Brutalism is an architectural style of the 1950s and 1960s characterised by simple, block-like forms and raw concrete construction. 

Paul Seawright.

The term was coined by the British architectural critic Reyner Banham to describe the approach to building particularly associated with the architects Peter and Alison Smithson in the 1950s and 1960s.The term originates from the use, by the pioneer modern architect and painter Le Corbusier, of ‘beton brut’ – raw concrete in French. Banham gave the French word a punning twist to express the general horror with which this concrete architecture was greeted in Britain.

Typical examples of brutalism are the Hayward Gallery and National Theatre on London’s South Bank.

The term brutalism has also sometimes been used to describe the work of artists influenced by art brut.

Art brut is a French term that translates as 'raw art', invented by the French artist Jean Dubuffet to describe art such as graffiti or naïve art which is made outside the academic tradition of fine art. 

It is unclear whether Baudry believed that Dubuffet, then a rising figure within the French art world, would delight in the region’s meadows and hill towns, or uncover the less-obvious appeal of the nation’s famous sanatoriums. However, it was in the Swiss asylums Dubuffet focussed during his trip, as he gathered artworks unblemished by conventional sensibilities.

As Paulhan would later recall, Dubuffet “ran around the asylums” gathering “different drawings and gouaches”; works that would form the basis of his famous movement, Art Brut.

Dubuffet was already a practicing painter, with an interest in works made by psychiatric patients. As author John Maizels explains in our book Raw Creation, the French artist was greatly influenced by the German book, Bildnerei der Geisteskranken or Artistry of the Mentally Ill, which he first read in 1923, a year after it had been published.

Indeed, the art of the insane asylum had always attracted a small audience. Yet, as a member of the French avant-garde, Dubuffet understood how works by psychiatric patients fulfilled certain Surrealist ideals, in that they seemed to flow directly from the subconscious.

He had already begun to buy such pieces prior to his 1945 trip. However, it in the Swiss institutions that he truly established his mad collection. “He came across the works of [artist and psychotic sex offender] Adolf Wölfli and [French-born psychiatric patient and illustrator] Heinrich Anton Müller at the Waldau asylum,” writes Maizels, “he met [Swiss schizophrenic painter] Aloïse Corbaz at the psychiatric clinic of La Rosiere, near Laussanne, and saw the chewed bread sculptures of [Italian prisoner and sculptor] Joseph Giavarini at Basel prison.”

Dubuffet was sure that these artists fulfilled Modernist ideals better than the habitués of Parisian salons. Yet how could he get this across to the greater art world? Dubuffet knew that refined cultural circles would never accept a simple collection of works by lunatics. “He was aware of the stigma attached to ‘insane’ or ‘psychotic art’ and felt the need for a more dignified term,” writes Maizels.

Almanac.

Drawer, 1957

Untitled. 

Target. 

'Jasper John: Gray'

________________

Jasper Johns’s career began with a desperate act. At 24, in 1954, he said he wanted to “stop becoming, and to be an artist,” and destroyed nearly all his art. Then came a kind of vision. “I dreamed I painted a large American flag.” The next morning he began doing just that. His thoughts must have been racing; the enamel house paint he was using wasn’t drying fast enough to capture them. So he switched to something he “had read or had heard about”—wax encaustic. This extraordinarily sensual ancient medium, made of heated beeswax mixed with pigment, dries almost immediately, preserving every brushstroke and favoring process over deliberation. Using this technique, he began replicating something, as he put it, “the mind already knows.” Applying red, white, and blue encaustic over a collaged surface of newspaper and fabric, he created a sort of flickering movie and optical aftereffects under his fleshy material. By spring 1955, he completed the paradoxical machine for thought known as Flag, a painting that seems to take a second to see but a lifetime to come to terms with.

Since then, Johns’s career highs and lows have been documented and debated; admirers have turned him into a cult; detractors have disparaged him as “undernourished and overthought”; his art has been exhibited and sorted according to motif, medium, period, and iconography. “Jasper Johns: Gray,” the Metropolitan’s exhibition of 119 paintings, prints, sculptures, and drawings in shades of gray spanning 50 years, ushers us into Middle Kingdom Johns. Although the show is ravishing and brings you into close contact with the numinous ways Johns combines process, materials, tangibility, language, thought, and seeing, it’s too big. That in turn robs it of some of the radiance it had this fall at the Art Institute of Chicago. At the Met, the works are set too close together; a small alcove is crammed with ten pieces; shiny black floors, stark white walls, and a lack of natural light impede the resonant sensuality and obdurate otherness of Johns’s work. As alluring as “Gray” is, it reminds us that although the Met gets the first 50,000 years of art so right, it often gets the last 50 wrong.

What is great about this show, however, is the resilient way Johns’s art fights back. Initially, gray sounds like an arbitrary idea for a show, and a dreary one. In fact, looking at Johns’s work through this prism gives life to something buried. It helps viewers avoid the banal trap of trying to decipher his specific meanings (“the flag represents America’s place in the world,” blah blah blah, and all the other boilerplate). With gamesmanship and decoding set aside, you start to understand not only how Johns imposes thought on his work but how his work imposes thought on him. His short, repeating Cézanne-like brushstrokes, preserved in the encaustic, have the uncanny effect of slowing down seeing but speeding up thought.

Although Johns is a mysterious, rigorous artist, he isn’t a traditionally imaginative one. He doesn’t invent motifs, symbols, and subjects. Instead, he finds and then endlessly redeploys them. He’s like an icon painter, always returning to the same touchstones. As with icons, there’s almost no air, light, or space in Johns’s work—just physicality, faith in materials, and a devotion to craft. At the same time, Johns always seems to be starting over. His work has the perpetual laboriousness and diligence of a novice. He’s constantly circling back, trying out old things in new ways and new things in old ways. His marvelous show of new drawings at Matthew Marks Gallery contains American flags, numbers, letters, flagstones, and hatch marks. He painted his first flags and numbers more than 50 years ago, yet they’re still a fresh mystery to him. And to us.

The show begins with a whoosh. On the first wall is False Start, a wild 1959 Rorschach of colorful brushstrokes depicting names of colors. Next to it is Jubilee, from the same year, a look-alike patchwork all in grays. The startling evaporation of color from one painting to the other flips a switch, and suddenly you’re in a psychic-cerebral state where everything, by its removal, also calls attention to itself.

