Red is the color of blood, rubies and strawberries. It is the color of the wavelength of light from approximately 620–740 nm on the electromagnetic spectrum. Next to orange at the end of the visible spectrum, red is commonly associated with danger, sacrifice, passion, fire, beauty, blood, anger, Christmas, socialism, communism, and in China and many other cultures, with happiness.
Etymology and definitions
The word red is derived from the Old English rēd. The word can be further traced to the Proto-Germanic rauthaz and the Proto-Indo European root reudh-. In Sanskrit, the word rudhira means red or blood. In the Akkadian language of Ancient Mesopotamia and in the modern Inuit language of Inuit, the word for red is the same word as "like blood".
The words for 'colored' in Latin (coloratus) and Spanish (colorado) both also mean 'red.' whereas in Portuguese the word for red is vermelho, which comes from Latin "vermiculus", meaning "little worm".
In the Russian language, the word for red, Кра́сный (krasniy), comes from the same old Slavic root as the words for "beautiful"—красивый (krasiviy) and "excellent"—прекрасный (prekrasniy). Thus Red Square in Moscow, named long before the Russian Revolution, meant simply "Beautiful Square".
In heraldry, the word gules is used for red.
Shades and varieties
Red can vary in hue from orange-red to violet-red, and for each hue there are a wide variety of shades and tints, from very light pink to dark burgundy.
Red is the color of most ripe strawberries.
Pure, or solid red, with no other colors added.
Scarlet, on a traditional color wheel, is one quarter of the way between the colors red and orange. It is the color worn by a cardinal of the Roman Catholic Church. This is Cardinal Théodore-Adrien Sarr of Senegal.
The cardinal is named for the color cardinal red, which takes its name from the color worn by Roman Catholic cardinals.
Vermilion is similar to scarlet, but slightly more orange. This is sindoor, a red cosmetic powder used in India; Hindu women put a stripe of sindoor in their hair to show they are married.
Crimson is a strong, deep red containing a little blue. The emblem of Harvard University.
Alizarin crimson is closer to purple than to orange on the traditional color wheel. Alizarin is an organic compound found in the root of the madder plant, which was the most common red dye from antiquity until the 19th century.
Maroon is a dark brownish red. Its name comes from marron, the French word for chestnut. This is the flag of Latvia, which has two maroon stripes.
Wine red, or burgundy, is a dark red containing a little blue.
Ruby is the color of a cut and polished ruby gemstone.
(Lists of shades of red and shades of pink are found at the end of this article.)
In the ancient world
Inside cave 13B at Pinnacle Point, an archeological site found on the coast of South Africa, paleoanthropologists in 2000 found evidence that, between 170,000 and 40,000 years ago, Late Stone Age people were scraping and grinding ochre, a clay colored red by iron oxide, probably with the intention of using it to color their bodies.
Red hematite powder was also found scattered around the remains at a grave site in a Zhoukoudian cave complex, near Beijing. The site has evidence of habitation as early as 700,000 years ago. The hematite might have been used to symbolize blood in an offering to the dead.
Red, black and white were the first colors used by artists in the Upper Paleolithic age, probably because natural pigments such as red ochre and iron oxide were readily available where early people lived. Madder, a plant whose root could be made into a red dye, grew widely in Europe, Africa and Asia. The cave of Altamira in Spain has a painting of a bison colored with red ochre that dates to between 15,000 and 16,500 BC. Red was also the first color, after black and white, to have its own name.
A red dye called Kermes was made beginning in the Neolithic Period by drying and then crushing the bodies of the females of a tiny scale insect in the genus Kermes, primarily Kermes vermilio. The insects live on the sap of certain trees, especially Kermes oak tree near the Mediterranean region. Jars of kermes have been found in a Neolithic cave-burial at Adaoutse, Bouches-du-Rhône. Kermes from oak trees was later used by Romans, who imported it from Spain. A different variety, called Kermes of Armenia, was made from Kermes insects which lived on the roots and stems of certain herbs. It was mentioned in texts as early as the 8th century BC, and it was used by the ancient Assyrians and Persians.
Kermes is also mentioned in the Bible. In the Book of Exodus, God instructs Moses to have the Israelites bring him an offering including cloth "of blue, and purple, and scarlet." The term used for scarlet in the 4th century Latin Vulgate version of the Bible passage is coccumque bis tinctum, meaning "colored twice with coccus." Coccus, from the ancient Greek Kokkos, means a tiny grain, and is the term that was used in ancient times for the Kermes vermilio insect used to make the Kermes dye. This was also the origin of the expression "dyed in the grain."
In ancient Egypt, red was associated with life, health, and victory. Egyptians would color themselves with red ochre during celebrations. Egyptian women used red ochre as a cosmetic to redden cheeks and lips, and also used henna to color their hair and paint their nails.
But, like many colors, it also had a negative association, with heat, destruction and evil. A prayer to god Isis said: "Oh Isis, protect me from all things evil and red." The ancient Egyptians began manufacturing pigments in about 4000 BC. Red ochre was widely as a pigment for wall paintings, particularly as the skin color of men. An ivory painter's palette found inside the tomb of King Tutankhamun had small compartments with pigments of red ochre and five other colors. The Egyptians used the root of the rubia, or madder plant, to make a dye, later known as alizarin, and also used it to color white power to use as a pigment, which became known as madder lake, alizarin or alizarin crimson.
