to A.1986,

Искусствовед is the Russian term closest to 'art critic'.
It implies a person that has studied art professionally (not necessariliy as practicing artist) and is thus capable of some expertise and professional advice on certain aspects or art, very often just theory and history of art. As far I can see, it often implies a person specializing in 'painting', but not necessarily that.

The word 'critic' is used though in Russian when certain kinds of art are described, E.g. музыкальный критик (music critic), кинокритик (cinema critic), театральный критик, литературный критик.

Художественный критик is probably used, but I am not sure it's a very professional term. Искусствовед is a good term and in most cases it suits well.