ULTRAMARINE BLUE PIGMENT

Synthetic Ultramarine Blue Pigment, being very cheap, is used for wall painting, the printing of paper hangings, and calico. 
Ultramarine Blue Pigment was often used for the robes of the Virgin Mary and symbolized holiness and humility. 
Ultramarine Blue Pigment can be used in acrylic, oil, tempera, watercolor and gouache. 

CAS Number: 57455-37-5
EC Number: 209-144-0
Molecular Formula: Na₈Al₆Si₆O₂₄S₂ / Al6Na8O24S3Si6

SYNONYMS:
Ultramarine Blue, Azure blue, 57455-37-5, UNII-I39WR998BI, I39WR998BI, C. I. 77007, Lazurite, Ultramarine, LAZURITE [MI], ULTRAMARINE [MI], 3516 ULTRA BLUE, 3522 ULTRA BLUE, ULTRAMARINE (MINERAL), IRERQBUNZFJFGC-UHFFFAOYSA-L, ULTRAMARINE BLUE (MINERAL), ULTRAMARINE BLUE CI 77007, AKOS032950034, ALUMINUM SODIUM THIOSILICATE BLUE, LAZURITE (NA5(AL3(SIO4)3S), LAZURITE (CA2NA6(AL6(SIO4)6(SO4)S), Q219660

Ultramarine Blue Pigment is a deep blue color pigment which was originally made by grinding lapis lazuli into a powder.
Ultramarine Blue Pigment's lengthy grinding and washing process makes the natural pigment quite valuable—roughly ten times more expensive than the stone it comes from and as expensive as gold.

The name Ultramarine Blue Pigment comes from the Latin ultramarinus. 
The word means 'beyond the sea', as the pigment was imported by Italian traders during the 14th and 15th centuries from mines in Afghanistan.
Much of the expansion of Ultramarine Blue Pigment can be attributed to Venice which historically was the port of entry for lapis lazuli in Europe.

Ultramarine Blue Pigment was the finest and most expensive blue used by Renaissance painters. 
Ultramarine Blue Pigment was often used for the robes of the Virgin Mary and symbolized holiness and humility. 
It remained an extremely expensive pigment until a synthetic Ultramarine Blue Pigment was invented in 1826.

Ultramarine Blue Pigment is a permanent pigment when under ideal preservation conditions. 
Otherwise, Ultramarine Blue Pigment is susceptible to discoloration and fading.
Ultramarine Blue Pigment is famous for its characteristic bright blue color. 

Ultramarine Blue Pigment can be used in acrylic, oil, tempera, watercolor and gouache. 
Ultramarine Blue Pigment has been obtained synthetically since 1829. 
Previously, real Ultramarine Blue Pigment was a distinct luxury product because it was extracted from the semi-precious stone lapis lazuli. 

Lapis lazuli is still as precious as gold even today.
Ultramarine Blue Pigment is a blue pigment consisting primarily of a zeolite-based mineral containing small amounts of sulfur. 
Ultramarine Blue Pigment is one of the most complex of the mineral pigments, composed of the blue mineral lazurite, which is the major component of the rare and semi-precious stone lapis lazuli.

The mineral occurs in nature as a product of limestone metamorphism. 
Ultramarine Blue Pigment is typically associated with calcite, pyrite, diopside, humite, forsterite, hauyne, and muscovite minerals, sometimes found in lava as a by-product of volcanic eruptions. 

The story of Ultramarine Blue Pigment in art is as deep and captivating as the color itself. 
Ultramarine Blue Pigment, known for its rich and luminous hue, has been a symbol of beauty and prestige for centuries. 

Originating from the precious lapis lazuli stone, Ultramarine Blue Pigment was once more valuable than gold. 
Artists coveted it for its unparalleled depth and brilliance, making it a marker of wealth and status in paintings. 
The journey of Ultramarine Blue Pigment, from remote mines to Renaissance and modern studios, reflects a fascinating interplay of art, history, and science.

USES and APPLICATIONS of ULTRAMARINE BLUE PIGMENT:
Synthetic Ultramarine Blue Pigment, being very cheap, is used for wall painting, the printing of paper hangings, and calico. 
Ultramarine Blue Pigment also is used as a corrective for the yellowish tinge often present in things meant to be white, such as linen and paper. 
Bluing or "laundry blue" is a suspension of synthetic Ultramarine Blue Pigment, or the chemically different Prussian blue, that is used for this purpose when washing white clothes. 

Ultramarine Blue Pigment is often found in makeup such as mascaras or eye shadows.
Large quantities are used in the manufacture of paper, and especially for producing a kind of pale blue writing paper which was popular in Britain.

During World War I, the RAF painted the outer roundels with a color made from Ultramarine Blue Pigment. 
This became BS 108(381C) aircraft blue. 
Ultramarine Blue Pigment was replaced in the 1960s by a new color made on phthalocyanine blue, called BS110(381C) roundel blue

Ultramarine Blue Pigment was often used for the robes of the Virgin Mary and symbolized holiness and humility. 
Ultramarine Blue Pigment can be used in acrylic, oil, tempera, watercolor and gouache. 

NOTABLE USES OF ULTRAMARINE BLUE PIGMENT IN ART:
As noted by Merimee, a chemist and paint technologist of the same period, Guimet, upon successfully synthesizing Ultramarine Blue Pigment, promptly distributed samples of this pigment to several artists. 
Merimee’s accounts include a notable usage by Ingres, who employed Guimet’s synthetic Ultramarine Blue Pigment in the drapery of a key figure in his work “The Apotheosis of Homer.” 

This artwork, part of the ceiling decoration in the Musee Charles X at the Louvre, is both signed and dated 1827. 
This date is particularly significant as it predates Guimet’s official presentation of his findings to the Societe d’Encouragement pour l’Industrie Nationale by a year.