 Since Johns seems to want to create new units for thought and to get objects to work in more than one way, I suggest you forgo wall labels, and instead see what the work tells you about its own making, and about art in general. Think about Drawer, a monochrome canvas with a drawer embedded in the surface, as the idea of painting as an object with space behind and inside it. The painting is a place to put things; the knobs are tools to open or close something. Even though you can’t actually open this drawer, you can think it open, or imagine what is or isn’t inside. Johns shows you how the viewer makes the art. Likewise Coat Hanger, a monochrome painting from which dangles an empty metal hanger: It allows you to think about painting as a place to hang your ideas. In 4 the News, four gray canvases bolted together stand in for the first word of the title; the word the is stenciled on the bottom panel; a newspaper is wedged between the top sections. Johns inserts the real world into the unreal realm of painting and also asserts that painting, like a dog bringing you the paper, is man’s best friend. A gray canvas with the word the makes you understand that the is to language as a target or flag is to symbols—that painting is a staging ground, a sculptural pedestal for thought.

Oscar Murillo is a contemporary Colombian painter and installation artist. Working in a wide-ranging practice that incorporates a variety of different media and techniques, Murillo investigates the cross-cultural ties in a globalized economy. He is noted for his use of text, recycled materials, and fragments collected from his studio. As a painter, he uses a scribbling method of applying looping lines and the occasional word such as milk, pollo, yucca, to the canvas, which is then slowly covered in debris by being left out in the open of his studio, a process the artist has likened to aging cheese. Born in La Paila, Colombia in 1986, he moved to London, England when he was just 10 years old. In 2012, he graduated from the Royal College of Art in London, and joined the stable of David Zwirner gallery’s artists a year later. For his first major solo exhibition in New York in 2014, he transformed the David Zwirner gallery space into a fully functional chocolate factory, mimicking the factories in his native Colombia where generations of families had worked together. Murillo has had several solo exhibitions in cities across the globe, including London, Bogotá, and Baku. His long-term project, titled Frequencies, is a global initiative attempting to cover school desktops into canvases to encourage children to paint on them, effectively creating one large, internationally scattered work. 

Untitled. Media: photography

Oscar Murillo, Birds In multilateral action , 2016–2018 (detail), © Oscar Murillo. Courtesy the artist and David Zwirner, Hong Kong, New York, London

 Layers upon layers of fragmented materials, thick gestural strokes of impasto paint, and wildly erratic scribbled forms, all animated with intense bursts of colour, constitute a collaged aesthetic overwhelming even the largest of canvases. Encapsulating an impassioned, spirited vigour, Murillo’s paintings radiate a raw energy drawing viewers and evoking curiosity.      

Serving as a foundation for “the physical accumulation of time spent in motion, removed from all sense of place and in between time zones,” Murrilo’s canvases yield a literal build up of content and information consolidated over travel.  In a global context this extends itself to transnational movement in an era of globalization and the effect it has on individuals and the artist himself.  Born and raised in Colombia until the age of 10, when his family immigrated to the UK, Murillo who now lives and works in different locations, considers “transnational movement an integral part” of his practice, and ascribes flight as a source of inspiration during which creativity transpires.  The aeroplane becomes a site of production for his work where he amasses physical and conceptual material.  

“…A space in limbo, a space in transition, which is a flight, or arriving in a place and accumulating things which become part of a painting through process.  In terms of collecting materials, we’re talking about iconography.” 

Installation view, Oscar Murillo, the build-up of content and information, David Zwirner Hong Kong, 2018. © Oscar Murillo. Courtesy David Zwirner, Hong Kong

The act of challenging, confronting, and contending is firmly embedded in Murillo’s practice, both conceptually and aesthetically. The visual complexity formed by the multiplicity and overlay of materials challenges viewers to investigate and unpack a narrative.  On a more personal level, challenging himself to grow and evolve as an artist certainly seems to be a priority in the process of conceptualizing exhibitions.  In addition to this being his first solo show in Asia, it is also the first dedicated to painting.  Known for engaging with a multitude of mediums, particularly performance art and installations (often supplemented by or supplementing paintings), Murillo has now focused solely on painting.  Acknowledging the significance of growth and reinvention, especially after receiving overwhelming success early on, he directly addresses the question of sustaining a successful and evolving practice.   

“Why a painting show? For me right now in my practice, it would have been too easy to turn this gallery into a performative or installation based show, it would be too easy because I have the power to do so.  Some people were a little taken aback.  I thought about being antagonistic, but I have been antagonistic, and to be antagonistic again becomes conservative, so then this is more challenging for me.”

This “antagonistic” intention, in the context of this exhibition and Murilo’s practice, assumes the role of a cataylst, an agent initiating change through dialogue.  Visually this is aptly captured in Catalyst, a part of an entire series of paintings also entitled Catalyst.  A large red canvas is overrun by an intense continuing streak of blue spirals, with seemingly endless energy.  The notion of using “art as a catalyst” to produce cultural discourse steers Murillo to make gestures or events with a performative dimension that often supplement his art or form the very core of the work. Augmenting the show, and activating his “antagonistic” intent, he invited twenty five members of his family to accompany him to Hong Kong.  

“What makes this more antagonistic is to invite twenty five members of my family, who don’t belong here, staying at the Mandarin Oriental…Letting twenty five Colombians loose in Hong Kong…that’s just gestural and performative, it’s beyond art, more of a social experiment.”   

Oscar Murillo, Catalyst, 2017.

It is the experimental, and somewhat provocative nature of these events or gestures which feed into his goal of creating dialogue,

“I utilize those as viable means of engagement, it’s culture production.”       

This was particularly evident from the unforgettable incident he staged as a part of his contribution to the Sydney Biennale.  On the plane en route to Sydney, he tore up his British passport, posing the question, “what will happen if one cannot be identified?”  Even though he still had his Colombian passport, he was detained on arrival and deported to Singapore, as he could not enter Australia without a visa.  This obviously generated a lot of publicity, many assumed he intended to cause a spectacle.  However, unexpectedly, Murilo’s motivation stemmed from discontentment  with being unable to fulfill the curatorial criteria. 

