even say: **Interior decorator**, as the basic white coating is just the most simple ability of Interior painters.