Periscope

Periscope (pronounced per-uh-skohp)

(1) Any of a number of optical instruments used to view objects that are above the level of direct sight or in an otherwise obstructed field of vision, consisting essentially of a tube with an arrangement of prisms or mirrors and, usually, lenses; used especially in submarines and military reconnaissance.

(2) A periscopic lens.

(3) A now defunct live video streaming app for Android and iOS, acquired by Twitter (before launch) in 2015 and depreciated between 2016-2021.

(4) A general or comprehensive view (obsolete).

1815–1825: The construct was peri + scope, a back formation from periscopic from the Ancient Greek periskopein (to look around).  Peri- was from the Ancient Greek περί (perí) (about, around) and was cognate with the primitive Indo-European via.  Scope was from the From Italian scopo (purpose), from the Latin scopus (target), from the Ancient Greek σκοπέω (skopéō) & σκοπός (skopós) (examine, inspect, look to or into, consider), from σκέπτομαι (sképtomai), from the primitive Indo-European speḱ- and etymologically related to both skeptic and spectrum.  Periscope is a noun (and a largely archaic verb), periscopic is an adjective and periscopically an adverb.  The present participle is periscoping and the past participle periscoped); the noun plural is periscopes.

Periscope concepts using mirrors and lens.

Although variations of the device had existed for decades, the word periscope either wasn’t used or was at least not in general use before 1899 but as early as 1865 it attested as a technical term in photography.  The concept of the periscope (then called the polemoscope) and using two angled lens had been described as early a 1647 in a work discussing the geological nature of the moon although then it was envisaged as device suitable for military observation.  Undocumented and undated sketches thought to date from decades earlier have also been unearthed but, although conceptually accurate, their exact purpose is unclear and they may have been architectural drawings.

Kim Jong-un (b circa 1994, Supreme Leader or DPRK (North Korea) since 2011), looking through the periscope of DPRK submarine.

The first naval periscopes appeared in 1854, constructed by placing two mirrors in a vertical tube, fixed at each end at a 45° angle and were a noted feature of the early submarines used in the US Civil War (1861-1865); by the dawn of the twentieth century they’d begun regularly to be part of the design although the great innovation was the retractable periscope in 1902, then known as the skalomniscope or omniscope.  The retractable periscope quickly became a standard fitting to submarines and proved an important factor in the success they enjoyed during the First World War.

Kim Jong-un looking at South Korea through infantry observation periscopic binoculars.

Surprisingly, given how simple the adaptation would have been, periscopes were little-used by nineteenth century armies but proved to be an invaluable addition to the kit in the trench warfare of 1914-1918, providing a wide vista for observation without exposing the viewer to the risk of attracting sniper fire.  One invention which proved of less utility was the so-called periscope-rifle, a kind of remote-controlled infantry rifle mounted atop the trench parapet, aimed and fired by a soldier in a safe position below.  Success was limited.  More useful were devices called stereoscopic rangefinders, periscopic binoculars with grids which enabled trained observers to estimate the distance to a target.

The Lamborghini Countach "Periscopio"

1971 Lamborghini Countach LP500 concept (note periscopio bulge in the centre of roof).

When shown at the 1961 Geneva Motor Show, the Jaguar E-Type (XKE) created a sensation.  At the same event, ten years later, the Lamborghini Countach LP500 created almost as much excitement and its lines have been the template for most Lamborghinis since.  In a sense, progress in the design of such machines paused at that point, everything since (and not just by Lamborghini) a refinement of the yellow wedge.  Although it was a small and functionally unsatisfactory aspect of the dramatic LP500, it was the abortive periscopio (periscope) which would be used to characterize the first 157 (some sources insist 158) LP400 production cars, the periscopio rear view concept lending the roof its distinct shape.  The factory’s documents don’t reveal whether the idea of the periscope was the inspiration of an individual or emerged from a committee but the thought was that in such a low-slung vehicle, the driver would be afforded a better view from a lens mounted atop the roof than would be provided by a conventional rear-view mirror aligned with the rear-window.  Donnelly Corporation in the US delivered a working version of the periscope mirror system, a number of which had actually be built in the era for use in the ESV (Experimental Safety Vehicle) projects which a number of manufacturers had developed to test their implementation of the engineering which would be required to conform with the safety regulations soon to come into force.