“I think a lot of it started with my disappointment, and not putting together a good enough proposal for the biennale. Stephanie Rosenthal as a curator, was challenging, and posed the statement, ‘the future is here, but it’s not equally distributed.’  What do you do with that?  I was feeling frustrated, useless, and not being able to respond to this question adequately enough.  So I thought to create a jarring situation of entropy… its a kind of shamefulness, a sacrifice of sorts.  In the 90s when people would travel from Latin America, they would destroy their passports, so when they landed in the UK they were ‘non identifiable’ and had to be embraced under asylum conventions. I like things to get really close to life and reality, and to have a gut-full experience.” 

Oscar Murillo. Courtesy the artist and David Zwirner, Hong Kong, New York, London

The repercussions of this action were real and definite, more importantly they led to a series of events that stimulated discourse not only about politics and identity, but also about the ever expanding range of what constitutes art.  In the context of Murillo’s varied practice, the plane yet again became a significant site of production as it is where he performed the physical act of destroying his passport. From a drastic performative gesture as this, to drawing delicate works on paper (on display, encased in double sided glass frames), a range of works are created mid-flight. 

Installation view, Oscar Murillo, the build-up of content and information, David Zwirner

Considering the breadth of Murillo’s practice and the mediums and materials he employs, the paintings featured in A Build Up of Content and Information, may seem to lack a conceptually provocative gestural dimension.  In holding a show dedicated to painting, Murillo seems to demonstrate a desire to challenge himself and evolve as an artist. The heavily layered collaged surfaces of his canvases emit an almost urgent energy, imploring and beckoning viewers to consider all the elements that compose the work,  presenting a channel for engagement.  It is a subtle sense of contention, but one that reflects a genuine intention to initiate and develop discourse highlighting the significance of “culture production” – the ultimate function of art.   

Oscar Murillo, Emergent and upbeat , 2017–2018 (detail), © Oscar Murillo. 

Light absorption

2. The rise of sensations, as physiology teaches us, is regularly dependent on certain physical processes that have their origin partly in the external world surrounding us, partly in certain bodily organs. We designate these conditioning processes by a name borrowed from physiology, as sense stimuli or sensation stimuli. If the stimulus is a process in the outer world we call it a physical stimulus; if it is a process in our own body we call it a physiological stimulus. Physiological stimuli may be divided, in turn, into peripheral and central, according as they are processes in the various bodily organs outside of the brain, or processes in the brain itself. In many cases a sensation is attended by all three forms of stimuli. Thus, an external impression of light acts as a physical stimulus on the eye; in the eye and optic nerve there arises a peripheral physiological stimulation; finally, a central physiological stimulation takes place in the corpora quadrigemina and in the occipital regions of the cerebral cortex where the optic nerve terminates. In many cases the physical stimulus may be wanting, while both forms of physiological stimuli are present, as when we perceive a flash of light in consequence of a violent ocular movement. In still other cases the central stimulus alone is present, as when we recall a light impression previously experienced. The central stimulus is, accordingly, the only one that always accompanies sensation. When a peripheral stimulus causes a sensation, it must be connected with a central stimulus, and when a physical stimulus causes a sensation it must be connected with both a peripheral and a central stimulus.

In the auditory organ in particular the receptive parts do not seem to possess the same significance as do the receptive parts in the organs of smell, taste and vision. In their lowest stage of development auditory organs are not distinguished either in structure or function from the sense-organ of equilibration and of kinesthetic impression. The organ of equilibration and kinesthetic impression is the sense-organ which supplies position-sensations and movement-sensations of the body and is probably to be regarded as an inner modification of the general touch sense, although it is not improbable that as a primitive organ of hearing it is also capable of receiving impressions from sound waves. 

The organs of smell, taste and vision differ essentially from the auditory organs. In these organs the physiological structures render the direct action of the stimulus upon the sensory nerves impossible. They interpose between the direct stimulus and the nerve cell specialized structures which modify the external stimuli. The energy as thus modified becomes the stimulus acting upon the sensory nerves. The modifying organs in the three senses under discussion are specially developed cells derived from the external layer of the body and known as sensory cells. One end of such sensory cells is turned toward the stimulus while the other is in communication with the nerve-fibers. In the olfactory organ in the nose these sensory cells, which can be distinguished by their narrow fiber-like endings, are distributed among certain broader insensitive cells, (E). In the tongue, the sensory cells are organized into certain bulb-shaped organs made up of compact layers of these cells and known as taste-bulbs, (F). Finally, in the eye, the sensory cells are developed into two classes: first, the large cones distributed chiefly through the middle of the retina, and second, the rods, which are slender organs and are most numerous in the peripheral regions of the retina. These rods and cones with their connecting fibers, which pass into the nerve-fibers, constitute a unique membrane known as the retina, (G). Everything goes to show that these receiving structures are not merely transmitting organs but transforming organs which modify the character of the stimulus. The transformation process in the three organs under discussion is probably of a chemical character. In the case of the olfactory and gustatory organs, the true chemical reagents produce changes in the nerve cells, which then become the true sensory stimuli. In the case of the eye, the chemical process is produced by the action of light.

These three senses may be distinguished as chemical senses, from the mechanical senses of pressure and sound. It is impossible to say with any degree of certainty, to which of these two classes sensations of cold and heat belong. One indication of the direct relation between stimuli and sensation in mechanical senses, as contrasted with the indirect relation in chemical senses, is that in the case of the mechanical senses, the sensation lasts only a very little longer than the external stimulus, while in the case of the chemical senses, the sensation persists much longer. Thus, in a quick succession of pressures and more especially in a quick succession of sounds, it is possible to distinguish clearly the single stimuli from one another; lights, tastes and smells, on the other hand, run together even when given at a very moderate rate of succession. Temperature stimuli received by the skin seem to behave in this respect like chemical stimuli. We are probably justified for this reason in regarding the mode of action as indirect.

4. Since stimuli are regular physical concomitants of elementary sensational processes, the attempt to determine the relation between stimuli and sensations is very natural. In attempting to determine this relation, physiology generally considers sensations as the result of physiological stimuli, but assumes at the same time that in this case any proper explanation of the effect from its cause is impossible, and that all that can be undertaken is to determine the constancy of the relations between particular stimuli and the resulting sensations. Now, it is found in many cases that different stimuli acting on the same end-organ produce the same sensations; thus, for example both mechanical and electrical stimulations of the eye produce light sensations. This result was generalized in the principle that every receiving element of a sense-organ and every simple sensory nerve-fiber together with its central terminus, is capable of only a single sensation of fixed quality; that the various qualities of sensation are, therefore, due to the various physiological elements with their different specific energies.

