Edmond Becquerel: 2 Early Test Daguerreotype Plates for the Production of Colored Daguerreotypes, pre June 1842. (see the auction!)
Edmond Becquerel: 2 tests pour la production de daguerréotypes couleur, avant Juin 1842. (voir la vente aux enchères!)
Edmond Becquerel 2 pruebas para la producción de daguerrotipos color, antes de junio de 1842. (véase la subasta!)
Here is a reproduction of the auction description: “Edmond Becquerel, Paris. A milestone in the discovery of color photography: “The conservation of natural color in photography”. As part of his doctorate thesis, he was trying to record and fix the image of the solar spectrum. The immediate result was indeed colorful, but he failed to fix the image permanently. The 2 trials presented here were obtained on electroplated copper plates: the first one labeled “silver iodide prepared with the battery”, the second one, on the same copper silver plated piece but heated to 90? C for 4 days, labeled “idem, heated to 90 ? for 4 days”. He found that the heated plate obtained better results in the red spectrum. His first almost satisfactory attempts were achieved by 1850.
An example can be found at the Conservatoire National des Arts et Métiers in Paris.”
Becquerel, Spectres solaires, 1848, Daguerréotype obtenu par Reproduction directe des couleurs, 1848 (Musée des arts et métiers, Paris)
Here is a link to the original article.