| Ultramarine | |
|---|---|
 Synthetic ultramarinepigment | |
 Color coordinates | |
| 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[1] |
| ISCC–NBS descriptor | Deep blue |
| B: Normalized to [0–255] (byte) | |
Ultramarine is a deep bluepigment which was originally made by grindinglapis lazuli into a powder.[2] Its lengthy grinding and washing process makes the natural pigment quite valuable—roughly ten times more expensive than the stone it comes from. In the 14th to the 15th Century in Europe it was as expensive asgold.[3][4]
The name ultramarine comes from theLatin wordultramarinus. The word means 'beyond the sea', as the pigment was imported byItalian traders during the14th and15th centuries frommines inAfghanistan.[5][6] Much of the expansion of ultramarine can be attributed toVenice which historically was the port of entry for lapis lazuli in Europe.
Ultramarine was the finest and most expensive blue used byRenaissance painters. It was often used for the robes of theVirgin Mary and symbolized holiness and humility. It remained an extremely expensive pigment until a synthetic ultramarine was invented in 1826.[7]
Ultramarine is a permanent pigment when under ideal preservation conditions. Otherwise, it is susceptible to discoloration and fading.[8]
The pigment consists primarily of azeolite-based mineral containing small amounts ofpolysulfides. It occurs in nature as a proximate component oflapis lazuli containing a blue cubic mineral calledlazurite. In theColour Index International, the pigment of ultramarine is identified as P. Blue 29 77007.[9]
The major component of lazurite is a complex sulfur-containing sodium-silicate (Na8–10Al6Si6O24S2–4), which makes ultramarine the most complex of all mineralpigments.[10] Somechloride is often present in the crystal lattice as well. The blue color of the pigment is due to theS−
3radicalanion, which contains anunpaired electron.[11]
The best samples of ultramarine are a uniform deep blue while other specimens are of paler color.[12]
Particle size distribution has been found to vary among samples of ultramarine 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.[13]
| Electric Ultramarine | |
|---|---|
| Color coordinates | |
| 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[14][15] |
| B: Normalized to [0–255] (byte) | |
International Klein Blue (IKB) a deep blue hue first mixed by the French artistYves Klein.[16]
Electric ultramarine is the tone of ultramarine that is halfway betweenblue andviolet on theRGB (HSV) color wheel, the expression of theHSV color space of theRGB color model.[17][dubious –discuss]
Lapis lazuli stone was historically mined nearSar-i-Sang in modern-day Afghanistan and traded to Mesopotamia and ancient Egypt as early as the third millennium BCE.[18]
A method to produce ultramarine from lapis lazuli was introduced by the 5th century for use in Buddhist cave temples.[19] The method was described byCennino Cennini in the 15th century. This process consisted of grinding the lapis lazuli mineral, mixing the ground material with meltedwax,resins, andoils, wrapping the resulting mass in a cloth, and then kneading it in a dilute lye solution, apotassium carbonate solution prepared by combiningwood 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 ash which is prized as aglaze for its pale blue transparency.[20] This extensive process was specific to ultramarine because the mineral from which it is derived 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.[21]
Although the lapis lazuli stone itself is relatively inexpensive, the lengthy process of pulverizing, sifting, and washing to produce ultramarine 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 as expensive asgold.[3][4]
In 1990, an estimated 20,000 tons of ultramarine were produced industrially. The raw materials used in the manufacture of synthetic ultramarine are the following:
The preparation is typically made in steps:
Ultramarine poor insilica 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 rich in silica is generally obtained by heating a mixture of pure clay, very fine whitesand, sulfur, and charcoal in amuffle furnace. A blue product is obtained at once, but a red tinge often results. The different ultramarines—green,blue,red, andviolet—are finely ground and washed with water.[22]
Synthetic ultramarine 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 thereforediffuse light more evenly.[24] Its color is unaffected by light nor by contact with oil or lime as used in painting.Hydrochloric acid immediately bleaches it with liberation ofhydrogen sulfide. Even a small addition ofzinc oxide to the reddish varieties especially causes a considerable diminution in the intensity of the color.[22] Modern, synthetic ultramarine blue is a non-toxic, soft pigment that does not need much mulling to disperse into a paint formulation.[25]
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Ultramarine is the aluminosilicatezeolite with asodalite structure. Sodalite consists of interconnected aluminosilicate cages. Some of these cages containpolysulfide (Sn−
x) groups that are the chromophore (color centre). The negative charge on these ions is balanced byNa+
ions that also occupy these cages.[11]
The chromophore is proposed to beS−
4 or S4.[11]
The name derives from MiddleLatinultramarinus, literally "beyond the sea" because it was imported from Asia by sea.[5] In the past, it has also been known asazzurrum ultramarine,azzurrum transmarinum,azzuro oltramarino,azur d'Acre, pierre d'azur,Lazurstein. The current terminology for ultramarine includes natural ultramarine (English),outremer lapis (French),Ultramarin echt (German),oltremare genuino (Italian), andultramarino verdadero (Spanish). The first recorded use ofultramarine as a color name in English was in 1598.[26]
AncientEgyptians used lapis lazuli in solid form for ornamental applications in jewelry, however, there is no record of them successfully formulating lapis lazuli into paint.[27] 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 authorsTheophrastus andPliny. There is no evidence that lapis lazuli was used ground as a painting pigment by ancientGreeks andRomans. Like ancient Egyptians, they had access to a satisfactory blue colorant in the synthetic copper silicate pigment,Egyptian blue.[4]
The first noted use of lapis lazuli as a pigment can be seen in 6th and 7th-century paintings inZoroastrian andBuddhist 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 onAnglo-Saxon andNorman illuminated manuscripts fromc. 1100.[4] Ultramarine also appears in Islamicilluminated manuscripts from the 15th and 16th centuries throughout modern-day Afghanistan andIran.[28]
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Venice was central to both the manufacturing and distribution of ultramarine during the early modern period. The pigment was imported byItalian traders during the14th and15th centuries frommines inAfghanistan.[5][6] Other European countries employed the pigment less extensively than in Italy; the pigment was not used even by wealthy painters inSpain at that time.[29]
During theRenaissance, ultramarine was the finest and most expensive blue that could be used by painters.Color infrared photogenic studies of ultramarine in 13th and 14th-centurySienese 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.[30] The 15th century artistCennino Cennini wrote in his painters' handbook: "Ultramarine blue 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."[31] Natural ultramarine 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.[32]
The pigment was most extensively used during the 14th through 15th centuries, as its brilliance complemented thevermilion andgold of illuminated manuscripts and Italian panel paintings. It was valued chiefly on account of its brilliancy of tone and its inertness in opposition to sunlight, oil, and slakedlime. It is, however, extremely susceptible to even minute and dilute mineralacids and acid vapors. Dilute HCl, HNO3, and H2SO4 rapidly destroy the blue color, producinghydrogen sulfide (H2S) in the process.Acetic acid attacks the pigment at a much slower rate than mineral acids.