Persons congenitally blind and deaf do not have any sensations of light or tone whatever, so far as we know, even when the sensory nerves and centers were originally present.

5. From the very nature of the case, it is impossible to explain the character of sensations from the character of physical and physiological stimuli. Stimuli and sensations can not be compared with one another at all, for stimuli belong to the mediate experience of the natural sciences, while sensations belong to the immediate experience of psychology. An interrelation between sensations and physiologicalstimuli must necessarily exist, however, in the sense that different kinds of stimulation always correspond to different sensations. This principle of the parallelism of changes in sensation and in physiological stimulation is an important supplementary principle in both the psychological and physiological doctrines of sensation. In psychology it is used in producing definite changes in sensation, by means of intentional variation of the stimulus. In physiology it is used in inferring the identity or non-identity of physiological stimulations from the identity or non-identity of the sensations. Furthermore, the same principle is the basis of our practical life and of our theoretical knowledge of the external world.

5a. The principle of "specific energy" appears as the implicit assumption in many of the earlier physiological discussions, but it remained for johannes MÜLLER to give it a definite formulation. The principle was later employed, especially by helmholtz in his theories of hearing and vision.  The only ground for the principle is, therefore, to be found in the phenomena of like sensations arising from different stimuli, and these phenomena, as already remarked, do not give the principle any adequate ground for general application. Wherever the principle seems to apply, the facts are much better explained by referring them to the general principle of the adaptation of the sensory elements to stimuli.

6. The definition of the "general sense" includes a spatial and a temporal factor. In point of time the general sense is that which precedes all others and therefore belongs to all beings endowed with mind. In point of spatial attributes, the general sense has the most extensive sensory surface exposed to stimuli. This surface includes not only the whole external skin and the adjoining areas of the mucous membrane, but also a large number of internal organs supplied with sensory nerves, such as joints, muscles, tendons, and bones, which are accessible to stimuli either regularly, or at least at certain times and under special conditions, as is the case with bones.

The general sense includes four specific, distinct sensational systems, namely sensations of pressure, heat, cold, and pain. Not infrequently a single stimulus arouses more than one of these sensations. The sensation is then immediately recognized as made up of a mixture of components from the different systems. For example, we may have together sensations of pressure and pain, or sensations of heat and pain. In a similar manner, as a result of the extension of the sense-organ, we may often have mixtures of the various qualities of one and the same system, for example, we may experience qualitatively different sensations of pressure when an extended region of the skin is touched.

The four systems of general sense are all homogeneous systems (§ 5, 5). This shows that the sense is genetically earlier than the others, the systems of which are all complex. The sensations of pressure from the external skin, and those due to the tensions and movements of the muscles, joints, and tendons, are generally grouped together under the name touch sensations, and distinguished from the common sensations, which include sensations of heat, cold and pain, and the sensations of pressure which sometimes arise in the other internal organs (stomach, intestines, lungs, etc.). Touch sensations may in turn be divided into external touch sensations and internal touch sensations. The first include the external skin impressions of pressure, the second, the impressions arising in the joints, muscles, and tendons during movement. The internal touch sensations are again subdivided, with reference to the physiological organs from which they rise, as joint sensations and muscle sensations, with reference to the conditions which produce them, as sensations of movement or contraction, and as sensations of tension or effort.

In still another respect the two systems of temperature sensations are peculiar. They are to a great extent dependent on the varying conditions under which the stimuli act upon the sense-organ. A considerable increase above the temperature of the skin is perceived as heat, while a considerable decrease below the temperature of the skin is perceived as cold. The temperature of the skin itself, which is thus the indifference-zone between the two forms of sensation, can, within fairly wide limits, adapt itself rapidly to the existing external temperature. The fact that in this respect too, both sensations are alike, favors the view that they are interconnected and also antagonistic.
  
B. SENSATIONS OF SOUND.

9. We possess two independent systems of simple auditory sensations, which are, however, generally connected with each other as a result of the mixture of the two kinds of impressions. The two systems are, the system of noise sensations, and that of tone sensations.

Simple noise sensations can be produced only under conditions under which the simultaneous rise of a tone sensation is impossible, as for example when a sound vibration acts upon the ear for so short a time that a tone sensation can not arise. The simple noise sensations which are aroused in this way may differ very notably in intensity, but they seem always to be relatively uniform in quality. 
  
  
 C. SENSATIONS OF SMELL AND TASTE.

12. Sensations of smell form a complex system the arrangement of which is still unknown. All we know is that there are a great many different olfactory qualities, between which there are all possible transitional forms. There can, then, be no doubt that the system is a continuity of many dimensions.

12a. Olfactory qualities may be grouped in certain classes, each of which contains those sensations which are more or less related. This fact may be regarded as an indication of how these sensations may perhaps be reduced to a small number of principal qualities. Such classes are, for example, sensations like those from ether, balsam, musk, benzine, those known as aromatic, etc. It has been observed in a few cases that certain olfactory sensations which come from definite substances, can also be produced by mixing other substances. But these observations are still insufficient to reduce the great number of simple qualities contained in each of the classes mentioned, to a limited number of primary qualities and their mixtures. Finally, it has been observed that many odors neutralize each other, so far as the sensation is concerned, when they are mixed in the proper intensities. This is true not only of substances which neutralize each other chemically, as acetic acid and ammonia, but also of others, such as caoutchouc and wax or tolu-balsam, which do not act on each other chemically outside of the olfactory cells. Since this neutralization takes place when the two stimuli act on entirely different olfactory surfaces, one on the right and the other on the left mucous membrane of the nose, it is probable that we are dealing, not with phenomena analogous to those exhibited by complementary colors (22), but with a reciprocal central inhibition of sensations. Another observed fact tells against the notion that such neutralizing qualities are complementary. One and the same olfactory quality can neutralize several entirely different qualities, sometimes even those which in turn neutralize one another, while among colors it is always two fixed qualities, and only two, that are in each case complementary.

D. SENSATIONS OF LIGHT.

14. The system of light sensations is made up of two partial systems: that of sensations of achromatic light and that of sensations of chromatic light. Between the qualities in these two systems, all possible transitional forms exist.

