Léon Vidal conducted successful early experiments in color collotypes in the late 1870s eventually patenting the Photochromie process (1872 and 1874 patents using a woodburytype with chromolithographic under printings, on specially prepared Woodbury paperx) The Photochromie used a series of registered lithographic colors manually separated, to produce a color image. Not necessarily accurate to reality, colors were printed over each other over which a Woodburytype, in registration, was placed yielding a color print. The use of metallic inks or papers, when dealing with metal objects, such as armor, created startling results. One of the drawbacks was that the prints had to be mounted inside stiff mats due to the need for them to expand and contract with atmospheric conditions. This made it extremely difficult for the process to be used in books. 
This print is a test print from Le Trésor Artistique de la France (Treasury of French Art) a book illustrated by photographs intended to popularize the French artistic heritage and published by the Société Anonyme des Publications Périodiques (Corporation for Periodical Publications). Planning for Le Trésor began in 1876 and publishing began in 1878, and it ceased publication after its initial series, devoted to the works of the Galerie d’Apollon. Compared to similar works and considered in the context of the cultural, technological, and economic issues of the day, the evidence points to the work’s actual mission as the promotion of a new photographic process, an objective that takes precedence over the popularization of artworks. The Trésor emerges as a representative example of a type of book I propose to call the ‘livre-spécimen,’ or ‘specimen book.’ That it was never completed becomes less a sign of failure than of the changes taking place in the relations between books and photographs at the turn of the 1880s. 
 Hanson, David A, and Sidney Tillim. Photographs in Ink: [exhibition], May 1-29, 1996, University College Art Gallery, Teaneck. Teaneck: NJ, 1996. plate 17 (alt).
 Laureline Meizel. ”Le Trésor artistique de la France” : un cas exemplaire de “ livre-spécimen ” au tournant des années 1870-1880. Etudes photographiques, Société française de photographie, 2012. Fig. 3
A. Hamber, A Higher Branch of the Art, p. 90