1974 Lamborghini Countach LP400 roof detail.

However, during testing, it became obvious it was not a desirable solution, the positioning dictated by the then unique profile requiring the driver too often to avert their eyes from what was ahead adequately to focus on what lay behind.  Nor did the designers warm to the small bulge which would have to be added to the roofline to accommodate the hardware; aesthetics meant little to those who penned ESVs but they were prized by Italian stylists and consequently the periscope was abandoned.  However, whether for reasons of economy or constraints of time, although the bulge was deleted, the remaining periscopio roof shape was retained and in 1974 entered production as part of the LP400 although it now provided no obvious functional advantage except making the cabin a little brighter and perhaps adding some rigidity to the structure although there may have been some aerodynamic cost, the interruption to what would otherwise be a smooth surface presumably generating additional drag.  Whatever the drawbacks however, stylistically, it’s always been admired.

1977 Lamborghini Countach LP400.

Those first 157 LP400s were also the closest the production cars would be to the original, unadorned wedge which had made such an impact when displayed at the 1971 Geneva Motor Show as the Lamborghini LP500 concept.  That it was described as a concept was important because the LP500, although fully-functional, was no prototipo (prototype), and the uncompromising original could not without modification be transformed into a practical production car, hence the many scoops to ensure adequate cooling as well as the deletion of the periscope, changes to the construction method used for the frame, a reduced-capacity engine, the substitution of analogue instruments for the space-age electronica and some enlargement of the platform to make the thing more habitable.  Still, the LP400 was remarkably close to the startling original and tellingly, of all two-thousand odd which would in five generations be produced between 1974-1990, it would be the one with the best aerodynamics, the wings, flares and fat tyres added over the years all adding to drag.  If the smooth roof, introduced on the LP400 S in 1978, improved aerodynamics, it wasn’t enough to compensate.

The influential but short-lived service

The evolution of the internet since it began to assume its modern form (after the world wide web was “bolted on” in 1991, gaining something like critical mass around 1993) is characterized by a number of separate, parallel and sometimes intersecting threads and probably no application (although technically it was a service) was so emblematic of the trends than Periscope.  Periscope was created because someone found the then text-only Twitter (now X) compelling but was annoyed at having to go elsewhere look for video feeds relating to what was being tweeted.  The Periscope model was to take advantage of the ubiquity of (1) smartphones meaning high-definition video could, worldwide, be created by billions of users at a moment’s notice and (2) the increasing availability of bandwidth which made real-time streaming practical and what emerged was a system noted for its simplicity; a few taps and whatever one was filming was being streamed.

Send (left) & receive (right): Periscope's simple streaming model.    

In the way corporations sometimes do things, Twitter bought Periscope even before the product’s official release and success was immediate, the service quickly among the most popular with support notably coming from legacy broadcasters including the BBC which used the system as a low-cost form of content dissemination; in effect what used to be an “outside broadcast van” (literally a truck packed with cameras and transmission equipment which, with staff and other overheads cost sometimes millions a year to run and could be in one place at a time) was suddenly in the pockets of every staff member.  It was also in the pockets of everyone else, some of who were entrepreneurial and before long, Periscope streams of live events (for which broadcasters and others had paid sometimes millions for exclusive rights) and content on screens (cinemas, televisions etc) were being packaged for profit, cannibalizing many pay-per-view (PPV) business models.  A flurry of takedown notices (a specialized form of a C&D (cease & desist letter) ensued.  Periscope however became a victim of its own success, its model quickly available in many other ways and its functionality was “folded into” Twitter, the service discontinued in March 2021, much of the (not legally challenged) legacy content remaining available on X to this day.

Dazzle

Dazzle (pronounced daz-uhl)

(1) To overpower or dim the vision of by intense light.

(2) Deeply to impress, to astonish with delight

(3) To awe, overwhelm, overpower, stupefy.

(4) To shine or brilliantly reflect.

(5) To excite admiration by a display of brilliance.

(6)To be overpowered by light.

(7) Something that dazzles.

(8) A form of camouflage used on early-mid twentieth century warships.

(9) The collective noun to describe zebras.

1475-1485: A frequentative of daze, the construct being daze + le, from the Middle English dasen, from the Old Norse dasa (as in dasask (to become weary)) and related to the Danish dase (to doze, mope).  1475-1485: Daze was a Middle English, back-formation from the Middle English dazed, from the Old Norse dasaðr (weary) & dasask (to become weary), from the Proto-Germanic dasōjan-, from the adjective daza-, which may have been a variant of the primitive Indo-European der- (to hold, support) and related to the Armenian դադարել (dadarel) (to settle, stop, end).  The -le suffix was a frequentative form from the Middle English -elen, -len & -lien, from the Old English -lian (the frequentative verbal suffix), from the Proto-Germanic -lōną (the frequentative verbal suffix) and was cognate with the West Frisian -elje, the Dutch -elen, the German -eln, the Danish -le, the Swedish -la and the Icelandic -la.  It was used as a frequentative suffix of verbs, indicating repetition or continuousness.