Sensations of achromatic light, when considered alone, form a system of one dimension, which extends, like the tonal line, between two limiting qualities. The sensations in the neighborhood of one of these limits we call black, those in the neighborhood of the other we call white, while between the two we insert gray in its different shades (dark gray, gray, and light gray). This one-dimensional system of achromatic sensations differs from that of tones in being at once a system of quality and of intensity; since every qualitative change in the direction from black to white is seen at the same time as an increase in intensity, and every qualitative change in the direction from white to black is seen as a decrease in intensity. Each point in the series, which thus has a definite quality and intensity, is called a degree ofbrightness. The whole system may, accordingly, be designated as that of sensations of pure brightness. The use of the word "pure" indicates the absence of all sensations of color. The system of pure brightness is absolutely one-dimensional; both the variations in quality and those in intensity belong to one and the same dimension. This system differs essentially, in this respect, from the tonal line, in which each point is merely a degree of quality, and has by itself a whole series of gradations in intensity. Simple tone sensations thus form a two-dimensional continuity so soon as we take into account both determinants, quality and intensity, while the system of pure brightness is always one-dimensional, even when we attend to both determinants. The whole system may, therefore, be regarded as a continuous series of grades of brightness, in which the lower grades are designated black so far as quality is concerned, and weak so far as intensity is concerned, while the higher grades are called white and strong. Our sensitivity for differences in brightness is, especially for medium intensities, very great. The ratio is from ¹/₁₀₀ to ¹/₁₅₀ of the brightness with which we start in the comparison of two intensities. Like the ratios of sound intensities (p. 59), this ratio of brightness intensities is constant in its relative magnitude. (weber's Law 17, 10.)

15. Sensations of color also form a one-dimensional system when their qualities alone are taken into account. Unlike sensations of pure brightness, this system returns upon itself from whatever point we start, for at first, after leaving a given quality, we pass gradually to a quality that shows the greatest difference, and going still further we find that the qualitative characteristics again become like those with which we began, until finally we reach the starting point once more. The color spectrum obtained by refracting sunlight through a prism, or that found in the rainbow, shows this characteristic, though not completely. If in these cases we start from the red end of the spectrum (Fig. 5) we come first to orange, then to yellow, yellow-green, green-blue, blue, indigo-blue, and finally to violet, which last is more like red than any of the other colors except orange, which lies next to red. The line of colors in the spectrum does not return quite to its starting-point, because it does not contain all of the colors which we have in sensation. Purple shades, which can be obtained by the objective mixture of red and violet rays, are wanting in the spectrum. Only when we fill out the spectrum series with purple, is the system of actual color sensations complete, and then the system constitutes a line which returns upon itself. This can be represented most easily by a circle such as is used in the color circle in Fig. 5.

From a given point in this system we pass, when the sensation is gradually varied, first to similar sensations, then to those most markedly different, and finally to others similar to the first quality, but lying on the opposite side. Every color must, accordingly, be related to some other color which constitutes a maximum of difference in sensation (p. 36, Fig. 1, E' E"). Such pairs of colors may be called opposite colors, and in the representation of the color system by a circle, two opposite colors are to be placed at the two extremities of a diameter. Thus, for example, purple and green, yellow and blue, light green and violet, are pairs of opposite colors, that is, colors which exhibit the greatest qualitative differences. Sensitivity for either absolute or relative objective color differences as expressed in the number of vibrations, is entirely irregular, changing constantly from point to point on the color line. Sensitivity is generally at its maximum in yellow and blue, at its minimum in red and violet. It has a third relatively low point between yellow and blue, that is, in green. A regularity such as is to be found in the case of tonal qualities (p. 58), or in the case of different degrees of brightness (p. 63), is entirely wanting here.

The quality determined by the position of a sensation in the color circle, as distinguished from other qualitative determinations is called color-tone, a figurative term borrowed from tone sensations. In addition to color-tone, every color sensation has two other attributes, one we call chromatic character or saturation of the color, the other its brightness. Of these two attributes saturation is peculiar to chromatic or color sensations, while brightness belongs to both chromatic and achromatic sensations.

18. If we neglect for the moment the somewhat different relations of the maximal saturations of the various colors with respect to the line of brightness, we may represent the general relation which exists by virtue of the gradual transition of colors into white and black, that is, we may represent the general relation between sensations of chromatic brightness and sensations of pure, or achromatic, brightness in the simplest manner by the following figure. First, we may represent the system of pure color-tones, that is, of the colors at their maximal saturation, by a circle, as above. (Fig. 5.) Then we may draw through the center of this circle, perpendicular to its plane, the straight line of pure brightness (Fig. 4), in such a way that where it cuts the plane of the circular surface, it represents the sensation of pure brightness corresponding to the minimum of saturation of the colors with which we started. In like manner, the other color circles for increasing and decreasing grades of brightness, may be arranged at right angles along this line, above and below the circle of greatest saturation. The decreasing saturation of the colors in these latter circles must also be expressed, and this can be done by the shortening of their radii; just as in the first circle, the shorter the distance from the center, the less the saturation. The radii in successive circles grow continually shorter, until finally, at the two extremities of the line of brightness the circles disappear entirely. This corresponds to the fact that for every color the maximum of brightness passes into the sensation white, while its minimum passes into black²⁾.

The whole system of color sensations and brightness sensations can be represented by a closed solid figure in the form of two cones which are placed with their bases together (Fig. 6), or by a sphere, one of the poles of which corresponds to the darkest black, the other to the brightest white. In these geometrical representations there is a complete exhibition of the fact that the system of light sensations is a three-dimensional and closed continuum. The three-dimensional character of this system arises from the fact that every light sensation is made up of three determining characteristics, namely, color-tone, saturation, and brightness. Pure colorless brightness sensations and color sensations of maximum saturation are to be looked upon as the two limiting cases in the complete series of color variations. The fact that the system is closed grows out of the two facts that the color sensations can be arranged in a single circle and the fact that colorless brightness qualities are bounded by the same pure brightness sensations as are the grades of saturation. A special peculiarity of the system consists in the fact that only variations in the two dimensions of color-tone and saturation grade are pure qualitative changes, while every variation in the third dimension, that is, in the direction of brightness sensations, is at once a qualitative and intensive variation. In view of this last fact, the whole three-dimensional system is required in order to show the qualitative characteristics of light sensations in their completeness. The system includes, however, at the same time, not only the qualitative characteristics but also sensation intensity.

