^{Footnote 1} It must be pointed out that, besides pictorial arts, conservation concerns also films, archives in written or magnetic form and other sorts of products of the human activity that are part of the global cultural heritage.

^{Footnote 2} When we talk about posterior interventions, we refer to those interventions been made upon the object after the completion of its creation by the artist. Such cases are e.g. over-paintings on easel paintings or attempts to fix mechanical injuries e.g. mending a torn piece of a paper object with adhesive tape.