Iron oxide red

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

Properties

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

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).

Indian red

Indian red is a pigment, a variety of ocher, which gets its colour from ferric oxide, used to be sourced in India, now made artificially. 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 the red laterite soil found in India, which is composed of naturally occurring iron oxides. The first recorded use of ''Indian red'' as a color term in English language, English was in 1672.

Deep Indian red

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, Etymology) believed the name represented the Color metaphors for race, skin color of Indigenous peoples of the Americas, Native Americans, Crayola changed the name of their crayon color ''Indian Red'' to ''Chestnut'' in 1999.

Indian red in culture

;Railroads/Railways

* The Talyllyn Railway painted their locomotives ''Talyllyn'' and ''Dolgoch'' Indian Red in honour of the 150th anniversary of the line in 2015.

* The Furness Railway in the UK used ''Indian Red'' for its locomotive livery.
* The Department of Railways New South Wales, Public Transport Commission and State Rail Authority, the State Rail Authority painted their diesel locos and passengers cars in Indian red.

Venetian red

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 (color), 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.

English red

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 colour name in English language, English was in the 1700s (exact year uncertain). In the ''Encyclopédie'' of Denis Diderot in 1765, alternate names for Indian red included "what one also calls, however improperly, English Red."

Kobe

At right is displayed colour kobe.

The colour 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 language, English was in 1924.

The Wikipedia:WikiProject Color/Normalized Color Coordinates, normalized colour coordinates for Kobe are identical to sienna, first recorded as a colour name in English in 1760.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

See also

* Chestnut (color)
* List of colors

References

Sources

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{{Color topics

Iron oxide pigments
Shades of red
Shades of brown
Indian culture