19. Certain principal sensations are prominent in this system, because we use them as points of reference for the arrangement of all the others. These are white and black, in the achromatic series, and in the chromatic series the four principal colors: red, yellow, green and blue. This group of four colors was first pointed out as important by leonardo da vinci. Only these six sensations have clearly distinguished names in the early development of language. All other sensations are then named either with reference to these or even with modifications of the names themselves. Thus, we regard gray as a stage in the achromatic series lying between white and black. We designate the different grades of saturation according to their brightness, as whitish or blackish, light or dark, color-tones; and we generally choose compound names for the colors between the principal ones, as, for example, purple-red, orange-yellow, yellow-green, etc. These all show their relatively late origin by their very composition.

19a. From the early origin of the names for the six qualities mentioned, the conclusion has been drawn that they are fundamental qualities of vision, and that the others are compounded from them. Gray is declared to be a mixture of black and white, violet and purple to be mixtures of blue and red, etc. Psychologically there is no justification for calling any light sensations compound in comparison with others. Gray is a simple sensation just as much as white or black; such colors as orange and purple are just as much simple colors as red and yellow; and any grade of saturation which we have placed in the system between a pure color and white, is by no means, for that reason, a compound sensation. The closed, continuous character of the system makes it necessary for language to pick out certain especially marked differences in reference to which all other sensations are then arranged, for the simple reason that it is impossible to have an unlimited number of names. It is most natural that white and black should be chosen as such points of reference for the achromatic series, since they designate the greatest differences. When once these two are given, all other achromatic sensations will be considered as transitional sensations between them, since the extreme differences are connected by a series of all possible grades of brightness. The case of color sensations is similar: only here, on account of the circular form of the color line, it is impossible to choose directly two absolutely greatest differences. Other motives besides the necessary qualitative difference, are decisive in the choice of the principal colors. We may regard as such motives, the frequency and affective intensity of certain light impressions, due to the natural conditions of human existence. The red color of blood, the green of vegetation, the blue of the sky, and the yellow of the heavenly bodies in contrast with the blue of the sky, may well have furnished the earliest occasions for the choice of certain colors as those to receive names. Language generally names the sensation from the object which produced it, not the object from the sensation. In this case too, when certain principal qualities were once determined, all others must, on account of the continuity of the series of sensations, seem to be intermediate color-tones. The difference between principal colors and transitional colors is, therefore, very probably due entirely to external conditions. If these conditions had been other, red might have been regarded as a transitional color between purple and orange, just as orange is now placed between red and yellow ³⁾. 
  
 

3) The same false reasoning from the names of sensations, has even led to the assumption that the sensation blue developed later than other color sensations, because, for example, even in Homer the word for blue is the same as that for "dark" (L. geiger, Zur Entwicklungsgeschichte der Menschheit, 1871). Tests of the color sensations of uncivilized peoples whose languages are much more deficient in names for colors than that of the Greeks at the time of Homer, have given us a superabundance of evidence that this assumption is utterly without ground (grant allen, On Color, 1880). 
  

20. The attributes of the system of light sensations above described, are so peculiar that they lead us to expect a priori that the relation between the psychological attributes and the objective processes of stimulation, is essentially different from that which we inferred in the cases of the sensational systems discussed before, especially in the case of the general sense and auditory sense. Most striking in this respect, is the difference between the system of colors and that of tones. In the case of tones the principle of parallelism between sensation and stimulus (p. 49), holds, not only for the physiological processes of stimulation, but to a great extent for the physical processes as well. A simple sensation corresponds to a simple form of sound vibration, and a plurality of simple sensations corresponds to a compound form of vibration. Furthermore, the intensity of the sensation varies in proportion to the amplitude of the vibrations, and its quality varies with the form, so that in both directions the subjective difference between sensations increases with the growing difference between the objective physical stimuli. The relation in the case of light sensations is entirely different. Like objective sound, objective light also consists of vibrations of a certain medium. To be sure, the actual form of these vibrations is still a question, but from physical experiments on the phenomena of interference we know that they consist of very short and rapid waves. Those seen as light vary in wave-length from 688 to 393 millionths of a millimetre, and in rate from 450 to 790 billion vibrations per second. For light, as for sound, simple sensations correspond to simple vibrations, that is, to vibrations of like wave-length; and the quality of the sensations varies continuously with the wavelength and with the rate of vibration. Thus, red corresponds to the longest and slowest waves, and violet to the shortest and most rapid, while the other color-tones form a series between these, varying with the changes in wave-length. Even here, however, an essential difference appears, for the colors red and violet, which are the most different in wave-length, are more like each other in sensation than are most of the colors which lie between ⁴⁾. There are also other differences. 1) Every change in the amplitude of the physical vibrations corresponds, as we noted above in the discussion of sensations of brightness, to a subjective change in both intensity and quality. 2) All light, even though it be made up of all the different kinds of vibrations, is simple in sensation, just as much as objectively simple light, which is made up of only one kind of waves. This is immediately apparent if we make a subjective comparison of sensations of chromatic light with those of achromatic light. From the first of these facts it follows that light which is physically simple may produce not only chromatic, but also achromatic sensations, for the sensation from such simple light approaches white when the amplitude of its vibrations increases, and black when the amplitude decreases. The quality of an achromatic sensation does not, therefore, determine unequivocally its source; such a sensation may be produced either through a change in the amplitude of objective light vibrations or through a mixture of simple vibrations of different wave-lengths. In the first case, however, there is always connected with the change in amplitude a change in the grade of brightness, which does not necessarily take place when a mixture is made. 

21. Even when the grade of brightness remains constant, an achromatic sensation may have one of several sources. A sensation of pure brightness of a given intensity may result not only from a mixture of all the rates of vibration contained in solar light, as, for example, in ordinary daylight, but it may also result when only two kinds of lightwaves are mixed in proper proportions. The kinds of light necessary to thus produce a sensation of pure brightness are those which correspond to sensations subjecti vely the most different, that is, to opposite colors, or at least to colors very nearly opposite in quality. Whenever the objective mixture of two colors produces white, these colors are called complementary colors. As examples of such complementary colors, we may mention spectral red and green-blue, orange and sky-blue, yellow and indigo-blue. (Fig. 5.)