In Ancient China, artisans were making red and black painted pottery as early as the Yangshao Culture period. (5000-3000 BC). A red-painted wooden bowl was found at a Neolithic site in Yuyao, Zhejiang. Other red-painted ceremonial objects have been found at other sites dating to the Spring and Autumn Period (770–221 BC).
During the Han Dynasty (200 BC to 200 AD) Chinese craftsmen made a red pigment, lead tetroxide, which they called ch-ien tan, by heating lead white pigment. Like the Egyptians, they made a red dye from the madder plant to color silk fabric for gowns, and used pigments colored with madder to make red lacquerware.
Red lead or Lead tetroxide pigment was widely used as the red in Persian and Indian miniature paintings, and in European art, where it was called minium.
In India, the rubia plant has been to make dye since ancient times. A piece of cotton dyed with rubia dated to the third millennium BC was found at an archaeological site at Mohenjo-daro. It has been used by Indian monks and hermits for centuries to dye their robes.
The early inhabitants of America had their own vivid crimson dye, made from the cochineal, an insect of the same family as the Kermes of Europe and the Middle East, which feeds on the Opuntia, or prickly pear cactus plant. Red-dyed textiles from the Paracas culture (800–100 BC) have been found in tombs in Peru.
Red also featured in the burials of royalty in the Maya city-states. In the Tomb of the Red Queen inside Temple XIII in the ruined Maya city of Palenque, (600–700 AD), the skeleton and ceremonial items of a noble woman were completely covered with bright red powder made from cinnabar.
Image of a human hand created with red ochre in Pech Merle cave, France (Gravettian era, 25,000 BC).
Image of a bison from the cave of Altamira in Spain, painted with red ochre between 15,000 and 16.500 BC.
Painted statues of the ruler Akhenaten and Queen Nefertiti (1345 BC)
Painted red and black bowl from the Yangshao culture period in China (4500 BC), in the National Museum of Beijing
A dyed silk robe from the tomb of a Chinese aristocratic woman (Lady Dai) of the Han Dynasty (about 168 BC)
Chinese lacquerware from the Han Dynasty (200 BC – 200 AD)
Textiles dyed red from the Paracas culture of Peru (about 200 BC), in the British Museum
In ancient Greece and the Minoan civilization of ancient Crete, red was widely used in murals and in the polychrome decoration of temples and palaces. The Greeks began using red lead as a pigment.
In Ancient Rome, Tyrian purple was the color of the Emperor, but red had an important religious symbolism. Romans wore togas with red stripes on holidays, and the bride at a wedding wore a red shawl, called a flammeum. Red was used to color statues and the skin of gladiators. Red was also the color associated with army; Roman soldiers wore red tunics, and officers wore a cloak called a paludamentum which, depending upon the quality of the dye, could be crimson, scarlet or purple. In Roman mythology red is associated with the god of war, Mars. The vexilloid of the Roman Empire had a red background with the letters SPQR in gold. A Roman general receiving a triumph had his entire body painted red in honor of his achievement.
The Romans liked bright colors, and many Roman villas were decorated with vivid red murals. The pigment used for many of the murals was called vermilion, and it came from the mineral cinnabar, a common ore of mercury. It was one of the finest reds of ancient times – the paintings have retained their brightness for more than twenty centuries. The source of cinnabar for the Romans was a group of mines near Almadén, southwest of Madrid, in Spain. Working in the mines was extremely dangerous, since mercury is highly toxic; the miners were slaves or prisoners, and being sent to the cinnabar mines was a virtual death sentence.
A restored mural, called The Prince of Lilies, from the Bronze Age Palace of Minos at Knossos on Crete
Etruscan dancers in the Tomb of the Triclinium (470 BC)
The ancient Romans were lavish in their use of red in interior decoration. This is a fresco in the House of the Vettii in Pompeii, from about 62 AD. It was buried by the eruption of Vesuvius in 79 AD and preserved.
Roman wall painting showing a dye shop, Pompeii (40 BC). Dyed fabrics have been hung up to dry.
In the Middle Ages
After the fall of the Western Roman Empire, the Byzantine Empire, the princes of Europe and the Roman Catholic Church adapted red as a color of majesty and authority. It also played an important part in the rituals of the Catholic Church - it symbolized the blood of Christ and the Christian martyrs - and it associated the power of the kings with the sacred rituals of the Church.
Red was the color of the banner of the Byzantine emperors. In Western Europe, Emperor Charlemagne painted his palace red as a very visible symbol of his authority, and wore red shoes at his coronation. Kings, princes and, beginning in 1295, Roman Catholic cardinals began to wear red costumes. When Abbe Suger rebuilt Saint Denis Basilica outside Paris in the early 12th century, he added stained glass windows colored blue cobalt glass and red glass tinted with copper. Together they flooded the basilica with a mystical light. Soon stained glass windows were being added to cathedrals all across France, England and Germany. In Medieval painting red was used to attract attention to the most important figures; both Christ and the Virgin Mary were commonly painted wearing red mantles.
Red clothing was a sign of status and wealth. It was worn not only by cardinals and princes, but also by merchants, artisans and townpeople, particularly on holidays or special occasions. Red dye for the clothing of ordinary people was made from the roots of the rubia tinctorum, the madder plant. This color leaned toward brick-red, and faded easily in the sun or during washing. The wealthy and aristicrats wore scarlet clothing dyed with kermes, or carmine, made from the carminic acid in tiny female scale insects, which lived on the leaves of oak trees in Eastern Europe and around the Mediterranean. The insects were gathered, dried, crushed, and boiled with different ingredients in a long and complicated process, which produced a brilliant scarlet.
