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A short history of blue pigments
Ultramarine was ground from lapis lazuli mined in Afghanistan and cost more than gold in the fifteenth century. A synthetic version followed in 1828, when a French prize for a cheaper process was finally won. Prussian blue, found by accident in Berlin around 1706, was the first modern synthetic pigment. Painters still mix it with burnt sienna for deep shadows. Cobalt blue arrived in 1802 and cerulean in the 1860s, giving landscape painters a clean, cool sky colour that did not fade.