The original, fifteenth century, meaning was “be stupefied, be confused” which many dictionaries list as obsolete but there are certainly at least echoes of that sense in the modern use.  Originally intransitive; the transitive sense of “overpower with strong or excessive light” dates from the 1530s while the figurative sense of “overpower or excite admiration by brilliancy or showy display” is from the 1560s.  As a noun in the sense of “brightness, splendour”, it’s been known since the 1650s.  The verb bedazzle (to blind by excess of light) emerged in the 1590s but is now far more common in figurative use.  The late nineteenth century coining of “razzle-dazzle” originally suggested “bewilderment or confusion, rapid stir and bustle, riotous jollity or intoxication etc but came soon to be used of “deception, fraud; extravagant or misleading claims”.  At the turn of the twentieth century it was used also to mean “a state of confusion” but the modern trend is to use “razzle-dazzle” to mean anything flashy, especially unstructured, inventive performances on the sporting field.  Forms such as overdazzle, outdazzle, outdazzling, overdazzle, overdazzled, overdazzling, redazzle & undazzled have been coined as required.  The adjective antidazzle is commonly used in commerce (often as anti-dazzle).  Dazzle is a noun & verb, endazzlement, dazzlement & dazzler are nouns, bedazzle & (the archaic) endazzle are verbs, adazzle is an adjective, dazzling & dazzled are verbs & adjectives and dazzlingly is an adverb; the noun plural is dazzles.

Dazzling: Lindsay Lohan in zebra-print dress from Balmain's autumn-winter 2013 collection, GQ Men Of The Year Awards, London, September 2014.  Cohort, crossing, harem, herd and zeal have all been cited as the collective noun for zebras but most zoologists seem to prefer dazzle.

Developed first by the Royal Navy during World War I (1914-1918) to counter the German U-Boat (submarine) threat, dazzle camouflage for ships was a counterintuitive adaptation of techniques known to have been used during antiquity, the fleets of both the Greeks and Romans having been painted in shades of green and blue to blend with the surface and horizon.  The modern approach however was rather than concealment, the vessel would be exposed to the enemy.

View through periscope, with and without dazzle.

The British Admiralty adopted the scheme as an experiment.  It had been suggested in 1917 by a Royal Navy Volunteer Reserve (RNVR) lieutenant commander with a pre-war background in painting, his argument being that while it wasn’t possible actually to conceal a ship, a suitable paint scheme should make difficult the task of a submarine captain trying to estimate a vessel’s speed and direction while viewing through a periscope for a limited time and that was no easy task in 1917.  A U-Boat captain, while maintaining a distance from his target between around a quarter mile (400m) and a mile (1600m), had to predict the speed and direction of the target’s travel while factoring in ocean currents which could affect a torpedo’s travel, all within the short time he could risk his periscope being visible above the surface.  The dazzle concept of camouflage differed from traditional methods of concealment in that it sometimes made the target actually easier to see but tried instead to make it harder to sink.  A U-Boat carried very few torpedoes and they couldn't be wasted.  The captain had to hit a moving target, often in a rolling sea and to maximize the chance of success, needed the torpedo to hit the ship in her most vulnerable spots and this was done by aiming not at where the target was, but where the target would be more than half a minute later.  The idea of the dazzle was not to hide the ship but to make it even harder for a U-Boat commander to estimate variables like direction and speed of travel.    

After encouraging findings in small-scale tests, the admiralty authorised trials and artists experimented with both colours and shapes, intending usually to distort the perception of the shape of the bow and stern, disrupting perspective and falsely suggesting a ship’s smokestacks or superstructure pointed in a different direction than truly it sat on the water.  Many of the ideas were shamelessly borrowed from modernist art, especially the concepts of cubism, a theft so blatant that Pablo Picasso (1881–1973), in conversation with the American poet and novelist Gertrude Stein (1874–1946), observed the Cubist movement deserved some credit from the Admiralty.

A Dazzled dreadnought, 1919.

The programme spread to merchant vessels and then across the Atlantic.  Soon thousands of ships were painted in lurid colour schemes but unfortunately, the extensive archive of photographs from this era are mostly monochrome which not only fail fully to capture the vivid variety of the artists’ work but also don’t convey the contrasts created by the blues, reds, greens, purples and greys light & dark which created the optical illusions.  Both navies undertook analysis of the losses in shipping to evaluate the effectiveness of dazzle but the results, so impressive in laboratory conditions, were inconclusive, it being statistically impossible to account for external factors but U-Boat captains interviewed after the war attested to the problems dazzle created for them.

