The term "proof" is generally, but not consistently, applied only to prints from the late eighteenth-century onwards, beginning with the English mezzotinters, who began the practice of issuing small editions of proofs for collectors, often before the "lettering" or inscription below the image was added. The practices of signing or numbering impressions in the main edition had not begun, and in the absence of this, it is normally only when the image is clearly different from the final form that the term proof has any meaning.