What knowledge should precede value judgment or opinion?

There are cases when an opinion which is based on the understanding of the particular work of art, which is aware of its cultural and contextual meaning, is more reliable than that of one which does not own neither of these. Examples for this are the Terracotta Warriors from China, the Throne of Weapons by Kester and the Raven, the First Men by Bill Reid Haida and the Shadow puppet of Bima. In case of these works of art, the audience must have some kind of background knowledge to understand and interpret them in the way they are intended to be. For example, The Terracotta Warriors had a task, to guard the Emperor after his death; the Throne of Weapons is made of weapons used in the First World War; these functions give them extra contextual meaning, which cannot be found without the knowledge of these facts.

On the other hand, art has a characteristic that works of art are able to make us respond and understand them to some extent, even if the particular art form is unfamiliar or if we know little indeed about its context. It is indeed true that a work of art accomplish its function (to mediate a value or message) only if it can be understood and interpreted always, independent from time and place. In evaluation of a work of art, an immediate response is sufficient, which can be made only if it is understood without any previous background knowledge. Examples for this are the Annunciation with St. Margaret and St. Asano by Simone Martini, Guernica by Pablo Picasso. These works of art can be evaluated by an immediate response, without aware of the intention of the artist. The beauty of these works of art is that we can understand and adjudge them in our own interpretation without being aware of their initial message created by the artist.

Can we understand or interpret works of art only with previous background knowledge, or it is not essential to have to some extent these facts? In my opinion, both of them are true., it depends on the particular work of art.