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85-427: Indigo is a color between blue and violet. Indigo or INDIGO may also refer to: Indigo Indigo is a term used for a number of hues in the region of blue . The word comes from the ancient dye of the same name . The term "indigo" can refer to the color of the dye, various colors of fabric dyed with indigo dye, a spectral color, one of the seven colors of the rainbow as described by Newton , or
170-503: A dark purple hue. This has resulted in violet and purple hues also being associated with the term "indigo" since that time. Because of the Abney effect , pinpointing indigo to a specific hue value in the HSV color wheel is elusive, as a higher HSV saturation value shifts the hue towards blue. However, on the new CIECAM16 standard , the hues values around 290° may be thought of as indigo, depending on
255-459: A few months. Perkin began making the intermediates for his dyes in-house, for example, nitro-benzene, expanding the scale of operations. By the summer of 1859, according to a satirical magazine Punch , London had fallen ill with 'the mauve measles'. By the end of 1858 there were already eight firms producing aniline dyes . By 1861 there were twenty-nine British patents on coloring matters from aniline. By 1864 68 firms were producing dyes. This
340-463: A history dating back to the early eighteenth century, Prussian blue remains a popular artistic pigment. Studies of Prussian Blue lead to discoveries about hydrogen cyanide . It is an antidote for heavy metal poisoning, and is famed for being used to color the uniforms of the Prussian army in the eighteenth century. Mauveine was discovered when Henry Perkin was trying to convert an artificial base into
425-484: A huge market that was formerly served by natural dye makers. Alizarin was the first dye whose structure chemist determined, and they quickly set it as a target of synthesis, succeeding by 1868. Other chemical components of natural madder were identified and applied by the mid-nineteenth century, including purpurin, which produced a delicate lilac colour, and green alizarin, which was patented in Britain and famously displayed at
510-514: A laboratory in description of his studio. Interestingly, Degas was known to be in correspondence with chemist Marcellin Berthelot , considered the father of organic synthetic chemistry in France. Pierre-Auguste Renoir ’s later paintings relied heavily on alizarin crimson. He also employed cobalt blue or a mixture of ultramarine and cobalt blue, a synthetic pigment. New pigments and dyes were not limited to
595-402: A list of colors for the X Window Operating System. The color identified as "indigo" was not the color indigo (as generally understood at the time), but was actually a dark purple hue; the programmers assigned it the hex code #4B0082 . This collection of color names was somewhat arbitrary: Thomas used a box of 72 Crayola crayons as a standard, whereas Ravelling used color swabs from
680-419: A major step in the synthesis, as his "first love," and was excited to have Perkin working with it. Perkin communicated with the textile industry, including Pullars of Perth, and John Hyde Christie, the chemist and general manager of John Orr Ewing and Co. about how to best market and produce his dye. He started production of aniline purple near London at the end of 1857 and remained the only producer for at least
765-416: A prism to produce a rainbow-like band of colors on the wall. In describing this optical spectrum , Newton acknowledged that the spectrum had a continuum of colors, but named seven: "The originall or primary colours are Red, yellow, Green, Blew, & a violet purple; together with Orang, Indico, & an indefinite varietie of intermediate gradations." He linked the seven prismatic colors to the seven notes of
850-452: A product belonging to a new class of compounds: azo dyes . Later, a new class of azo dyes that were based on "coupling" reactions entered the market. The new azo dyes were easy to make and assumed a vast variety of incredibly intense colors based on the chosen precursors. The chemists Z. Roussin, H. Caro, O. Witt, and P. Griess all put azo dyes on the market, and attempted to keep the syntheses as industrial secrets, Hoffman, however, determined
935-577: A region on the color wheel , and can include various shades of blue, ultramarine , and green-blue. Since the web era, the term has also been used for various purple and violet hues identified as "indigo", based on use of the term "indigo" in HTML web page specifications. The word "indigo" comes from the Latin word indicum , meaning "Indian", as the naturally based dye was originally exported to Europe from India . The Early Modern English word indigo referred to