August Renior made extensive use of synthetic Ultramarine Blue Pigment in the second stage of painting (c.1886) Les Parapluies. 
The first stage of the composition (c.1881) contains exclusively cobalt blue. 

For example, large amounts of synthetic Ultramarine Blue Pigment were used in the child’s coat to the right edge of the picture.
In the deepest blues and specific samples of mixed green, Vincent van Gogh used synthetic Ultramarine Blue Pigment in the Cornfield with Cypresses.

SUSTAINABILITY AND PRODUCTION OF ULTRAMARINE BLUE PIGMENT:
A significant byproduct of this chemical reaction is sulfur dioxide. 
Consequently, flue gas desulfurization becomes a necessary part of the manufacturing process to adhere to environmental regulations. 
Historically, large chimneys were employed to disperse the sulfur dioxide produced during production. 

This often led to the Ultramarine Blue Pigment tinting of nearby ground surfaces and roof vents, a telltale sign of the pigment’s presence and production.
The sustainable production of Ultramarine Blue Pigment is a growing concern in the art world. 

Environmentally friendly methods of synthesizing the pigment are being explored, ensuring that the legacy of Ultramarine Blue Pigment is preserved without compromising the health of our planet. 
These efforts highlight the art community’s commitment to eco-conscious practices, ensuring that Ultramarine Blue Pigment remains a pigment for future generations.

DIFFERENCES BETWEEN NATURAL AND SYNTHETIC ULTRAMARINE BLUE PIGMENT:
Natural Ultramarine Blue Pigment consists of large particles of blue lazurite combined with accessory minerals, such as calcite and silica (seen as transparent edges or particles in the photomicrograph). 
Synthetic Ultramarine Blue Pigment offers a more intense blue compared to its natural counterpart. 

This is attributed to the smaller and more uniform particle size in the synthetic variant, which allows for a more consistent diffusion of light. 
Remarkably stable, Ultramarine Blue Pigment's color remains unaffected by light and, when used in oil or fresco. 

However, exposure to weak acid causes Ultramarine Blue Pigment to bleach rapidly, releasing hydrogen sulfide in the process. 
Interestingly, adding even a modest amount of zinc oxide, particularly to the reddish variants of Ultramarine Blue Pigment, markedly reduces the intensity of the color, demonstrating the pigment’s sensitivity to chemical alterations.

PROPERTIES OF ULTRAMARINE BLUE PIGMENT:
Ultramarine Blue Pigment exhibits surprisingly effective covering capabilities, exceeding expectations given its low refractive index. 
When used in oil, Ultramarine Blue Pigment serves as a semi-transparent glazing color. 

Its tinting power is considerable, surpassing older blue pigments like azurite or smalt, though Ultramarine Blue Pigment doesn’t quite match the intensity of modern phthalocyanine blues. 

Ultramarine Blue Pigment retains its distinct, vibrant blue hue when mixed with water-based media, such as gum acacia or egg tempera. 
However, due to its low refractive index in oil mediums, Ultramarine Blue Pigment tends to appear as a much darker blue when applied in thick layers. 

For optimal results in oil, Ultramarine Blue Pigment is either blended with a white pigment to create a luminous opaque blue or applied as a sheer glazing layer atop a lighter underpainting.

Synthetic Ultramarine Blue Pigment absorbs a moderate to high amount of oil (38 to 42 grams of linseed oil per 100 grams of pigment), which may slow the drying of oil paint and hence is a slow-drying oil color. 

(The oil absorption value is the weight in grams of refined linseed oil required to convert 100 grams of dry Ultramarine Blue Pigment by the rubbing together to a coherent mass, which will not smear the glass plate on which it has been rubbed with a palette knife.) 

Ultramarine Blue Pigment is a highly refractive pigment and is difficult to grind in oil because of its poor wetting properties in oil, although it easily disperses in water.

MODERN HISTORY OF SYNTHETIC ULTRAMARINE BLUE PIGMENT:
The genesis of synthetic Ultramarine Blue Pigment can be traced back to the observations of Johann Wolfgang von Goethe. 
Around 1787, Goethe noted the presence of blue deposits on the walls of lime kilns near Palermo, Sicily. 

He recognized these glass-like deposits as a potential alternative to lapis lazuli for ornamental purposes, although he did not comment on their viability as a grindable pigment.

The path to synthetic Ultramarine Blue Pigment gained momentum in 1814 when Tassaert observed the spontaneous formation of a blue substance in a lime kiln at Saint-Gobain. 
This substance bore a striking resemblance to Ultramarine Blue Pigment. 

This discovery prompted the Societé pour l’Encouragement d’Industrie in 1824 to announce a reward for the successful synthetic replication of this esteemed color. 

This challenge was met by Jean Baptiste Guimet in 1826 and Christian Gmelin in 1828, the latter a professor of chemistry at Tübingen. 
While Guimet kept his method confidential, Gmelin openly published his technique, laying the groundwork for the synthetic Ultramarine Blue Pigment industry.

THE MAKING OF ULTRAMARINE BLUE PIGMENT: TRADITIONAL AND MODERN TECHNIQUES
The traditional method of creating Ultramarine Blue Pigment was labor-intensive and expensive, involving heating lapis lazuli with wax, resin, and linseed oil. 
Modern synthetic production of Ultramarine Blue Pigment, developed in the early 19th century, has made this once-elusive pigment accessible to all artists. 

This democratization of Ultramarine Blue Pigment has expanded its use beyond the elite circles of the past, allowing a broader range of artists to explore its rich potential.
In the production of Ultramarine Blue Pigment, selecting raw materials is crucial. 

This includes iron-free kaolin or a similar pure clay, which ideally should have a silica and alumina content close to the ratio SiO2:Al2O3 as found in perfect kaolin. 
Should there be a lack of silica, Ultramarine Blue Pigment is compensated for by adding a precise amount of finely divided silica.

