Small modifications, added or reinforced, intended to improve a part of the painting and to conclude the work. The term is widely documented at the end of the 14th Century with different implications and references, even if they all refer to the concept of "touching again." The term may also assume the meaning of completing a work using a diverse technique from that with which the work was executed. This is what happens in the fresco technique, where one speaks of retouching "a secco" (see fresco a secco) in tempera on a mural painting which is already dry. For the most part, the retouching is foreseen and thus not to be intended as a modification or addition. Cennino Cennini writes "and note that everything that is done in fresco wants to be treated in the end and retouched a secco." On the other hand, Giorgio Vasari (1568) believes that retouching indicates the uncertainty of the artist other than a technical error: "Those who seek to work in mural paintings, must work like a man in fresco, and they do not retouch 'a secco,' because other than showing their incompetence, it makes the life of the painting shorter."