RMS Titanic's sister ship, RMS Olympic in dazzle, Pier 2 in Halifax, Nova Scotia, Canada, 1918.  Painting by Arthur Lismer (1885–1969)

Despite there being no consensus about the advantage of dazzle, allied naval authorities continued to employ it on both some warships and merchant fleets in World War II (1939-1945).  The Imperial German Navy had shown little interest in camouflaging ships during the Great War but did adopt a variation of dazzle early in World War II although OKM’s ((Oberkommando der Marine, High Command of the Kriegsmarine (Navy)) designs were intended to disguise the identity of a ship from surface and air observation rather than raise doubts about speed or direction.  It’s not documented why this was abandoned by OKM but, after 1941, all naval assets were repainted in regulation shades of grey.

Although never as widely used as in 1917-1918, allied navies retained faith in the subterfuge throughout the war although this time it was the Americans who were much more systematic and it wasn’t until late in 1942 the Admiralty released their Intermediate Disruptive Pattern and not until 1944 was a Standard Scheme promulgated.  Wartime developments in radar were already reducing the effectiveness of dazzle and this was accelerated by post-war advances in range-finding which rendered dazzle wholly obsolete.  For decades after 1946, no dazzle schemes were commissioned but (much toned-down) aspects of the idea have in recent years been interpolated into modern "stealth" naval architecture.

Materiel

Materiel (pronounced muh-teer-ee-el)

(1) In military use, arms, ammunition, and military equipment in general.

(2) The aggregate of things used or needed in any business, undertaking, or operation as distinguished from personnel (rare).

1814: A borrowing from the French matériel (equipment; hardware), from the Old French, from the Late Latin māteriālis (material, made of matter), from the Classical Latin māteria (wood, material, substance) from māter (mother).  Ultimate source was the primitive Indo-European méhtēr (mother).  Technically, materiel refers to supplies, equipment, and weapons in military supply chain management, and typically supplies and equipment only in a commercial context but it tends most to be used to describe military hardware and then to items specific to military use (ie not the office supplies etc used by armed forces personnel).  Materiel is a noun; the noun plural is materiels.

Illustrating military materiel: Lindsay Lohan does Top Gun by BlueWolfRanger95 on Deviant Art.  An aircraft is materiel as is a pilot's flight kit.  Just about every piece of equipment in this photo would be classed as materiel except perhaps the aviator sunglasses (may be a gray area).  Even non-combat, formal attire like dress shirts and ties are regarded by most military supply systems as materiel so materiel can be made from material.

Materiel is sometime notoriously, scandalously and even fraudulently expensive, tales of the Pentagon's purchase of US$1000 screwdrivers, toilet seats and such legion.  Of late though, there have been some well-publicized economies, the US Navy's latest Virgina-class submarine using an Xbox controller for the operation of its periscope rather than the traditional photonic mast system and imaging control panel.  The cost saving is approximately US$38,000 and there's the advantages (1) replacements are available over-the-counter at video game stores world-wide, (2) the young sailors operating the controller are almost all familiar with its feel and behavior and (3) the users report its much better to use than the heavy, clunky and less responsive standard device.  In the military context, materiel refers either to the specific needs (excluding manpower) of a force to complete a specific mission, or the general sense of the needs (excluding personnel) of a functioning force.  Materiel management is an all-encompassing term covering planning, organizing, directing, coordinating, controlling, and evaluating the application of resources to ensure the effective and economical support of military forces. It includes provisioning, storing, requirements determination, acquisition, distribution, maintenance, and disposal.  In the military, the terms "materiel management", "materiel control", "inventory control", "inventory management", and "supply management" are synonymous.

DPRK personnel: DPRK female soldiers stepping out, seventieth anniversary military parade, Pyongyang, September 2018.  Note the sensible shoes, an indication of the Supreme Leader’s thoughtfulness.

The French origins of materiel and personnel are usefully illustrative.  The French matériel (the totality of things used in the carrying out of any complex art or technique (as distinguished from the people involved in the process(es))) is a noun use of the adjectival matériel and a later borrowing of the same word that became the more familiar noun material. By 1819, the specific sense of "articles, supplies, machinery etc. used in the military" had become established.  The 1837 personnel (body of persons engaged in any service) is from the French personnel and was originally specific to the military, a contrastive term to materiel and a noun use of the adjectival personnel (personal), from the Old French personel.