Ultramarine was only used forfrescoes when it was appliedsecco because frescoes' absorption rate made its use cost prohibitive. The pigment was mixed with a binding medium like egg to form atempera and applied over dry plaster, such as inGiotto di Bondone's frescos in theCappella degli Scrovegni or theArena Chapel inPadua.
European artists used the pigment sparingly, reserving their highest quality blues for the robes ofMary and theChrist 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 throughVenice, the 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 increased dramatically.[33]
![Sassoferrato's depiction of the Blessed Virgin Mary, The Virgin in Prayer, c. 1654. Her blue cloak is painted in ultramarine.[34]](/mt/?noimg=&dark=on&url=http%3a%2f%2fen.wikipedia.org%2fwiki%2fFile%3aSassoferrato_-_Jungfrun_i_b%25C3%25B6n.jpg)
Johannes Vermeer made extensive use of ultramarine in his paintings. The turban of theGirl with a Pearl Earring is painted with a mixture of ultramarine and lead white, with a thin glaze of pure ultramarine over it.[35] InLady Standing at a Virginal, the young woman's dress is painted with a mixture of ultramarine and green earth, and ultramarine was used to add shadows in the flesh tones.[36] Scientific analysis by theNational Gallery in London ofLady Standing at a Virginal showed that the ultramarine 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.[37]
The beginning of the development of artificial ultramarine blue is known fromGoethe. In about 1787, he observed the blue deposits on the walls oflimekilns nearPalermo inSicily. He was aware of the use of these glassy deposits as a substitute for lapis lazuli in decorative applications. He did not mention if it was suitable to grind for a pigment.[38][39]
In 1814,Tassaert observed the spontaneous formation of a blue compound, very similar to ultramarine, if not identical with it, in a lime kiln belonging to the glass and mirror manufacturerSaint-Gobain.[40] In 1824, this caused theSocieté pour l'Encouragement d'Industrie to offer a prize for the artificial production of the precious color. Processes were devised byJean Baptiste Guimet (1826) and byChristian 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" industry.[41][22]
Easel paintings andilluminated manuscripts have revealed natural ultramarine in a perfect state of preservation even though the art may be several centuries old. In general, ultramarine is a permanent pigment. Although it is asulfur-containing compound from which sulfur is readily emitted as H2S, historically, it has been mixed withlead white with no reported occurrences of the lead pigment blackening to becomelead sulfide.[8]
A plague known as "ultramarine sickness" has occasionally been observed among ultramarine oil paintings as a grayish or yellowish gray discoloration of the paint surface. This can occur with artificial ultramarine that is used industrially. The cause of this has been debated among experts, however, potential causes include atmosphericsulfur dioxide andmoisture, 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.[8]
Both natural and artificial ultramarine are stable toammonia and causticalkalis in ordinary conditions. Artificial ultramarine has been found to fade when in contact with lime in 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 offresco paintings.[8]
Synthetic ultramarine, being very cheap, is used for wall painting, the printing of paper hangings, andcalico. It also is used as a corrective for the yellowish tinge often present in things meant to be white, such aslinen andpaper.Bluing or "laundry blue" is a suspension of synthetic ultramarine, or the chemically differentPrussian blue, that is used for this purpose when washing white clothes. It is often found in makeup such asmascaras oreye shadows.[22]
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.[22] During World War I, theRAF painted the outerroundels with a color made from ultramarine blue. This became BS 108(381C) aircraft blue. It was replaced in the 1960s by a new color made onphthalocyanine blue, called BS110(381C) roundel blue.[citation needed]
Ultramarine was a term used for a color available on Apple'siPhone 16, released in 2024.[42]
Ultramarine is a blue made from naturallapis lazuli, or its synthetic equivalent which is sometimes called "French Ultramarine".[43] More generally "ultramarine blue" can refer to a vivid blue.
The term ultramarine 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.[44]
The term "ultramarine green" indicates a dark green whilebarium chromate is sometimes referred to as "ultramarine yellow".[43] Ultramarine pigment has also been termed "Gmelin's Blue," "Guimet's Blue," "New blue," "Oriental Blue," and "Permanent Blue".[45]
One or more of the preceding sentences incorporates text from a publication now in thepublic domain: Chisholm, Hugh, ed. (1911). "Ultramarine".Encyclopædia Britannica (11th ed.). Cambridge University Press.
