French
DeutschEarth pigment
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Earth pigments are naturally occurring minerals that have been used since prehistoric times as pigments. Among the primary types of earth pigments include the reddish-brown ochres, siennas, and umbers, which contain various amounts of iron oxides and manganese oxides.[1][2] Other earth pigments include the green earth pigments or terres vertes, blue earth pigments such as vivianite-based "blue ochre", white earth pigments such as chalk, and black earth pigments such as charcoal.[3][4]
Earth pigments are known for their fast drying time in oil painting, relative inexpensiveness, and lightfastness. Cave paintings done in sienna still survive today.
Production
[edit]After mining, the mineral used for making a pigment is ground to a very fine powder (if not already in the form of clay), washed to remove water-soluble components, dried, and ground again to powder. For some pigments, notably sienna and umber, the color can be deepened by heating (calcination) in a process known as "burning", although it does not involve oxidation but instead dehydration.
References
[edit]- ^ Roelofs, Isabelle (2012). La couleur expliquée aux artistes. Groupe Eyrolles. ISBN 978-2-212-134865. p. 30
- ^ "What processes can chameleon pigment powder be used in? - KingChroma". 2023-11-22. Retrieved 2023-12-06.
- ^ Siddall, Ruth (2018). "Mineral Pigments in Archeology: Their Analysis and Range of Available Minerals". Minerals. 8 (5): 201. doi:10.3390/min8050201.
- ^ Hirst, Kris (15 April 2017). "Ochre - The Oldest Known Natural Pigment in the World". thoughtco.com. ThoughtCo. Retrieved 31 August 2017.
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