Unique etched and inked steel heliogravure plate by Charles Négre. Honoré Théodoric d’Albert, Duc de Luynes by Louis Auguste Bisson 1867

While the common material for his plates was steel and the common application was intaglio printing, Nègre’s patent details numerous potential materials, applications, and modifications that characterize his process as inherently flexible and versatile. This includes the use of photographic negatives, positives, inverted negatives, or inverted positives on either paper or glass as the initial images; the creation of intaglio plates, relief plates on copper or steel, as well as lithographic plates on zinc; the decoration of metal with photographic images in a wide variety of colorized metal transferred by galvanoplasty imitating the effects of damascening, niello, or encrustation. [1]