The other vital components are:
Anhydrous sodium sulfate (Na2SO4);
Anhydrous sodium carbonate (Na2CO3);
Finely ground sulfur;
Charcoal powder, or alternatively, ash-free coal or colophony in solid form.

The manufacturing process unfolds in several stages. 
Initially, the mixture undergoes heating in an enclosed furnace at temperatures ranging from 700° to 750° Celsius. 

This environment, enriched with sulfur, carbon, and organic materials, creates reducing conditions, forming a yellow-green intermediate, sometimes used as a pigment.

In the subsequent phase, this intermediate product is exposed to air or sulfur dioxide at temperatures between 350° and 450° Celsius. 
This step is crucial for oxidizing sulfide sulfur into S2 and Sn chromophore molecules, responsible for the pigment’s final blue (or sometimes purple, pink, or red) hue.

The production of Ultramarine Blue Pigment with low silica content involves melting a blend of soft clay, sodium sulfate, charcoal, sodium carbonate, and sulfur. 

Initially, the mixture appears white but transforms into “green ultramarine” upon adding sulfur and applying heat. 
During this process, the sulfur combusts, yielding a fine blue pigment. 

In contrast, “ultramarine rich in silica” is typically produced by heating a concoction of pure clay, extremely fine white sand, sulfur, and charcoal in a muffle furnace. 
This method produces a blue pigment, though occasionally with a red hue.

Post-reactive heating in a kiln, often in brick-sized quantities, the resultant solid matter is then pulverized and subjected to a washing process, typical of most insoluble pigment manufacturing. 

The various shades of Ultramarine Blue Pigment, including green, blue, red, and violet, undergo grinding and are subsequently washed with water to achieve the desired purity and texture.

TERMINOLOGY OF ULTRAMARINE BLUE PIGMENT:
Ultramarine Blue Pigment is a blue made from natural lapis lazuli, or its synthetic equivalent which is sometimes called "French Ultramarine".
More generally "Ultramarine Blue Pigment" can refer to a vivid blue.

The term Ultramarine Blue Pigment can also refer to other pigments. 
Variants of the pigment such as "ultramarine red," "ultramarine green," and "ultramarine violet" all resemble ultramarine with respect to their chemistry and crystal structure.

The term "ultramarine green" indicates a dark green while barium chromate is sometimes referred to as "ultramarine yellow".
Ultramarine Blue Pigment has also been termed "Gmelin's Blue," "Guimet's Blue," "New blue," "Oriental Blue," and "Permanent Blue"

ORIGIN OF THE NAME ULTRAMARINE BLUE PIGMENT:
The term “ultramarine” is derived from the Latin word ultramarinus, signifying “beyond the sea.” 
This name reflects the pigment’s exotic origins in Afghanistan, as it was brought to Italy by merchants during the 14th and 15th centuries from far-off mines in Afghanistan. 

The spread and popularity of ultramarine are primarily credited to the city of Venice, which, in historical times, served as the principal European gateway for the import of lapis lazuli, the source of this esteemed blue pigment.

THE SOURCE OF ULTRAMARINE BLUE PIGMENT: UNDERSTANDING ITS UNIQUE COLOR
The deep color of Ultramarine Blue Pigment lies in its complex chemistry. 
At its core, Ultramarine Blue Pigment is a sodium aluminum silicate with sulfur impurities, which give its distinctive blue color. 

Ultramarine Blue Pigment is one of the most complex mineral pigments, a sulfur-containing compound of sodium-silicate, essentially a mineralized limestone containing a blue cubic mineral called lazurite (the major component of lapis lazuli). 

Lazurite is the blue component of the decorative rock lapis lazuli, which is composed of many minerals—calcite, pyrite, sodalite, and others—that have been mined as a precious stone for some 9,000 years. 
The Dana System of Mineralogy considered lapis lazuli to be the dark blue crystals in this rock, but these were renamed lazurite in 1891.

The Colour Index designation of ultramarine is Pigment Blue 29, and the Colour Index number is 77007. 
The term ultramarine designates both the natural mineral and the synthetic pigment, although today, most distinguish the natural mineral by its name, lazurite, or the rock containing it, lapis lazuli.

THE HISTORY OF ULTRAMARINE BLUE PIGMENT:
Lapis lazuli, known since ancient Egyptian times as a semi-precious stone and for decorative purposes, was first documented as a painting pigment in sixth and seventh-century A.D. wall paintings in the Bamiyan caves of Afghanistan, close to the primary source of the mineral. 

Further usage was identified in Persian miniatures from the 13th and 14th centuries and Chinese paintings from the 10th to 11th centuries. 
Indian mural paintings from the 11th, 12th, and 17th centuries also featured natural ultramarine. 

In Europe, its most extensive use was during the 14th to mid-15th centuries, particularly in illuminated manuscripts and Italian panel paintings, where its brilliance complemented vermilion and gold. 

Due to its high cost and labor-intensive extraction process, ultramarine was as expensive as gold, often specified in painting contracts, with patrons sometimes supplying the pigment.

Ultramarine was primarily reserved for the robes of Christ and the Virgin in 14th- to 16th-century artworks, indicating its value and the status of the artist and commission. 

In some instances, less costly pigments like azurite or even carbon black were used for underpainting, as seen in Byzantine wall paintings and polychrome sculptures. 

Traditional blue pigments, including indigo, were also used as underlayers for ultramarine.
While Italy used ultramarine lavishly, its use was less extensive in Northern Europe. 

Azurite was more common in German and Early Netherlandish Schools, with ultramarine used mainly for iconographically significant figures or as a glaze. 
The late 16th and 17th centuries saw a shortage of azurite, increasing the demand for costly ultramarine. 

