THE STRANGENESS OF COLOR PERCEPTION.

(2011)

PAUL S. SIDLE.

Refraction of white light via a prism, first conducted by Isaac Newton 1666.

THE STRANGENESS OF COLOR PERCEPTION.

2011

PAUL S. SIDLE.

Color theory (explanation for, premise, etc) represents a Human construct: in 'reality' (Latin realitātem: that underlying appearances, 'existent', of actuality, etc) an illusion (Latin illūsio from illūdere, jest at; from Greek eikasia): perversion, falsification, mis-interpretation, etc., of perception, past experiences, etc., thus is not concrete (Latin concrētus, to grow): 'existing', 'real', etc., not abstract (Latin abstractus, to draw: representing, organizing, etc., of events by objects, symbols, etc., for example, perceiving, visualizing, words, formulas, etc), particular not general; formed into one mass, etc.; practical, useful, etc. Consequently, we need ways to define what we mean by color, furthermore, how we structure (Latin structūra from struere, to build: emergent from ordered relations; equivalent to gestalt, whole, representation, etc.; interchangeable with function) colors, specifically, how we order colors, relate them, aswell as adjust them to become new colors. Color theory attempts to meld together the facts (observations, observed actualities, what happened; of non-verbal events) we have about color in a way that gives us common ground to discuss-and-use colors. Early theories of color remained pure speculation; but eventually, with more data at hand, the theories began to mirror-and-explain how the brain really perceives color.

Color involves a perception (Latin percipere, to take: sensing, representing [percepts] via 'sensory' processes: 'visual', 'auditory', 'taste', 'olfactory', 'tactile', etc.; interchangeable with 'feeling(s)', otherwise 'emotion(s)'; furthermore interpreting, apprehending, etc), a 'response' of the brain to data 'received' by the visual-systems. Just as artificial flavors evoke a similar smell to actual foods, otherwise as artificial sugar 'stimulates' our 'sense' of sweetness, such that different combinations of light can become perceived as the 'same' color. Ofcourse, if something we perceive appears the 'same' (Greek homos, 'identical': not other, different; exactly alike, undifferentiated in 'all' respects), this involves an illusion by mis-interpretation, otherwise a indifference to any differences in perceiving the color. What remains 'concrete' involves that objects (Latin objectāre: thing: 'figure', organized whole, gestalt of an external event) emit light in various mixtures of electro-magnetic wavelengths. Whereupon, our 'minds' perceive those wavelength mixtures as a phenomenon we term as color.

What we mean by color, involves the visible array of the Electro-Magnetic Spectrum. The electro-magnetic spectrum (gradation, degree, range, etc) represents a gradation of wavelengths (a change in the electric-and-magnetic field intensities from their equilibrium values which represents the wave disturbance) of waves (time-varying quantity which moreover involves a function of position) of energized radiation: one formed of time-dependent mutually-perpendicular electro-magnetic fields. The Spectrum of Electro-magnetic (EM) waves includes radio waves, heat (infrared, IR) radiation (emission-and-propagation of electro-magnetic energy from a source), ultra-violet (UV) rays, radio-waves, microwave, X-rays, ((gamma)-rays, aswell as visible-light rays. The electro-magnetic spectrum grew from the theory of electro-magnetism (Science concerned with the characteristics, relations between, etc., of magnetism, to that of electric currents), after James Clerk Maxwell's (1873), Scottish physicist, mathematician, equations. Though the electro-magnetic spectrum ranges approximately <10-16->108m, the visible part of the spectrum ranges between the wavelengths of 4-700nm (measured in micro- otherwise nano-meters, nm: approximately 1x10-9 ( 1/1,000,000,000mm); as the term suggests we can perceive only the rays of the visible part of the electro-magnetic spectrum.

Ofcourse, the discovery of the sequence of the electro-magnetic spectrum was not immediate, since most of the spectrum of radiation required the devising of detection equipment, moreover since not detectable by our vision, their discovery often came about by accident.

The visible-light part of the electro-magnetic spectrum (wavelength ranges approximately 380-740nm), represents what we see as 'colors': red through to ultra-violet. Ofcourse we cannot infact see colors, because color does not 'exist' other than as constructs of our nervous system, based on the wavelengths of visible light impinging upon our Retinas, irritating cones, evolved as

Figure 1.

Electro-Magnetic Spectrum.

Visible Spectrum between Wavelengths of 4-700nm, the restricted reception by

Cones.

Figure 8.

James Clerk Maxwell (June 13, 1831 – November 5, 1879);

Ernest Rutherford (August 30, 1871 – October 19, 1937);

Heinrich Rudolf Hertz (February 22, 1857 – January 1, 1894);

Sir Frederick William Herschel

(Friedrich Wilhelm Herschel; November 15, 1738 – August 25, 1822);

Paul Ulrich Villard (September 28, 1860 – January 13, 1934);

Jagadish Chandra Bose

(Jôgodish Chôndro Boshu; November 30, 1858 – November 23 1937).

Wilhelm Konrad Röntgen (March 27, 1845 – February 10, 1923);

Johann Wilhelm Ritter (December 16, 1776 – January 23, 1810)

'sensitive' to specific electro-magnetic wavelengths of light.

Frederick William Herschel (1800), German-born British astronomer, physicist, composer, discovered infrared (IR; wavelength: approximately 0.74-300nm, 7.4x10-6 -10-3m) radiation. On 11 February 1800, while Herschel tested filters for the Sun, so he could observe Sun spots, noticed that when using a red filter, he found there appeared a lot of heat produced. Herschel, decided to investigate the temperature of each color of the spectrum produced as produced by Isaac Newton's (1666) experiment of passing Sun-light through a prism. To do this, Herschel used three thermometers whose bulbs he blacked out, to better absorb heat. Herschel placed one bulb directly in the color, whilst the other two past the spectrum to function as controls, measuring the ambient air temperature in the room. Herschel noticed two trends, first that the temperature of the thermometer placed in the color appeared greater than the controls; the second trend involved a temperature increase from violet to red. Another remarkable observation made by Herschel occurred when he noticed that the temperature of the region just beyond the red part of the spectrum appeared even higher than the red itself! Further experimentation led to Herschel's conclusion that there must involve an invisible form of light beyond the visible spectrum, which Herschel dubbed this radiation "Calorific rays". Herschel carried out further experiments in which he demonstrated that what now appears known as Infrared radiation (heat) can become absorbed, transmitted, reflected, refracted, etc. Infrared radiation, involves light as an electro-magnetic radiation with a wavelength longer than that of visible-light, measured from the nominal edge of visible red light at 0.74nm, extending conventionally to 300nm. These wavelengths correspond to a frequency range of approximately 1 to 400THz, including most of the Thermal radiation emitted by objects near room temperature. Microscopically, IR light becomes typically emitted-or-absorbed by molecules when they change their rotational vibrational movements. Sun-light at zenith provides an irradiance of just over 1kw/m2 (kilo-watt per square meter) at sea level. Of this energy, 527watts involves infrared radiation, 445watts involves visible-light, while 32watts involves Ultra-violet radiation.

Figure 2.

Frederick William Herschel's (1800) experiment measuring the temperature of

light rays.

Ultra-Violet (UV) radiation (wavelength; approximately 10-400nm, 4x10-7-5x10-9m), termed because the spectrum consists of electro-magnetic waves with frequencies higher than those that Humans recognize as the color violet; UV light found in Solar Sun-light, emitted by electric-arcs, further by specialized lights such as Black-lights. UV represents bleaching rays, the source of Solar sun-burning, however most UV has become 'classified' as non-ionizing radiation, but the higher energies of the UV spectrum from about 150nm ('vacuum' ultra-violet) do ionize, causes many materials to glow-or-fluoresce, but not very penetrating, can become blocked by air. However, causal of chemical 'reactions', for example, has the benefit of providing the energy for the producing of Vitamin D, in Human skin; energy for important chemical synthesis of amino acids, proteins, constituents of nucleic acids, etc., essential in the early formation of life.

Johann Wilhelm Ritter (1801), German chemist, physicist, philosopher, inspired by Herschel's (1800) experiments, heard that silver chloride, a chemical turned black when exposed to Sun-light, with exposure to blue light causes a greater chemical 'reaction' in silver chloride than exposure to red light. Ritter decided to measure the rate at which silver chloride 'reacted', when exposed to the different colors of light. To do this, Ritter directed Sun-light through a glass prism to create a spectrum. Ritter then placed silver chloride saturated paper in each color of the spectrum. Ritter noticed that the silver chloride showed little change in the red part of the spectrum, but increasingly darkened toward the violet end of the spectrum; thus proved that exposure to blue light did result in silver chloride turning black much more efficiently than exposure to red light.