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#17331250175581020-457: A rose colored dye, the first of the triphenylmethane dyes . Further work by Hoffman along with the discovery of benzene ’s structure (1858) and carbon’s tetravalency (1865), this science built the groundwork for modern organic chemistry. In the late 1860s many companies began offering a full spectrum of colors, and were already outcompeting many natural dyes for market share. Prices continually fell, and new colors and products regularly entered
1105-472: A spectral color between blue and violet. However, the article states that Wilhelm von Bezold, in his treatise on color, disagreed with Newton's use of the term, on the basis that the pigment indigo was a darker hue than the spectral color; and furthermore, Professor Ogden Rood points out that indigo pigment corresponds to the cyan-blue region of the spectrum, lying between blue and green, although darker in hue. Rood considers that artificial ultramarine pigment
1190-453: A substrate via impregnation, while pigments are insoluble and require a binding agent to adhere to a substrate. Dyes, therefore, must have an affinity for the substance they are intended to color. Chemically speaking, pigments can be organic or inorganic , while dyes are only organic. Furthermore, organic white pigments do not exist, despite the fact that the majority of purified crystalline organic products are white in appearance. This story
1275-492: A synthetic process for indigo in 1915, and American industry and universities worked together to reverse engineer German chemical production secrets. After the war some American munitions factories converted to dye-works, intuiting that if the reverse was possible for the German chemical industry during the war, then it ought to be feasible. Synthetic colorants gained popularity as quickly with artists as with industry. The painters of
1360-470: A tub and soaked it overnight, and the next day we foamed it up by beating it with a gourd. We let it stand overnight again, and the next day rubbed tallow on our hands to kill the foam. Afterwards, we poured the water off, and the sediment left in the bottom we would pour into a pitcher or crock to let it get dry, and then we would put it into a poke made of cloth (i.e. sack made of coarse cloth) and then when we wanted any of it to dye [there]with, we would take
1445-421: A western major scale , as shown in his color wheel, with orange and indigo as the semitones . Having decided upon seven colors, he asked a friend to repeatedly divide up the spectrum that was projected from the prism onto the wall: I desired a friend to draw with a pencil lines cross the image, or pillar of colours, where every one of the seven aforenamed colours was most full and brisk, and also where he judged
1530-442: Is also known as "deep indigo". The color box on the right displays the web color indigo, the color indigo as it would be reproduced by artists' paints as opposed to the brighter indigo above (electric indigo) that is possible to reproduce on a computer screen. Its hue is closer to violet than to indigo dye for which the color is named. Pigment indigo can be obtained by mixing 55% pigment cyan with about 45% pigment magenta . Compare
1615-785: Is an aromatic benzene ring or system of benzene rings, often substituted . The second is a chromophore , a conjugated double bond system with unsaturated groups. When exposed to visible light, this part absorbs or reflects color. Other components of colorant molecules can tune intensity, color, solubility and substrate affinity. Dyes and pigments can be categorized according to their synthetic or chemical properties. British chemist Edward Chambers Nicholson showed that pure aniline produced no dye. Hofmann showed that toluidine must be present to make these dyes. Aniline dyes, including mauve, are prepared from aniline-containing amounts of toluidine. One can also classify dyes based on chemical formulas, azo-dyes from coupling, or diazonation—reactions with
1700-518: Is closer to the point of the spectrum described as "indigo", and proposed renaming that spectral point as "ultramarine". The article goes on to state that comparison of the pigments, both dry and wet, with Maxwell's discs and with the spectrum, that indigo is almost identical to Prussian blue , stating that it "certainly does not lie on the violet side of 'blue.'" When scraped, a lump of indigo pigment appears more violet, and if powdered or dissolved, becomes greenish. Several modern sources place indigo in
1785-699: Is complicated somewhat by lake pigments , or lakes, which are dyes modified with a chemical process to form an insoluble pigment. Typically this involves precipitating the natural extracts as salts in alkaline conditions. The historical importance of both pigments and dyes is closely related, as the markets for both, as well as the types and variety available, have always been closely tied. Early colorants date to prehistoric times. Human beings were already relying on natural substances, primarily from vegetables, but also from animals, to color their homes and artifacts. Cave drawings like those in Altamira or Lascaux were made in