Outside Italy, its scarcity was notable, with minimal usage even among wealthy Spanish painters of the time.
Counterfeiting and adulteration of ultramarine were common, given its costliness. 

In terms of color mixing, its slightly violet-blue hue made it preferable for creating purples, either through physical mixing with crimson lake pigments or by layering glazes of ultramarine and crimson. 
Despite these challenges, the use of ultramarine in historical paintings predominantly remains pure, mixed only with white to retain its unique hue.

NATURAL PRODUCTION OF ULTRAMARINE BLUE PIGMENT:
Historically, lapis lazuli stone was mined in Afghanistan and shipped overseas to Europe.
A method to produce Ultramarine Blue Pigment from lapis lazuli was introduced and later described by Cennino Cennini in the 15th century. 

This process consisted of grinding the lapis lazuli mineral, mixing the ground material with melted wax, resins, and oils, wrapping the resulting mass in a cloth, and then kneading Ultramarine Blue Pigment in a dilute lye solution, a potassium carbonate solution prepared by combining wood ash with water. 
The blue lazurite particles collect at the bottom of the pot, while the colorless crystalline material and other impurities remain at the top. 

This process was performed at least three times, with each successive extraction generating a lower quality material. 
The final extraction, consisting largely of colorless material as well as a few blue particles, brings forth Ultramarine Blue Pigment ash which is prized as a glaze for its pale blue transparency.

This extensive process was specific to Ultramarine Blue Pigment because the mineral it comes from has a combination of both blue and colorless pigments. 
If an artist were to simply grind and wash lapis lazuli, the resulting powder would be a greyish-blue color that lacks purity and depth of color since lapis lazuli contains a high proportion of colorless material.

Although the lapis lazuli stone itself is relatively inexpensive, the lengthy process of pulverizing, sifting, and washing to produce Ultramarine Blue Pigment makes the natural pigment quite valuable and roughly ten times more expensive than the stone it comes from. 

The high cost of the imported raw material and the long laborious process of extraction combined has been said to make high-quality Ultramarine Blue Pigment as expensive as gold.

SYNTHETIC PRODUCTION OF ULTRAMARINE BLUE PIGMENT:
In 1990, an estimated 20,000 tons of Ultramarine Blue Pigment were produced industrially. 
The raw materials used in the manufacture of synthetic Ultramarine Blue Pigment are the following:
*white kaolin,
*anhydrous sodium sulfate (Na2SO4),
*anhydrous sodium carbonate (Na2CO3),
*powdered sulfur,
*powdered charcoal or relatively ash-free coal, or colophony in lumps.

The preparation is typically made in steps:
The first part of the process takes place at 700 to 750 °C in a closed furnace, so that sulfur, carbon and organic substances give reducing conditions. 
This yields a yellow-green product sometimes used as a pigment.

In the second step, air or sulfur dioxide at 350 to 450 °C is used to oxidize sulfide in the intermediate product to S2 and Sn chromophore molecules, resulting in the blue (or purple, pink or red) pigment.
The mixture is heated in a kiln, sometimes in brick-sized amounts.

The resultant solids are then ground and washed, as is the case in any other insoluble pigment's manufacturing process; the chemical reaction produces large amounts of sulfur dioxide. 
(Flue-gas desulfurization is thus essential to its manufacture where SO2 pollution is regulated.)

Ultramarine Blue Pigment poor in silica is obtained by fusing a mixture of soft clay, sodium sulfate, charcoal, sodium carbonate, and sulfur. 
The product is at first white, but soon turns green "green ultramarine" when it is mixed with sulfur and heated. 
The sulfur burns, and a fine blue pigment is obtained. 

Ultramarine Blue Pigment rich in silica is generally obtained by heating a mixture of pure clay, very fine white sand, sulfur, and charcoal in a muffle furnace. 

A blue product, Ultramarine Blue Pigment, is obtained at once, but a red tinge often results. 
The different ultramarines—green, blue, red, and violet—are finely ground and washed with water.

Synthetic Ultramarine Blue Pigment is a more vivid blue than natural ultramarine, since the particles in synthetic ultramarine are smaller and more uniform than the particles in natural ultramarine and therefore diffuse light more evenly.

Ultramarine Blue Pigment's color is unaffected by light nor by contact with oil or lime as used in painting. 
Hydrochloric acid immediately bleaches Ultramarine Blue Pigment with liberation of hydrogen sulfide. 

Even a small addition of zinc oxide to the reddish varieties especially causes a considerable diminution in the intensity of the color.
Modern, synthetic Ultramarine Blue Pigment is a non-toxic, soft pigment that does not need much mulling to disperse into a paint formulation

STRUCTURE AND CLASSIFICATION OF ULTRAMARINE BLUE PIGMENT:
Ultramarine Blue Pigment is the aluminosilicate zeolite with a sodalite structure. Sodalite consists of interconnected aluminosilicate cages. 
Some of these cages contain polysulfide (Sn−x) groups that are the chromophore (color centre). 
The negative charge on these ions is balanced by Na+ ions that also occupy these cages.
The chromophore is proposed to be S−4 or S4.

HISTORY OF ULTRAMARINE BLUE PIGMENT:
Antiquity and Middle Ages
The name derives from Middle Latin ultramarinus, literally "beyond the sea" because it was imported from Asia by sea.
In the past, it has also been known as azzurrum Ultramarine Blue Pigment, azzurrum transmarinum, azzuro oltramarino, azur d'Acre, pierre d'azur, Lazurstein. 

The current terminology for Ultramarine Blue Pigmentincludes natural ultramarine (English), outremer lapis (French), Ultramarin echt (German), oltremare genuino (Italian), and ultramarino verdadero (Spanish). 
The first recorded use of Ultramarine Blue Pigment as a color name in English was in 1598.

The first noted use of lapis lazuli as a pigment can be seen in 6th and 7th-century paintings in Zoroastrian and Buddhist cave temples in Afghanistan, near the most famous source of the mineral.