Ritter then decided to place silver chloride in the area just beyond the violet end of the spectrum, in a region where no Sun-light was visible, whereupon to Ritter's amazement, the silver chloride displayed an intense chemical 'reaction'. This showed experimentally that for the first 'time', that an invisible form of light persisted beyond the violet end of the spectrum. Ritter termed this new type of light, "Oxidizing Rays" (simpler term "chemical rays" adopted shortly thereafter, remaining popular throughout the 19th century), however later became known as Ultra-violet radiation (the word ultra means beyond). Ritter's (1801) experiment, along with Herschel's discovery, proved that invisible forms of light occurred beyond both ends of the visible spectrum.

Victor Schumann (1841-1913), physicist, discovered UV radiation below 200nm in 1893, termed vacuum Ultra-violet, since strongly absorbed by air. Schumann (1893), the first to measure spectra below 200nm, used a prism, lenses in fluorin instead of quartz, self-prepared photographic plates with a reduced layer of gelatin, placing the entire apparatus under vacuum; whereupon he found that indeed, oxygen gas absorbs the radiation with a wavelength below 195nm.

The EM spectrum of UV radiation can become sub-divided in a number of ways.

Name Abbreviation Wavelenght Range Energy

(nm) per Photon

(eV)

Ultra-violet A, Long-wave, UVA 400-315 3.10-3.94

Black light

Near NUV 400-300 3.10-4.13

Ultra-violet B, Medium-wave UVB 315-280 3.94-4.43

Middle MUV 300-200 4.13-6.20

Ultra-violet C, Short-wave UVC 280-100 4.43-12.4

Germicidal

Far FUV 200-122 6.20-10.2

Vacuum VUV 200-100 6.20-12.4

Low LUV 100-88 12.4-14.1

Super SUV 150-10 8.28-124

Extreme EUV 121-10 10.2-124

Table 1.

Draft ISO standard on determining Solar irradiances (ISO-DIS-21348).

The Sun emits UV radiation in the UVA, UVB, UVC bands. The Earth's ozone layer blocks 97-99% of this UV radiation from penetrating through the atmosphere; UVC along with more energetic radiation appears responsible for the generation of ozone in the ozone layer. Of the UV radiation that reaches the Earth's surface, 98.7% involves UVA. UVA, UVB, can not only remain harmful for Sun-burning, but causing mutations in our Deoxyribonucleic acid molecules (genes), cancers such as skin-cancer, etc.

Heinrich Rudolf Hertz (1886), German physicist, who clarified and expanded the electro-magnetic theory of light put forth by Maxwell (1865) in his equations, moreover predicted by Michael Faraday. Hertz appears the first to satisfactorily demonstrate the occurrence of EM waves by building an apparatus to produce-and-detect short-waves such as VHF, UHF radio-waves (Radio Frequency (RF) wavelength: approximately 10- >10-12m), moreover microwaves (wavelength: approximately 1m-1mm; including VHF,UHF: 10-1cm) in the UHF region. Hertz (1886), developed the Hertz antenna receiver: this involved a set of terminals that was not electrically grounded for their operation. Hertz further developed a transmitting type of Dipole antenna, which involved a centre-fed driven component for transmitting UHF radio waves. Hertz (1887), experiments followed Albert Abraham Michelson's (1881) experiment (1852-1931), which did not detect the occurrence of aether drift, whereupon Hertz altered Maxwell's equations to take this view into account for electro-magnetism.

Hertz used for his transmitter, a high voltage induction coil, a condenser otherwise capacitor, termed Leyden (Leiden) jars, which involves a device that stores static electricity between two electrodes on the inside-and-outside of a glass jar; invented independently by Ewald Georg Von Kleist (October 11, 1745), German cleric, along with Pieter Van Musschenbroek (1745–1746), Dutch scientist, of Leiden, a Ruhmkorff (1851) Induction coil (after Heinrich Daniel Rühmkorff (1803-77), often credited with the invention of the Induction coil, but in fact invented by Nicholas Callan (1836), involving a disruptive discharge coil, a type of electrical transformer used to produce high-voltage pulses from a low-voltage direct current (DC) supply), coil-driven spark gap involving spheres of 2cm radius on poles for a spark gap, along with 1m wire pair as a radiator, capacity spheres became positioned at the ends for circuit resonance adjustments, where the electric-current oscillated at a frequency determined by the values of the capacitor, aswell as the induction coil. Hertz's receiver, a precursor to the Dipole antenna, involved a simple half-wave Dipole antenna for short-waves. Hertz used as detector consisted of another coil with a spark gap, whereupon a spark would become seen upon detection of EM waves, involving a piece of copper wire, 1mm thick, bent into a circle of a diameter of 7.5cm, with a small brass sphere on one end, whilst other end of the wire pointed towards the sphere. Hertz included a screw mechanism so that the wire-point can become altered in relation to the sphere. Hertz's design allowed a correlation between the two currents oscillating in the wires of both instruments. The presence of oscillating charge in the receiver would become signaled by sparks across the (tiny) gap between the point-and-sphere, a gap typically hundredths of a millimeter. Hertz placed the apparatus in a darkened box to see the spark better. Hertz observed that the maximum spark length became reduced when in the box, a glass panel placed between the source of EM waves to that of the receiver, absorbed UV radiation that assisted the electrons in jumping across the gap.

Hertz in more advanced experiments, measured the velocity of electro-magnetic radiation, finding found it as that of the velocity of light. Hertz further showed that the nature of radio waves' reflection-and-refraction appeared similar to that of light, establishing beyond any doubt that light appears a form of electro-magnetic radiation determined by Maxwell's equations.

Through experimentation, Hertz (1887-8) proved that transverse free 'space' electro-magnetic waves can travel over some distance. This had become predicted by James Clerk Maxwell along with Michael Faraday. With his apparatus configuration, the electric-and-magnetic fields would radiate away from the wires as transverse waves. Hertz had positioned the oscillator about 12m from a zinc reflecting plate to produce standing waves; each wave produced, measured about 4m. Using the Ring detector, Hertz recorded how the magnitude aswell as wave's component direction vary. Hertz measured Maxwell's waves, demonstrated that the velocity of radio waves appears equal to the velocity of light. The electric-field intensity, along with polarity moreover measured by Hertz.

Figure 3.

Heinrich Rudolf Hertz's (1887) parabolic experimental setup (above).

Leyden Jars (below), the origianl capacitor (first Battery), after Ewald Georg

Von Kleist (October 11, 1745), German cleric, along with Pieter Van

Musschenbroek (1745–1746).

Figure 4.

Heinrich Rudolf Hertz (1887), experimental results.

However, Hertz did not realize the practical importance of his experiments, stating:

"It's of no use whatsoever(...) this is just an experiment that proves Maestro Maxwell was right - we just have these mysterious electromagnetic waves that we cannot see with the naked eye. But they are there".

Nevertheless, Hertz' experiments explain reflection, refraction, polarization, interference, moreover the velocity of electric-waves.

The Hertzian cone, first described by Hertz involved a type of wave-front propagation through various media. Hertz's experiments expanded the field of electro-magnetic transmission, while his apparatus became developed further by others in the radio. Hertz further found that radio waves could become transmitted through different types of materials, whilst reflected by others, leading in the distant future to Radar.

Hertz helped establish the Photo-electric 'effect' (later explained by Albert Einstein) when he noticed that a charged object loses their charge more readily when illuminated by UV light. When removed, the spark length would increase. Hertz observed no decrease in spark length when he substituted quartz for glass, as quartz does not absorb UV radiation. Though Hertz reported the results obtained, he did not further pursue investigation of this 'effect', nor did he make any attempt at explaining how the observed phenomenon occurred.

Hertz (1892), demonstrated that Cathode rays could penetrate very thin metal foil, for example, aluminium. Philipp Eduard Anton Von Lénárd (Fülöp Eduárd Antal Lénárd; 1862–1947), Hungarian-German physicist, a student of Hertz, further researched this "Ray effect", developing a version of the Cathode tube, which allowed Von Lénárd to study the penetration by X-rays of various materials. Von Lénárd, though, did not realize that his apparatus produced

X-rays. Von Helmholtz had formulated mathematical equations for the occurrence of X-rays, postulating a dispersion theory before Röntgen made his discovery.

In Jagadish Chandra Bose (1894), Bengali polymath, physicist, biologist, botanist, archaeologist, Science Fiction writer, etc., publicly demonstrated radio-control of a bell using millimetre wavelengths, moreover conducted research into the propagation of microwaves. Microwaves represent electro-magnetic radiation (waves) with wavelengths ranging from as long as 1m to as short as 1mm, otherwise equivalently, with frequencies between 300MHz (0.3GHz) to 300GHz. The microwave spectrum usually becomes defined as electro-magnetic energy ranging from approximately 1-100GHz in frequency, but older usage includes lower frequencies. This broad definition includes both UHF, along with EHF (millimetre waves), moreover various sources use different boundaries. In these various cases, microwave includes the entire SHF band (3-30GHz, otherwise

A.

B.

Figure 5.

(A). William Crookes (1875) X-ray tube from early 1910. The Cathode appears on

the right, the anode on the centre with attached heat sink at left; the

electrode at the 10 o'clock position involes the anti-cathode. The device

at top involves a 'softener' used to regulate the gas pressure.