Brazilin was another popular red dye in the Middle Ages. It came from the Sapanwood tree, which grew in India, Malaysia and Sri Lanka. A similar tree, brazilwood, grew on the coast of South America. The red wood was ground into sawdust and mixed with an alkaline solution to make dye and pigment. It became one of the most profitable exports from the New World, and gave its name to the nation of Brazil.
The crimson coronation mantle of Roger II of Sicily (1133-1134), dyed with Kermes, the most prestigious red of the Middle Ages.
Interior of a Byzantine church, the Cathedral of Monreale in Sicily, with a mosaic portrait of Christ dressed in red (12th century)
The Annunciation scene in stained glass, from the Saint Denis Basilica (early 12th century). Abbe Suger himself, the builder of the church, is pictured at the feet of the Virgin Mary, at right. She wears red with a green cloak.
King Richard II of England (1390s) dressed in red
Pope Innocent IV (1400-1410) dressed in red, the symbol of the blood of Christ
Dyeing wool, England (1482), from the British Museum
In the Renaissance and Baroque eras
In Renaissance painting, red was used to draw the attention of the viewer; it was often used as the color of the cloak or costume of Christ, the Virgin Mary, or another central figure. In Venice, Titian was the master of fine reds, particularly vermilion; he used many layers of pigment mixed with a semi-transparent glaze, which let the light pass through, to create a more luminous color.
During the Renaissance trade routes were opened to the New World, to Asia and the Middle East, and new varieties of red pigment and dye were imported into Europe, usually through Venice, Genoa or Seville, and Marseille. Venice was the major depot importing and manufacturing pigments for artists and dyers from the end of the 15th century; the catalog of a Venetian Vendecolori, or pigment seller, from 1534 included vermilion and kermes.
There were guilds of dyers who specialized in red in Venice and other large Europeans cities. The Rubia plant was used to make the most common dye; it produced an orange-red or brick red color used to dye the clothes of merchants and artisans. For the wealthy, the dye used was Kermes, made from a tiny scale insect which fed on the branches and leaves of the oak tree. For those with even more money there was Polish Cochineal; also known as Kermes vermilio or "Blood of Saint John", which was made from a related insect, the Margodes polonicus. It made a more vivid red than ordinary Kermes. The finest and most expensive variety of red made from insects was the Kermes of Armenia, made by collecting and crushing the Porphyophora hameli, an insect which lived on the roots and stems of certain herbs. The pigment and dye merchants of Venice imported and sold all of these products and also manufactured their own color, called Venetian red, which was considered the most expensive and finest red in Europe. Its secret ingredient was arsenic, which brightened the color.
But early in the 16th century, a brilliant new red appeared in Europe. When the Spanish conquistador Hernán Cortés and his soldiers conquered the Aztec Empire in 1519-1521, they discovered slowly that the Aztecs had another treasure beside silver and gold; they had the tiny cochineal, a parasitic scale insect which lived on cactus plants, which, when dried and crushed, made a magnificent red. The cochineal in Mexico was closely related to the Kermes varieties of Europe, but unlike European Kermes, it could be harvested several times a year, and it was ten times stronger than the Kermes of Poland. It worked particularly well on silk, satin and other luxury textiles. In 1523 Cortes sent the first shipment to Spain. Soon cochineal began to arrive in European ports aboard convoys of Spanish galleons.
At first the guilds of dyers in Venice and other cities banned cochineal to protect their local products, but the superior quality of cochineal dye made it impossible to resist. By the beginning of the 17th century it was the preferred luxury red for the clothing of cardinals, bankers, courtisans and aristocrats.
The painters of the early Renaissance used two traditional lake pigments, made from mixing dye with either chalk or alum, kermes lake, made from kermes insects, and madder lake, made from the rubia tinctorum plant. With the arrival of cochineal, they had a third, carmine, which made a very fine crimson, though it had a tendency to change color if not used carefully. It was used by almost all the great painters of the 15th and 16th centuries, including Rembrandt, Vermeer, Rubens, Anthony van Dyck, Diego Velázquez and Tintoretto. Later it was used by Thomas Gainsborough, Seurat and J.M.W. Turner.
The Assumption, by Titian (1516-1518). The figures of God, the Virgin Mary and two apostles are highlighted by their vermilion red costumes.
The young Queen Elizabeth I (here in about 1563) liked to wear bright reds, before she adopted the more sober image of the "Virgin Queen". Her satin gown was probably dyed with kermes.
The Wedding Dance (1566), by Pieter Bruegel the Elder. In Renaissance Flanders, people of all social classes wore red at celebrations. The dye came from the root of the madder plant, which tended toward orange.
Woman with a wine glass, by Johannes Vermeer (1659-1660). Vermeer used different shades and tints of vermilion to paint the red skirt, then glazed it with madder lake to make a more luminous color.
Dyed feather headdress from the Aztec people of Mexico and Central America. For red they used cochineal, a brilliant scarlet dye made from insects.
A native of Central America collecting cochineal insects from a cactus to make red dye (1777). From the 16th until the 19th century, it was a highly profitable export from Spanish Mexico to Europe.
Rembrandt used carmine lake, made of cochineal, to paint the skirt of the bride in the painting known as "The Jewish bride" (1665-1669).
The red heels of the shoes of King Louis XIV of France were discreet symbols of his royal status.