Lapis lazuli has been identified in Chinese paintings from the 10th and 11th centuries, in Indian mural paintings from the 11th, 12th, and 17th centuries, and on Anglo-Saxon and Norman illuminated manuscripts from c. 1100.

Ancient Egyptians used lapis lazuli in solid form for ornamental applications in jewelry, however, there is no record of them successfully formulating lapis lazuli into paint.

Archaeological evidence and early literature reveal that lapis lazuli was used as a semi-precious stone and decorative building stone from early Egyptian times. 

The mineral is described by the classical authors Theophrastus and Pliny. 
There is no evidence that lapis lazuli was used ground as a painting pigment by ancient Greeks and Romans. 

Like ancient Egyptians, they had access to a satisfactory blue colorant in the synthetic copper silicate pigment, Egyptian blue.
Renaissance
Venice was central to both the manufacturing and distribution of Ultramarine Blue Pigment during the early modern period. 

The pigment was imported by Italian traders during the 14th and 15th centuries from mines in Afghanistan.
Other European countries employed Ultramarine Blue Pigment less extensively than in Italy; the pigment was not used even by wealthy painters in Spain at that time.

During the Renaissance, Ultramarine Blue Pigment was the finest and most expensive blue that could be used by painters. 
Color infrared photogenic studies of Ultramarine Blue Pigment in 13th and 14th-century Sienese panel paintings have revealed that historically, ultramarine has been diluted with white lead pigment in an effort to use the color more sparingly given its high price.

The 15th century artist Cennino Cennini wrote in his painters' handbook: "Ultramarine Blue Pigment is a glorious, lovely and absolutely perfect pigment beyond all the pigments. 
It would not be possible to say anything about or do anything to it which would not make it more so."

Natural Ultramarine Blue Pigment is a difficult pigment to grind by hand, and for all except the highest quality of mineral, sheer grinding and washing produces only a pale grayish blue powder.

Ultramarine Blue Pigment was most extensively used during the 14th through 15th centuries, as its brilliance complemented the vermilion and gold of illuminated manuscripts and Italian panel paintings. 

Ultramarine Blue Pigment was valued chiefly on account of its brilliancy of tone and its inertness in opposition to sunlight, oil, and slaked lime. 
Ultramarine Blue Pigment is, however, extremely susceptible to even minute and dilute mineral acids and acid vapors. 

Dilute HCl, HNO3, and H2SO4 rapidly destroy the blue color, producing hydrogen sulfide (H2S) in the process. 
Acetic acid attacks the pigment at a much slower rate than mineral acids.

Ultramarine Blue Pigment was only used for frescoes when it was applied secco because frescoes' absorption rate made its use cost prohibitive. 
Ultramarine Blue Pigment was mixed with a binding medium like egg to form a tempera and applied over dry plaster, such as in Giotto di Bondone's frescos in the Cappella degli Scrovegni or the Arena Chapel in Padua.

European artists used Ultramarine Blue Pigment sparingly, reserving their highest quality blues for the robes of Mary and the Christ child, possibly in an effort to show piety, spending as a means of expressing devotion. 

As a result of the high price, artists sometimes economized by using a cheaper blue, azurite, for under painting. 
Most likely imported to Europe through Venice, Ultramarine Blue Pigment was seldom seen in German art or art from countries north of Italy. 
Due to a shortage of azurite in the late 16th and 17th century, the price for the already-expensive Ultramarine Blue Pigment increased dramatically.

17th and 18th centuries
Johannes Vermeer made extensive use of Ultramarine Blue Pigment in his paintings. 
The turban of the Girl with a Pearl Earring is painted with a mixture of Ultramarine Blue Pigment and lead white, with a thin glaze of pure ultramarine over it.

In Lady Standing at a Virginal, the young woman's dress is painted with a mixture of ultramarine and green earth, and Ultramarine Blue Pigment was used to add shadows in the flesh tones.

Scientific analysis by the National Gallery in London of Lady Standing at a Virginal showed that the Ultramarine Blue Pigment in the blue seat cushion in the foreground had degraded and become paler with time; it would have been a deeper blue when originally painted.

19th century (invention of synthetic Ultramarine Blue Pigment)
The beginning of the development of artificial Ultramarine Blue Pigment blue is known from Goethe. 

In about 1787, he observed the blue deposits on the walls of lime kilns near Palermo in Sicily. 
He was aware of the use of these glassy deposits as a substitute for lapis lazuli in decorative applications. 
He did not mention if Ultramarine Blue Pigment was suitable to grind for a pigment.

In 1814, Tassaert observed the spontaneous formation of a blue compound, very similar to Ultramarine Blue Pigment, if not identical with it, in a lime kiln at St. Gobain.

In 1824, this caused the Societé pour l'Encouragement d'Industrie to offer a prize for the artificial production of the precious color. 
Processes were devised by Jean Baptiste Guimet (1826) and by Christian Gmelin (1828), then professor of chemistry in Tübingen. 
While Guimet kept his process a secret, Gmelin published his, and became the originator of the "artificial Ultramarine Blue Pigment" industry.

PERMANENCE OF ULTRAMARINE BLUE PIGMENT:
Easel paintings and illuminated manuscripts have revealed natural Ultramarine Blue Pigment in a perfect state of preservation even though the art may be several centuries old. 
In general, Ultramarine Blue Pigment is a permanent pigment. 

Although it is a sulfur-containing compound from which sulfur is readily emitted as H2S, historically, Ultramarine Blue Pigment has been mixed with lead white with no reported occurrences of the lead pigment blackening to become lead sulfide.

A plague known as "ultramarine sickness" has occasionally been observed among Ultramarine Blue Pigment oil paintings as a grayish or yellowish gray discoloration of the paint surface. 
This can occur with artificial Ultramarine Blue Pigment that is used industrially. 