DPRK materiel: Mock ups of the Pukguksong-5 SLBM displayed at military parade Thursday to mark the conclusion of the North Korea’s Workers’ Party congress (the first since 2016), Pyongyang, January 2021.

In January 2021, the DPRK (North Korea) included in a military parade, what appeared to be mock-ups of what’s described as the Supreme Leader’s latest submarine-launched ballistic missile (SLBM), the supposedly new Pukguksong-5.  Apparently, and predictably, an evolution of the Pukguksong-4 paraded a few months earlier, although retaining a similar 6 foot (1.8m) diameter, the payload shroud appeared about 28 inches (700mm) longer, suggesting the new SLBM’s estimated length is circa 35 feet (10.6m).  Given the constraints of submarine launch systems, the dimensions are broadly in line with expectations but do hint the DPRK has yet to finalise a design for its next-generation SLBM.  Nor have there been recent reports of the regime testing any big solid-rocket motors, this thought to confirm the views of Western analysts that development is in the early stages.

Pukguksong-4, October 2020.

As a brute force device, with performance measured merely by explosive force, based on the dimensions, it’s possible the DPRK could match similarly sized Western SLBMs.  However, the US Navy’s Poseidon multiple-warhead SLBM, which uses two solid-fuel stages and has a range of over 2800 miles (4800 km), uses very high-energy propellants and a light-weight structure, directed by sophisticated navigation, guidance and control systems.  It features also some very expensive engineering tricks such as rocket exhaust nozzles submerged within the rocket stages, reducing the length, thereby allowing it to be deployed in the confined launch tube.  Lacking the US’s technological and industrial capacity, the Pukguksong-5 is expected to be more rudimentary in design, construction, and propellant technology, range therefore likely not to exceed 1900 miles (3000 km) and almost certainly it won’t be capable of achieving the same precision in accuracy.

Snorkel

Snorkel (pronounced snawr-kuhl)

(1) A device permitting a submarine to remain submerged for prolonged periods, consisting of tubes extended above the surface of the water to (1) take in air for the diesel engine, (2) for general ventilation and (3) to discharge exhaust gases and foul air.

(2) In military jargon, a similar device on a tanks (and other vehicles), enabling it to cross shallow water obstacles (later adopted for civilian use in 4WD (four-wheel-drive) off-road vehicles and sometime fitted (for visual effect) even to to those used only in urban environments.

(3) In swimming, a device (usually of plastic or rubber), allowing a swimmer to breathe while face down on the surface of the water, consisting of a bent tube fitting into the mouth and projecting above the surface.

(4) To engage in snorkeling.

(5) In clothing design, a specialized style of hoodie, a type of parka or anorak with a hood projecting beyond the face (a la Kenny in South Park).

(6) In fire fighting, a bendable arm for hydraulic platforms or buckets.

(7) A proprietary fountain pen piston filling system used by the Sheaffer pen company.

1945:  A Modern English borrowing from the German Schnorchel ((submarine) snorkel), an airshaft for submarines, related to schnarchen (to snore) and thus named because of (1) the submarine snorkel's functional similarity to a nose and (2) its noise when in use.  The anglicized spelling was first recorded in 1945 in US documents, apparently not appearing in the UK until 1949 although there had been earlier references to the technology using the noun “snort”.  The meaning "curved tube used by a swimmer to breathe under water" was first recorded in 1951.  Snorkel & snorkelling are nouns & verbs, snorkeler is a noun and snorkeled &  are verbs; the noun plural is snorkels.

Breath deeply

Lindsay Lohan snorkeling in the Aegean, 2016.

Adding a snorkel to a conventional (ie one with diesel/electric rather than nuclear propulsion) submarine allows the vessel to operate while submerged for extended periods.  From their origins in the nineteenth century until late in the World War II (1939-1945), submarines were more properly regarded as “submersibles”; small boats which could be used underwater for short periods.  Until snorkels were adopted, submarines were compelled to operate mostly on the surface, submerging only to attack during daylight or to avoid being attacked.  This was less of a disadvantage than it might seem because the limitations of the early sonar systems meant submarines on the surface were close to invisible until visual contact was made.  That changed with the increasing deployment of radar and other detection systems which compelled submarines to spend more time underwater, using electric motors that offered little speed and range.

