French engraver and writer. He trained as a reproductive engraver with Pierre-François Basan and later with Jacques-Philippe Lebas but soon turned to small-scale engraving. He specialized in the extremely meticulous execution of small portraits; he made more than 100 of these, the most popular being those of Marie Leczinska, Queen of France (1768) after Jean-Marc Nattier and the portrait of the Comtesse du Barry (1770) after Hubert Drouais. His greatest work was the Crowning of the Bust of Voltaire at the Comédie Française after a drawing by Jean-Michel Moreau (1778; Fitzwilliam Museum, Cambridge), on which he worked from 1778 to 1782. Gaucher was also a writer on theory and wrote several articles on engravers for the Abbé de Fontenai's Dictionnaire des artistes as well as obituaries of Lebas and Jean-Jacques Flipart for the Journal de Paris and several polemical writings in defence of engraving. The Académie des Sciences asked him to write a treatise on the art of engraving; he abandoned this at the onset of the French Revolution, and only his Essai sur l'origine et les avantages de la gravure (1798) gives some idea of it. //