In the 18th and 19th centuries
During the French Revolution, Red became a symbol of liberty and personal freedom used by the Jacobins and other more radical parties. Many of them wore a red Phrygian cap, or liberty cap, modeled after the caps worn by freed slaves in Ancient Rome. During the height of the Reign of Terror, Women wearing red caps gathered around the guillotine to celebrate each execution. They were called the "Furies of the guillotine". The guillotines used during the Reign of Terror in 1792 and 1793 were painted red, or made of red wood. During the Reign of Terror a statue of a woman titled liberty, painted red, was placed in the square in front of the guillotine. After the end of the Reign of Terror, France went back to the blue, white and red tricolor, whose red was taken from the traditional color of Saint Denis, the Christian martyr and patron saint of Paris.
In the mid-19th century, red became the color of a new political and social movement, socialism. It became the most common banner of the worker's movement, of the French Revolution of 1848, of the Paris Commune in 1870, and of socialist parties across Europe. (see red flags and revolution section below).
As the Industrial Revolution spread across Europe, chemists and manufacturers sought new red dyes that could be used for large-scale manufacture of textiles. One popular color imported into Europe from Turkey and India in the 18th and early 19th century was Turkey red, known in France as rouge d'Adrinople. Beginning in the 1740s, this bright red color was used to dye or print cotton textiles in England, the Netherlands and France. Turkey red used madder as the colorant, but the process was longer and more complicated, involving multiple soaking of the fabrics in lye, olive oil, sheep's dung, and other ingredients. The fabric was more expensive but resulted in a fine bright and lasting red, similar to carmine, perfectly suited to cotton. The fabric was widely exported from Europe to Africa, the Middle East and America. In 19th century America, it was widely used in making the traditional patchwork quilt.
In 1826, the French chemist Pierre-Jean Robiquet discovered the organic compound alizarin, the powerful coloring ingredient of the madder root, the most popular red dye of the time. In 1868, German chemists Carl Graebe and Liebermann were able to synthesize alizarin, and to produce it from coal tar. The synthetic red was cheaper and more lasting than the natural dye, and the plantation of madder in Europe and import of cochineal from Latin America soon almost completely ceased.
The 19th century also saw the use of red in art to create specific emotions, not just to imitate nature. It saw the systematic study of color theory, and particularly the study of how complementary colors such as red and green reinforced each other when they were placed next to each other. These studies were avidly followed by arists such as Vincent van Gogh. Describing his painting, The Night Cafe, to his brother Theo in 1888, Van Gogh wrote: "I sought to express with red and green the terrible human passions. The hall is blood red and pale yellow, with a green billiard table in the center, and four lamps of lemon yellow, with rays of orange and green. Everywhere it is a battle and antithesis of the most different reds and greens."
A Phrygian cap, or liberty cap, was worn by the supporters of the French Revolution of 1789.
During the Reign of Terror during the later French Revolution, the "Furies of the Guillotine" cheered on each execution.
Red flag over a barricade on Rue Soufflot in Paris during the French Revolution of 1848.
The Night Cafe, (1888), by Vincent van Gogh, used red and green to express what Van Gogh called "the terrible human passions."
In Imperial China
Red has been an important color in Chinese culture, religion, industry, fashion and court ritual since ancient times. Silk was woven and dyed as early as the Han Dynasty (25–220 BC). China had a monopoly on the manufacture of silk until the 6th century AD, when it was introduced into the Byzantine Empire. In the 12th century, it was introduced into Europe.
At the time of the Han Dynasty, Chinese red was a light red, but during the Tang Dynasty new dyes and pigments were discovered. The Chinese used several different plants to make red dyes, including the flowers of carthamus tinctorius, the thorns and stems of a variety of sorghum plant called Kao-liang, and the wood of the sappanwood tree. For pigments, they used cinnabar, which produced the famous vermillion or "Chinese red" of Chinese laquerware.
Red played an important role in Chinese philosophy. It was believed that the world was composed of five elements: metal, wood, water, fire and earth, and that each had a color. Red was associated with fire. Each Emperor chose the color that his fortune-tellers believed would bring the most prosperity and good fortune to his reign. During the Zhou, Han, Jin, Song and Ming Dynasties, red considered a noble color, and it was featured in all court ceremonies, from coronations to sacrificial offerings, and weddings.
Red was also a badge of rank. During the Song Dynasty (906–1279), officials of the top three ranks wore purple clothes; those of the fourth and fifth wore bright red; those of the sixth and seventh wore green; and the eighth and ninth wore blue. Red was the color worn by the royal guards of honor, and the color of the carriages of the imperial family. When the imperial family traveled, their servants and accompanying officials carried red and purple umbrellas. Of an official who had talent and ambition, it was said "he is so red he becomes purple."
Red was also featured in Chinese Imperial architecture. In the Tang and Song Dynasties, gates of palaces were usually painted red, and nobles often painted their entire mansion red. One of the most famous works of Chinese literature, A Dream of Red Mansions by Cao Xueqin (1715–1763), was about the lives of noble women who passed their lives out of public sight within the walls of such mansions. In later dynasties red was reserved for the walls of temples and imperial residences. When the Manchu rulers of the Qing Dynasty conquered the Ming and took over the Forbidden City and Imperial Palace in Beijing, all the walls, gates, beams and pillars were painted in red and gold.
Red is not often used in traditional Chinese paintings, which are usually black ink on white paper with a little green sometimes added for trees or plants; but the round or square seals which contain the name of the artist are traditionally red.
