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Iron oxide red is a generic name of aferric oxide pigment ofreddish colors. Multiple shades based on bothanhydrousFe
2O
3 and itshydrates were known to painters sinceprehistory. 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 thePersian Gulf Oxide with 75%Fe
2O
3 and 25%silica,Spanish red with 85% of oxide,Tuscan red.[1] Other shades of iron oxides includeVenetian Red,English Red, andKobe.
The anhydrous pigment has a dark purple-red ormaroon 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 concentratedacids); heat only affects the hydrated variants (the water is removed, and the color darkens).[1]
| Indian Red | |
|---|---|
 Color coordinates | |
| Hex triplet | #CD5C5C |
| sRGBB (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 apigment, a variety ofocher, which gets its colour fromferric oxide, used to be sourced inIndia,[2] now made artificially.[3] ⁸
Chestnut is a colour similar to but separate and distinct from Indian red.[citation needed]
The nameIndian red derives from this pigment being originally imported from India,[3] where redlaterite soil is found, composed of naturally occurringiron oxides.[citation needed] The first recorded use ofIndian red as a color term inEnglish was in 1672.[4]
| Deep Indian Red | |
|---|---|
| Color coordinates | |
| Hex triplet | #B94E48 |
| sRGBB (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 calledIndian red from its formulation in 1903 until 1999, but now calledchestnut, inCrayolacrayons. This colour was also produced in a special limited edition in which it was calledVermont maple syrup.
At the request of educators worried that children (mistakenly; seeEtymology) believed the name represented theskin color ofNative Americans, Crayola changed the name of their crayon colorIndian Red toChestnut in 1999.[5]
Railroads/Railways
| Venetian Red | |
|---|---|
| Color coordinates | |
| Hex triplet | #C80815 |
| sRGBB (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 colourVenetian red.
Venetian red is a light and warm (somewhat unsaturated) pigment that is a darker shade ofscarlet, derived from nearly pureferric oxide (Fe2O3) of thehematite type. Modern versions are frequently made with synthetic red iron oxide.
The first recorded use ofVenetian red as a colour name in English was in 1753.[8]
| English Red | |
|---|---|
| Color coordinates | |
| Hex triplet | #AB4E52 |
| sRGBB (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 colourEnglish red.
Thisred is a tone of Indian red, made like Indian red with pigment made from iron oxide.
The first recorded use ofEnglish red as a color name inEnglish was in the 1700s (exact year uncertain).[10] In theEncyclopédie ofDenis Diderot in 1765, alternate names for Indian red included "what one also calls, however improperly, English Red."[11]
| Kobe | |
|---|---|
| Color coordinates | |
| Hex triplet | #882D17 |
| sRGBB (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 colorkobe.
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 inEnglish was in 1924.[13]
Thenormalized colour coordinates for Kobe are identical tosienna, first recorded as a color name in English in 1760.[14]
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