Heterochromatic

Heterochromatic (pronounced het-er-uh-kroh-mat-ik or het-er-oh-kruh-mat-ik)

(1) Of, having, or pertaining to more than one color (especially as related to relating to heterochromia (in medicine & ophthalmology, the anatomical condition in which multiple pigmentations or colorings occur in the eyes, skin or hair).

(2) Having a pattern of mixed colors.

(3) Of light, having more than one wavelength.

(4) In genetics, of or relating to heterochromatin (in cytology, tightly coiled chromosome material; believed to be genetically inactive).

1890–1895: The construct was hetero- + chromatic + -ic.  The hetero- prefix was from the Ancient Greek ἕτερος (héteros) (the other (of two), another, different; second; other than usual) and was itself an ancient compound, the first element meaning "one, at one, together", from the primitive Indo-European root sem- (one; as one, together with), the second cognate with the second element in the Latin al-ter, the Gothic an-þar and the Old English o-ðer "other."  It's familiar in constructs such as “heterosexual”, “heterogeneity” et al.  In Classical Greek, there was quite a range of application including Heterokretes (true Cretan (ie one bred from the old stock)), heteroglossos (of or from a foreign language), heterozelos (zealous for one side (ie “one-eyed” in the figurative sense)), heterotropos (of a different sort or fashion (literally “turning the other way”) and the useful heterophron (raving (literally “of other mind” (ie “he’s barking mad”))).  The adjective chromatic dates from the turn of the seventeenth century and was used first of music in the sense of “involving tones foreign to the normal tonality of the scale, not diatonic” and was from the Latin chromaticus, from the Ancient Greek khrōmatikos (relating to color, suited for color) (which was applied also to music), from khrōma (genitive khrōmatos) (color, complexion, character (but used mostly metaphorically of embellishments in music); the original meaning was “skin, surface”.  In the Greek, khrōma was used also for certain modifications of the usual diatonic music scale but quite why it came to be used of music remains unclear, the most supported speculation being the influence of the extended sense of khrōma ("ornaments, makeup, embellishments) via the idea of it being “characteristic” of a musical scale or speech.  The -ic suffix was from the Middle English -ik, from the Old French -ique, from the Latin -icus, from the primitive Indo-European -kos & -ḱos, formed with the i-stem suffix -i- and the adjectival suffix -kos & -ḱos.  The form existed also in the Ancient Greek as -ικός (-ikós), in Sanskrit as -इक (-ika) and the Old Church Slavonic as -ъкъ (-ŭkŭ); A doublet of -y.  In European languages, adding -kos to noun stems carried the meaning "characteristic of, like, typical, pertaining to" while on adjectival stems it acted emphatically; in English it's always been used to form adjectives from nouns with the meaning “of or pertaining to”.  A precise technical use exists in physical chemistry where it's used to denote certain chemical compounds in which a specified chemical element has a higher oxidation number than in the equivalent compound whose name ends in the suffix -ous; (eg sulphuric acid (H₂SO₄) has more oxygen atoms per molecule than sulphurous acid (H₂SO₃).  Heterochromatic, heterochrome & heterochromous are adjectives, heterochrony, heterochromia & heterochromatism are nouns and heterochromatically is an adverb; the noun plural is heterochromias.

The obvious synonym is monochromatic (although is modern use that’s come often to mean “black & white” rather than “a single color”.  The -mono- prefix was from the Ancient Greek μόνος (mónos) (alone, only, sole, single), from the Proto-Hellenic mónwos and the ending may be compared with οἶος (oîos) (only, single) from óywos.  The etymology of the initial element remains murky but may be from the primitive Indo-European men- (small) and it may be compared with the Ancient Greek μανός (manós) (sparse, rare), the Armenian մանր (manr) (slender, small) and even the Proto-West Germanic muniwu (small fish, minnow).  The sense it’s understood in photography dates from 1940 when (presumably almost instantly), the verbal shorthand became “mono”, exactly the same pattern of use when the need arose to distinguish between color printers and those using only black consumables.  The word was used as an adjective after 1849 although monochromatic (of one color, consisting of light of one wavelength and probably based either on the French monochromatique or the Ancient Greek monokhrōmatos) had been used thus since at least 1807 (presumably it pre-dated this because the adverb monochromatically is documented since 1784).  The alternative forms are both self-explanatory: unicolour used usually single solids and monotint, rare and used mostly as a technical term in art-production where, properly, it describes a reproduction of a multi-color image using just shades of a single color.  Monochrome is a noun & adjective, monochromaticity, monochromy & monochromist are nouns, monochromic is an adjective and monochromatically is an adverb.

