Just north of Apt, there is a 25 km stretch where the ochre lies in strata 15 meters wide. Ochre is a pigment of which 10% is iron oxide, mixed with sand and clay. The intense colour varies from yellow, crimson lake, to reddish-brown, and even violet and this makes it fantastic for landscape photography. The low lighting in the morning and in the evening extends further the appearance of an amazing range of colours. Ochre was exploited by the Romans and rediscovered in 1780 when a flourishing industry grew up here, supplying colour powder to the textile and soap making industries and the paper mills. The processing of the sand is quite simple. It’s first washed, to separate the sand from the oxides. The ore is then crushed, washed again and decanted into shallow basins. After being left to dry for a month, it’s crushed to fine colour powder. But ochre was replaced for most industrial purposes by chemical dyes after 1940.