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#17331250175581870-406: Is composed of 25.1% red , 0% green and 100% blue . Whereas in a CMYK color space, it is composed of 74.9% cyan , 100% magenta , 0% yellow and 0% black . It has a hue angle of 255.1 degrees, a saturation of 100% and a lightness of 50%. Indigo(color wheel) could be obtained by blending violet with blue . "Electric indigo" is brighter than the pigment indigo reproduced above. When plotted on
1955-404: Is customary to list indigo as a color lying between blue and violet, but it has never seemed to me that indigo is worth the dignity of being considered a separate color. To my eyes, it seems merely deep blue." In 1821, Abraham Werner published Werner's Nomenclature of Colours , where indigo, called indigo blue , is classified as a blue hue, and not listed among the violet hues. He writes that
2040-421: Is equivalent to the web color indigo and approximates the color indigo that is usually reproduced in pigments and colored pencils. The color of indigo dye is a different color from either spectrum indigo or pigment indigo. This is the actual color of the dye. A vat full of this dye is a darker color, approximating the web color midnight blue . The color "electric indigo" is a bright and saturated color between
2125-417: Is portrayed using hex code #184FA1 . The 2004 indigo crayon color is depicted by #5D76CB , and the 2019 iridescent indigo is portrayed by #3C32CD . Like many other colors ( orange , rose , and violet are the best-known), indigo gets its name from an object in the natural world—the plant named indigo once used for dyeing cloth (see also Indigo dye ). The color pigment indigo
2210-471: Is repeatedly boiled in an indigo dye bath-solution (boiled and left to dry, boiled and left to dry, etc.), the blue pigment becomes darker on the cloth. After dyeing, the cloth is hung in the open air to dry. A Native American woman described the process used by the Cherokee Indians when extracting the dye: We raised our indigo which we cut in the morning while the dew was still on it; then we put it in
2295-506: Is the color that is called añil in the Guía de coloraciones (Guide to colorations) by Rosa Gallego and Juan Carlos Sanz, a color dictionary published in 2005 that is widely popular in the Hispanophone realm. Marina Warner's novel Indigo (1992) is a retelling of Shakespeare's The Tempest and features the production of indigo dye by Sycorax. The French Army adopted dark blue indigo at
2380-506: The Better Call Saul episode " Hero ", Howard Hamlin mentions that his law firm Hamlin Hamlin & McGill trademarked a colour called "Hamlindigo" whilst confronting Jimmy McGill over trademark infringement in a billboard advertisement he produced for his own legal services. The spiritualist applications use electric indigo , because the color is positioned between blue and violet on
2465-497: The CIE chromaticity diagram , this color is at 435 nanometers, in the middle of the portion of the spectrum traditionally considered indigo, i.e., between 450 and 420 nanometers. This color is only an approximation of spectral indigo, since actual spectral colors are outside the gamut of the sRGB color system. At right is displayed the web color "blue-violet", a color intermediate in brightness between electric indigo and pigment indigo. It
2550-431: The electromagnetic spectrum between 420 and 450 nanometers, which lies on the short-wave side of color wheel (RGB) blue , towards (spectral) violet. The correspondence of this definition with colors of actual indigo dyes, though, is disputed. Optical scientists Hardy and Perrin list indigo as between 445 and 464 nm wavelength, which occupies a spectrum segment from roughly the color wheel (RGB) blue extending to
2635-463: The electromagnetic spectrum . Later scientists have concluded that what Newton called "blue" was what is now called cyan or blue-green; and what Newton called "indigo" was what is now called blue. In the 1980s, programmers produced a somewhat arbitrary list of color names for the X Window computer operating system, resulting in the HTML and CSS specifications issued in the 1990s using the term "indigo" for
Indigo (disambiguation) - Misplaced Pages Continue
2720-496: The 1867 Paris International Exhibition. Similar to aniline dyes, the precursors for Synthetic Alizarin were easily obtainable from coal tar. Germany dominated the synthetic alizarin market, however foreign competition was not non-extant, for example the British Alizarine Company Ltd. In 1858 Peter Griess passed ‘nitrous fumes’ (N 2 O 3 ) into a solution of picramic acid (2-amino-4,6-dinitrophenol) and isolated
2805-465: The 1878 Universal Exposition commented, "The abundance, the variety of combinations is such that we do not know whether to be more amazed by their multiplicity or by the imagination required to name them. Indeed, it is by the thousands that dyers create, every season, new colors for their sample cards." Professional societies based on the synthetic dye industries began to form. By the First World War,