Woven silk from the Western Han Dynasty, 2nd century BC.
Emperors of China usually wore ceremonial costumes of either yellow or red, depending upon which color their astrologers decided was more auspicious for their reign. This was the Emperor Gaozong of Song (1127–1162 AD).
The Meridan Gate of the Forbidden City in Beijing. Walls, columns, windows and gates of palaces and temples were traditionally painted red.
A red lacquerware tray with engraved gold foil decoration (12–13th century), from the Song Dynasty
The red coach of the Chinese Emperor Xuande (1425–1435 AD), pulled by elephants
Dancer in a red dress, Tang Dynasty, from the Astana Tombs
In the 20th and 21st century
In the 20th century, red was the color of Revolution; it was the color of the Bolshevik Revolution in 1917 and of the Chinese Revolution of 1949, and later of the Cultural Revolution. Red was the color of Communist Parties from Eastern Europe to Cuba to Vietnam.
In the late 19th and early 20th century, the German chemical industry invented two new synthetic red pigments: cadmium red, which was the color of natural vermilion, and mars red, which was a synthetic red ochre, the color of the very first natural red pigment.
The French painter Henri Matisse (1869–1954) was one of the first prominent painters to use the new cadmium red. He even tried, without success, to persuade the older and more traditional Renoir, his neighbor in the south of France, to switch from vermilion to cadmium red.
Matisse was also one of the first 20th-century artists to make color the central element of the painting, chosen to evoke emotions. "A certain blue penetrates your soul", he wrote. "A certain red affects your blood pressure." He also was familiar with the way that complementary colors, such as red and green, strengthened each other when they were placed next to each other. He wrote, "My choice of colors is not based on scientific theory; it is based on observation, upon feelings, upon the real nature of each experience ... I just try to find a color which corresponds to my feelings."
Later in the century, the American artist Mark Rothko (1903–1970) also used red, in even simpler form, in blocks of dark, somber color on large canvases, to inspire deep emotions. Rothko observed that color was "only an instrument;" his interest was "in expressing human emotions tragedy, ecstasy, doom, and so on."
Rothko also began using the new synthetic pigments, but not always with happy results. In 1962 he donated to Harvard University a series of large murals of the Passion of Christ whose predominant colors were dark pink and deep crimson. He mixed mostly traditional colors to make the pink and crimson; synthetic ultramarine, cerulean blue, and titanium white, but he also used two new organic reds, Naphtol and Lithol. The Naphtol did well, but the Lithol slowly changed color when exposed to light. Within five years the deep pinks and reds had begun to turn light blue, and by 1979 the paintings were ruined and had to be taken down.
Bathing of a Red Horse, by the Russian symbolist painter Kuzma Petrov-Vodkin (1912), used a bright red horse to surprise and shock viewers. It provoked a furious discussion among Russian critics.
The Dessert – Harmony in Red, (1908) by Henri Matisse. Matisse used red to stimulate the emotions he wanted the viewer to feel.
Four Darks in Red by Mark Rothko (1958). The somber dark reds were chosen to inspire deep human emotions.
Pigments and dyes
Hematite, or iron ore, is the source of the red color of red ochre.
Red ochre cliffs near Roussillon in France. Red ochre is composed of clay tinted with hematite. Ochre was the first pigment used by man in prehistoric cave paintings.
The mineral cinnabar, the ore of mercury, is the source of the color vermilion. In Roman times, most cinnabar came from mines at Almadén in Spain, where the miners were usually prisoners and slaves. Mercury is highly toxic, and working in the mines was often a death sentence for the miners.
Vermilion pigment, made from cinnabar. This was the pigment used in the murals of Pompeii and to color Chinese lacquerware beginning in the Song Dynasty.
Despite its yellow greenish flower, the roots of the Rubia tinctorum, or madder plant, produced the most common red dye used from ancient times until the 19th century.
Red lead, also known as minium, has been used since the time of the ancient Greeks. Chemically it is known as lead tetroxide. The Romans prepared it by the roasting of lead white pigment. It was commonly used in the Middle Ages for the headings and decoration of illuminated manuscripts.
Dragon's blood is a bright red resin that is obtained from different species of a number of distinct plant genera: Croton, Dracaena, Daemonorops, Calamus rotang and Pterocarpus. The red resin was used in ancient times as a medicine, incense, dye and varnish for making violins in Italy.
The tiny female cochineal insect of Spanish Mexico (on the left), was crushed to make the deep crimson color used in Renaissance costumes.
Extract of carmine, made by crushing cochineal and other scale insects which feed on the sap of live oak trees. Also called kermes, it was used from the Middle Ages until the 19th century to make crimson dye. Now it is used as a coloring for yoghurt and other food products.
The Sappanwood tree, native to India, Malaysia and Sri Lanka, and later the related Brazilwood tree (shown here), from the coast of South America, were the source of a popular red pigment and dye called brazilin. The red wood was ground to powder and mixed with an alkaline solution. The brazilwood gave its name to the nation of Brazil.
Alizarin was the first synthetic red dye, created by German chemists in 1868. It duplicated the colorant in the madder plant, but was cheaper and longer lasting. After its introduction, the production of natural dyes from the madder plant virtually ceased.
Red lac, red lake and crimson lake
Red lac, also called red lake, crimson lake or carmine lake, was an important red pigment in Renaissance and Baroque art. Since it was translucent, thin layers of red lac were built up or glazed over a more opaque dark color to create a particularly deep and vivid color.
