Blue vs. Indigo — What's the Difference?

Blue is a primary color in the visible spectrum.

Indigo is a color between blue and violet in the visible spectrum.

In mood, blue means feeling sad or depressed.

Indigo is a plant used for a blue dye.

In politics, blue represents the Democratic Party in the United States.

In literature, "Indigo children" refers to kids believed to possess special traits or abilities.

In idioms, "out of the blue" means unexpectedly.

In spirituality, indigo is often linked to the third eye chakra.

In business, "blue-chip" refers to companies that are reliable and profitable.

In fashion, indigo is the typical dye used for blue jeans.

Blue is one of the three primary colours of pigments in painting and traditional colour theory, as well as in the RGB colour model. It lies between violet and green on the spectrum of visible light.

Indigo is a deep color close to the color wheel blue (a primary color in the RGB color space), as well as to some variants of ultramarine, based on the ancient dye of the same name. The word "indigo" comes from the Latin for Indian as the dye was originally exported to Europe from India.

The hue of that portion of the visible spectrum lying between green and indigo, evoked in the human observer by radiant energy with wavelengths of approximately 420 to 490 nanometers; any of a group of colors that may vary in lightness and saturation, whose hue is that of a clear daytime sky; one of the additive or light primaries; one of the psychological primary hues.

Any of various shrubs or herbs of the genus Indigofera in the pea family, having pinnately compound leaves and usually red or purple flowers in axillary racemes.

A pigment or dye imparting this hue.

A dark blue crystalline compound, C16H10N2O2, that is obtained from these plants or produced synthetically and is widely used as a textile dye. Also called indigotin.

Bluing.

Any of several related plants, especially those of the genera Amorpha and Baptisia.

An object having this hue.

The hue of that portion of the visible spectrum lying between blue and violet, evoked in the human observer by radiant energy with wavelengths of approximately 420 to 450 nanometers; a dark blue to grayish purple blue.

Dress or clothing of this hue

A purplish-blue colour

A person who wears a blue uniform.

An indigo-colored dye obtained from certain plants (the indigo plant or woad), or a similar synthetic dye.

Blues A dress blue uniform, especially that of the US Army.

An indigo plant, such as from species in genera Indigofera, Amorpha (false indigo), Baptisia (wild indigo), and Psorothamnus and Dalea (indigo bush).

A member of the Union Army in the Civil War.

Having a deep purplish-blue colour

The Union Army.

A kind of deep blue, one of the seven prismatic colors.

A bluefish.

A blue dyestuff obtained from several plants belonging to very different genera and orders, such as, the woad, Isatis tinctoria (family Cruciferae), Indigofera suffroticosa, Indigofera tinctoria (family Leguminosae), Indigofera Anil, Nereum tinctorium, Polygonum tinctorium Ait. (family Polygonaceae), etc.; called also natural indigo. It is a dark blue earthy substance, tasteless and odorless, with a copper-violet luster when rubbed. Indigo does not exist in the plants as such, but is obtained by decomposition of the glycoside indican.

Any of various small blue butterflies of the subfamily Polyommatinae.

Having the color of, pertaining to, or derived from, indigo.

The sky.

A blue dye obtained from plants or made synthetically

The sea.

Deciduous subshrub of southeastern Asia having pinnate leaves and clusters of red or purple flowers; a source of indigo dye

Of the color blue.

A blue-violet color

Bluish or having parts that are blue or bluish, as the blue spruce and the blue whale.

Having a gray or purplish color, as from cold or contusion.

Wearing blue.

Being a trail, as for skiing, marked with a sign having a blue square, indicating an intermediate level of difficulty.

Relating to or being a blue state.

Gloomy; depressed.

Dismal; dreary

Puritanical; strict.

Aristocratic; patrician.

Indecent; risqué

To make or become blue.

Having blue as its color.

(informal) Depressed, melancholic, sad.

(health care) Having a bluish or purplish shade of the skin due to a lack of oxygen to the normally deep red blood cells.

Pale, without redness or glare; said of a flame.

(politics) Supportive of, run by (a member of), pertaining to, or dominated by a political party represented by the colour blue.

Supportive of, run by (a member of), pertaining to, or dominated by the Democratic Party.

Supportive of or related to the Liberal Party.

(UK politics) Supportive of or related to the Conservative Party.

(astronomy) Of the higher-frequency region of the part of the electromagnetic spectrum which is relevant in the specific observation.

(of steak) Extra rare; left very raw and cold.