The cause of this has been debated among experts, however, potential causes include atmospheric sulfur dioxide and moisture, acidity of an oil- or oleo-resinous paint medium, or slow drying of the oil during which time water may have been absorbed, creating swelling, opacity of the medium, and therefore whitening of the paint film.

Both natural and artificial Ultramarine Blue Pigment are stable to ammonia and caustic alkalis in ordinary conditions. 
Artificial Ultramarine Blue Pigment has been found to fade when in contact with lime when it is used to color concrete or plaster. 
These observations have led experts to speculate if the natural pigment’s fading may be the result of contact with the lime plaster of fresco paintings.

STRUCTURE OF ULTRAMARINE BLUE PIGMENT:
Ultramarine Blue Pigment consists primarily of a zeolite-based mineral containing small amounts of polysulfides. 
Ultramarine Blue Pigment occurs in nature as a proximate component of lapis lazuli containing a blue cubic mineral called lazurite. 
In the Colour Index International, the pigment of Ultramarine Blue Pigment is identified as P. Blue 29 77007.

The major component of lazurite is a complex sulfur-containing sodium-silicate (Na8–10Al6Si6O24S2–4), which makes Ultramarine Blue Pigment the most complex of all mineral pigments.
Some chloride is often present in the crystal lattice as well. 
The blue color of Ultramarine Blue Pigment is due to the S−3 radical anion, which contains an unpaired electron.

VISUAL PROPERTIES OF ULTRAMARINE BLUE PIGMENT:
The best samples of Ultramarine Blue Pigment are a uniform deep blue while other specimens are of paler color.
Particle size distribution has been found to vary among samples of Ultramarine Blue Pigment from various workshops. 

Numerous grinding techniques used by painters have resulted in different pigment/medium ratios and particle size distributions. 
The grinding and purification process results in pigment with particles of various geometries. 
Different grades of pigment may have been used for different areas in a painting, a characteristic that is sometimes used in art authentication.

*Shades and variations
International Klein Blue (IKB) is a deep blue hue first mixed by the French artist Yves Klein.

*Electric
Electric Ultramarine Blue Pigment is the tone of ultramarine that is halfway between blue and violet on the RGB (HSV) color wheel, the expression of the HSV color space of the RGB color model.

THE COMPLEX XOMPOSITION OF ULTRAMARINE BLUE PIGMENT:
Ultramarine Blue Pigment is sodium aluminum silicates of the composition Na8Al6Si6O24.Sx(Na-rich) or Na, _yAl6_ySi6+yO.Sx (Si-rich). 
Small sulfur-containing anions (e.g., S3 or S2) are bound as chromospheres in the interstices of the crystal lattice.

Depending on the composition, blue, red, green, or violet pigments can be obtained, the hue being altered by varying the amount of silica. 
Ultramarine Blue Pigment has high heat resistance, but their universal use in paint is limited because of their poor hiding power and weather resistance. 
Special Ultramarine Blue Pigment is coated with silica to reduce ultramarine’s susceptibility to acid and improve its weather resistance.

Synthetic ultramarine is a more vivid blue than natural Ultramarine Blue Pigment because the particles of synthetic ultramarine are more finely divided and uniform and contain fewer impurities than natural ultramarine or lapis lazuli. 

ORIGIN OF THE NAME "ULTRAMARINE"
The name derives from the Middle Latin ultramarinus, literally “beyond the sea,” because it was imported from Asia by sea. 
In the past, it has also been known as azzurrum ultramarine, azzurrum transmarinum, azzuro oltramarino, azur d'Acre, pierre d'azur, Lazurstein. 

Current terminology for ultramarine include natural ultramarine (English), outremer lapis (French), Ultramarin echt (German), oltremare genuino (Italian), and ultramarino verdadero (Spanish). 
The first recorded use of ultramarine as a color name in English was in 1598. 

Before the nineteenth century, the word ultramarine designated the pigment derived from natural lazurite. 
After the mid-nineteenth century, it signified the synthetic analog of the mineral lazurite. 
Today, natural ultramarine is distinguished by the names lapis lazuli, lazurite, or genuine ultramarine.

 
ULTRAMARINE BLUE PIGMENT'S HISTORY:
In Renaissance Europe, lapis lazuli was immensely expensive thanks to Ultramarine Blue Pigment's rarity and the time-intensive process of grinding the mineral into paint. 
The yield was small, with 1kg of mineral producing around only 30g of pigment. 

As a result, Ultramarine Blue Pigment was used sparingly, usually reserved for the robes of the Virgin Mary and other holy figures. 
The colour came to symbolise humility and purity, as well as signifying the wealth of the patron who commissioned Ultramarine Blue Pigment's use. 

An artist would often charge for the pigment separately on the invoice so that the patron could choose how much Ultramarine Blue Pigment they wanted to pay for. 

In the 17th Century, Dutch artist Johannes Vermeer used the pigment extensively in almost all of his paintings. 
The turban of the Girl With a Pearl Earring is painted with Ultramarine Blue Pigment and Lead White and finished with a glaze of pure Ultramarine.

 

THE DEVELOPMENT OF SYNTHETIC ULTRAMARINE BLUE PIGMENT:
In 1826, a synthetic version of Ultramarine Blue Pigment was developed by French chemist Jean-Baptiste Guimet by heating kaolinite, sodium carbonate and sulfur in a kiln to create a pigment which is chemically identical to lapis lazuli, but even more vivid in colour. 

In order to differentiate it from its mineral counterpart, it was called French Ultramarine Blue Pigment. 
Due to its affordability and effectiveness as a lapis lazuli alternative, French Ultramarine Blue Pigment quickly became more prevalent than the original mineral pigment and is now considered an essential colour in an artist’s palette. 

