A counter-proof in copper-plate printing is an image that is made on a new sheet of blank paper from a freshly-printed pull from an engraved plate. The ink, which is still wet, transfers from the printed pull to the blank sheet to produce a reversed, much paler, image on the new sheet. The example shown is that of a siege map by Tommaso Barlacchi done during the working process. It is the only known exemplar of a counter-proof of a Malta map. Counter-proof sheets obviously have no imprint.