(B). Cathode Ray Tube (CRT), diagram showing the internal workings; based on

William Crookes' (1875) tube.

10-1cm) at minimum, with RF engineering often putting the lower boundary at 1GHz

(30cm), whilst the upper around 100GHz (3mm).

Wilhelm Konrad Röentgen (1895), German physicist, discovered X-radiation (wavelength: approximately 0.01-10nm), while working with a Cathode-ray tube (William Crookes (1832-1919), English physicist, chemist, experimental discharge tubes, invented 1875) in his laboratory, the source of energized electron beams. Röentgen evacuated the tube of air, then filled it with a special gas, after which passed a high electric-voltage through it. When Röentgen did this, the tube would produce a fluorescent glow, further he observed that crystals of barium platino-cynaide glowed brightly when near an exhausted Cathode-ray tube, moreover affected wrapped photo-graghic plates. Crookes (1875) tubes, created free electrons by ionization of the residual air in the tube by a high Direct Current (DC) voltage of anywhere between a few kilo-volts (kV) to 100kV, which accelerated the electrons coming from the Cathode to a high enough velocity that they created X-rays when they struck the anode, otherwise the glass wall of the tube.

Johann Wilhelm Hittorf (1824-1914), German physicist, first observed cathode rays (streams of electrons observed in vacuum tubes), in 1869, whilst named by Eugen Goldstein (1850-1930), German physicist, as kathodenstrahlen, otherwise "Cathode rays", further termed an electron beam, otherwise e-beam, in 1876. If an evacuated glass tube becomes equipped with two electrodes, then a voltage applied, the glass opposite of the negative electrode (cathode: the electrode connected to the negative terminal of the voltage supply) becomes observed to glow, due to electrons emitted from and travelling perpendicular to the cathode. Joseph John Thompson (1846-1940), British physicist, first discovered the constituents of cathode rays as composed of a previously unknown negatively charged particle-wave, later named the "Electron", in 1897. Cathode ray tubes (CRTs) using a focused beam of electrons, if then deflected by electric-or-magnetic fields, can create the image as in the later television set.

Figure 6.

X-ray of Wilhelm Konrad Röentgen, wife's hand.

Röentgen shielded the Cathode-ray tube with heavy black paper, thus found that a green colored fluorescent light came from a screen setting a few feet away from the tube. Röentgen realized that he had produced a previously unknown

"invisible light", otherwise ray, tracing the 'effect' to rays emitting from the walls of the Cathode-ray tube; a ray capable of passing through the heavy paper covering the tube. Röentgen through following experiments found that the new ray would pass through most materials casting shadows of solid objects on pieces of film. Röentgen termed the new ray X-ray, because "X" in Mathematics indicated an unknown quantity. Röentgen for the discovery of X-rays, received the Nobel Prize for Physics, in 1901. Röentgen found that the X-ray would pass through Human tissue leaving the bones, metals, etc., visible. One of Röentgen's first experiments late in 1895 involved a film of his wife Bertha's hand with a ring on her finger.

Paul Ulrich Villard (1900), French chemist, physicist, investigated the radiation from radium salts that escaped from a narrow aperture in a shielded container onto a photographic plate, through a thin layer of lead known to stop Georgiy (George) Antonovich Gamov's (1928), Russian-born theoretical physicist, cosmologist, alpha(()-(basically atoms of Helium striped of their electrons, hence doubly positive charged; composed of 2 protons, with 2 neutrons)rays, discovered with mathematical help from Nikolai Evgrafovoch Kochin (1901-44), former Soviet mathematician; a problem solved independently by Ronald Wilfrid Gurney (1898-1953), physicist, along with Edward Uhler Condon (1902– 1974), American nuclear physicist. Villard showed that the remaining radiation consisted of a second-and-third type of rays. One of those deflected by a magnetic field (as were the familiar "Canal rays"), appeared to involve Ernest Rutherford's (1899), English physicist, beta(()-(electron [negatron], otherwise positron emitted from a nucleus of an atom)-rays; during the investigation of radioactivity he coined the terms alpha ray, with beta rays in 1899 to describe the two distinct types of radiation emitted by thorium along with uranium; the last type appeared a very penetrating kind of radiation which had not before discovered. Villard a modest man, did not suggest a specific name for the type of radiation he had discovered. Instead Rutherford (1903), proposed to call Villard's radiation Gamma((-) rays (wavelength: approximately <10-3->10-12m), because they appeared far more penetrating than the (-, (-, rays which Rutherford himself had previously differentiated-and-named (in 1899) on the basis of their respective penetrating powers. (-rays, represents a form of electro-magnetic radiation of high frequency (very short wavelength), with their origins in nuclear fission (splitting of atoms, otherwise atomic-nuclear decay of radioactive chemicals), an electro-magnetic radiation of high quantum energy emitted after nuclear 'reactions', otherwise by radioactive atoms when nucleus

becomes excited after emission of (-, (-, radioactive 'particles'. Gamma ray production events range from production of a single gamma photon ('particle' of light) in nuclear decay processes, to explosive bursts of gamma rays that remain the most powerful explosions of any type observed in the visible universe.

Color Pre-Science.

In Ancient Greece, Aristotle (350 B.C.), philosopher, systemizer, developed the first known theory of color. Aristotle postulated that Zeus sent down color from the heavens as celestial rays. Aristotle 'identified' ('same', not other, etc) four colors corresponding to the four 'elements' (Latin elementum from Greek Stoichia, to 'analyse', 'atomize', etc.; 'el': divide to the indivisible parts, the non-separable, contextually interchangeable whole(s) from part(s)): earth, fire, wind, water.

Figure 7.

Aristotle (c. 384–322 B.C.).

Figure 8.

Aristotle's (350 B.C.) four colors corresponding to the four 'elements': earth,

fire, wind, with water.

Aristotle wrote that color involves a mixture of light-and-dark, since white light 'always' becomes seen as somewhat darkened when seen as a color. Aristotle (c. 350 B.C.), "On Sense And Its Objects", III:

"White and black may be juxtaposed in such a way that by the minuteness of the division of its parts each is invisible while their product is visible, and thus color may be produced".

Leonardo da Vinci, Italian painter, sculptor, inventor, appeared the first to suggest an alternative 'hierarchy' of color. Da Vinci in his "Treatise On Painting", said that while philosophers viewed white as the "cause, or the receiver" of colors, whilst black as the absence of color, both appeared essential to the painter, with white representing light, while black, darkness. Da Vinci listed his six colors in the following order: white, yellow (earth), green (water), blue (air), red (fire), finally black.

Figure 9.

Examples of Leonardo Da Vinci's use of color.

Mona Lisa (further known as La Gioconda, La Joconde, otherwise Portrait of Lisa Gherardini, wife of Francesco del Giocondo, Lisa del Giocondo) involves a portrait by the Florentine artist Leonardo Da Vinci. A painting in oil on a

Poplar panel, completed circa 1503-1519.

On permanent display at the Musée Du Louvre, Paris.

Figure 10.

Leonardo di ser Piero Da Vinci, (April 15, 1452 – May 2, 1519).

Arthur Schopenhauer (1854), German philosopher, in "On Vision And Colors: An Essay", introduced-argued the notion that the brain perceives, thus

Figure 11.

Arthur Schopenhauer (February 22, 1788 – September 21, 1860).

organizes. The importance of this work is not so much in the details of the color theory that Schopenhauer produced, since he proposed that color perception took place in the Retina. Rather, Schopenhauer's supposition that colors lie within the observer. To Schopenhauer, color involves an immediate percept, therefore 'intuitive':

"All intuitive perception (Anschauung) is intellectual, for without the understanding (Verstand) we could never achieve intuitive perception".

Thus implying a formal contribution of the brain to perception. Schopenhauer's second volume "Die Welt Als Wille Und Vorstellung", he wrote that:

"...perception is not only the source of all knowledge, but is itself knowledge... it alone is the unconditionally true genuine knowledge".

We can interpret Schopenhauer's use of the word "Verstand" to mean the operation undertaken by the brain, thus leading to the 'intuitive' perception (Anschauung; apprehension), since Schopenhauer tells us:

"...the forms underlying Verstand, the Verstand is a function of the brain".

Color In Science.

Scientific theories of color-vision arose during the Renaissance, with the questioning of the works of Aristotle (350 B.C.) as indisputable.

Isaac Newton's (1704) Theory.

Isaac Newton, English physicist, alchemist, began in 1666 with a series of experiments the detailed understanding of the Science of color, which he later published as "Opticks" in 1704. Newton's (1704) discovery, involved that 'white' light appears composed of the 'colors' of the visible spectrum; using two prisms, he observed that white light appeared composed of 'all' the colors of the rainbow, thus could become 'identified' further ordered. Newton (1704), first used the word "Spectrum" for the array of colors produced by a glass prism. Newton recognized that the colors comprising white light become "refracted" (bent) by different amounts, furthermore he understood that there is no "colored" light, the color remains in the eye of the beholder. Instead, there merely occurs a range of energies, otherwise the proportional frequencies, further the inverse wavelengths. Newton assigned 7 colors to the spectrum in an analogy to the musical scale.

