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French Researchers Examine 18th Century Color Photographs

It is accepted that early photography was a difficult path for an enthusiast to take. Cameras were bulky and heavy. The person who took photos had to be a virtual specialist chemist. It is so different from the ease of trapping a moment in the present. A pioneer in this field was Ducos du Haurun a brilliant Frenchman. He took color photographs. Three different colored filters were used to capture negative shots developed on gelatin film. The yellow, red and blue layers were then assembled to produce a single print. Over time, Ducos du Hauron introduced practises to speed up the process. French investigators have analyzed some of the 18th century pictures. They used x-ray florescent spectroscopy, synchrotron-based infrared (IR) spectroscopy and Raman spectroscopy to determine the chemicals used as pigments for the different colors. Photographs taken in 1878 showed that Prussian blue was the ingredient used for the blue gelatin layer. Carmine lake was the foundation pigmen