(of a dog or cat) Having a coat of fur of a slaty gray shade.

(archaic) Severe or overly strict in morals; gloomy.

Literary; bluestockinged.

(particle physics) Having a color charge of blue.

(informal) Risqué; obscene; profane; pornographic.

The colour of the clear sky or the deep sea, between green and purple in the visible spectrum, and one of the primary additive colours for transmitted light; the colour obtained by subtracting red and green from white light using magenta and cyan filters; or any colour resembling this.

Anything coloured blue, especially to distinguish it from similar objects differing only in color.

A blue dye or pigment.

Blue clothing.

(in the plural) A blue uniform. See blues.

A member of a sports team that wears blue colours; (in the plural) a nickname for the team as a whole. See also blues.

An umpire, in reference to the typical dark blue color of the umpire's uniform. Sometimes perceived by umpires as derogatory when used by players or coaches while disputing a call.

Sporting colours awarded by a university or other institution for sporting achievement, such as representing one's university, especially and originally at Oxford and Cambridge Universities in England. See also full blue, half blue.

A person who has received such sporting colours.

(slang) A member of law enforcement.

A bluestocking.

The sky, literally or figuratively.

The ocean; deep waters.

The far distance; a remote or distant place.

A dog or cat with a slaty gray coat.

(snooker) One of the colour balls used in snooker, with a value of five points.

(entomology) Any of the butterflies of the subfamily Polyommatinae in the family Lycaenidae, most of which have blue on their wings.

A bluefish.

An argument.

A liquid with an intense blue colour, added to a laundry wash to prevent yellowing of white clothes.

Any of several processes to protect metal against rust.

(British) A type of firecracker.

(particle physics) One of the three color charges for quarks.

(UK) A member or supporter of the Conservative Party.

(ergative) To make or become blue; to turn blue.

To treat the surface of steel so that it is passivated chemically and becomes more resistant to rust.

To brighten by treating with blue (laundry aid).

To fight, brawl, or argue.

To spend (money) extravagantly; to blow.

Having the color of the clear sky, or a hue resembling it, whether lighter or darker; as, the deep, blue sea; as blue as a sapphire; blue violets.

Pale, without redness or glare, - said of a flame; hence, of the color of burning brimstone, betokening the presence of ghosts or devils; as, the candle burns blue; the air was blue with oaths.

Low in spirits; melancholy; as, to feel blue.

Suited to produce low spirits; gloomy in prospect; as, thongs looked blue.

Severe or over strict in morals; gloom; as, blue and sour religionists; suiting one who is over strict in morals; inculcating an impracticable, severe, or gloomy mortality; as, blue laws.

Literary; - applied to women; - an abbreviation of bluestocking.

One of the seven colors into which the rays of light divide themselves, when refracted through a glass prism; the color of the clear sky, or a color resembling that, whether lighter or darker; a pigment having such color.

A pedantic woman; a bluestocking.

Low spirits; a fit of despondency; melancholy.

To make blue; to dye of a blue color; to make blue by heating, as metals, etc.

The color of the clear sky in the daytime;

Blue clothing;

Any organization or party whose uniforms or badges are blue;

The sky as viewed during daylight;

Used to whiten laundry or hair or give it a bluish tinge

The sodium salt of amobarbital that is used as a barbiturate; used as a sedative and a hypnotic

Any of numerous small chiefly blue butterflies of the family Lycaenidae

Turn blue

Having a color similar to that of a clear unclouded sky;

Used to signify the Union forces in the Civil War (who wore blue uniforms);

Low in spirits;

Characterized by profanity or cursing;

Belonging to or characteristic of the nobility or aristocracy;

Morally rigorous and strict;

Causing dejection;

Yes, blue is a primary color.

Indigo can be both natural (from plants) and synthetic.

Yes, blue is common in nature, especially in skies and oceans.

Generally, indigo is a darker, deeper blue.

Indigo is used as a dye and also has symbolic meanings.

Blue often represents calmness or sadness.

Yes, blue is a common color in many national flags.

No, indigo is a specific wavelength color.

In color theory, blue is usually considered a cool color.

Indigo is often associated with intuition or spirituality.

Indigo can be used in place of blue but will give a darker hue.

Yes, indigo is mentioned in various cultural and spiritual texts.

Blue can create various shades when mixed with other colors.

Blue has slightly less energy compared to indigo in terms of wavelength.

Yes, indigo is associated with the third eye chakra.