Figure 12.

Isaac Newton (January 4, 1643 – March 31, 1727 [25 December 1642 –

20 March 1727]).

In Newton's (1666), own words, in a letter written to the Royal Society after elected a fellow in 1672:

"I procured me a Triangular glass-Prisme, to try therewith the celebrated Phaenomena of Colours. And in order thereto having darkened my chamber, and made a small hole in my window-shuts, to let a convenient quantity of the Sun light, I placed my Prisme at his entrance, that it might be thereby

Figure 13.

Isaac Newton's (1666), five experiments of the refraction of white light into

constituent wavelengths of colors.

refracted to the opposite wall. It was at first a very pleasing divertissement,

to view the vivid and intense colours produced thereby; but after a while applying my self to consider them more circumspectly, I became surprised to see them in an oblong form; which, according to the received laws of Refraction, I expected should have been circular.

And I saw...that the light, tending to (one) end of the Image, did suffer a Refraction considerably greater then the light tending to the other. And so the true cause of the length of that Image was detected to be no other, then that Light consists of Rays differently refrangible, which, without any respect to a difference in their incidence, were, according to their degrees of refrangibility, transmitted towards divers parts of the wall".

According to Jacob Bronowski (1973), Polish-Jewish British mathematician, biologist, historian of Science:

"The elongation of the spectrum was now explained; it was caused by the separation and fanning out of the colours. Blue is bent or refracted more than red, and that is an absolute property of the colours".

Figure 14.

Jacob Bronowski (January 18, 1908 – August 22, 1974).

As Newton (1666), continues:

"Then I placed another Prisme...so that the light...might pass through that also, and be again refracted before it arrived at the wall. This done, I took the first Prisme in my hand and turned it to and fro slowly about its Axis, so much as to make the several parts of the Image...successively pass through...that I might observe to what places on the wall the second Prisme would refract them.

When any one sort of Rays hath been well parted from those of other kinds, it hath afterwards obstinately retained its colour, notwithstanding my utmost endeavours to change it".

As Bronowski (1973) explains:

"With that, the traditional view was routed; for if light were modified by glass, the second prism should produce new colours, and turn red to green or blue. Newton called this the critical experiment. It proved that once the colours are separated by refraction, they cannot be changed any further".

Newton (1666) continues:

"I have refracted it with Prismes, and reflected with it Bodies which in Day-light were of other colours; I have intercepted it with the coloured film of Air interceding two compressed plates of glass; transmitted it through coloured Mediums, and though Mediums irradiated with other sorts of Rays, and diversely terminated it; and yet could never produce any new colour out of it.

But the most surprising, and wonderful composition was that of Whiteness. There is no one sort of Rays which alone can exhibit this. ‘Tis ever compounded, and to its composition are requisite all the aforesaid primary Colours, mixed in a due proportion. I have often with Admiration beheld, that all the Colours of the Prisme being made to converge, and thereby to be again mixed, reproduced light, intirely and perfectly white.

Hence therefore it comes to pass, that Whiteness is the usual colour of light; for, Light is a confused aggregate of Rays induced with all sorts of Colours, as they are promiscuously darted from the various parts of luminous bodies".

However, Newton refrained from publishing until 1704 as "Opticks", because of disputes with other physicists, especially Robert Hooke (1635–1703), English physicist, innovator, architect.

Newton deepened our understanding of the true nature of light, furthermore the first to create a color circle. Newton (1666), ordered the colors as follows: red (musical note C), orange (D), yellow (E), green (F), blue (G), indigo (A), while violet (B). Though purple is not a color of the dispersion spectrum, Newton included it to complete the circle, bridging the gap between red-and-violet.

INCLUDEPICTURE "http://www.webexhibits.org/causesofcolor/images/content/1Bcolorcircle.jpg" \* MERGEFORMATINET

Figure 15.

Isaac Newton's (1666), Color Circle.

However, though Newton (1666) appears to have correctly 'analysed' the diversity of light rays that constitute Sun-light. But Newton did not consider the limitations of the eye in 'responding' selectively to these diverse rays.

Von Goethe's (1810) Theory.

Johann Wolfgang Von Goethe (1810), German biologist, theoretical physicist, poet, writer, pictorial artist, polymath, vigorously attacked Newton's (1704) theory of light-and-color. Goethe's (1810), "Zur Farbenlehre" ("Theory Of Colours"), presents Von Goethe the poet's view on the nature of colors, how these become perceived by Humans. Though incorrect, Von Goethe did point out some of the earliest published descriptions of phenomena such as color contrast 'effects', refraction, chromatic aberration, colored shadows ("Goethe's Shadows"), these shadows cast by colored lights appear the complementary color of the light.

Von Goethe's (1810) theory, was not so much a theory, but a conviction that Newton was wrong, based on Von Goethe's systematic experiments-and-observations. The original German edition of Von Goethe's (1810) "Zur Farbenlehre", has three sections:

(i). Didactic section in which Von Goethe presents his own observations.

(ii). Polemic section in which Von Goethe makes his case against Newton. (iii). Historical section.

From the publication in 1810, the book became controversial for the stance against Newton. So much so, that only the 'Didactic' color observations appear in Charles Eastlake's translation of the text into English in 1840, which he omitted the content of Von Goethe's polemic against Newton. In his preface, Eastlake explains that he deleted the historical-and-entoptic parts of the book because they 'lacked scientific interest', furthermore censored Von Goethe's polemic, because the 'violence of his objections' against Newton would prevent readers from fairly judging Von Goethe's color observations.

Von Goethe initially occupied himself with the theory of colors by the questions of hue in painting. Dennis L. Sepper (2007), states:

"During his first journey to Italy (1786-88), he noticed that artists were able to enunciate rules for virtually all the elements of painting and drawing except color and coloring. In the years 1786—88, Goethe began investigating whether one could ascertain rules to govern the artistic use of color".

Figure 16.

Johann Wolfgang Von Goethe (August 28, 1749 – March 22, 1832).

Von Goethe (1810), in the preface to "Zur Farbenlehre", explained that he tried to apply the Principle of Polarity (of opposites: not one without the other, here with color light-and-darkness), in the work, a proposition that belonged to his earliest convictions, constitutive for his entire study of nature.

It is not easy to present Von Goethe's 'theory', since he refrains from setting up any actual theory (apart from his application of the principle of polarity); as Von Goethe states in "Scientific Studies", first published in 1988, Douglas Miller (editor, translator): "...its intention is to portray rather than explain". For Von Goethe:

"...the highest is to understand that all fact is really theory. The blue of the sky reveals to us the basic law of color. Search nothing beyond the phenomena, they themselves are the theory".

Von Goethe (1810), in "Data for a Theory of Color", delivered in full measure, containing important, complete, significant data, rich material for a future theory of color. Von Goethe, has not however, undertaken to furnish the theory itself, hence, as he remarks-and-admits on page xxxix of the introduction; the physiological colors, he represents as a phenomenon, complete-and-existing by itself, without even attempting to show their relation to the 'Physical' colors, his principal theme, such that it represents a systematic presentation of facts, but it stops short at this.

According to Von Goethe, "Newton's error...was trusting math over the sensations of his eye". Hence, Von Goethe's (1810) color theory emphasizes experiential source, rather than impose theoretical statements; Von Goethe sought to display light-and-color in an ordered series of experiments that readers could experience for themselves. As such, Von Goethe would reject the both 'conceptually' (Latin conceptum, to conceive: 'generalized-universal' idea else notion) inferred (thus not directly perceived by the Human 'senses') wave-and-particle theories. Von Goethe's theory of the origin of the spectrum is not a theory, there is no Experimentum Crucis for Von Goethe's (1810) theory of color, since nothing can be predicted by means of it.

An argument that Von Goethe developed, involved Louis Bertrand Castel's (1740), published a criticism of Newton's spectral description of prismatic colour, where he observed that the colors of light split by a prism depended on the distance from the prism, as Newton's special case.

Figure 17.

Louis Bertrand Castel's (1740) comparison of Isaac Newton's (1704) spectral colour description with his explanation in terms of the 'interaction' of light-and-dark, which Johann Wolfgang Von Goethe (1810) later developed into his

"Zur Farbenlehre".

In Von Goethe's era, it became generally acknowledged that, as Newton (1704) had shown in his "Opticks", colourless (white) light becomes split up into colors when one directs it through a prism. As Von Goethe states:

"Along with the rest of the world I was convinced that all the colours are contained in the light; no one had ever told me anything different, and I had never found the least cause to doubt it, because I had no further interest in the subject.

But how I was astonished, as I looked at a white wall through the prism, that it stayed white! That only where it came upon some darkened area, it showed some colour, then at last, around the window sill all the colours shone... It didn't take long before I knew here was something significant about colour to be brought forth, and I spoke as through an instinct out loud, that the Newtonian teachings were false".