2890-510: The 1990s, this list which came with version X11 became the basis of the HTML and CSS color rendition used in websites and web design. This resulted in the name "Indigo" being associated with purple and violet hues in web page design and graphic design. Physics author John Spacey writes on the website Simplicable that the X11 programmers did not have any background in color theory, and that as these names are used by web designers and graphic designers,
2975-534: The American colonies. Isaac Newton introduced indigo as one of the seven base colors of his work. In the mid-1660s, when Newton bought a pair of prisms at a fair near Cambridge , the East India Company had begun importing indigo dye into England, supplanting the homegrown woad as source of blue dye. In a pivotal experiment in the history of optics , the young Newton shone a narrow beam of sunlight through
3060-654: The Ice Age 15,000 to 30,000 years ago. Using pigments for coloration is among the oldest cultural activities of mankind. The important substrates of pre-industrial societies were generally naturally occurring (cotton, silk, wool, leather, paper) and therefore share similarities, since they are primarily saccharide or peptide polymers. The nineteenth and twentieth century in particular saw an expansion in colorant use and production, yielding many pigments and dyes in use today. The availability of strong acidic or alkaline environments like sulphuric acid and synthetic sodium carbonate
3145-587: The Netherlands, Belgium, and Italy. At the end of this period, this grew to include Rumania (one firm), Greece (one firm), and Canada (two firms). The scale of the chemical plants also grew, for instance the Bayer company in 1907 had a reactor to make azo dye with a capacity of 20,000 liters. From 1900 to the first World War German firms controlled around 75% of the dye market. The concentration of chemical producers in Germany
3230-537: The artists of Europe, even Japanese printmakers were using dyes like rosaniline as early as 1863. Prussian Blue , also known as Berlin Blue , Paris Blue , or Turnbull's Blue , is an inorganic pigment, produced in large quantities for both artistic purposes and textiles. It has the chemical formula FeIII 4 [ FeII ( CN ) 6 ] 3 {\displaystyle {\ce {FeIII4[FeII(CN)6]3}}} . With
3315-431: The color fastness properties were not good, thus it had very limited commercial success. It was, however, purchased in limited amounts by French dyers. In 1856, 18 year old William Perkin accidentally discovered a dye he called mauve while trying to make quinine from the oxidation of allyl toluene in his home lab for his academic advisor and boss August Wilhelm von Hoffman . Hoffman reportedly referred to aniline,
3400-458: The color he called indigo, we would normally call blue; his blue is then what we would name blue-green or cyan ." If this is true, Newton's seven spectral colors would have been: The human eye does not readily differentiate hues in the wavelengths between what are now called blue and violet. If this is where Newton meant indigo to lie, most individuals would have difficulty distinguishing indigo from its neighbors. According to Isaac Asimov , "It
3485-521: The color is composed of " Berlin blue , a little black, and a small portion of apple green," and indicating it is the color of blue copper ore , with Berlin blue being described as the color of a blue jay 's wing, a hepatica flower, or a blue sapphire . According to an article, Definition of the Color Indigo published in Nature magazine in the late 1800s, Newton's use of the term "indigo" referred to
Indigo (disambiguation) - Misplaced Pages Continue
3570-411: The dibromination of anthraquinone, followed by fusion with sodium hydroxide. The second, much cheaper, synthetic path was developed in 1869 by Graebe, Liebermann and Heinrich Caro . It entailed the treatment of anthraquinone with fuming sulphuric acid, followed by a treatment with sodium hydroxide and potassium chlorate. Perkin submitted his own patent for a nearly identical process just a day later, and
3655-442: The dry indigo. In Sa Pa , Vietnam, the tropical Indigo ( Indigo tinctoria ) leaves are harvested and, while still fresh, placed inside a tub of room-temperature to lukewarm water where they are left to sit for 3 to 4 days and allowed to ferment, until the water turns green. Afterwards, crushed limestone ( pickling lime ) is added to the water, at which time the water with the leaves are vigorously agitated for 15 to 20 minutes, until
3740-462: The dye, not to the color (hue) itself, and indigo is not traditionally part of the basic color-naming system . The first known recorded use of indigo as a color name in English was in 1289. Isaac Newton regarded indigo as a color in the visible spectrum , as well as one of the seven colors of the rainbow : the color between blue and violet ; however, sources differ as to its actual position in