The need for a snorkel seems obvious and it was, the first patent issued in the UK in 1916 but neither the British Admiralty nor any other navy experimented with the design until some Italian prototypes were built in 1926 and these were soon scrapped.  The Royal Netherlands Navy was the first with a practical production model (which they called the snuiver (sniffer)) and it was this the Kriegsmarine (German Navy) copied.  Initially, the Germans were interested only in a fresh-air system for ventilation but by 1943, the U-Boats (the German term for submarines) were suffering unsustainably high losses and OKM (the naval high command) began development of the Dutch design which enabled diesel propulsion at periscope depth, while also charging the batteries.  Operational use began in 1944 and the vessels produced by 1945 were essentially the first modern submarines, designs which, when later combined with nuclear propulsion, were for decades produced with only detail refinements.  Snorkels continue to be installed on nuclear-powered submarines because they still have on-board diesel engines for backup power.  The time a nuclear submarine can remain submerged is limited not by the fuel supply or the need to replenish fresh air (which can be generated aboard) but by how much food can be stored.

German Type XII Elektroboot (1945).

In World War II (1939-1945), the course of the war could have been very different had OKM (Oberkommando der Marine; the high command of the Kriegsmarine (the German Navy 1935-1945)) followed the advice of the commander of the submarines and made available a fleet of 300 rather than building a surface fleet which wasn’t large enough to be a strategic threat but of sufficient size to absorb resources which, if devoted to submarines, could have been militarily effective.  With a fleet of 300, it would have been possible permanently to maintain around 100 at sea but at the outbreak of hostilities, only 57 active boats were on the navy’s list, not all of which were suitable for operations on the high seas so in the early days of the conflict, it was rare for the Germans to have more than 12 committed to battle in the Atlantic.  Production never reached the levels necessary for the numbers to achieve critical mass but even so, in the first two-three years of the war the losses sustained by the British were considerable and the “U-Boat menace” was such a threat that much attention was devoted to counter-measures and by 1943 the Allies could consider the battle of the Atlantic won.

The Germans’ other mistake was not building a true submarine capable of operating underwater (and therefore undetected) for days at a time.  It was only in 1945 when Karl Dönitz (1891–1980; as Grand Admiral head of the German Navy 1943-1945, German head of state 1945) and Albert Speer (1905–1981; Nazi court architect 1934-1942; Nazi minister of armaments and war production 1942-1945) were assessing their “revolutionary” new design that it was concluded there was no reason why such craft couldn’t have been built in the 1930s because the capacity and technology existed even then.  It was a classic case of what Donald Rumsfeld (1932–2021: US defense secretary 1975-1977 & 2001-2006) would later call an “unknown known”.  The Germans in 1939 knew how to build a modern submarine but didn’t know they knew.  Despite the improvements however, military analysts have concluded that even if deployed in numbers, such was the strength of forces arrayed against Nazi Germany that by 1945, not even such a force could have been enough to turn the tide of war.  Dönitz and Speer had plenty of time to reflect on such missed opportunities of 1939-1940, both war criminals sentenced by the IMT (International Military Tribunal) at the first Nuremberg Trial (1945-1946) to imprisonment respectively for 10 & 20 years in prison.  The admiral was debatably unlucky to be found guilty but had all the evidence of Speer's wartime conduct been brought before the court, he'd have been hanged.

Equiluminant

Equiluminant (pronounced ee-kwuh-loom-uh-nuhnt)

(1) In optics, the quality of two or more objects or phenomenon being equally luminant.

(2) Figuratively, two or more people being judged equally illustrious, attractive, talented etc.

1860s: The construct was equi- +‎ luminant.  As an adjective, luminant means "that which illuminates; that which is luminous" while as a noun it describes "an illuminating agent".  Luminant was from the Latin verb lūminant, the third-person plural present active indicative of lūminō, the construct being lūmen, from the Proto-Italic louksmən, from the primitive Indo-European léwk-s-mn̥, from the root lewk- (bright) +‎ -ō (appended to form agent nouns).  The accepted synonym is isoluminant and equiluminescent is the alternative form.  When used figuratively, although it would make no sense in science, the comparative is “more equiluminant” and the superlative most “equiluminant”.  Equiluminant & equiluminescent are adjectives and equiluminance is a noun; the noun plural is equiluminances (which some list as non-standard).