Von Goethe (1793), had formulated his arguments against Newton in his essay "Über Newtons Hypothese Der Diversen Refrangibilität" ("On Newton's Hypothesis Of Diverse Refrangibility"). Von Goethe's starting point involved the supposed discovery of how Newton erred, in the prismatic experiment. Von Goethe began to shift away from this view, in early 1794, strongly suspecting the meaning of the physiological side of colors.

Announcing the publication of the "Zur Farbenlehre", Von Goethe (1810) stated:

"The theory but that we postulate with certainty indeed also begins with colourless light, avails itself of outward conditions, to produce coloured phenomena; but it concedes worth and dignity to these conditions. It does not arrogate to itself developing colours from the light, but rather seeks to prove by numberless cases that colour is produced as well by light as by what is pitted against this".

Von Goethe strove to overcome what he perceived as a mere interpretation of the phenomena, thus to gain an insight into the complete phenomenon, itself. As a look through the prism shows that one does not see white areas split evenly into seven colors, but rather one sees colors at some edge, otherwise light-dark border, which Von Goethe concluded that the spectrum is not a primary, but a compound phenomenon. Color appears at light-dark boundaries; furthermore where the yellow-red along with the blue-violet edges overlap, there arises green.

Von Goethe unlike his contemporaries did not see darkness as an absence of light, but rather as polar to, moreover 'interacting' with light; colour resulted from this 'interaction' of light-and-shadow. For Von Goethe, light in a letter to Jacobi:

"...the simplest most undivided most homogenous being that we know. Confronting it is the darkness".

Figure 18.

Rudolf Joseph Lorenz Steiner (February 25/27, 1861 – March 30, 1925).

Otherwise, as Johann Eckermann (January 4, 1824), in "Conversations Of Goethe":

"...they maintained that shade is a part of light. It sounds absurd when I express it; but so it is: for they said that colours, which are shadow and the result of shade, are light itself".

Based on his experiments with turbid media, Von Goethe characterized color as arising from the dynamic inter-play of darkness-and-light. Steiner (1897), Austrian philosopher, social reformer, artitect, esotericist, gives the following analogy:

"Modern natural science sees darkness as a complete nothingness. According to this view, the light which streams into a dark space has no resistance from the darkness to overcome. Goethe pictures to himself that light and darkness relate to each other like the north and south pole of a magnet. The darkness can weaken the light in its working power. Conversely, the light can limit the energy of the darkness. In both cases color arises".

Von Goethe writes:

"Yellow is a light which has been dampened by darkness. Blue is adarkness weakened by the light".

Von Goethe's Color Wheel.

Von Goethe (1810), challenged Newton's (1666) established color-system, by creating his own. Von Goethe sought a system to determine the use of color in art. At first Von Goethe intended to create a new color wheel, but found that an equilateral triangle appeared exactly suited to representing his discoveries. The apex triangles in Figure 15, represent the primary colors used by printers. The secondary triangles between them represent the primary colors for painters, whilst the tertiary colors formed represent the dark neutrals. While Newton's system appeared based on scientific observation of 'additive' color-mixing, Von Goethe's method appeared more 'conceptual', based on the psychological 'effects' of color. Von Goethe's aim involved distilling laws of color harmony that incorporated the 'subjectivity' of our color perception, which depends on the object, the light, furthermore how we perceive them. Von Goethe studied complementary colors, the colors of shadows, furthermore after-images. Von Goethe recognized the origin of our understanding of complementary colors as stemming from the processes within our visual-system, rather than a 'property' of the light that reaches our eyes. Von Goethe's (1810) theory opened the door for our modern understanding of color-vision.

Von Goethe (1810), in "Zur Farbenlehre":

"When the eye sees a color it is immediately excited and it is its nature, spontaneously and of necessity, at once to produce another, which with the original colour, comprehends the whole chromatic scale".

Goethe (1810) anticipated Ewald Hering's (1920) Opponent Process theory by proposing a 'symmetric' color wheel. Von Goethe (1810) writes:

"The chromatic circle...(is) arranged in a general way according to the natural order...for the colours diametrically opposed to each other in this diagram are those which reciprocally evoke each other in the eye. Thus, yellow demands violet; orange, blue; red, green; and vice versa: thus...all intermediate gradations reciprocally evoke each other; the simpler colour demanding the compound, and vice versa".

Von Goethe moreover expressed his understanding of the light-and-dark spectra in including magenta in his color wheel. Whereas for Newton magenta remains an 'extra-spectral' color, for Von Goethe magenta appears a natural result of violet-and-red mixing in a dark spectrum, just as green resulted from the mixing of blue-and-yellow in the light spectrum. Von Goethe (1810), states:

"For Newton, only spectral colors could count as fundamental".

By contrast, Von Goethe's more empirical approach led him to recognize the essential role of (non-spectral) magenta in a complete color circle, a role that it still has in modern color systems. Furthermore, Von Goethe attributed inner qualities to the several colors of the wheel. Red relates to the beautiful, orange to the noble, yellow to the 'good', green to the useful, blue to the mean, violet to the unnecessary, etc.

Figure 19.

Johann Wolfgang Von Goethe's (1810), Color Triangle, which he prepared over the

wheel.

Experiments With Turbid Media: Boundary Conditions, Light-And-Dark Spectra.

For Von Goethe, the 'action' of turbid media (such as Newton's prism) represented the ultimate fact, the Urphänomen, of the world of colors.

Von Goethe's studies of color began with 'subjective' experiments which examined the 'effects' of turbid media on the perception of light-and-dark. Von Goethe observed that light seen through a turbid medium appears yellow, whilst darkness seen through an illuminated medium appears blue. As Von Goethe (1810) states:

"The highest degree of light, such as that of the sun... is for the most part colourless. This light, however, seen through a medium but very slightly thickened, appears to us yellow. If the density of such a medium be

Figure 20.

When seen at through a prism, the colors seen at a light-dark boundary depend

upon the orientation of this light-dark boundary.

Figure 21.

Light-and-dark spectra: when the colored edges overlap in a light spectrum,

green results; when they overlap in a dark spectrum, magenta results.

increased, or if its volume become greater, we shall see the light gradually assume a yellow-red hue, which at last deepens to a ruby colour.

If on the other hand darkness is seen through a semi-transparent medium, which is itself illumined by a light striking on it, a blue colour appears: this becomes lighter and paler as the density of the medium is increased, but on the contrary appears darker and deeper the more transparent the medium becomes: in the least degree of dimness short of absolute transparence, always supposing a perfectly colourless medium, this deep blue approaches the most beautiful violet".

Starting from these observations, Von Goethe began numerous experiments, observing the 'effects' of darkening-and-lightening on the perception of color in many different circumstances.

When viewed through a prism, the orientation of a light-dark boundary with respect to the prism's axis appears significant. With white above a dark boundary, we observe the light extending a blue-violet edge into the dark area; whereas dark above a light boundary results in a red-yellow edge extending into the light area. Von Goethe became intrigued by this difference, considering that this arising of color at light-dark boundaries remains fundamental to the creation of the spectrum, which he considered as a compound phenomenon. When varying the experimental conditions by using different shades of grey, shows that the intensity of colored edges increases with boundary contrast.

Since the color phenomenon relies on the adjacency of light-and-dark, there appear two ways to produce a spectrum: with a light beam in a dark room, whereas with a dark beam (such as a shadow) in a light room. Von Goethe recorded the sequence of colors projected at various distances from a prism for both cases. Von Goethe found that the yellow-and-blue edges remain closest to the light side, whereas red-and-violet edges remain closest to the dark side. At a specific distance, these edges overlap, whereby we obtain Newton's spectrum. When these edges overlap in a visible spectrum, green results; when they overlap in a dark spectrum, magenta results.

With a light spectrum, coming out of the prism, one sees a shaft of light surrounded by dark. We find yellow-red colors along the top edge, whilst blue-violet colors along the bottom edge. The spectrum with green in the middle

arises only where the blue-violet edges overlap the yellow-red edges. With a dark spectrum (such as a shadow surrounded by light), we find violet-blue along the top edge, whilst red-yellow along the bottom edge, where these edges overlap, we find magenta.

Critique-Reception.

For Von Goethe's aim, he had welcome acknowledgement, when several pictorial artists, including Philipp Otto Runge, took an interest in his color studies. Since after Eastlake's (1840) translation, Von Goethe's investigations became widely adopted by the Art world, especially among the Pre-Raphaelites; Joseph Mallord William Turner (1775-1851), studied it comprehensively, while referenced it in the titles of several paintings.

Though Von Goethe's work was never well received by physicists, a number of philosophers, along with physicists have concerned themselves with it, including Thomas Johann Seebeck (1770-1831), Arthur Schopenhauer (1788–1860), Herman Von Helmholtz (1821–1894), Rudolf Joseph Lorenz Steiner (1861–1925), Ludwig Josef Johann Wittgenstein (1889–1951), Werner Heisenberg (1901–1976), Kurt Gödel (1906-78), Mitchell Jay Feigenbaum, etc. Herman Von Helmholtz's (1892) lecture on Von Goethe's scientific works:

"...(the perceived phenomena) circumstantially, rigorously true to nature, and vividly, puts them in an order that is pleasant to survey, and proves himself here, as everywhere in the realm of the factual, to be the great master of exposition".