3825-400: The early major producing countries Britain (1857), France (1858), Germany (1858), and Switzerland (1859), and expansion of associated chemical industries followed. The mid-nineteenth century through WWII saw an incredible expansion of the variety and scale of manufacture of synthetic colorants. Synthetic colorants quickly became ubiquitous in everyday life, from clothing to food. This stems from
3910-408: The first time on an industrial scale and introduced synthetic white pigments. The first insoluble organic pigments, the red naphthols , containing neither acid nor basic groups, were produced and sold. Furthermore, the quality of the new dyes increased. Chemist Rene Bohn developed a brilliant blue vat dye, indanthrone , with excellent color fastness in 1901. BASF ( Badische Anilin und Soda Fabrik ),
3995-453: The impressionist school in particular were famous early adopters. Critical reviews of Impressionists’ blues made comparisons to laundresses’ tubs, in particular the practice of laundry bluing, and to chemical waste dumped into the Seine by dye factories. One critic accused Edgar Degas , known for experiments in aquatint , pastel and oil painting as having an obsession with "chemistry," evoking
4080-403: The introduction of the first modern synthetic dyes, which brought more color and variety of color to Europe. In addition to being multi-varied and extraordinarily intense, these new dyes were notoriously unstable, rapidly fading and turning when exposed to sunlight, washing, and other chemical or physical agents. This led to new systems of categorization and study of colorants, which in turn lead to
4165-433: The invention of industrial research and development laboratories in the 1870s, and the new awareness of empirical chemical formulas as targets for synthesis by academic chemists. The dye industry became one of the first instances where directed scientific research lead to new products, and the first where this occurred regularly. Colorants can be divided into pigments and dyes . Broadly, dyes are soluble and become fixed to
4250-456: The largest manufacturer of vat dyes, sold it as Indanthren Blue RS , along with the synthetic indigo they placed on the market in 1897. Allegedly James Morton , a leader in England's textile industry, was out walking when he saw some tapestries he produced using aniline dyes had already faded, despite only recently being put on display. He was so dismayed that he began to have dye samples exposed to
4335-482: The largest number of dyes sold in the market fell into the class of azo dyes. 1885, an azo-naphthol, Para-red , became the first water-insoluble organic pigment not containing acidic or basic groups. The twentieth century was again characterized by increases in scope and scale of chemical production. Pigments like cadmium selenide , manganese blue , molybdenum red, and bismuth vanadate were synthesized. High purity titanium dioxide and zinc oxide were produced for
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#17331250175584420-434: The long-wave side, towards azure . Other modern color scientists , such as Bohren and Clothiaux (2006), and J.W.G. Hunt (1980), divide the spectrum between violet and blue at about 450 nm, with no hue specifically named indigo. Towards the end of the 20th century, purple colors also became referred to as "indigo". In the 1980s, computer programmers Jim Gettys , Paul Ravelling, John C. Thomas and Jim Fulton produced
4505-569: The market. On January 1, 1868, there were 52 producers of aniline dyes. Members of enlightened scientific societies from all over Europe competed for expertise and authority with dyers and printers in factories and workshops. Many soluble salts of acid dyes synthesized for textile-related purposes were transformed into insoluble salts or lake pigments by reaction with water-soluble salts of calcium, barium or lead, whereas basic dyes were treated with tannins or antimony potassium tartrate to yield pigments. The development of synthetic alizarin opened up
4590-514: The mid nineteenth century, the coal tar industry, particularly in England, produced the precursors needed for a large amount of organic syntheses, in large quantities. For the first eight years after the first marketable synthetic dye, Mauveine , until the middle of the 1860s, British and French firms were the major dye producers. The second half of the 1860s saw German dye works surpassing their competition in both capacity and market share. During 1870, German firms were responsible for roughly half of
4675-457: The modern word indigo . In early Europe the main source was from the woad plant Isatis tinctoria , also known as pastel. For a long time, woad was the main source of blue dye in Europe. Woad was replaced by "true indigo", as trade routes opened up. Plant sources have now been largely replaced by synthetic dyes . Spanish explorers discovered an American species of indigo and began to cultivate