The prefixes: equi-, homo-, peri- & iso-

The prefixes “equi-”, “homo-”, “peri-” & “iso-” are all used to in same way suggest a concept of sameness or equality, but by tradition and convention, are used in different contexts to produce different meanings or emphasis:

Equi- is used to indicate equality, evenness, or uniformity and is often seen in mathematical, scientific & technical publications to describe something is equal in measure or evenly distributed such as equilateral (a shape having all sides of equal length, equidistant (being at equal distances from two or more points) & equilibrium (a state of balance where opposing forces or influences are equal).  Homo- is used to imply “same” or “alike” and thus sameness or (sometimes by degree) similarity.  In technical use it is a standard form in biology, chemistry & the social sciences to indicate sameness in kind, structure, or composition and by far the most common modern use is in the now familiar “homosexual” which in many jurisdictions is now a proscribed (or at least discouraged) term because of negative associations (“homo” as a stand-alone word also having evolved as a slur used of, about or against homosexual men).  The uses of the prefix are illustrated by homogeneous (composed of parts or elements that are all of the same kind, homologous (having the same relation, relative position, or structure) & homonym (in linguistics words which sound the same or are spelled the same but have different meanings).  Iso- is used to denote equality, uniformity, or constancy in terms of specific characteristics like size, number, or configuration and is most used in scientific and mathematical publications.  Examples of use include isometric (having equal dimensions or measurements, isothermal (having constant temperature) & isosceles (having two sides of equal length).  Peri- is used to denote “surrounding or enclosing”, or “something near or around a specific area or object”, examples including perimeter (the continuous line forming the boundary of a closed geometric figure), periscope (an optical instrument for viewing objects that are above the level of direct sight, using mirrors or prisms to reflect the view & peripheral (relating to or situated on the edge or periphery of something.

So equi-focuses on equality in measure, distance, or value, homo- focuses on sameness in kind, structure, or composition, iso- focuses on equality or uniformity in specific characteristics or conditions while peri- :focuses on surrounding or enclosing, or being near or around something.  For most purposes equi- & iso- can be used interchangeably and which is used tends to be a function of tradition & convention.

Equiluminant colors

An example the equiluminant in blue & orange.  In color the text appears at the edges to "shimmer" or "vibrate".  When re-rendered in grayscale, because the value of the luminance is so close, the two shades become almost indistinguishable.

In optics, “equiluminant” is a technical term used to colors with the same (or very similar) luminance (brightness) but which differ in hue (color) or saturation (intensity).  The standard test for the quality is to convert a two-color image to grayscale and, if equiluminant, the colors would appear nearly indistinguishable because they share the same level of “lightness”.  It’s of some importance in fields as diverse as military camouflage, interior decorating, fashion, astronomy and cognitive psychology.  In the study of visual Perception, when colors are equiluminant, the human visual system relies primarily on the differences in hue and saturation rather than brightness to distinguish them and can create unique visual effects and challenges in perception, as the brain struggles will in most cases struggle to segregate colors based solely on luminance; essentially, there is a lack of information.

An enigmatic abstraction (2024) by an unknown creator.  This is an example of the use of non-equiluminant shades of orange & blue.

In art and design, the qualities of is used to create visual effects, the perception of some “shimmering” or “vibrating” at the edges where colors meet actually a product of the way the different hues are perceived by the brain to be “less defined” (a process not dissimilar to the “grayscaling”) and thus “dynamic”, lending the impression of movement even in a static image, especially if seen with one’s peripheral vision.  While a handy device for visual artists, that’s something of significance in the world of practicalities because the close conjunction of equiluminant colors can make certain visual tasks more difficult, most obviously reading text or distinguishing shapes and objects.  All that happens is the luminance contrast can means there’s a perception of fuzziness at the edges of shapes which means people can suffer a diminished ability to distinguish fine details and the smaller the object (text, numerals or geometric shape), the more acute the problem.  The phenomenon has been well researched, scientists using the properties in equiluminant colors to study how the brain processes color and the findings have been important in fields like instrumentation the production of warning signs.

Richard Petty's 1974 NASCAR Dodge Charger (left) and 3 ton Super-Duty Jack, produced under licence by the Northern Tool Company (right).  1974 was the last year in which the big-block engines were allowed to run in NASCAR; the big-block era (1962-1973) was NASCAR's golden age.  Richard Petty (b 1937) used a "reddish orange" to augment his traditional blue when he switched from Plymouth to Dodge as the supplier of his NASCAR stockers in the early 1970s.  His team was actually sponsored by STP rather than Gulf and STP wanted their corporate red to be used but in the end a "reddish orange" compromise was negotiated.  However, when he licenced the Northern Tool Company to sell a "Richard Petty" jack, the shade used appeared to be closer to the Gulf orange.

1968 Lamborghini 1R tractor in signature colors (left) and rendered in grey-scale (right); the combination non-equiluminant.  This version of 1R is known as the cofano squadrato (squared hood (bonnet)).  It was produced between 1966-1969 and replaced the earlier 1R (1961-1965) which featured a rounded hood.  The earlier model seems not retrospectively to have been christened but presumably it would have been the cofano arrotondato, proving everything sounds better in Italian than English.  An Italian could read from a lawnmower repair manual and it would sound poetic.  