Von Helmholtz (1892), ultimately rejects Von Goethe's theory as the work of a poet, but expresses his perplexity in the agreement of facts, yet but in violent contradiction about their interpretation:

"And I for one do not know how anyone, regardless of what his views about colours are, can deny that the theory in itself is fully consequent, that its assumptions, once granted, explain the facts treated completely and indeed simply".

Though the accuracy of Von Goethe's observations does not admit a great deal of criticism, his theory's failure to demonstrate significant predictive validity eventually rendered it scientifically irrelevant. Seebeck (1810), physicist, who worked with Von Goethe on his (1810) "Zur Farbenlehre", remained the only prominent scientist among Von Goethe's contemporaries who acknowledged the theory, though later still saw it critically. Von Goethe's (1810) Color theory has in many ways borne fruit in Art, Physiology, Aesthetics, etc.; but victory, hence influence on the research of the following century, has remained with Newton.

Figure 22.

Thomas Johann Seebeck (April 9, 1770 – December 10, 1831).

Seebeck, in 1810 at Jena, described the 'action' of the spectrum of light on silver chloride. Seebeck observed that the exposed chemical would occasionally take on a pale version of the color of light that exposed it, furthermore reported the 'action' of light for a considerable distance beyond the violet end of the spectrum.

Much controversy stems from two different ways of investigating light-and-color. Von Goethe was not interested in Newton's (1710) 'analytic' treatment of color, but he presented an excellent description of the phenomenon of Human color perception. As such, we must view Von Goethe's book as a collection of color observations. Most of Von Goethe's explanations of color have been thoroughly demolished, but no criticism has been leveled at his reports of the facts to observed; nor should any be. Von Goethe's book can lead the reader through a demonstration course not only in 'subjectively' produced colors such as after images, light-and-dark adaptation, irradiation, colored shadows, pressure phosphenes, etc., but furthermore in 'physical' phenomena detectable qualitatively by observation of color, such as absorption, scattering, refraction, diffraction, polarization, interference, etc. A reader who attempts to follow the 'logic' of Von Goethe's explanations, moreover who attempts to compare them with the currently accepted views might, even with the advantage of 2011 sophistication, become convinced that Von Goethe's (1810) theory, otherwise at least a part of it, has been dismissed too quickly.

James Gleick (1987), in "Chaos":

"As Feigenbaum understood them, Goethe's ideas had true science in them. They were hard and empirical. Over and over again, Goethe emphasized the repeatability of his experiments. It was the perception of colour, to Goethe, that was universal and objective. What scientific evidence was there for a definable real-world quality of redness independent of our perception?".

Where Mitchell Jay Feigenbaum, has coined the phrase "Goethe had been right about colour!".

Figure 23.

Mitchell Jay Feigenbaum (born December 19, 1944).

Von Goethe (1810) in his book, provides a general exposition of how color gets perceived in a variety of circumstances, considering Newton's observations as a special case. Von Goethe's concern was not so much with the 'analytic' measurement of color phenomenon, as with the qualities of how phenomena become perceived. Philosophers have come to understand the distinction between the optical spectrum as observed by Newton, with that of the phenomenon of Human color perception as presented by Von Goethe, a subject 'analyzed' at length by Ludwig Wittgenstein (1950) in his exegesis of Von Goethe in "Remarks On Colour".

A Critique Of Newton (1666, 1710), Von Goethe (1810) Theories.

Due to their different approaches to a common subject, many mis-understandings have arisen between Newton's (1704) mathematical understanding of optics, compared to Von Goethe's (1810) experiential approach.

Since Newton understands white light as composed of individual colors, whilst Von Goethe sees color arising from the 'interaction' of light-and-dark, they come to different conclusions on the question: whether the optical spectrum involves a primary, otherwise a compound phenomenon?

For Newton, the prism is immaterial to the occurrence of color, as the colors compose white light, such that the prism merely fans them out according to their refrangibility. Von Goethe sought to show that, as a turbid medium, the prism appears an integral factor in the arising of color.

Alex Kentsis (2005), states:

"Whereas Newton observed the colour spectrum cast on a wall at a fixed distance away from the prism, Goethe observed the cast spectrum on a white card which was progressively moved away from the prism... As the card was moved away, the projected image elongated, gradually assuming an elliptical shape, and the coloured images became larger, finally merging at the centre to produce green. Moving the card farther led to the increase in the size of the image, until finally the spectrum described by Newton in the Opticks was produced... The image cast by the refracted beam was not fixed, but rather developed with increasing distance from the prism. Consequently, Goethe saw the particular distance chosen by Newton to prove the second proposition of the Opticks as capriciously imposed".

Whereas Newton narrowed the beam of light in order to isolate the phenomenon, Von Goethe observed that with a wider aperture, there was no spectrum. Von Goethe saw only reddish-yellow edges, furthermore blue-cyan edges with white between them, where the spectrum arose only where these edges came close enough to overlap. For Von Goethe, the spectrum could become explained by the simpler phenomena of color arising from the 'interaction' of light-and-dark edges.

Qualities Of Newton (1704) Von Goethe (1810)

Light

White light composed of Light the simplest most

Homogeneity colored 'elements' undivided most homogenous thing

(heterogeneous). (homogenous).

Darkness Darkness, an absence of light. Darkness as polar to, moreover

'interacts' with light.

Colors fanned out of light Coloured edges which arise at

Spectrum according to their refraction light-dark borders overlap to

(primary phenomenon). form a spectrum

(compound phenomenon).

Prism The prism is immaterial to the As a turbid medium, the prism

existence of color. plays a role in the arising of

color.

Role of Light decomposes through Refraction, inflection,

Refraction refraction, inflection, reflection can ocurr without

reflection. The appearance of color.

'Analysis' White light decomposes into Only two pure colors: blue-and-

seven pure colors. yellow; the rest degrees of

these.

Synthesis White light can decompose, Colors recombine to shades of

Aswell as recombine. grey.

'Particle 'Particle', corpuscular. Neither, since inferences, not

or Wave'? observed with 'senses'.

Colour Wheel Asymmetric, 7 colours. 'Symmetric', 6 colours

Table 2.

Comparing Isaac Newton (1704), to Johann Wolfgang Von Goethe (1810) theory on

spectra.

Newton (1704), explains:

"...the fact that all the colors appear only when the prism is at a certain distance from the screen, whereas the middle otherwise is white...(by saying) the more strongly diverted lights from the upper part of the image and the more weakly diverted ones from the lower part fall together in the middle and mix into white. The colors appear only at the edges because there none of the more strongly diverted parts of the light from above can fall into the most weakly diverted parts of the light, and none of the more weakly diverted ones from below can fall into the most strongly diverted ones".

Von Goethe's (1810) experiments, as a array of observations, remain useful data for understanding the complexities of Human color perception; Von Goethe focused on exploring how color appears perceived in a wide array of conditions. Instead, Newton (1666) sought to develop a mathematical model for the 'behaviour' of light.

Von Goethe's reification of darkness has resulted in nearly the entire modern Physics to reject Von Goethe's (1810) theory. Both Newton along with Christiaan Huygens (1726-97), Dutch mathematician, physicist, defined darkness as an absence of light. Thomas Young along with Augustian Jean Fresnel (1788-1827), French physicist, combined Newton's (1687) corpuscular ('particle') theory with Huygen's 'wave' theory to show that color involves the visible manifestation of light's wavelength. Physicists today attribute both a 'corpuscular and undulatory' character to light, the duality particle-waves of Quantum Mechanics. Curiously, since the crux of Von Goethe's (1810) theory remains tied to what appears experiential, he would reject both the 'wave and particle' theories since 'conceptually' inferred, not directly perceived by the Human 'senses'.

Von Goethe started out by accepting Newton's (1704) 'physical' theory but soon abandoned it, finding modification more in keeping with his own insights. One beneficial consequence of this involved that Von Goethe developed an awareness of the importance of the physiological aspect of color perception, therefore able to demonstrate that Newton's (1704) theory of light-and-colours is too simplistic; that there remains more to color than variable refrangibility.

Von Goethe's (1810), "Zur Farbenlehre" not only parted radically with Newton's (1704) optical theories of that period, but with the entire Enlightenment methodology of 'Reductive' (explanation of complexities by underlying simplicities by process of 'analysis') Science. Holism in Science (Holistic Science), involves an approach to research that emphasizes the study of complex systems, in contrast to a purely 'analytic' (from Greek analusis, to loosen: to find 'elements') tradition (called occasionally Reductionism) which aims to gain understanding of systems by dividing them into smaller composing 'elements', whereby gaining understanding of the system through understanding their 'elemental properties'. The Holism-Reductionism Dichotomy often appears evident in conflicting interpretations of experimental findings, furthermore the setting of priorities for future research. Holistic theorists-and-scientists such as Rupert Sheldrake, English bio-chemist, plant physiologist, still refer to the Von Goethe's (1810) color-theory as an inspiring example of holistic Science. The introduction to the book lays out Von Goethe's unique Philosophy of Science.