Unlike vermilion or red ochre, made from minerals, red lake pigments are made by mixing organic dyes, made from insects or plants, with white chalk or alum. Red lac was made from the gum lac, the dark red resinous substance secreted by various scale insects, particularly the Laccifer lacca from India.Carmine lake was made from the cochineal insect from Central and South America, Kermes lake came from a different scale insect, kermes vermilio, which thrived on oak trees around the Mediterranean. Other red lakes were made from the rose madder plant and from the brazilwood tree.
Red lake pigments were an important part of the palette of 16th century Venetian painters, particularly Titian, but they were used in all periods. Since the red lakes were made from organic dyes, they tended to be fugitive, becoming unstable and fading when exposed to sunlight.
The most common synthetic food coloring today is Allura Red AC is a red azo dye that goes by several names including: Allura Red, Food Red 17, C.I. 16035, FD&C Red 40, It was originally manufactured from coal tar, but now is mostly made from petroleum.
In Europe, Allura Red AC is not recommended for consumption by children. It is banned in Denmark, Belgium, France and Switzerland, and was also banned in Sweden until the country joined the European Union in 1994. The European Union approves Allura Red AC as a food colorant, but EU countries' local laws banning food colorants are preserved.
In the United States, Allura Red AC is approved by the Food and Drug Administration (FDA) for use in cosmetics, drugs, and food. It is used in some tattoo inks and is used in many products, such as soft drinks, children's medications, and cotton candy. On June 30, 2010, the Center for Science in the Public Interest (CSPI) called for the FDA to ban Red 40.
Because of public concerns about possible health risks associated with synthetic dyes, many companies have switched to using natural pigments such as carmine, made from crushing the tiny female cochineal insect. This insect, originating in Mexico and Central American, was used to make the brilliant scarlet dyes of the European Renaissance.
The human eye sees red when it looks at light with a wavelength between 620 and 740 nanometers. Light just past this range is called infrared, or below red, and cannot be seen by human eyes, although it can be sensed as heat.
Primates can distinguish the full range of the colors of the spectrum visible to humans, but many kinds of mammals, such as dogs and cattle, have dichromacy, which means they can see blues and yellows, but cannot distinguish red and green (both are seen as gray). Bulls, for instance, cannot see the red color of the cape of a bullfighter, but they are agitated by its movement. (See color vision).
One theory for why primates developed sensitivity to red is that it allowed ripe fruit to be distinguished from unripe fruit and inedible vegetation. This may have driven further adaptations by species taking advantage of this new ability, such as the emergence of red faces.
Red light is used to help adapt night vision in low-light or night time, as the rod cells in the human eye are not sensitive to red.
Red illumination was (and sometimes still is) used as a safelight while working in a darkroom as it does not expose most photographic paper and some films. Today modern darkrooms usually use an amber safelight.
In color theory and on a computer screen
On the color wheel long used by painters, and in traditional color theory, red is one of the three primary colors, along with blue and yellow. Painters in the Renaissance mixed red and blue to make violet: Cennino Cennini, in his 15th century manual on painting, wrote, "If you wish to make a pretty violet color, take fine lac (Red lake) and ultramarine blue, in equal parts." he noted that it could also be made by mixing blue indigo and red hematite.
In modern color theory, also known as the RGB color model, red, green and blue are additive primary colors. Red, green and blue light combined together makes white light, and these three colors, combined in different mixtures, can produce nearly any other color. This is the principle that is used to make all of the colors on your computer screen and your television. For example, purple on a computer screen is made by a similar formula to used by Cennino Cennini in the Renaissance to make violet, but using additive colors and light instead of pigment: it is created by combining red and blue light at equal intensity on a black screen. Violet is made on a computer screen in a similar way, but with a greater amount of blue light and less red light.
So that the maximum number of colors can be accurately reproduced on your computer screen, each color has been given a code number, or sRGB, which tells your computer the intensity of the red, green and blue components of that color. The intensity of each component is measured on a scale of zero to 255, which means the complete list includes 16,777,216 distinct colors and shades. The sRGB number of pure red, for example, is 255, 00, 00, which means the red component is at its maximum intensity, and there is no green or blue. The sRGB number for crimson is 220, 20, 60, which means that the red is slightly less intense and therefore darker, there is some green, which leans it toward orange; and there is a larger amount of blue,which makes it slightly blue-violet.
(See Web colors and RGB color model)
In a traditional color wheel from 1708, red, yellow and blue are primary colors. Red and yellow make orange, red and blue make violet.
In modern color theory, red, green and blue are the additive primary colors, and together they make white. A combination of red, green and blue light in varying proportions makes all the colors on your computer screen and television screen.
Tiny Red, green and blue sub-pixels (enlarged on left side of image) create the colors you see on your computer screen and TV.
Why the sunset is red
As a ray of white sunlight travels through the atmosphere to the eye, some of the colors are scattered out of the beam by air molecules and airborne particles due to Rayleigh scattering, changing the final color of the beam that is seen. Colors with a shorter wavelength, such as blue and green, scatter more strongly, and are removed from the light that finally reaches the eye. At sunrise and sunset, when the path of the sunlight through the atmosphere to the eye is longest, the blue and green components are removed almost completely, leaving the longer wavelength orange and red light. The remaining reddened sunlight can also be scattered by cloud droplets and other relatively large particles, which give the sky above the horizon its red glow.
