The opposite of "art loose" could be described as "art precise" or "art polished." These terms connote a greater sense of discipline and control over one's artistic expression. For instance, a painter who practices "art precise" might spend hours refining the details of a piece or experimenting with color palettes - while someone who favors "art loose" may prioritize the raw or wild nature of their work. Other possible antonyms for "art loose" might include "art formal" or "art rigid," both of which emphasize the structured, rule-bound aspects of art-making. In any case, finding the balance between looseness and discipline is key for any artist who hopes to succeed in their chosen medium.