Iron oxide red

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Iron oxide pigments in jars: yellow, red, brown Iron oxide pigments.jpg
Iron oxide pigments in jars: yellow, red, brown

Iron oxide red is a generic name of a ferric oxide pigment of reddish colors. Multiple shades based on both anhydrous Fe
2
O
3
and its hydrates were known to painters since prehistory. The pigments were originally obtained from natural sources, since the 20th century they are mostly synthetic. These substances form one of the most commercially important groups of pigments, and their names sometimes reflect the location of a natural source, later transferred to the synthetic analog. Well-known examples include the Persian Gulf Oxide with 75% Fe
2
O
3
and 25% silica, Spanish red with 85% of oxide, Tuscan red. [1]

Contents

Properties

The anhydrous pigment has a dark purple-red or maroon color, hydrates' colors vary from dull yellow (yellow ochre) to warm red. [1]

The iron oxide red is extremely stable: it is not affected by light and most chemicals (soluble in hot concentrated acids); heat only affects the hydrated variants (the water is removed, and the color darkens). [1]

Indian red

Indian Red
 
Gtk-dialog-info.svg    Color coordinates
Hex triplet #CD5C5C
sRGB B (r, g, b)(205, 92, 92)
HSV (h, s, v)(0°, 55%, 80%)
CIELChuv (L, C, h)(53, 85, 12°)
Source X11
ISCC–NBS descriptor Moderate red
B: Normalized to [0–255] (byte)

Indian red is a pigment, a variety of ocher, which gets its colour from ferric oxide, used to be sourced in India, [2] now made artificially. [3] Other shades of iron oxides include Venetian Red, English Red, and Kobe, all shown below.

Chestnut is a colour similar to but separate and distinct from Indian red.

Etymology

The name Indian red derives from this pigment being originally imported from India, [3] where red laterite soil is found, composed of naturally occurring iron oxides.[ citation needed ] The first recorded use of Indian red as a color term in English was in 1672. [4]

Deep Indian red

Deep Indian Red
 
Gtk-dialog-info.svg    Color coordinates
Hex triplet #B94E48
sRGB B (r, g, b)(185, 78, 72)
HSV (h, s, v)(3°, 61%, 73%)
CIELChuv (L, C, h)(47, 83, 14°)
Source Crayola
ISCC–NBS descriptor Dark reddish orange
B: Normalized to [0–255] (byte)

Deep Indian red is the colour originally called Indian red from its formulation in 1903 until 1999, but now called chestnut, in Crayola crayons. This colour was also produced in a special limited edition in which it was called Vermont maple syrup.

At the request of educators worried that children (mistakenly; see Etymology) believed the name represented the skin color of Native Americans, Crayola changed the name of their crayon color Indian Red to Chestnut in 1999. [5]

Indian red in culture

Railroads/Railways

Venetian red

Venetian Red
 
Gtk-dialog-info.svg    Color coordinates
Hex triplet #C80815
sRGB B (r, g, b)(200, 8, 21)
HSV (h, s, v)(356°, 96%, 78%)
CIELChuv (L, C, h)(42, 136, 12°)
Source halfords.com [7]
ISCC–NBS descriptor Vivid red
B: Normalized to [0–255] (byte)

At right is displayed the colour Venetian red.

Venetian red is a light and warm (somewhat unsaturated) pigment that is a darker shade of scarlet, derived from nearly pure ferric oxide (Fe2O3) of the hematite type. Modern versions are frequently made with synthetic red iron oxide.

The first recorded use of Venetian red as a colour name in English was in 1753. [8]

English red

English Red
 
Gtk-dialog-info.svg    Color coordinates
Hex triplet #AB4E52
sRGB B (r, g, b)(171, 78, 82)
HSV (h, s, v)(357°, 54%, 67%)
CIELChuv (L, C, h)(45, 67, 10°)
Source ISCC-NBS [9]
ISCC–NBS descriptor Moderate red
B: Normalized to [0–255] (byte)

At right is displayed the colour English red.

This red is a tone of Indian red, made like Indian red with pigment made from iron oxide.

