Also known in the past as azzurrum ultramarine, azzurrurrum transmarinum, azzuro oltramarino, azur d'Acre, pierre d'azur, Lazurstein, ultramarine has been called the most brilliant blue. Current terminology for ultramarine include natural ultramarine (English), outremer lapis (French), Ultramarin echt (German), oltremare genuino (Italian), and ultramar ino/ verdaero (Spanish). The pigment color code is P. Blue 29 77007.
History of Use by Artists
Some believe that Lapis Lazuli, the mineral from which ultramarine is extracted, was the sapphire of the Bible and other early writings. (Mayer) However, the first noted use of lapis lazuli as a pigment can be seen in the sixth- and seventh century AD cave paintings in Afghanistan temples, near the most famous source of the mineral. Lapis lazuli has also been identified in Chinese paintings from the tenth- and eleventh centuries and in Indian mural paintings from the eleventh, twelfth, and seventeenth centuries. The pigment was most extensively used during the fourteenth through fifteenth centuries, as its brilliance complemented the vermilion and gold of illuminated manuscripts and Italian panel paintings. (Roy) As an imported raw material and due to the labor of the extraction process, it has been the costliest and most precious of artists materials. The finest quality of ultramarine pigment equaled gold, and sometimes exceeded, in price. Patrons often agreed to buy ultramarine for artists to use in paintings. Artists used the pigment sparingly, reserving their highest quality blues for the robes of Mary and the Christ child. 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, Italy, the pigment was seldom seen in German art or art from countries north of Italy. Due to a shortage of the less expensive blue pigment, azurite, in the late sixteenth and seventeenth century, the demand for the already-expensive ultramarine increased dramatically. Considering the high price of natural ultramarine, the synthetic version of ultramarine was rapidly adopted soon after its invention in 1828. It is said that the invention of the synthetic pigment was "one of the major events in the history of artist's materials" (Mayer) Natural ultramarine is no longer offered for sale, except occasionally in England, and still at a high price (often equal or exceeding the price of gold). (Wehlte) Any painter wishing to use natural ultramarine must obtain lapis lazuli from mineral or gem shops and make the pigment in the same arduous method as painters of past.
Some believe that Lapis Lazuli, the mineral from which ultramarine is extracted, was the sapphire of the Bible and other early writings. (Mayer) However, the first noted use of lapis lazuli as a pigment can be seen in the sixth- and seventh century AD cave paintings in Afghanistan temples, near the most famous source of the mineral. Lapis lazuli has also been identified in Chinese paintings from the tenth- and eleventh centuries and in Indian mural paintings from the eleventh, twelfth, and seventeenth centuries. The pigment was most extensively used during the fourteenth through fifteenth centuries, as its brilliance complemented the vermilion and gold of illuminated manuscripts and Italian panel paintings. (Roy) As an imported raw material and due to the labor of the extraction process, it has been the costliest and most precious of artists materials. The finest quality of ultramarine pigment equaled gold, and sometimes exceeded, in price. Patrons often agreed to buy ultramarine for artists to use in paintings. Artists used the pigment sparingly, reserving their highest quality blues for the robes of Mary and the Christ child.
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, Italy, the pigment was seldom seen in German art or art from countries north of Italy. Due to a shortage of the less expensive blue pigment, azurite, in the late sixteenth and seventeenth century, the demand for the already-expensive ultramarine increased dramatically. Considering the high price of natural ultramarine, the synthetic version of ultramarine was rapidly adopted soon after its invention in 1828. It is said that the invention of the synthetic pigment was "one of the major events in the history of artist's materials" (Mayer) Natural ultramarine is no longer offered for sale, except occasionally in England, and still at a high price (often equal or exceeding the price of gold). (Wehlte) Any painter wishing to use natural ultramarine must obtain lapis lazuli from mineral or gem shops and make the pigment in the same arduous method as painters of past.