Lasers emitting in the red region of the spectrum have been available since the invention of the ruby laser in 1960. In 1962 the red helium–neon laser was invented, and these two types of lasers were widely used in many scientific applications including holography, and in education. Red helium–neon lasers were used commercially in LaserDisc players. The use of red laser diodes became widespread with the commercial success of modern DVD players, which use a 660 nm laser diode technology. Today, red and red-orange laser diodes are widely available to the public in the form of extremely inexpensive laser pointers. Portable, high-powered versions are also available for various applications. More recently, 671 nm diode-pumped solid state (DPSS) lasers have been introduced to the market for all-DPSS laser display systems, particle image velocimetry, Raman spectroscopy, and holography.
Red's wavelength has been an important factor in laser technologies; red lasers, used in early compact disc technologies, are being replaced by blue lasers, as red's longer wavelength causes the laser's recordings to take up more space on the disc than would blue-laser recordings.
- Mars is called the Red Planet because of the reddish color imparted to its surface by the abundant iron oxide present there.
- Astronomical objects that are moving away from the observer exhibit a Doppler red shift.
- Jupiter's surface displays a Great Red Spot caused by an oval-shaped mega storm south of the planet's equator.
- Red giants are stars that have exhausted the supply of hydrogen in their cores and switched to thermonuclear fusion of hydrogen in a shell that surrounds its core. They have radii tens to hundreds of times larger than that of the Sun. However, their outer envelope is much lower in temperature, giving them an orange hue. Despite the lower energy density of their envelope, red giants are many times more luminous than the Sun due to their large size.
- Red supergiants like Betelgeuse and Antares are the biggest variety of red giants, They are huge in size, with radii 200 to 800 times greater than our Sun, but relatively cool in temperature (3500-4500 K), causing their distinct red tint. Because they are shrinking rapidly in size, they are surrounded by an envelope or skin much bigger than the star itself. The envelope of Betelgeuse is 250 times bigger than the star inside.
- A red dwarf is a small and relatively cool star, which has a mass of less than half that of the Sun and a surface temperature of less than 4,000 K. Red dwarfs are by far the most common type of star in the Galaxy, but due to their low luminosity, from Earth, none is visible to the naked eye.
Mars appears to be red because of iron oxide on its surface.
The red giant called Mira, a star which is glowing from thermonuclear fusion.
Artist's impression of a red dwarf, a small, relatively cool star that appears red instead of white because of its lower temperature.
- Fire is often shown as red in art, but flames are usually yellow, orange or blue. Some elements exhibit a red color when burned: calcium, for example, produces a brick-red when combusted.
Red is commonly associated with flames and fire, but flames are almost always yellow, orange or blue
- The red of autumn leaves is produced by pigments called Anthocyanins. They are not present in the leaf throughout the growing season, but are actively produced towards the end of summer. They develop in late summer in the sap of the cells of the leaf, and this development is the result of complex interactions of many influences—both inside and outside the plant. Their formation depends on the breakdown of sugars in the presence of bright light as the level of phosphate in the leaf is reduced.
During the summer growing season, phosphate is at a high level. It has a vital role in the breakdown of the sugars manufactured by chlorophyll. But in the fall, phosphate, along with the other chemicals and nutrients, moves out of the leaf into the stem of the plant. When this happens, the sugar-breakdown process changes, leading to the production of anthocyanin pigments. The brighter the light during this period, the greater the production of anthocyanins and the more brilliant the resulting color display. When the days of autumn are bright and cool, and the nights are chilly but not freezing, the brightest colorations usually develop.
Anthocyanins temporarily color the edges of some of the very young leaves as they unfold from the buds in early spring. They also give the familiar color to such common fruits as cranberries, red apples, blueberries, cherries, strawberries, and plums.
Anthocyanins are present in about 10% of tree species in temperate regions, although in certain areas—most famously New England—up to 70% of tree species may produce the pigment. In autumn forests they appear vivid in the maples, oaks, sourwood, sweetgums, dogwoods, tupelos, cherry trees and persimmons. These same pigments often combine with the carotenoids' colors to create the deeper orange, fiery reds, and bronzes typical of many hardwood species. (See Autumn leaf color).
The vivid reds of autumn leaves are produced by natural pigments called anthocyanins. They also produce the red of strawberries, apples, and plums.
Cranberries also get their red color from anthocyanins.
Blood and other reds in nature
Oxygenated blood is red due to the presence of oxygenated hemoglobin.
- When used to describe natural animal coloration, "red" usually refers to a brownish, reddish-brown or ginger color. In this sense it is used to describe coat colors of reddish-brown cattle and dogs, and in the names of various animal species or breeds such as red fox, red squirrel, red deer, European robin, Red Grouse, Red Knot, Redstart, Redwing, Red Setter, Red Devon cattle, etc. This reddish-brown color is also meant when using the terms red ochre and red hair.
- The red herring dragged across a trail to destroy the scent gets its color from the heavy salting and slow smoking of the fish, which results in a warm, brown color.
- When used for flowers, red often refers to purplish (red deadnettle, red clover, red helleborine) or pink (red campion, red valerian) colors.
Red blood cell agar. Blood appears red when it has contact with oxygen.
A red setter or Irish setter
A pair of European red foxes.
The European robin or robin redbreast
A cooked lobster
Red hair occurs naturally on approximately 1–2% of the human population. It occurs more frequently (2–6%) in people of northern or western European ancestry, and less frequently in other populations. Red hair appears in people with two copies of a recessive gene on chromosome 16 which causes a mutation in the MC1R protein.
