Many named colors start with I across the major catalogs — Wikipedia's color lists, Crayola's crayon catalog, Pantone's archives, the xkcd Color Survey, and historical pigment references. This page currently lists 35 notable I-color names. Three CSS named-color keywords start with I: indianred (#CD5C5C), indigo (#4B0082), and ivory (#FFFFF0), all inherited from the X11 color set when the W3C standardized the CSS named-color list.

Several strong candidates. Indigo is one of the seven colors Isaac Newton named in the spectrum and the W3C CSS named color indigo (#4B0082). International Orange is the vivid reddish-orange used in aerospace and famously on San Francisco's Golden Gate Bridge. Illuminating (PANTONE 13-0647) was one of Pantone's two Colors of the Year for 2021, paired with Ultimate Gray. Ivory and Indian Red are both CSS named colors (ivory and indianred). Indian Yellow is a historical artists' pigment, and Isabelline is a pale parchment tone with an unusually old, much-debated name.

The CSS named color indigo has the value #4B0082, which sits at a hue angle of about 275° — well into the blue-violet range, with the violet character visually dominant. Tradition places indigo "between blue and violet" in Newton's spectrum, and the historical indigo dye is a deep blue; but the specific sRGB value standardized as CSS indigo reads as a deep purple on screen. This catalog classifies by the dominant visual impression of the actual swatch rather than by the name or by spectral tradition, so #4B0082 joins the Purple family. The hex value itself is unchanged.

Not exactly. The public "List of colors" entry labeled International Orange (Golden Gate Bridge) gives #C0362C, a deep brick-red, and that is the cataloged value shown here. The bridge's actual specified paint is a brighter, more orange tone — commonly cited near #F04A00 and matched to roughly Pantone 173, 174, or 180 — selected by consulting architect Irving Morrow so the structure would blend with the surrounding hills while contrasting with the sea and sky. So the catalog swatch is a darker reference value, not the bridge's true paint color.

Indian Red is a red-earth color named after a naturally occurring iron-oxide pigment historically imported from India. The soft, dusty version (#CD5C5C) is the W3C CSS named color indianred, inherited from the X11 color set. The name refers to the pigment's geographic source, not to any people; some style guides now prefer terms like "red ochre" for the pigment to avoid ambiguity. The deep-brick variant on this page (#850E04) is a darker catalog value of the same family.

For the three CSS-named I-colors — indianred (#CD5C5C), indigo (#4B0082), and ivory (#FFFFF0) — yes. The W3C CSS Color Module specification fixes the exact sRGB values, and every modern browser renders them identically. For Pantone references like Illuminating (PANTONE 13-0647, a 2021 Color of the Year), the cataloged hex is an sRGB approximation of a physical textile swatch standard and varies slightly across third-party sources. For institutional and flag colors like India Green and the International Orange variants, the hex is a widely cited reference value rather than a single legally fixed digital standard — and as with the Golden Gate Bridge, the cataloged swatch can differ from the object's actual specified paint. For historical pigments like Indian Yellow, the hex is a digital approximation of a material whose real appearance varied with its source and preparation.