Source/Preparation of Pigment
The pigment ultramarine is extracted from a semi-precious stone, the mineral Lapis Lazuli (L. lapis, a stone; Latinized Persian, blue). Lapis lazuli is essentially a mineralized limestone containing a blue cubic mineral called lazurite. The mineral occurs mainly in a single blue shade, but the color of the extracted pigment depends largely on the quality of the rock, the number of refinements, and the care taken in the extraction process. (Wehlte) The best samples are of uniform deep blue; those of a paler color or those intermingled with white crystalline material are low quality or impure. The mineral itself is characterized by scattering or veining of silver or golden-colored particles. The main source of the mineral in the past was in Asia in quarries in what is now Afghanistan, which supplied nearly all of the lapis lazuli for Europe. Today, other sizable deposits are found near Lake Baikal in Siberia and in the Chilean Andes, with Argentina, Burma, Canada, and the United States holding smaller deposits. Natural ultramarine, made from Lapis Lazuli, is the most difficult pigment to grind by hand. And, for all except the highest quality of mineral, sheer grinding and washing, sufficient for most other pigments, produces only a pale grayish blue powder. At the beginning of the thirteenth century, an improved method came into use, a process described by the fifteenth century artist Cennino Cennini. This process consisted of mixing the ground material with melted wax, resins, and oils, wrapping the mass in a cloth, and then kneading it under a dilute lye solution (potassium carbonate). (Roy) Through this process, the blue particles are collected at the bottom of a holding vessel, while the impurities and colorless crystals remain in the mass. 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, prized as a glaze for its pale blue transparency. Discovered by Goethe in 1787 as a byproduct of lime kilns near Palermo, France, artificial ultramarine today is made by heating clay, soda, sulfur, and coal in furnaces. In 1928, Jean Baptiste Guimet perfected a method of producing an artificial, and cheaper, ultramarine pigment. However, synthetic ultramarine is not as vivid a blue as natural ultramarine. Because the particles in synthetic ultramarine are smaller and more uniform than natural ultramarine, they diffuse light more evenly. Synthetic ultramarine is also not as permanent as natural ultramarine.
The pigment ultramarine is extracted from a semi-precious stone, the mineral Lapis Lazuli (L. lapis, a stone; Latinized Persian, blue). Lapis lazuli is essentially a mineralized limestone containing a blue cubic mineral called lazurite. The mineral occurs mainly in a single blue shade, but the color of the extracted pigment depends largely on the quality of the rock, the number of refinements, and the care taken in the extraction process. (Wehlte) The best samples are of uniform deep blue; those of a paler color or those intermingled with white crystalline material are low quality or impure. The mineral itself is characterized by scattering or veining of silver or golden-colored particles. The main source of the mineral in the past was in Asia in quarries in what is now Afghanistan, which supplied nearly all of the lapis lazuli for Europe. Today, other sizable deposits are found near Lake Baikal in Siberia and in the Chilean Andes, with Argentina, Burma, Canada, and the United States holding smaller deposits.
Natural ultramarine, made from Lapis Lazuli, is the most difficult pigment to grind by hand. And, for all except the highest quality of mineral, sheer grinding and washing, sufficient for most other pigments, produces only a pale grayish blue powder. At the beginning of the thirteenth century, an improved method came into use, a process described by the fifteenth century artist Cennino Cennini. This process consisted of mixing the ground material with melted wax, resins, and oils, wrapping the mass in a cloth, and then kneading it under a dilute lye solution (potassium carbonate). (Roy) Through this process, the blue particles are collected at the bottom of a holding vessel, while the impurities and colorless crystals remain in the mass. 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, prized as a glaze for its pale blue transparency.
Discovered by Goethe in 1787 as a byproduct of lime kilns near Palermo, France, artificial ultramarine today is made by heating clay, soda, sulfur, and coal in furnaces. In 1928, Jean Baptiste Guimet perfected a method of producing an artificial, and cheaper, ultramarine pigment. However, synthetic ultramarine is not as vivid a blue as natural ultramarine. Because the particles in synthetic ultramarine are smaller and more uniform than natural ultramarine, they diffuse light more evenly. Synthetic ultramarine is also not as permanent as natural ultramarine.
Chemistry of the Pigment
Chemically, ultramarine is the most complex of the mineral pigments. Lapis lazuli, from which ultramarine is made, is a complex sulfur-containing sodio-silicate [Na8-10Al6Si6O24S2-4 ], essentially a mineralized limestone containing a blue cubic mineral called lazurite. Some chloride is often present in the crystal lattice as well. The blue color of the pigment is due to the S3- radical anion, which contains an unpaired electron. The chief chemical properties of ultramarine are (Roy): unaffected by heating up to redness unaffected by ammonia or caustic alkalis unaffected by sodium hydroxide unreactive with base chemicals extremely susceptible to even minute and dilute mineral acids and acid vapors. Dilute HCl, HNO3, and H2SO4 rapidly destroy the blue color, evolving hydrogen sulfide gas (H2S). Acetic acid attacks the pigment at a much slower rate than mineral acids. Because of this susceptibility, ultramarine is never used for frescoes the pigment is almost entirely permanent and highly stable in light
Chemically, ultramarine is the most complex of the mineral pigments. Lapis lazuli, from which ultramarine is made, is a complex sulfur-containing sodio-silicate [Na8-10Al6Si6O24S2-4 ], essentially a mineralized limestone containing a blue cubic mineral called lazurite. Some chloride is often present in the crystal lattice as well. The blue color of the pigment is due to the S3- radical anion, which contains an unpaired electron.
