I think art would have to be subjective because it is produced through a person's mind and not applicable to everyone whereas something objective is without human bias and therefore cannot include emotion. Since most people would determine that art must include emotion, then art must be subjective. I think that art itself has to be subjective but that does not mean that a definition cannot be objective. For example, Wikipedia defines emotion as associated with mood, temperament, personality, and disposition. Although beginning a definition with association seems to make it unnecessarily vague, the point stands that the definition itself is applicable to everyone and without emotion. There is a problem in ever having something be considered completely objective because people can only know what people have determined. This means that all knowledge is a creation of people and so can never completely exclude human bias. If everything is subjective, though, the question becomes irrelevant. It is easier to think of objectivity as something people strive to achieve and is always slightly out of reach. If art appeals to the same emotion in all people then it is maybe closer to be an objective example of that emotion. I do not believe that emotion can be understood as anything other than as belonging to an individual and that the goal of objectivity is to be without emotion or with equal representation of all emotions as newspaper articles aim to achieve. Art is not objective then because it is aiming to appeal to emotion and I return to the determination I started with.
We can never know exactly what emotion someone else feels, even when they call it the same thing because we are judging other people’s emotional states based on what we have felt in similar circumstances. I can never experience your feeling of happiness; I can only assume it is what I feel in certain situations. This does not mean that Tolstoy was wrong if we assume that approximations are enough. The artist was trying to communicate what they define as sad and I felt what I define as sad is probably close enough. If this is true than an artist may have more leeway because what I define as sad may be what you define as depressing. Then the communication is accurate but the language is not. If we have miscommunication of feeling in art it seems just as logical that we have miscommunication in language and we may not be aware that the other does not share our understanding.
Is art a more or less difficult to understand form of communication to traditional language? Does it depend on what is being communicated?