Each of the color sensations may, like achromatic sensations, though to a more limited extent, have one of several sources. When two objective colors which lie nearer each other in the color-circle than opposites, are mixed, the mixture appears, not white, but of a color which in the series of objectively simple qualities lies between the two with which we started. The saturation of the resulting color is, indeed, very much diminished when the components of the mixture approach complementary colors; but when the component colors are near each other, the diminution in saturation is no longer perceptible, and the mixture and the corresponding simple color are generally subjectively alike. Thus the orange of the spectrum is absolutely indistinguishable from a mixture of red and yellow rays. In this way, all the colors in the color-circle between red and green can be obtained by mixing red and green, all between green and violet by mixing green and violet, and, finally, purple, which is not in the solar spectrum, can be produced by mixing red and violet. The whole series of color-tones possible in sensation can, accordingly, be obtained from the three objective colors, red, green and violet. By means of the same three colors we can also produce white with its intermediate stages. The mixture of red and violet gives purple, and this is the complementary color of green, and, finally, the white secured by mixing purple and green gives, when mixed in different proportions with the various colors, the different grades of saturation.

22. The three objective colors which may be used in this way to produce the whole system of light sensations, are called fundamental colors. In order to indicate their significance, a triangular surface is chosen to represent the system of saturations, rather than the circular surface which is derived from the psychological relations alone. The special significance of the fundamental colors is then expressed by placing them at the angles of the triangle. Along the sides are arranged the color-tones in their maximal saturation, while on the triangular surface are the other grades of saturation in their transitions to white, the white lying in the center (Fig. 7). Theoretically any set of three colors could be chosen as fundamental colors, provided they were suitably distant from one another. Practically, those mentioned, namely red, green, and violet, are preferable because at the two ends of the spectrum sensations vary most slowly in proportion to the period of vibration, so that when the extreme colors of the spectrum are used as fundamental colors, the result obtained by mixing two neighboring colors is most like the intermediate, objectively simple color ⁵⁾.

5) In the neighborhood of green this advantage does not exist, and the mixtures always appear less saturated than the intermediate simple colors. This is a clear proof that the choice of the three fundamental colors mentioned is indeed the most practical, but nevertheless arbitrary, and at bottom due to the familiar geometrical principle that a triangle is the simplest figure that can enclose a finite number of points in the same plane.

23. These phenomena show that in the system of light sensations a simple relation does not exist between the physical stimuli and the sensations. This can be understood from what has been said above (3) as to the character of the physiological stimulation. The visual sense is to be classified as one of the chemical senses, and we can expect a simple relation only between the photochemical processes in the retina and the sensations. Now, we know from experience that different kinds of physical light produce like chemical disintegrations, and this explains in general the possibility mentioned above, of having the same sensation from many different kinds of objective light. According to the principle of parallelism between changes in sensation and in the physiological stimulation (p. 49), it may be assumed that the various physical stimuli which cause the same sensation, all produce the same photochemical stimulation in the retina, and that altogether there are just as many kinds and varieties of the photochemical processes as kinds and varieties of distinguishable sensations. In fact, all that we know, up to the present time, about the physiological conditions of light sensations is based upon this assumption. The investigation of the physiological processes of light stimulation, has not yet given any further result than that the stimulation is in all probability a chemical process.

24. The relatively long time required for a light sensation to arise and the relatively long after-effect of such a sensation, which continues after the stimulus has been withdrawn, can be explained on the assumption that light stimulation is a chemical process in the retina (p. 46). The time during which a light stimulus must act, in order that it may produce the maximum sensation of which it is capable, is on the average for colorless light 0,268 sec., for colored lights it is 0.530 sec., little or no difference appearing for different wavelengths. These intervals are the same for different intensities of light. The short period required for the development of colorless excitation, as compared with the time required for the development of color stimulations from all parts of the spectrum, points unmistakably to a fundamental difference between the processes of colorless excitation and those which come from the different colors, and at the same time, the uniformity of the period for all colors shows that there is an intimate relationship between these processes of color excitation. Similar results appear through the investigation of the after-effects of stimulation, which after-effects are commonly designated as after-images because of the fact that objects were used as the sources of stimulation. At first the after-image appears in the same brightness and color as the object: white when the object is white, black when the object is black, and if the object is colored, the after-image appears in the same color. These are the positive and like-colored after-images. After a short time the afterimage passes, in the case of achromatic impressions, into the opposite grade of brightness, white into black, or black into white; in the case of colors, it passes into the opposite or complementary color. These are the negative and complementary after-images. If light stimuli of short duration act upon the eye in darkness, this transition from positive to negative after-images may be repeated several times. A second positive after-image follows the negative, and so on, so that an oscillation between the two phases takes place. The positive after-image may be readily explained by the fact that the photochemical disintegration caused by any kind of light, lasts a short time after the action of the light. The negative and complementary after-images can be explained by the fact that disintegration in a given direction causes a partial consumption of the photochemical substance most directly concerned, and this results in a corresponding modification of the photochemical processes when the stimulation of the retina continues. This view is confirmed by the fact that when the retina which is gradually passing through the successive stages of an after-image is stimulated by a sudden light stimulus, the effect is always the sum of the new stimulus and the after-image, that is, the effect is the same as that which would be produced on the unfatigued retina by the new stimulus plus the remnant of the after-effect. (fechner-helmholtz law of negative and complementary after-images.) The rate of subsidence of chromatic and achromatic afterimages differs. The rate for all chromatic after-images of whatever color is essentially the same.

25. The phenomena of color induction and light induction are very closely related to positive and negative after-mages. These phenomena consist in the appearance of simultaneous sensations of opposite brightness and color in the neighborhood of any light impression. Positive light induction is the less common of these two kinds of phenomena. It appears most noticeably in those cases in which one part of the retina is intensely stimulated and a contiguous region is left entirely unstimulated. In such a case the positive light stimulation, or color stimulation, seems to spread out over the unstimulated area. In all other cases the opposite form of induction, namely, negativeinduction, appears. In consequence of such negative induction a white surface appears to be surrounded by a dark margin, a black surface by a bright margin, and a colored surface by a margin of the complementary color. These phenomena are, furthermore, accompanied by psychological contrast phenomena which belong under the general principle to be explained later (§ 17, 11), namely, the principle of emphasis of opposites. Indeed, the term "contrast" is, as a rule, applied to the total effects of such combined physiological and psychological influences. Such a use of the term is justified to a certain degree by the impossibility of separating the two kinds of influences from each other, but it would be much more appropriate to use the term induced excitation for the physiological factor, and to reserve the term contrast for the psychological factor. For this psychological factor corresponds fully to the psychological emphasizing of opposites which can be demonstrated in other spheres, especially among spatial and temporal ideas, and among the feelings. Light induction and color induction, in this purely physiological sense, consist probably in a kind of negative irradiation of the stimulation, in which the stimulation is not carried over directly to contiguous regions in its own proper quality as it is in the case of positive induction, but rather excites in these neighboring regions a stimulation process of opposite character. Such negative irradiation may possibly be due to the fact that the photochemical substances which are used up in the stimulation of a certain region of the retina, are replaced in part through an influx of other similar substances from the surrounding regions. If, then, a light impression is applied to these impoverished neighboring regions, the result would be the same as that which would appear in the case of an after-image on the originally stimulated area (p. 77). Evidence in favor of assuming this connection between the facts of induction and after-images, appears in the fact that in both cases the effects are heightened by an increase in the intensity of the light impressions. But just at this point there shows itself a very fundamental difference between these physiological processes of light induction and the psychological processes of contrast with which they are usually erroneously classified. To this fundamental difference we shall return when we come to the general treatment of contrasts (§ 17, 10).