The chief chemical properties of ultramarine are (Roy):
unaffected by heating up to redness unaffected by ammonia or caustic alkalis unaffected by sodium hydroxide unreactive with base chemicals extremely susceptible to even minute and dilute mineral acids and acid vapors. Dilute HCl, HNO3, and H2SO4 rapidly destroy the blue color, evolving hydrogen sulfide gas (H2S). Acetic acid attacks the pigment at a much slower rate than mineral acids. Because of this susceptibility, ultramarine is never used for frescoes the pigment is almost entirely permanent and highly stable in light
unaffected by heating up to redness
unaffected by ammonia or caustic alkalis
unaffected by sodium hydroxide
unreactive with base chemicals
extremely susceptible to even minute and dilute mineral acids and acid vapors. Dilute HCl, HNO3, and H2SO4 rapidly destroy the blue color, evolving hydrogen sulfide gas (H2S). Acetic acid attacks the pigment at a much slower rate than mineral acids. Because of this susceptibility, ultramarine is never used for frescoes
the pigment is almost entirely permanent and highly stable in light
Binders
The distinctive bright blue color of ultramarine is maintained only in aqueous solutions, gum Arabic and egg tempera; in oil, due to a low refractive index, the pigment is dark blue in thick layers. It is best used with a white pigment in oil, to produce a brilliant opaque blue, or otherwise as a translucent glaze. Artists generally find that, mixed in oil, ultramarine is a poor pigment. It has a tendency to yield a stringy consistency, instead of the desired buttery paste. Our results in lab confirm this; the ultramarine in oil was more viscous than many of the other pigments with which we experimented. In lab, we produced a usable ultramarine oil paint by mixing about 2.0 g of pigment with 45 drops (about 2.25 ml) of linseed oil. Our watercolor paint was made from about 1.0 g of the dry pigment and 20 drops of gum arabic solution (gum arabic, honey, glycerine, and sodium benzoate). To this mixture we added a little water to apply the paint. We produced a functional egg tempera from about 2.0 g of ultramarine pigment and an equal amount of egg yoke. Our ultramine sample."A" is ultramarine in linseed oil. "B" is ultramarine in a egg tempera binder. "C" is the pigment in a gum arabic solution.
The distinctive bright blue color of ultramarine is maintained only in aqueous solutions, gum Arabic and egg tempera; in oil, due to a low refractive index, the pigment is dark blue in thick layers. It is best used with a white pigment in oil, to produce a brilliant opaque blue, or otherwise as a translucent glaze.
Artists generally find that, mixed in oil, ultramarine is a poor pigment. It has a tendency to yield a stringy consistency, instead of the desired buttery paste. Our results in lab confirm this; the ultramarine in oil was more viscous than many of the other pigments with which we experimented.
In lab, we produced a usable ultramarine oil paint by mixing about 2.0 g of pigment with 45 drops (about 2.25 ml) of linseed oil. Our watercolor paint was made from about 1.0 g of the dry pigment and 20 drops of gum arabic solution (gum arabic, honey, glycerine, and sodium benzoate). To this mixture we added a little water to apply the paint. We produced a functional egg tempera from about 2.0 g of ultramarine pigment and an equal amount of egg yoke.
Our ultramine sample."A" is ultramarine in linseed oil. "B" is ultramarine in a egg tempera binder. "C" is the pigment in a gum arabic solution.
Ultramarine was used largely unmixed, except with white. However, its slight violet tinge allowed it to be used to produce purple colors, as opposed to greener azurite. Ultramarine is compatible with other pigments, as we noted by mixing the pigments with others in lab.