The first recorded use of English red as a color name in English was in the 1700s (exact year uncertain). [10] In the Encyclopédie of Denis Diderot in 1765, alternate names for Indian red included "what one also calls, however improperly, English Red." [11]

Kobe

Kobe
 
Gtk-dialog-info.svg    Color coordinates
Hex triplet #882D17
sRGB B (r, g, b)(136, 45, 23)
HSV (h, s, v)(12°, 83%, 53%)
CIELChuv (L, C, h)(32, 73, 18°)
Source ISCC-NBS [12]
ISCC–NBS descriptor Strong reddish brown
B: Normalized to [0–255] (byte)

At right is displayed color kobe.

The color kobe is a dark tone of Indian red, made like Indian red from iron oxide pigment.

The first recorded use of Kobe as a colour name in English was in 1924. [13]

The normalized colour coordinates for Kobe are identical to sienna, first recorded as a color name in English in 1760. [14]

See also

Related Research Articles

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Umber is a natural earth pigment consisting of iron oxide and manganese oxide; it has a brownish color that can vary among shades of yellow, red, and green. Umber is considered one of the oldest pigments known to humans, first seen in Ajanta Caves in 200 BC – 600 AD. Umber's advantages are its highly versatile color, warm tone, and quick drying abilities. While some sources indicate that umber's name comes from its geographic origin in Umbria, other scholars suggest that it derives from the Latin word umbra, which means "shadow". The belief that its name derives from the word for shadow is fitting, as the color helps create shadows. The color is primarily produced in Cyprus. Umber is typically mined from open pits or underground mines and ground into a fine powder that is washed to remove impurities. In the 20th century, the rise of synthetic dyes decreased the demand for natural pigments such as umber.

Venetian red is a light and warm (somewhat unsaturated) pigment that is a darker shade of red. The composition of Venetian red changed over time. Originally it consisted of natural ferric oxide (Fe2O3, partially hydrated) obtained from the red hematite. Modern versions are frequently made with synthetic red iron oxide produced via calcination of green vitriol (a.k.a. copperas) mixed with white chalk. The pigment contains up to 50% of the ferric oxide.

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References

  1. 1 2 3 Gettens & Stout 1966b.
  2. Church, Arthur Herbert (1915). The Chemistry of Paints and Painting (4th ed.). London: Seeley, Service & Co. pp. 202–203. OCLC   1041775719. OL   7214282M.
  3. 1 2 Gettens & Stout 1966a.
  4. "Indian, adj. and n. : Oxford English Dictionary" . Retrieved 4 July 2020.
  5. Crayon Chronology
  6. "Steam trains secret 150th paint job". BBC News. 2015-01-08. Retrieved 2020-06-07.
  7. Internet
  8. Maerz and Paul A Dictionary of Color New York:1930 McGraw-Hill p. 201; Color sample of Venetian red: p. 35 Plate 6 color sample I12
  9. "Retsof online version of ISCC-NBS Dictionary of Colo(u)r Names - Ea through Ez". November 22, 2012. Archived from the original on 22 November 2012.
  10. Maerz and Paul A Dictionary of Color New York:1930 McGraw-Hill p. 194; Color sample of English red: p. 31 Plate 4 color sample H12
  11. Jaucourt, Louis, chevalier de. "Indian Red." The Encyclopedia of Diderot & d'Alembert Collaborative Translation Project. Translated by Abigail Wendler Bainbridge. Ann Arbor: Michigan Publishing, University of Michigan Library, 2013. Web. 1 Apr. 2015, <http://hdl.handle.net/2027/spo.did2222.0003.009>. Trans. of "Rouge d'Inde," Encyclopédie ou Dictionnaire raisonné des sciences, des arts et des métiers, vol. 14. Paris, 1765.
  12. "Retsof online version of ISCC-NBS Dictionary of Colo(u)r Names - Ra through Rz". November 22, 2012. Archived from the original on 22 November 2012.
  13. Maerz and Paul A Dictionary of Color New York:1930 McGraw-Hill p. 197; Color sample of Kobe: p. 35 Plate 6 color sample K12
  14. Maerz and Paul A Dictionary of Color New York:1930 McGraw-Hill p. 204; Color Sample of Sienna: p. 37 Plate 7 Color Sample E12

Sources