25a. If we take the principle of parallelism between sensation and physiological stimulation as the basis of our suppositions in regard to the processes that occur in the retina, we may conclude that the photochemical processes corresponding to chromatic and achromatic sensations, are relatively independent of each other, in a way analogous to that in which the corresponding sensations are relatively independent. Two facts, one belonging to the subjective sensational system, the other to the objective phenomena of color-mixing, can be very naturally explained on this basis. The first is the fact that every color sensation tends to pass into one of pure brightness when the grade of its brightness undergoes a marked decrease or increase. (Fig. 6). This fact is most simply interpreted on the assumption that every color stimulation is made up of two physiological components, one corresponding to the chromatic, the other to the achromatic stimulation. To this assumption we must add the further condition, that for certain medium intensities of the stimuli the chromatic components are relatively the strongest, while for greater and smaller intensities the achromatic components predominate more and more. The second fact is, that there are complementary colors. This fact is most easily understood when we assume that opposite colors, which are subjectively the greatest possible differences in sensation (Fig. 5), depend upon objective photochemical processes which neutralize each other. The fact that as a result of this neutralization an achromatic stimulation arises, is very readily explained by the presupposition that such an achromatic stimulation accompanies every chromatic stimulation from the first, and is, therefore, all that is left when antagonistic chromatic stimulations counteract each other. This assumption of a relative independence between the chromatic and achromatic photochemical processes, is supported by the existence of an abnormality of vision, sometimes congenital, sometimes acquired through pathological changes in the retina, namely total color-blindness. In such cases all stimulations are seen, either on the whole retina or on certain parts of it, as pure achromatic brightness. This is proof that the chromatic and achromatic stimulations are separable physiological processes.

If we apply the principle of parallelism to the chromatic stimulations, two facts present themselves. The first is that two colors separated by a limited, short distance, when mixed give a color that is like the intermediate simple color. This indicates that color stimulation is a process which varies with the physical stimulus, not continuously, as the tonal stimulation, but in short stages, and in such a way that the stages in red and violet are longer than in green, where the mixture of colors fairly near each other shows pronounced effects of complementary action. The second fact is that certain colors which correspond to rather large differences in stimulation, namely, the complementary colors, evidently depend upon processes which neutralize each other. Now, let it be remembered that chemical processes can neutralize each other only when they are in some way opposite in character, and that for every color recognizable in sensation there is an opposite quality, it will then be seen that for every stage in the photochemical process of color stimulation there must be a stage of complementary action. The whole series of chromatic stimulations, beginning with red and passing beyond violet through purple mixtures back to its first point, running parallel, as it does, with continuous changes in the wave-length of objective light, is to be regarded as an indefinitely long succession of photochemical disintegrations. All these processes together form a closed circle in which there is, for every stage, a neutralizing opposite, and in which there are two possible paths of transition in different directions to this neutralizing opposite.

We know nothing about the total number of photochemical stages in this circle of processes. The numerous attempts made to reduce all color sensations to the smallest possible number of such stages, lack adequate foundation. Sometimes they indiscriminatingly translate the results of physical color-mixing into physiological processes, as in the assumption of threefundamental colors, red, green, and violet, from the different mixtures of which all sensations of light, even the achromatic, are to be derived (young-helmholtz' hypothesis). Sometimes they start with the psychologically untenable assumption that the naming of colors is not due to the influence of certain external objects, but to the real significance of the sensations themselves (v. sup. p. 71), and assume accordingly four fundamental colors as the sources of all color sensations. The four fundamental colors here assumed are the two pairs red and green, yellow and blue, to which are added the similar pair of sensations of pure brightness, black and white. All other light sensations such as gray, orange, violet, etc., are regarded as subjectively and objectively mixed colors (hering's hypothesis). The evidence in support of the first as of the second of these hypotheses has been derived for the most part from the not infrequent cases of partial color-blindness. Those who accept three fundamental colors, assert that all these cases are to be explained as a total lack of the red, green, or violet sensations, or else as a partial lack of these. Those who accept four, hold that partial color-blindness always includes two fundamental colors which belong together as opposites; that color-blindness is, accordingly, either red-green-blindness or yellow-blue-blindness. An unprejudiced examination of color-blindness does not justify either of these assertions. The three-color theory can not explain total color-blindness, and the four-color theory is in contradiction to cases of pure red-blindness and pure green-blindness. Finally, both theories are overthrown by the cases which unquestionably occur, in which such parts of the spectrum as do not correspond to any of the three or four fundamental colors, appear colorless. The only thing that our present knowledge justifies us in saying, is that every simple sensation of light is probably conditioned by a combination of two photochemical processes, an achromatic and a chromatic. The first is made up, in turn, of a process mainly of disintegration when the light is more intense, and a process of restitution when the light is weaker. The chromatic process varies by stages in such a way that the whole series of photochemical color disintegrations forms a circle of processes in which the products of the disintegration for any two relatively most distant stages, neutralize each other ⁶⁾.

6) The further assumption is made by the defenders of the four fundamental colors, that two opposite colors are related just as bright and dark achromatic stimulations, that is, that one of these colors is due to a photochemical disintegration (dissimilation), the other to a restitution (assimilation). This is an analogy that contradicts the actual facts. The result obtained by mixing complementary colors is on its subjective side a suppression of the color sensation, while the mixture of white and black, on the other hand, produces the intermediate sensation, gray.