4760-461: The name indigo has since that time been strongly associated with purple or violet. Spacey writes, "As such, a few programmers accidentally repurposed a color name that was known to civilisations for thousands of years." The Crayola company released an indigo crayon in 1999, with the Crayola website using the hex code #4F49C6 to approximate the crayon color . The 2001 iron indigo crayon
4845-532: The natural alkaloid quinine. He tried adding aniline – a different base with a simpler construction. This created a black product. After purification, drying and washing with alcohol, Perkin had a mauve dye. Perkin filed his patent in August 1856 and a new dye industry was born. He at first called his discovery Tyrian Purple evoking the value of the ancient, highly expensive, pigment. Other names include aniline purple and Perkin's mauve. Rather than one homogenous molecule,
4930-412: The nineteenth century were cobalt blue , Scheele's green, and chrome yellow . The availability of sulphuric and sulfurous acids facilitated further experiments, leading to the isolation of alizarin and purpurin in 1826. Madder based pigments such as Brown Madder (obtained in 1840) were developed due to research by British and German chemists into Turkey red , also known as Rouge d’Andrinopole. In
5015-422: The now-defunct Sinclair Paints company, resulting in the color list for version X11 of the operating system containing fanciful color names such as "papaya whip", "blanched almond" and "peach puff". The database was also criticised for its many inconsistencies, such as "dark gray" being lighter than "gray", and for the color distribution being uneven, tending towards reds and greens at the expense of blues. In
5100-664: The observer. Indigo dye is a blue color, obtained from several different types of plants. The indigo plant ( Indigofera tinctoria ) often called "true indigo" probably produces the best results, although several others are close in color: Japanese indigo (Polygonum tinctoria), Natal indigo ( Indigofera arrecta ), Guatemalan indigo ( Indigofera suffruticosa ), Chinese indigo ( Persicaria tinctoria ), and woad Isatis tinctoria . Indigofera tinctoria and related species were cultivated in East Asia , Egypt , India , Bangladesh and Peru in antiquity. The earliest direct evidence for
5185-426: The original mauvine was primarily a mix of four major compounds, mauveine A, mauveine B, mauveine C, and mauveine B2, although there were other mauvine and pseudo mauveines in the dye product. Natural Alizarin was the first colorant to have its structure determined, making it one of the first targets for synthesis. The first synthesis of alizarin was patented by Carl Graebe and Carl Liebermann in 1868. It entailed
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#17331250175585270-495: The path of the synthesis flowed: coal tar → nitrobenzene → aniline → dyes. According to Henry Perkin himself "This industry holds an [ sic ] unique position in the history of chemical industries, as it was entirely the outcome of scientific research." The first synthetic dye was picric acid . It was prepared in a laboratory in 1771, and commercially produced by M. Guinon in Lyon in 1845. It dyed silk fabric yellow; however
5355-574: The product in Guatemala . The English and French subsequently began to encourage indigo cultivation in their colonies in the West Indies . In North America, indigo was introduced by Eliza Lucas into colonial South Carolina, where it became the colony's second-most important cash crop (after rice). Before the Revolutionary War , indigo accounted for more than one-third of the value of exports from
5440-651: The red pigment vermilion ( mercury sulphide ), the yellow orpiment ( arsenic trisulphide ), the green malachite ( basic copper carbonate ) and the blue lapis lazuli (natural ultramarine ). Natural sources of white pigments include chalk and kaolin , while black pigments are often obtained as charcoal and as soot . In ancient times, through the Industrial Revolution , various inorganic pigments like Egyptian Blue were synthesized, many with toxic chemicals like arsenic and antimony. These toxic pigments were used for cosmetics and painting. In ancient Egypt , blue
5525-409: The robes of Mary because of the pigment's great expense, until the work of Jean-Baptiste Guimet and Christian Gmelin made it commercially available in larger, cheaper quantities. At the beginning of the eighteenth century, the first products of the fledgling color industry were Prussian blue and Naples yellow . The first synthetically produced white pigment was white lead ( lead carbonate ). It