Figure 24.

Rupert Sheldrake (born June 28, 1942).

Developments in understanding how the brain interprets colors, such as Color Constancy, Edwin Herbert Land's (1971) Retinex theory ("Goethe's Shadows" represent the starting point of Edwin Land's "Retinex" theory of color vision), bear striking similarities to Von Goethe's (1810) theory.

Tri-chromatic (Tri-chromacy-ticism) Theory Of Color-Vision.

Tri-chromacy, represents the condition of possessing three independent channels for conveying color information, derived from the three different cone types. Organisms with tri-chromacy become termed tri-chromats.

Tri-chromatic color-vision involves the ability of Humans aswell as some other Animals to see different colors, mediated by 'interactions' among three types of color-sensing Cone (photo-resonator cells; in vertebrates termed Cone cells) cells. The usual explanation of tri-chromacy involves that the organism's Retina contains three types of color 'receptors', having different absorption spectra, when hit by photons of light. In actuality the number of such 'receptor' types may be greater than three, since different types may become active at different light intensities. In vertebrates with three types of Cone cells, at low light intensities the Rod cells may contribute to

color-vision, giving a small region of Tetra-chromacy in the color-space.

The Tri-chromatic Color theory began in the 18th century, when Thomas Young (1854), physicist, in his lectures proposed that color-vision results of three different photo-'receptor' nerve cells, termed the Tri-receptor theory.

Figure 25.

'Responsivity' spectra of Human Cone cells.

Young (1801), at St. George's Hosiptal, London, realized that Human perception of fine detail implies a 'fine grain' of photo-receptors in the Retina, such that it unlikely that each 'grain' selectiviely 'responsive' to 'every' wavelength of light; nor this necessary to explain color discrimination.

Young (1854), suggested that each grain consisted of a triad of resonators, each thrown into vibration by light-waves. The green 'receptor' moved chiefly by waves from the middle (medium wavelengths) of the spectrum (which looks green), though neighbouring spectral waves further 'acted' upon it less vigorously. Another one for long wavelengths (which looks 'red'), along with one for short wavelengths (which looks 'blue'). Thus light of any composition falling upon the eye will throw these three resonators, R,G,B, into determinate amplitudes of vibration. Their 'sum', R+G+B defines the brightness, while their ratio R:G:B defines the color. Such that if we proceed from one end of the visible spectrum to another, it appears to become more-or-less 'red or blue' (where black is not a 'color', but absence of wavelengths of light) in 'color'. Young's (1854) explanation, should lead to a simple, but striking result. Each color (including white) should excite the R,G,B, 'receptors' in a characteristic set of ratios. Consequently, a mixture of red + green + blue lights, adjusted to produce this 'same' set of ratios, should appear white, otherwise whatever the initial color appeared. Herman Von Helmholtz (1801), German physicist, physician, later expanded on Young's ideas using color-matching experiments which showed that people with 'normal' vision needed three wavelengths to create the range of colors. Von Helmholtz showed that each color can become matched by a suitable mixture of red + green + blue 'primaries', though occasionally it appears necessary for the experimenter to mix one of his three primaries with the color requiring matching rather than with the other primaries.

Figure 26.

From left to right:

James Clerk Maxwell (June 13, 1831 – November 5, 1879);

Hermann Ludwig Ferdinand Von Helmholtz (August 31, 1821 – September 8, 1894);

Thomas Young (June 13, 1773 – May 10, 1829).

Von Helmholtz's (1851) "Handbuch Der Physiologischen Optik" ("Handbook Of Physiological Optics"), provided empirical theories on 'spatial' vision, color-vision, further motion perception, which became the fundamental reference work in his field during the second half of the 19th century. While James Clerk Maxwell (1854), devised the first color-systems based upon scientific principles. Maxwell's very first design around 1850 involved a rotating top with clipped-on colored discs.

Figure 27.

James Clerk Maxwell (1850), Color-System.

Rotating top with clipped-on colored discs.

Maxwell (1850), produced an Equilateral Triangle Chart, based on his scientific findings leading to the electro-magnetic theory of light, his choice of form appears very closely aligned to that of Von Goethe. They both mix the primaries in the outer triangles to produce the inner colors. However, Clerk Maxwell chose red, green, moreover blue as primaries, believing he could produce 'all' the known colors from these.

Figure 28.

James Clerk Maxwell's (1850) Equilateral Triangle Chart.

More More

Red Blue

Less Blue

ULTEA-

VIOLET INDIGO BLUE GREEN YELLOW ORANGE RED

380nm 480nm 510nm 580nm 600nm 740nm

OVERLAPS OF DEGREES, NOT ELEMENTS IF CHANGE INDEFINITE, THUS INFINITE.

Figure 29.

Color Circle of Electro-Magnetic Spectrum.

Illustrating how the three main colors red, green, with blue,

can continue to form other colors.

Later Gunnar Svaetichin (1956), Swedish-Finnish-Venezuelan physiologist, showed by examining the external layers of Fish Retinas that electro-retino-grams display particular 'sensitivity' to 3 different groups of wavelengths in the areas of blue, green, further red. This provided the first biological demonstration in support of the Young-Helmholtz-Maxwell Tri-chromatic theory. Svaetichin further gave name to the S-potential, which provided the first experimental evidence that opponency occurred in the visual-system.

This Tri-chromacy of vision confirmed by Von Helmholtz (1801), later became measured with spectral lights, with great accuracy independently by W.D. Wright, moreover by W.S. Stiles at the National Physical Laboratory.

The photo-chemical pigment involved has become termed Iodopsin, whereupon there appears 3 types of Cone L, M, S (Long, Medium, Short), according to George Wald (1950s), et colleagues Halden Keffer Hartline, with Ragnar Granit, involving a Tri-chromatic theory, each 'sensitive' to one of the 3 primary colors: red, blue, green. The blue cone 'responds' maximally to short wavelengths of about 450nm, green cones to medium wavelengths about 525nm, whilst red cones to long wavelengths about 550nm. Thus for example, a yellow light would irritate both red-and-green cones, where Iodopsin (visual violet) becomes split by photons in a similar way as Rhodopsin (visual purple) in rods.

Where in between 'red and blue', we shall expect to find a gradation (Latin gradātio-ōnem, from gradus, a step: orderly arrangement, succession, progression, array [ordered arrangement, gradation, degree, etc], continuum, etc.; step, stage, degree, rank, 'quality', intensity, grade, etc., in order; blending, etc) of degrees (Latin gradus, a step: relative, rank, step, stage, grade, intensity, 'quantity', 'quality', etc., unit in ascending, descending, angular, etc., array, spectrum, scale, measurement, etc), for example a 'yellow' may appear indistinguishable for a range of wavelengths, until they became 'perceptibly' lighter-or-richer; further usually we may rely on environmental cues in order to assist in our ability to distinguish between 'colors and brightness': 'Color Constancy'. Therefore not the 'same', even if we cannot easily distinguish between 'hues of color', neither 'elements' because of indistinguishable over-laps of 'colors'. Indeed the 'perceiving of color' differences appears to reach a saturation point, then jump to another 'hue' ('color tint'), as if emergent wholes: the non-elementalistic (ēl, non-el: after Lao-Tse (600 B.C.), over-lapping, interchangeable [equivalent, reversible, etc],

Figure 30.

Lao-Tse (c. 600 B.C.).

functional [non-linear-asymmetry-non-additive] packets, etc., emergent, holism) combination of parts. Such that it appears that we perceive wavelengths of light as gestalts (from German: form [shape hence 'figure'], pattern, configuration, unity, whole, organization, representation, etc., hence emergence, thus structure; after Max Wertheimer (1912)), when since light must arrive at our retinas as quantas (Latin quantus, how much) after Max Karl Ernst Ludwig Planck (1900), that 'energy' (Greek energeia, work: dynamic power, force, etc., capability of 'action') comes in packets. Therefore this process cannot involve an additive' 'sum' of values, where Lao-Tse (600 B.C.) in "Tao Te Ching" had remarked instead that "the sum of the parts is not the whole". Infact, we appear to have an interchangeable non-additive (not sum of values, but functional)-asymmetry (not 'uniform' [irregular],'same'[incommensurable], etc., in relations, for example left with right, up with down, etc)-non-linear (not 'uniform', 'straight', etc., but curvature; such that a 'straight line' becomes a point extending in a continuum from Latin continuus: thing of continuous structure, etc), more-or-less.

As shown in Figure 29, 'white' light emerges from the 'colors' of the spectrum:

W = f(visible spectrum: R, O, Y, G, B, I, V...) Equation 1.

where W, White light.

f, Function of within ( ).

R, Red light.

