Umbra is a mineral brown pigment made of clay stained with oxides of iron and manganese. In composition, natural umber is close to ocher , from which it differs in a high manganese content (from 6 to 16% in terms of manganese oxide).
| Umber | |
|---|---|
| Hex | 635147 |
| RGB ¹ ( r , g , b ) | (99, 81, 71) |
| CMYK ( c , m , y , k ) | (0, 18, 28, 61) |
| HSV ² ( h , s , v ) | (21 °, 28%, 39%) |
Content
Description
Umber is resistant to the action of light and alkalis , it gets dark when heated. The name comes from the name of the mountain region of central Italy, Umbria , according to other versions - from the Latin word umbra - shadow. Umbra has been used as a pigment since prehistoric times.
Chemical formula:
Variations
Umbra comes in different colors, depending on the content of iron oxide and silicate.
Natural umber
It can have a color from swamp to brown-gray.
Different manufacturers of paints for painting, under the name "Natural Umber", usually offer different shades.
| Natural Umber | |
|---|---|
| Hex | 826644 |
| RGB ¹ ( r , g , b ) | (130, 102, 68) |
| CMYK ( c , m , y , k ) | (0, 22, 48, 49) |
| HSV ² ( h , s , v ) | (33 °, 48%, 51%) |
Burnt umber
| Burnt umber | |
|---|---|
| Hex | 8A3324 |
| RGB ¹ ( r , g , b ) | (138, 51, 36) |
| CMYK ( c , m , y , k ) | (0, 63, 74, 46) |
| HSV ² ( h , s , v ) | (9 °, 74%, 54%) |
Burnt umber is obtained by calcining a natural umber at a temperature of 400-600 C.
For the first time, burnt umber was mentioned as a color dye in 1650 [1] .
Others
- Dark green umber is a mixture of green mineral pigments (green spinel, green chromoxide) and talc .
- Brown umber
- Umbra red
- Light green umber is a natural earth pigment, coloring components are iron hydrates with hydrates of manganese oxides and aluminosilicates.
See also
- Ocher
- Sienna
Literature
- Umbra // Uji - Fidel. - M .: Soviet Encyclopedia, 1956. - P. 224. - ( Great Soviet Encyclopedia : [in 51 vols.] / Ch. Ed. B. A. Vvedensky ; 1949-1958, vol. 44).
Notes
- ↑ Maerz and Paul A Dictionary of Color New York: 1930 McGraw-Hill Page 191; Color Sample of Burnt Umber: Page 53 Plate 15 Color Sample A12