Red hair varies from a deep burgundy through burnt orange to bright copper. It is characterized by high levels of the reddish pigment pheomelanin (which also accounts for the red color of the lips) and relatively low levels of the dark pigment eumelanin. The term redhead (originally redd hede) has been in use since at least 1510. Cultural reactions have varied from ridicule to admiration; many common stereotypes exist regarding redheads and they are often portrayed as fiery-tempered. (See red hair).
In animal and human behavior
Red is associated with dominance in a number of animal species. For example, in mandrills, red coloration of the face is greatest in alpha males, increasingly less prominent in lower ranking subordinates, and directly correlated with levels of testosterone. Red can also affect the perception of dominance by others, leading to significant differences in mortality, reproductive success and parental investment between individuals displaying red and those not. In humans, wearing red has been linked with increased performance in competitions, including professional sport and multiplayer video games. Controlled tests have demonstrated that wearing red does not increase performance or levels of testosterone during exercise, so the effect is likely to be produced by perceived rather than actual performance. Judges of tae kwon do have been shown to favor competitors wearing red protective gear over blue, and, when asked, a significant majority of people say that red abstract shapes are more "dominant", "aggressive", and "likely to win a physical competition" than blue shapes. In contrast to its positive effect in physical competition and dominance behavior, exposure to red decreases performance in cognitive tasks and elicits aversion in psychological tests where subjects are placed in an "achievement" context (e.g., taking an IQ test).
Courage and sacrifice
Surveys show that red is the color most associated with courage. In western countries red is a symbol of martyrs and sacrifice, particularly because of its association with blood. Beginning in the Middle Ages, the Pope and Cardinals of the Roman Catholic Church wore red to symbolize the blood of Christ and the Christian martyrs. The banner of the Christian soldiers in the First Crusade was a red cross on a white field, the St. George's Cross. According to Christian tradition, Saint George was a Roman soldier who was a member of the guards of the Emperor Diocletian, who refused to renounce his Christian faith and was martyred. The Saint George's Cross became the Flag of England in the 16th century, and now is part of the Union Flag of the United Kingdom, as well as the Flag of the Republic of Georgia.
In 1587, Mary, Queen of Scots, accused of treason against Queen Elizabeth I, wore a red shirt at her execution, to proclaim that she was an innocent martyr.
The Thin Red Line was a famous incident in the Battle of Balaclava (1854) during the Crimean War, when a thin line of Scottish Highlander infantry, assisted by Royal Marines and Turkish infantrymen, repulsed a Russian cavalry charge. It was widely reported in the British press as an example of courage in the face of overwhelming odds and became a British military legend.
In the 19th century novel The Red Badge of Courage by Stephen Crane, a story about the American Civil War, the red badge was the blood from a wound, by which a soldier could prove his courage.
The Crucified Martyr (Saint Julia) by the Dutch artist Hieronymus Bosch. Saint Julia wears red, the traditional color of Christian martyrs.
Roman Catholic Popes wear red as the symbol of the blood of Christ. This is Pope Innocent III, in about 1219.
Saint George and the Dragon, by Paolo Uccello (1456-1460). He wears the Saint George's Cross as a cape, which was also the banner of Milan.
The Thin Red Line at the Battle of Balaclava (1854), when a line of the Scottish Highland infantry repulsed a Russian cavalry charge. The name was given by the British press as a symbol of courage against the odds.
The red poppy flower is worn on Remembrance Day in Commonwealth countries to honor soldiers who died in the First World War.
Courtly love, the red rose, and Saint Valentine's Day
Red is the color most commonly associated with love, followed at a great distance by pink. It the symbolic color of the heart and the red rose, is closely associated with romantic love or courtly love and Saint Valentine's Day. Both the Greeks and the Hebrews considered red a symbol of love as well as sacrifice.
The Roman de la Rose, the Romance of the Rose, a thirteenth-century French poem, was one of the most popular works of literature of the Middle Ages. It was the allegorical search by the author for a red rose in an enclosed garden, symbolizing the woman he loved, and was a description of love in all of its aspects. Later, in the 19th century, British and French authors described a specific language of flowers; giving a single red rose meant 'I love you,'
Saint Valentine, a Roman Catholic Bishop or priest who was martyred in about 296 AD, seems to have had no known connection with romantic love, but the day of his martyrdom on the Roman Catholic calendar, Saint Valentine's Day (February 14), became, in the 14th century, an occasion for lovers to send messages to each other. In recent years the celebration of Saint Valentine' s day has spread beyond Christian countries to Japan and China and other parts of the world. The celebration of Saint Valentine's Day is forbidden or strongly condemned in many Islamic countries, including Saudi Arabia, Pakistan and Iran. In Saudi Arabia, in 2002 and 2011, religious police banned the sale of all Valentine's Day items, telling shop workers to remove any red items, as the day is considered a Christian holiday.
The Codex Manesse, a 14th-century collection of love songs. Red roses were symbol of courtly love.
Fifteenth-century Illustration from the Roman de la Rose, a thirteenth-century French poem about a search for a red rose symbolizing the poet's love.
A valentine from 1909. The tradition of sending messages of love on February 14, Valentine's Day, dates back to the 14th century.
God Speed!, a Victorian era painting by Edmund Leighton of a Lady giving a red token of love to her knight.