Optical characteristics: Looking through the microscope
Natural ultramarine particles are flattish and of irregular size and angular shape. The larger particles furnish the brilliance of the pigment; conversely, the more uniform, smaller particles cause a duller color in synthetic ultramarine. Under the microscope, ultramarine appears brilliantly blue in transmitted light, with a slight violet hue on the edges, and deep opaque blue by reflected light. The pigment's refracted light index is low (1.50), and it is isotropic; the blue particles in ultramarine are not birefractant, so that, when examined under a polarizing microscope, the pigment is almost entirely eclipsed. In contrast, certain mineral impurities exclusive to natural ultramarine, principally calcite, are strongly birefractant, appearing as bright spots in a dark field between crossed polaroids. This characteristics thus enables one to differentiate between natural and synthetic ultramarine under a microscope. However, it is impossible to differentiate between natural and synthetic pigments, as Jaeger discovered in 1929 in ultramarine's first x-ray diffraction photographs, with the use of an x-ray microscope; disregarding mineral impurities in natural material and irrespective of variations in color and in chemical composition, all ultramarines gave identical x-ray diffraction patterns, indicating the same crystal lattice. Ultramarine is highly reflective of infrared light. (Roy) In lab, the size of the ultramarine particles was found to differ with the type of pigment used. The granules of dry pigment were courser in comparison to those mixed with a binder, measuring about 3.75 micrometers. The pigment in gum arabic (watercolor) was arranged in a more evenly spaced out pattern than the dry sample. In egg tempera, the spacing between ultramarine pigment granules is even smaller and more uniform, measuring about 1.25 micrometers in diameter. When bound with linseed oil, ultramarine pigment granules are very finely spaced; the individual granules are indistinguishable. When viwed under a microscope through two crossed , polarized analyzers, samples of ultramarine pigment in gum arabic and in egg tempera showed only a darkening of the blue color, while those in an oil binder and without a binder were blacked out. The color of the ultramarine pigment was not completely static; in lab, we found that it differed according to what binder and on what surface the pigment was used. The following are results of our testing using a colorimeter, in L*a*b format: Water Color (gum arabic) on glass: Egg Tempera on glass: Oil on glass L 31.29, a +40.14, b -51.08 L 23.07, a +18.48, b -32.4 L 20.35, a +5.42, b -12.41 Water Color (gum arabic) on white paper: Egg Tempera on white paper: Oil on white paper L 29.92, a +44.8 , b -72.63 L 23.54, a +18.27, b -31.99 L 27.56, a +6.29, b -14.80
Natural ultramarine particles are flattish and of irregular size and angular shape. The larger particles furnish the brilliance of the pigment; conversely, the more uniform, smaller particles cause a duller color in synthetic ultramarine. Under the microscope, ultramarine appears brilliantly blue in transmitted light, with a slight violet hue on the edges, and deep opaque blue by reflected light. The pigment's refracted light index is low (1.50), and it is isotropic; the blue particles in ultramarine are not birefractant, so that, when examined under a polarizing microscope, the pigment is almost entirely eclipsed. In contrast, certain mineral impurities exclusive to natural ultramarine, principally calcite, are strongly birefractant, appearing as bright spots in a dark field between crossed polaroids. This characteristics thus enables one to differentiate between natural and synthetic ultramarine under a microscope. However, it is impossible to differentiate between natural and synthetic pigments, as Jaeger discovered in 1929 in ultramarine's first x-ray diffraction photographs, with the use of an x-ray microscope; disregarding mineral impurities in natural material and irrespective of variations in color and in chemical composition, all ultramarines gave identical x-ray diffraction patterns, indicating the same crystal lattice. Ultramarine is highly reflective of infrared light. (Roy)
In lab, the size of the ultramarine particles was found to differ with the type of pigment used. The granules of dry pigment were courser in comparison to those mixed with a binder, measuring about 3.75 micrometers. The pigment in gum arabic (watercolor) was arranged in a more evenly spaced out pattern than the dry sample. In egg tempera, the spacing between ultramarine pigment granules is even smaller and more uniform, measuring about 1.25 micrometers in diameter. When bound with linseed oil, ultramarine pigment granules are very finely spaced; the individual granules are indistinguishable.
When viwed under a microscope through two crossed , polarized analyzers, samples of ultramarine pigment in gum arabic and in egg tempera showed only a darkening of the blue color, while those in an oil binder and without a binder were blacked out.
The color of the ultramarine pigment was not completely static; in lab, we found that it differed according to what binder and on what surface the pigment was used. The following are results of our testing using a colorimeter, in L*a*b format:
Health Issues
Ultramarine, natural or synthetic, is not poisonous. (Rossol)
Ultramarine Sickness
Under certain conditions, ultramarine pigment turns gray over time, but this degeneration, known as ultramarine sickness, is rare and almost exclusive to oil and synthetic ultramarine paints. It has been suggested that the condition is due to the deposition of moisture containing sulfur dioxide in solution which becomes oxidized in the oil film to sulfuric acid. (Laurie) However, ultramarine sickness is probably due to some accidental cause, not yet determined.
Links to other Web sites
Check out Sinopia, producer of fine pigments, and browse their selection of ultramarine.
For more information on Lapis Lazuli, the gem from which ultramarine is made, click here or here visit the House of Onyx to purchase a gem.
Terry Miller, Emily Alquist 1998.