5610-757: The spectrum. Synthetic dyes A colorant is any substance that changes the spectral transmittance or reflectance of a material. Synthetic colorants are those created in a laboratory or industrial setting. The production and improvement of colorants was a driver of the early synthetic chemical industry, in fact many of today's largest chemical producers started as dye-works in the late 19th or early 20th centuries, including Bayer AG (1863). Synthetics are extremely attractive for industrial and aesthetic purposes as they have they often achieve higher intensity and color fastness than comparable natural pigments and dyes used since ancient times. Market viable large scale production of dyes occurred nearly simultaneously in
5695-510: The structure of their dyes and published his findings. This caused another rapid expansion, particularly in Germany. Between 1877 and 1887, 130 German patents for azo dyes were filed and 105 new dyes made it to market. It also lead to a difference in how chemical companies interacted with consumers. German dye firms developed in-house marketing and distribution capabilities coordinated directly with their research and development departments. Paul Schützenberger , in response to what he had seen at
5780-431: The subtractive colors to the additive colors in the two primary color charts in the article on primary colors to see the distinction between electric colors as reproducible from light on a computer screen (additive colors) and the pigment colors reproducible with pigments (subtractive colors); the additive colors are significantly brighter because they are produced from light instead of pigment. Web color indigo represents
5865-568: The sun to check for light-fastness. He then employed a Scottish chemist named John Christie to synthesize dyes based on the chemical structures that were more stable to sunlight, and began to market the dyes in his products as fast dyes , or sundour , which can translate to "hard to move" in Scots. Synthetic dyes were now produced in Britain, Germany, France, the US, Switzerland, Russia, the Austrian Empire,
5950-399: The synthesis of more color-fast modern colorants. Synthetic colors found themselves in not only dyes and paints but also inks and foodstuffs, permeating consumer culture. In ancient cave paintings natural manganese oxide and charcoal were used for black shades and iron oxides for yellow, orange, and red color tones. Examples of similar earth pigments that persisted to more modern times are
6035-577: The time of the French Revolution , as a replacement for the white uniforms previously worn by the Royal infantry regiments. In 1806, Napoleon decided to restore the white coats because of shortages of indigo dye imposed by the British continental blockade. However, the greater practicability of the blue color led to its retention, and indigo remained the dominant color of French military coats until 1914. In
6120-448: The traditional colors of the rainbow, the order of which is given by the mnemonics "Richard of York gave battle in vain" and Roy G. Biv . James Clerk Maxwell and Hermann von Helmholtz accepted indigo as an appropriate name for the color flanking violet in the spectrum. Later scientists concluded that Newton named the colors differently from current usage. According to Gary Waldman, "A careful reading of Newton's work indicates that
6205-459: The traditional indigo and violet. This is the brightest color indigo that can be approximated on a computer screen; it is a color located between the (primary) blue and the color violet of the RGB color wheel. The web color blue violet or deep indigo is a tone of indigo brighter than pigment indigo, but not as bright as electric indigo. Listed below are several indigo hues, some of which have included
6290-428: The truest confines of them to be, whilst I held the paper so, that the said image might fall within a certain compass marked on it. And this I did, partly because my own eyes are not very critical in distinguishing colours, partly because another, to whom I had not communicated my thoughts about this matter, could have nothing but his eyes to determine his fancy in making those marks. Indigo is therefore counted as one of
6375-584: The use of indigo dates to around 4000 BC and comes from Huaca Prieta , in contemporary Peru. Pliny the Elder mentions India as the source of the dye after which it was named. It was imported from there in small quantities via the Silk Road . The Ancient Greek term for the dye was Ἰνδικὸν φάρμακον ( indikon pharmakon , "Indian dye "), which, adopted to Latin as indicum (a second declension noun) or indico (oblique case) and via Portuguese , gave rise to
6460-435: The water turns blue. The blue pigment settles as sediment at the bottom of the tub. The sediment is scooped out and stored. When dyeing cloth, the pigment is then boiled in a vat of water; the cloth (usually made from yarns of hemp ) is inserted into the vat for absorbing the dye. After hanging out to dry, the boiling process is repeated as often as needed to produce a darker color. In a RGB color space , "Indigo(color wheel)"