Genuine lapis lazuli paints are still produced, but they are no longer labelled as Ultramarine Blue Pigment. 
Compared with the synthetic pigment, lapis lazuli is a more muted colour, and Ultramarine Blue Pigment is weaker in coverage and tinting strength.

 

ULTRAMARINE BLUE PIGMENT'S MIXING QUALITIES:
Synthetic Ultramarine Blue Pigment is usually a warm, reddish-blue, but there are variations of Ultramarine and some professional brands have more than one in their range. 
Sometimes they are differentiated as being either ‘green-shade’ or ‘red-shade’ to indicate the colour bias. 

The difference between these varieties may seem subtle, but whether a blue leans towards red or green is imperative in colour mixing. 
In watercolour, Schmincke and Daniel Smith offer both Ultramarine Blue Pigment and French Ultramarine. 

In both ranges, French Ultramarine is slightly warmer (redder) and more granulating, whereas Ultramarine Blue Pigment is cooler (greener) and less granulating. 

Additionally, Schmincke have an Ultramarine Finest which is non-granulating due to it’s small, finely milled pigment particles.
While it is transparent to semi-transparent, Ultramarine Blue Pigment has a high tinting strength which means that it holds its own in mixes without being overpowering. 

Ultramarine Blue Pigment can be mixed with Burnt Sienna or Burnt Umber to create subtle neutral tints. 
Combined with a bluey-red like Permanent Rose, Ultramarine Blue Pigment can make vibrant violets.

Ultramarine Blue Pigment’s extraordinary that a colour that was once worth its weight in gold is now one of the most common blues, popular in both professional and student grade paints. 

The story of Ultramarine Blue Pigment is the story of the power of colour— the lengths we will go to obtain it and the innovations of modern chemistry which put it within our reach.

PERMANENCE AND COMPATIBILITY OF ULTRAMARINE BLUE PIGMENT:
Unlike many pigments that fade over time, Ultramarine Blue Pigment’s molecular structure makes it remarkably stable and resistant to light and chemicals. 
This durability has preserved the vibrancy of ancient artworks, allowing us to witness the same vivid blue that inspired artists centuries ago. 

Examinations of easel paintings and illuminated manuscripts have shown that natural Ultramarine Blue Pigment retains its integrity remarkably well, even in several centuries-old artworks. 
Generally, Ultramarine Blue Pigment is recognized for its permanence as a pigment. 

Despite being a sulfur-containing compound, which typically releases sulfur as hydrogen sulfide, Ultramarine Blue Pigment has historically been combined with lead white without any significant incidents of the lead pigment darkening to form lead sulfide.
However, a condition known as “ultramarine sickness” has occasionally been observed, particularly in oil paintings. 

This manifests as a grayish or yellowish-gray discoloration on the surface of the pigment. 
Such occurrences are more common with synthetic Ultramarine Blue Pigment, especially in industrial uses. 
The exact cause of this discoloration is a subject of debate among conservation scientists. 

Possible factors include exposure to atmospheric sulfur dioxide and moisture, the acidity of an oil- or oleo-resinous paint medium, or the protracted drying of the oil, during which water absorption might lead to swelling, increased opacity of the medium, and consequently, whitening of the paint film.
Under normal conditions, synthetic Ultramarine Blue Pigment demonstrates considerable permanence. 

Lightfastness testing has confirmed its robustness to light exposure. 
However, it is notably susceptible to acidic environments. 

In urban settings with high concentrations of sulfur dioxide or similar acidic emissions, there have been instances where Ultramarine Blue Pigment used in outdoor posters has experienced fading. 

A notable occurrence of “ultramarine sickness” in synthetic ultramarine on a 20th-century painting was recorded, but the fading of the paint film was primarily attributed to the deterioration of the paint medium rather than the pigment itself. 

Investigations conducted by Wagner and Mertz in 1930 revealed that Ultramarine Blue Pigment can be safely combined with white lead, avoiding chemical reaction, as long as the white lead contains minimal lead acetate and the paint medium maintains a low level of acidity.

Both natural and synthetic Ultramarine Blue Pigment exhibit stability in alkalis under normal conditions. 
However, it has been noted that synthetic Ultramarine Blue Pigment can fade when in contact with lime (calcium oxide), such as in the coloring of concrete or plaster. 

These findings have prompted experts to consider whether the fading of the natural pigment in fresco paintings could be due to interaction with lime plaster.

HISTORY AND ORIGINS OF THE ANCIENT BLUE PIGMENT, ULTRAMARINE BLUE PIGMENT:
Ultramarine Blue Pigment is extracted from the earth – it is made from a semi-precious stone known as lapis lazuli (‘the blue stone’ in Latin) from Afghanistan. 
It is one of the oldest blue pigments, and early evidence of Ultramarine Blue Pigment  as a decorative stone in the cave temples of Bamiyan dates back to the 6th and 7th centuries AD.

Lapis lazuli is made up of the minerals lazurite, silicate and pyrite. 
The mined stone was used further afield in Ancient Egypt and Sumer, to decorate items such as jewellery, headdresses and even, reportedly, makeup in the form of Cleopatra’s eyeshadow. 

But the blue pigment was not extracted until much later. 
There is evidence of it having been used in Chinese paintings from the 10th and 11th centuries, in Indian mural paintings from the 11th, 12th and 17th centuries, and Anglo-Saxon and Norman illuminated manuscripts from circa 1100.

In the 15th century, the artist Cennino Cennini described Ultramarine Blue Pigment in his Il Libro dell’Arte as a ‘glorious, lovely and absolutely perfect pigment beyond all the pigments’. 
Lapis lazuli was later traded on the Silk Road. 