At scale, equiluminance doesn’t have to be obvious for it still to have desirable “side effects” and while it’s often noted two specific hues: (1) the blue Llewellyn Rylands pigments 3707 (Zenith Blue, replicated by Dulux as “Powder Blue”) & (2) the orange Rylands pigments 3957 (Tangerine, replicated by Dulux as “Marigold”) are “equiluminant colors”, that their use in combination appears so often on cars, motor-cycles and other stuff with wheels is due less to the claim the shades seem at the edge to “vibrate” that the striking combination appearing on some of the Gulf Oil sponsored Ford GT40s and Porsche 917s during sports car racing’s golden era which ended in the early 1970s.  Given the surface area involved, the effect is probably imperceptible which viewed at close range but the science does suggest that at speed (and these were fast machines), at the typical viewing range found on racetracks, there was what the optical analysts call “visual pop”, something which heightens the brain’s perception of motion,

Ford GT40 chassis# 1075, winner of the 1968 & 1969 Mans 24 hour endurance classic in Gulf livery.

Gulf Oil however didn’t explicitly have the equiluminescent in mind when they choose to adopt the combination.  Originally, the Gulf GT40s were painted in the their corporate colors of dark blue & orange but Gulf was an acquisitive conglomerate and in late 1967 it took over the Wilshire Oil Company of California, the corporate colors of which were powder blue and orange, something which Gulf’s management thought “more exciting” and better suited to a racing car.  The change was made for the 1968 season with the Fords now running as five-litre (302 cubic inch) sports cars, governing body having banned the seven-litre engines the cars previously had used (under a variety of names, motorsport has for decades been governed by some of sport’s dopiest regulatory bodies).  In the Gulf colors, GT40 chassis #1075 won the Le Mans 24 hour endurance classic in 1968 & 1969 (repeating the brace Ford had achieved with the seven-litre (427 cubic inch) machines in 1966-1967), the first time the same car had achieved victory twice.  In 1968, the same car won the BOAC International 500, the Spa 1000-kilometer race, and the Watkins Glen 6-hour endurance race, while in 1969 it also took the Sebring 12-hour race, a remarkable achievement for a race car thought obsolescent.  The livery has since been much replicated.

1971 Porsche 917K in Gulf livery.  The fins were added to improve straight-line stability and were strikingly similiar to those which appeared on some late 1950s US Chryslers although the aerodynamic properties of those were dubious.

Interestingly, the team painting the GT40s were aware of the issue created by equiluminant colors and as a matter of professional pride didn’t want it thought they’d created something with “fuzzy edges” so deliberately they included a dark blue hairline-border around the orange, reducing the optical illusion to ensure everything looked immaculately smart when photographed.  When the Gulf team in 1970 switched to using Porsche 917s for the World Sports Car championship, they adopted the expedient of a black line of definition between the blue & orange so the whole enduring appeal of the combination lies just in the striking contrast and relies not at all on the equiluminance.

Ford GT Heritage Edition First Generation (left) and Second Generation (right). 

Little more than 100 GT40s were built but Ford noted with interest the ongoing buoyancy of the replica market, thousands of the things built in a number of countries.  In the twenty-first century, the company decided to create their own replicas but the new GT (2004-2006) was hardly a clone and although it shared the basic mechanical layout and the shape (though larger) was close, it was a modern machine.  The car wasn’t called GT40 because the rights to the name had ended up with another company and Ford declined to pay the demanded price.  Over 4000 were built and one special run was a tribute to the 1968-1969 cars in Gulf livery, 343 of the “Heritage Editions” produced.  A second generation of GTs was produced between 2016-2022 and was very modern, the demands of the wind-tunnel this time allowed to prevail over paying tribute to the classic lines of the 1960s.  Although the supercharged 5.4 litre V8 didn’t return and the new car used a turbocharged 3.5 litre (214 cubic inch) V6, it outperformed all its predecessors over the last 60-odd years (all the original GT40 chassis built between 1964-1969) including the 7 litre (427 cubic inch) monsters which won at Le Mans in 1966 & 1967 so it took decades, but eventually there really was a "replacement for displacement".  The V6 also was used also in pick-up trucks which doesn't sound encouraging but versions of the small & big block V8s used in the GT40s also saw similar service, the latter even first appearing in the doomed Edsel.  Production of the second generation was limited to 1350 units, 50 of which were “Heritage Editions” in the Gulf colors, one of several “limited editions”.

Lindsay Lohan who when swimming uses both orange and blue, sometimes as solids (left and centre), sometimes in combination (right).