6545-423: The way the color indigo was always reproduced in pigments, paints, or colored pencils in the 1950s. By the 1970s, because of the advent of psychedelic art , artists became accustomed to brighter pigments. Pigments called "bright indigo" or "bright blue-violet" (the pigment equivalent of the electric indigo reproduced in the section above) became available in artists' pigments and colored pencils. 'Tropical Indigo'
6630-559: The word "indigo", with the adoption of HTML color names in the World Wide Web era. Indigo dye is a greenish dark blue color, obtained from either the leaves of the tropical Indigo plant ( Indigofera ), or from woad ( Isatis tinctoria ), or the Chinese indigo ( Persicaria tinctoria ). Many societies make use of the Indigofera plant for producing different shades of blue. Cloth that
6715-466: The world's production of dyes and pigments. Aniline dyes were produced at scale, in part because of many advances in the synthesis of their precursors. Antione Bechamp described a process for reducing nitrobenzene to aniline in 1854, known as the Bechamp Process , making the production of aniline easy. Widespread isolation of phenol from coal tar, made its nitration more economical, generally
6800-832: Was awarded the patent in England. Colorants function through selective electromagnetic absorbance in the visible spectrum . A given pigment or dye molecule absorbs different wavelengths of electromagnetic radiation according to its atomic structure and local chemical environment. The quantum behavior of a chemical typically results in distinct resonant frequencies of chemical bonds, which can be excited best by discrete wavelengths—meaning broad spectrum radiation has its spectra changed via absorption upon interaction. The physical shape, size, organization, and concentration of dyes and pigments can also drastically affect observed color. Pigments are particularly susceptible to altered appearances based on physical properties. Most modern synthetic dye molecules contain two components. The first part
6885-523: Was considered the color of the divine. As a result, the early synthetic compound Egyptian Blue, became an incredibly important pigment. It was used for the depiction of eyes, hair and decoration in the graphic representation of pharaohs. Blue, particularly ultramarine pigment made from ground lapis lazuli remained significant for depictions of the divine through the Renaissance . Pre-industrial revolution painters in Europe used ultramarine almost exclusively for
6970-546: Was crucial in this process. These conditions became possible due to price drops in reagents due to new industrial preparations like the LeBlanc process , where potassium carbonate formerly obtained from ashes was replaced by sodium carbonate. However, many early colorants are no longer produced due to economics, or high toxicity, for example Schweinfurt green (cupric acetate arsenite), Scheele's green (copper(II) arsenite), and Naples yellow (lead antimonate). The late 1850s saw
7055-575: Was driven by the textile industry, which employed new designs requiring the colorful aniline dyes. Even Hofmann, who had at first criticized his student for leaving his academic research of quinine, later synthesized his own aniline dye, rosaniline. In 1858 the German chemist Johann Peter Griess obtained a yellow dye by reacting nitrous acid with aniline. It didn't last commercially, but it created even more interest in aniline as precursor for colorful compounds. French chemist François-Emmanuel Verguin reacted aniline with stannic chloride to yield fuchsine ,
7140-675: Was known in Roman times. Around 1800, more inorganic white pigments were developed including zinc white ( zinc oxide ) was developed, followed by antimony white ( antimony oxide ) and zinc sulfide . The printers and dyers at that time had access to lead acetate , alum , copper acetate , nitric acid , ammonia and ammonium chloride , potassium carbonate , potassium tartrate , gallic acid , gums , bleaching lyes , hydrochloric acid , sulfuric acid , carbonates , sulfates , and acetates. Small scale workshops evolved into ever larger and larger manufactories. Other inorganic pigments developed in
7225-754: Was perturbed by WW1, however, and the chemical industry of the United States of America in particular expanded rapidly, although Germany always remained a major player. Through 1914, the US dye market was dominated by German imports, there were only a few small companies and German subsidiaries. With WW1, however, German dye factories now had to switch to making explosives and German shipping was cut off by British blockades. Prices quickly went up and U. S. companies built plants to meet demand. American pharmaceutical giants, even at that time, like Dow , DuPont , and others began to produce dyes and were extremely successful with simple sulphur and vat dyes. Dow Chemical developed
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