Sectoral heterochromia.

In medicine & ophthalmology, heterochromia describes a coloration variously of hair, skin and the eyes but it’s used most commonly of eyes.  At the cellular level, heterochromia is a function of the production, delivery, and concentration of the pigment melanin and the condition may be inherited or caused by genetic mosaicism, chimerism, disease, or injury.  It is not uncommon in certain breeds of domesticated animals (notably those subject to breeding programmes which tend to reduce the gene pool and cats with a predominantly white coat).  In clinical use heterochromia of the eye is known as heterochromia iridum or heterochromia iridis and can be complete, sectoral, or central.  The complete heterochromia is the best known by virtue of being the most photogenic for Instagram and other purposes: it exists when one iris is a wholly different color from the other.  In sectoral heterochromia, part of one iris is a different color from the rest while in central heterochromia, typically there is a ring around the pupil (less commonly seen as spikes radiating from the pupil) in a different color.

Ms Amina Ependieva (b 2008, left) was born in Grozny, the capital city of Chechnya, Russia; she has two rare, genetic conditions: (1) albinism which reduces the quantity the pigment melanin in the skin and (2) heterochromia, the latter manifesting as her having with one blue and one brown eye.  Ms Ependieva was photographed in 2019, aged eleven.  Alkira (b 2015, right) is a Persian cat with heterochromia, felines with predominately white coats the most prone to the condition; in domestic cats, it's most common for them to have one yellow and one blue eye.  The condition does not affect vision.

Bilateral gynandromorphs: butterfly (left), bird (centre) & lobster (right).  The visually related phenomenon is gynandromorphism (an organism (most typically an insect, crustacean or bird) with both male and female attributes & characteristics, the construct being the Ancient Greek γυνή (gynē) (female) + ἀνήρ (anēr) (male) + μορφή (morphē) (form).  In Western science it was first extensively documented in (notably where it was most obvious: in Lepidoptera (butterflies and moths)) but it has since been identified in literally dozens of species.

Lindsay Lohan likes the heterochromatic look, whether in the vertical (Mercedes-Benz Fall 2004 Fashion Week, Smashbox Studios, Culver City, California, September, 2003, left), the horizontal (Maxim Hot 100 Party, Gansevoort Hotel, New York, May 2007, centre) or the variegated (ABC’s Good Morning America studios, New York, November 2022, right).

1985 BMW 635CSi (E24, 1976-1989) with heterochromatic headlights.

In Europe and beyond, yellow headlights are still seen because although few jurisdictions still mandate their use, for some they’ve become an aesthetic choice.  Between 1936-1993, French law required all vehicles to have yellow headlights, the intent being to reduce glare and improve visibility in foggy or rainy conditions, the science being the belief yellow light (which has a longer wavelength) reduced eye strain and made driving at night safer by “cutting through” mist and fog more effectively than white light.  The German philosopher Goethe (Johann Wolfgang von Goethe (1749–1832)) was said to be heterochromatic and he was interested in eyes & color, in 1810 publishing a 1,400-page treatise on the topic, asserting he was the first to questioned the validity of Sir Isaac Newton’s (1642–1727) ideas about light and color: “That I am the only person in this century who has the right insight into the difficult science of colors, that is what I am rather proud of, and that is what gives me the feeling that I have outstripped many.”  Goethe did misinterpret the results of some of Newton’s experiments, thinking he was explaining their invalidity but he did reformulate the topic of color in an entirely new way.  While Newton had viewed color as a physical “process” in which light entered the eye after striking and reflecting off an object, Goethe was the first to explain the sensation of color is shaped also by our perception (the mechanics of human vision and by the way our brains process information (the eyes being an out-growth of the brain).  So, explained Goethe, what we see is a construct of (1) the properties of the object, (2) the dynamics of lighting and (3) our perception.