Ultramarine Blue Pigment was loaded onto ships in Syria sailing to Venice, from where it was traded throughout other parts of Europe.
The expensive legacy of natural Ultramarine Blue Pigment 

The time-consuming process of extracting Ultramarine Blue Pigment from lapis lazuli, combined with the distances it had to travel from its source, made natural Ultramarine a supremely expensive pigment. 

So much so that it was once considered more precious than gold when weighed gram by gram. 
To produce genuine Ultramarine Blue Pigment from lapis lazuli was a complex, lengthy process. 
The mineral mined was ground and mixed with resin, linseed oil or wax, and then heated to form a dough-like mixture. 

This was kneaded like bread and placed in a lye solution, allowing blue flakes to separate, sink and dry, with the result being a fine blue powder pigment. 
The process would then be repeated to produce a finer grade of pigment each time, meaning that a comparatively small amount of Ultramarine Blue Pigment could be extracted from the stone. 

Nonetheless, Ultramarine Blue Pigment created a high-quality blue pigment free from the invisible impurities which lay in the rock and damaged the paint colour.
The preciousness of Ultramarine Blue Pigment dictated how it was used in painting. 

Artists employed Ultramarine Blue Pigment sparingly and had to account for the hefty cost, which was sold at the best quality and price in Venice. 
Where Michelangelo purportedly couldn’t afford to use Ultramarine Blue Pigment for his works, Vermeer was so taken by the pigment he refused to paint without it, his frequent use eventually resulting in his family falling into debt.

From the year 1400, Ultramarine Blue Pigment was often used to paint the robes of the Virgin Mary, to illustrate her divinity. 
However, artists were still financially conflicted when using the pigment, so Ultramarine Blue Pigment was reserved for significant works of art, such as Sassoferrato’s Praying Madonna (circa 1660), and it remained a privilege to use the colour until a synthetic version came onto the scene.

PHYSICAL and CHEMICAL PROPERTIES of ULTRAMARINE BLUE PIGMENT:
Hex Triplet: #120A8F
sRGBB (r, g, b): (18, 10, 143)
HSV (h, s, v): (244°, 93%, 56%)
CIELChuv (L, C, h): (17, 65, 266°)
Source: ColorHexa
ISCC–NBS Descriptor: Deep blue
Hex Triplet: #3F00FF
sRGBB (r, g, b): (63, 0, 255)
HSV (h, s, v): (255°, 100%, 100%)
CIELChuv (L, C, h): (35, 133, 268°)
Source: Maerz and Paul
Molecular Weight: 994.5 g/mol
Hydrogen Bond Donor Count: 0
Hydrogen Bond Acceptor Count: 27

Rotatable Bond Count: 0
Exact Mass: 993.463108 g/mol
Monoisotopic Mass: 993.463108 g/mol
Topological Polar Surface Area: 581 Ų
Heavy Atom Count: 47
Formal Charge: 0
Complexity: 19.1
Isotope Atom Count: 0
Defined Atom Stereocenter Count: 0
Undefined Atom Stereocenter Count: 0
Defined Bond Stereocenter Count: 0
Undefined Bond Stereocenter Count: 0
Covalently-Bonded Unit Count: 21
Compound Is Canonicalized: Yes

CAS Number: 57455-37-5
EC Number: 209-144-0
Molecular Formula: Na₈Al₆Si₆O₂₄S₂
Molecular Weight: 384.45 g/mol
Color Index: C. I. 77007
Physical and Chemical Properties:
Appearance: Bright blue powder
Melting Point: Decomposes at 250–300 °C
Solubility: Insoluble in water, soluble in acids
Density: 2.3 g/cm³
pH: 7.0 - 9.0 (in water)
Stability: Stable under normal conditions

FIRST AID MEASURES of ULTRAMARINE BLUE PIGMENT:
-Description of first-aid measures
*General advice:
Show this material safety data sheet to the doctor in attendance.
*If inhaled:
After inhalation: 
Fresh air.
*In case of skin contact: 
Take off immediately all contaminated clothing. 
Rinse skin with
water/ shower.
*In case of eye contact:
After eye contact: 
Rinse out with plenty of water. 
Call in ophthalmologist. 
Remove contact lenses.
*If swallowed:
After swallowing: 
Immediately make victim drink water (two glasses at most). 
Consult a physician.
-Indication of any immediate medical attention and special treatment needed.
No data available

ACCIDENTAL RELEASE MEASURES of ULTRAMARINE BLUE PIGMENT:
-Environmental precautions:
Do not let product enter drains.
-Methods and materials for containment and cleaning up:
Cover drains. 
Collect, bind, and pump off spills. 
Observe possible material restrictions. 
Take up dry. 
Dispose of properly. 
Clean up affected area.

FIRE FIGHTING MEASURES of ULTRAMARINE BLUE PIGMENT:
-Extinguishing media:
*Suitable extinguishing media:
Carbon dioxide (CO2) 
Foam 
Dry powder
*Unsuitable extinguishing media:
For this substance/mixture no limitations of extinguishing agents are given.
-Further information:
Prevent fire extinguishing water from contaminating surface water or the ground water system.

EXPOSURE CONTROLS/PERSONAL PROTECTION of ULTRAMARINE BLUE PIGMENT:
-Control parameters:
--Ingredients with workplace control parameters:
-Exposure controls:
--Personal protective equipment:
*Eye/face protection:
Use equipment for eye protection. 
Safety glasses
*Body Protection:
protective clothing
*Respiratory protection:
Recommended Filter type: Filter A 
-Control of environmental exposure:
Do not let product enter drains.

HANDLING and STORAGE of ULTRAMARINE BLUE PIGMENT:
-Conditions for safe storage, including any incompatibilities:
*Storage conditions:
Tightly closed. 
Dry.

STABILITY and REACTIVITY of ULTRAMARINE BLUE PIGMENT:
-Chemical stability:
The product is chemically stable under standard ambient conditions (room temperature) .
-Possibility of hazardous reactions:
No data available