O, Orange light.

Y, Yellow light.

G, Green light.

B, Blue light.

I, Indigo light.

V, Ultra-violet light.

..., Etc.

Since the likelihood of 'response' of a given cone varies not only with the wavelength of the light that hits it, but furthermore with the intensity, the brain would not be able to discriminate different colors if it had input from only one type of cone. Thus, 'interaction' between at least two types of cone appears necessary to produce the ability to perceive color. With at least two types of cones, the brain can compare the signals from each type, thence determine both the intensity-and-color of the light. For example, moderate 'stimulation' of a medium-wavelength cone cell could mean that a 'stimulation' by very bright 'red' (long-wavelength) light, otherwise by not very intense 'yellowish-green' light. But very bright 'red' light would produce a stronger 'response' from L cones than from M cones, while not very intense 'yellowish' light would produce a stronger 'response' from M cones than from other cones. Thus Tri-chromatic color-vision appears accomplished by using combinations of cell 'responses'.

It appears estimated that each of the three cone types (in the absence of further cones) in the Human Retina can pick up about 100 different gradations. Assuming the brain can combine those variations exponentially, the average Human should become able to distinguish about 1x106 (one million) different colors.

Hering's (1892) Opponent (Tetra-Chromacy) Theory Of Color.

Karl Ewald Konstantin Hering, German physiologist, in his physiological researches, sought a synthesis of Physics with that of Psychology. Hering epitomized his outlook to purely 'physical analysis' in 'sensory' Physiology in his analogy of those who might understand a time-piece by dissecting it into component gears; would not a glance at their face-and-hands yield an indispensable insight into the function? Accordingly, Hering made the 'subjective' phenomena of 'sensation' full-fledged ingredients when assembling the bases for a physiological theory, most successfully in his theories of brightness perception, aswell as color-vision. In this Hering broke ranks with nearly the entire 'materialist' Natural Philosophy (Physics) of that period, except indeed with Ernst Mach (1838–1916), German physicist. Hering did not follow Gustav Theodor Fechner, German experimental psychologist, founder of Psycho-Physics, after Fechner (1860s) represents an area of Psychology concerned primarily with the quantitative relationships between 'physical stimuli', to that of the psychological experience of them, thus assumes a psycho-physical 'parallelism'. Fechner (1838), noticed the still-mysterious perceptual illusion termed the Fechner Color Effect, whereby colors when seen in a moving pattern appear black-and-white. Nor was Hering entirely in the tradition of Von Goethe,

Figure 31.

Karl Ewald Konstantin Hering (August 5, 1834 – January 26, 1918).

Figure 32.

Gustav Theodor Fechner (April 19, 1801 – November 18, 1887).

Figure 33.

Karl Ewald Konstantin Hering (1920), Color Wheel.

Schopenhauer, etc., who, while sponsoring Opponent theories of color-vision, placed nearly 'all' the emphasis on the 'subjective' 'elements'. Hering's (1892) theories of light-and-color postulated 'substances' (Latin substantia, that which a thing consists: 'permanent', unchanging 'matter' having 'essences', variable 'properties' involving a doctrine of 'predicables,' that which 'can be predicated or attributes, essences predicated'), further neural processes that could go in two directions from their neutral point, anabolic-and-catabolic. To arrive at these formulations, Hering used not only the available data on color-mixture that had appeared basic to previous theories, but further to the observations that 'subjectively' yellow did not appear as a mixture of green-and-red, that yellow remained a stable hue with changes in intensity, whilst that after-images, aswell as complementary colors fitted best into an opponent-color scheme. It took another 75 years before electro-physiologists demonstrated the occurrence at the cellular level of Hering's mechanisms: centre-surround organization of retinal ganglion cells; further opponent, such as, excitatory-and-suppressing, coding of color. However, Hering still remained very much a creature of Science of the middle of the 19th century. Hering postulated 'sensory' further neural processing may have appeared more advanced, further more encompassing than that of his contemporaries, yet he further believed it to reside in the cells of the organism. Their 'universality' (Latin ūniversālis, of 'everything': 'always same, all true'; 'common to all' cases), further presence at an early stage of development (in the case of perfect conjugacy of the eye movements even at, otherwise shortly after birth) led

Hering to conclude that the mechanism for this kind of processing (such that, of eye movements, of color-and-brightness detection) appeared inborn.

Hering disagreed with the leading theory developed mostly by Thomas Young further Herman Von Helmholtz. Helmholtz's (1801) theory stated that the human eye perceived 'all' colors in terms of three primary colors: red, green, with blue. Hering instead believed that the visual-system worked based on a system of Color Opponency. Both proposals now appear widely recognized as correct in different aspects of color-perception.

Hering's (1920), Color Wheel represents the four primary colors (red, green, blue, yellow) positioned according to their polarity as poles of two perpendicular axes. Intermediate colors form by 'additive' mixing from the primary colors. The modern Swedish Natural Color System (NCS) has a basis on this color wheel.

Discussion: Opponent Theory Of Color-Vision.

Von Goethe (1810), first studied the physiological 'effect' of opposed colors in his "Zur Farbenlehre". Goethe arranged his color wheel 'symmetrically', "...for the colours diametrically opposed to each other in this diagram are those which reciprocally evoke each other in the eye. Thus, yellow demands purple; orange, blue; red, green; and vice versa: thus again all intermediate gradations reciprocally evoke each other".

Hering (1892), proposed Opponent Color theory, whereby he considered that the colors red, yellow, green, along with blue, appear special in that any other color can become described as a mix of them, furthermore that they occur in opposite pairs. Such that, red-or-green becomes perceived, but never greenish-red; though yellow appears a mixture of red-and-green in the RGB Tri-color theory, the eye does not perceive it as such.

Leo M. Hurvich along with Dorothea Jameson (1957), using a method of "hue cancellation", provided quantitative data for Hering's (1892) Color Opponency theory. Hue cancellation experiments start with a color, for example, yellow, then attempt to determine how much of an opponent color, for example, blue, such that of one of the starting color's components must become 'added' to eliminate any hint of that component from the starting color. Griggs (1967), expanded the 'concept' to reflect a wide range of opponent processes for biological systems in his book "Biological Relativity". Richard L. Solomon (1970), expanded Hurvich's general neurological Opponent Process model to explain 'emotion', drug addiction, furthermore work motivation. The Opponent Color theory can become applied to computer vision, by implementing as the Gaussian Color model.

The Color Opponent process represents a color theory that states that the human visual-system interprets information about color by processing signals from cones-and-rods in an antagonistic manner. The three types of cones (L for long, M for medium, S for short) have some overlap in the wavelengths of light to which they 'respond', so it appears more efficient for the visual-system to record differences between the 'responses' of cones, rather than each type of cone's individual 'response'. The Opponent Color theory suggests that there appear three opponent channels: red versus green, blue versus yellow, finally black versus white; the latter type achromatic, detecting light-dark variation, otherwise luminance. 'Responses' to one color of an opponent-channel become antagonistic to those to the other color. Such that, opposite opponent colors are never perceived together, there is no "greenish red", otherwise "yellowish blue".

Figure 34.

Opponent colors based on experiment.

Deuteranopes see little difference between the two colors in the central column.

While the Tri-chromatic theory defines the way the Retina of the eye allows the visual-system to detect color with three types of cones, the Opponent Process theory accounts for mechanisms that 'receive-and-process' information from cones. Though the Tri-chromatic along with Opponent Processes theories were initially considered at odds, it later came to become understood that the mechanisms responsible for the Opponent Process 'receive' signals from the three types of cones, whilst process them at a more complex level.

Besides the cones, which detect light entering the eye, the biological basis of the Opponent theory involves two other types of cells: Bi-polar cells, furthermore Ganglion cells. Information from the cones passes to the bi-polar cells in the Retina, which may involve the cells in the Opponent Process that transform the information from cones. The information then passes to ganglion cells, of which there appear two major kinds: Magno-cellular, otherwise large-cell layers, furthermore Parvo-cellular, otherise small-cell layers. Parvo-cellular cells, otherwise P-cells, handle the majority of information about color, falling into two groups: one that processes information about differences between firing of L-and-M cones, furthermore one that processes differences between S cones, with that of a combined signal from both L-and-M cones. The first sub-type of cells appear responsible for processing red–green differences, while the second process blue–yellow differences. P-cells moreover transmit information about intensity of light, due to their 'receptive'-field.

Under normal circumstances, there is no hue one could describe as a mixture of opponent hues; such that, as a hue looking "red-green", otherwise "yellow-blue". However, H.D. Crane along with D.P. Piantanida (1983), carried out an experiment under special viewing conditions in which red-and-green stripes (otherwise blue-and-yellow stripes) became placed adjacent to each other, whilst the image held in position relative to the viewer's eyes, using an eye tracker to compensate for minor muscle movements. Under such conditions, the borders between the stripes seemed to disappear, whilst the colors flowed into each other, making it apparently possible to over-ride the opponency mechanisms, whilst for a moment, get some people to per