Sienna

Sienna

Colour coordinates
Hex triplet	#882D17
sRGB^B (r, g, b)	(136, 45, 23)
HSV (h, s, v)	(12°, 83%, 53%)
Source	ISCC-NBS
B: Normalized to [0–255] (byte)

Terra di Siena naturale, or raw sienna (Italian)

Colour coordinates
Hex triplet	#965434
HSV (h, s, v)	(20°, 65.3%, 58.8%)
Source	Ferrario 1919: Cartella colori, colour 69

Terra di Siena bruciata, or burnt sienna (Italian)

Colour coordinates
Hex triplet	#623034
HSV (h, s, v)	(-5°, 51%, 38.4%)
Source	Ferrario 1919: Cartella colori, colour 77

Burnt sienna (Maerz and Paul)

Colour coordinates
Hex triplet	#E97451
sRGB^B (r, g, b)	(233, 116, 81)
HSV (h, s, v)	(14°, 65%, 91%)
Source	Maerz and Paul
B: Normalized to [0–255] (byte)

Dark sienna

Colour coordinates
Hex triplet	#3c1414
sRGB^B (r, g, b)	(60, 20, 20)
HSV (h, s, v)	(0°, 67%, 24%)
Source	ISCC-NBS
B: Normalized to [0–255] (byte)

Sienna (X11 web colour)

Colour coordinates
Hex triplet	#A0522D
sRGB^B (r, g, b)	(160, 82, 45)
HSV (h, s, v)	(19°, 71.9%, 62.7%)
Source	forret.com
B: Normalized to [0–255] (byte)

Sienna (from Italian: terra di Siena, "Siena earth") is an earth pigment containing iron oxide and manganese oxide. In its natural state, it is yellow-brown and is called raw sienna. When heated, it becomes a reddish brown and is called burnt sienna. It takes its name from the city-state of Siena, where it was produced during the Renaissance. Along with ochre and umber, it was one of the first pigments to be used by humans, and is found in many cave paintings. Since the Renaissance, it has been one of the brown pigments most widely used by artists.

The first recorded use of sienna as a colour name in English was in 1760.

Like the other earth colours, such as yellow ochre and umber, sienna is a clay containing iron oxide, called limonite, which in its natural state has a yellowish colour. In addition to iron oxide, natural or raw sienna also contains about five percent of manganese oxide, which makes it darker than ochre. When heated, the iron oxide is dehydrated and turns partially to haematite, which gives it a reddish-brown colour. Sienna is lighter in shade than raw umber, which is also clay with iron oxide. but which has a higher content of manganese (5 to 20 percent) which makes it greenish brown or dark brown. When heated, raw umber becomes burnt umber, a very dark brown.

The clay soil of Tuscany (here near Monteriggioni) is rich in limonite, or hydrated iron oxide, the main ingredient of sienna pigment.

Limonite, a clay containing iron oxide, which gives the color to sienna pigment.

Haematite. When limonite is roasted, it turns partially to haematite and becomes more reddish.

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Wikipedia