Sunday, November 27, 2011

Art and Nature: The Alchemy of Blue (2 of 2)

In France, the manufacture of paint was controlled by the Academie de St. Luc (the Painters’ Guild of France).  In 1764, this guild seized a local factory making Prussian Blue, claiming that the production of the pigment was not authorized by them.  Then, the factory owners asked the Paris Academy of Sciences to determine the nature of Prussian Blue.  They stressed that they were manufacturing a chemical widely used by various groups such as textile manufactures as well as artists.  Was this synthetic pigment a paint or a chemical?  The French chemist Jean Hellot (1685 - 1715) determined that Prussian Blue was a product of chemistry and not art.  Therefore the painters’ guild had no control over its manufacture.  The factory was allowed to reopen, and to continue manufacture this synthetic pigment.

Because of its unique chemistry, Prussian Blue is used by art experts to detect earlier fakes.  The first painting to use this pigment is “Entombment of Christ” by Pieter van der Werff (Dutch, 1665-1722) in 1709.  (The sky and the Virgin Mary’s veil are Prussian Blue.)Through the use of searching for Prussian Blue in paintings, several fakes were uncovered such as “Entrance to the Cannaregio” purported to be painted by Francesco Guardi (Venice, 1712-1793).

The chemical composition of Prussian Blue is structurally complex.  The synthetic pigment is an iron hexacyanoferrate complex compound called iron ferrocyanide.  The idealized chemical formula for Prussian Blue is Fe7(CN)18.  This pigment is produced by the oxidation of ferrous ferrocyanide.  Since the cyanide of the pigment is tightly bound to the iron, Prussian Blue is nontoxic.  

Because Prussian Blue is so easily produced, it became the preferred blue of artists.  By 1713, this pigment was used by Prussian artists in painting official court portraits.  Later, Picasso (Spanish, 1881-1973) used Prussian Blue extensively during his famous “Blue Period”.

Besides painting, Prussian Blue has other uses.  The color “Midnight Blue” of crayons is made from this pigment.  The blue of blueprints is Prussian Blue.  Meanwhile, pathologists use the pigment to detect iron in biopsies.  In addition, this pigment is effective therapy for people who have ingested thallium.

A success story of alchemy, Prussian Blue became one of the essentials of the modern world.  In the 18th Century, it became indispensable for color work.  Later Prussian Blue came to be used in textiles, printing, and other manufacturers. Combining art and science, this pigment symbolizes humanity’s ability to invent beauty out of usefulness.  Like the exploration of color, Prussian Blue was at the junction of artistic and useful pursuits.
Works Used:
Bartoll, Jens, “The Early Use of Prussian Blue in Paintings”, paper, International Conference on NDT of Art, Israel, May 2008.,

Boddy-Evans Marion, “All About Painting”,,,

Copeland, Jessica and Christy Rochelle, “Pigments and Binders: Prussian Blue”, Chemistry and Art, Swanee University, 1998,,

Douma, Michael, “Pigments through the Ages”, Institute for Dynamic Educational Development, 2008,,

Leland, Nita, “Exploring Color”, North Light Books: Cincinnati, 1998.

Lowengard, Sarah, “The Creation of Color in 18th Century Europe”, Columbia University Press, 2006,,

Saturday, November 26, 2011

Art and Nature: The Alchemy of Blue (1 of 2)

Prussian blue
The primary color blue was difficult to obtain naturally.  In Ancient Egypt, blue was regarded as a sacred color.  The Egyptians experimented with various elements until they created the first synthetic pigment – Egyptian blue.  This formula for blue pigment was used throughout Europe until the Fall of the Roman Empire in the 5th Century, when it was lost.

After that, people had several unsatisfactory choices for blue paint.  For example, created from lapis-lazuli that had to be transported from Afghanistan, ultramarine color was more costly than gold.  Meanwhile, the color indigo often turned black with age, and was not very versatile.  Also azurite and other copper-based blues often changed to green.  Creating a useable blue was imperative for painters everywhere. Knowing that the color blue was created once, artists through the ages experimented in search of a replacement formula. 

When Prussian Blue was made available in the early 1700s, it took Europe and later Asia by storm.  The first synthetic pigment of the Modern Era, Prussian Blue became widely used by printers, manufacturers, and others.  In fact, it was the synthetic pigment most widely used from 1708 to 1970, when phthaloryanine blue replaced it.

Prussian Blue was first mentioned in a letter written by Johann Frisch (German, 1666-1743).  He was promoting its virtues to Gottfried Leibniz (German, 1646 – 1716), the president of the Royal Academy of Sciences in Prussia in 1708.  Frisch, the product manager who oversaw the manufacture of Prussian Blue, sent product samples throughout Europe.

The apocryphal story of how Prussian Blue came about centers on the discovery being an accident.  This pigment was created through serendipity. Colormaker (Johann) Diesbach (German) was trying to create a red pigment in his laboratory in 1704.  Diesbach mixed iron sulphate with potash that was accidentally contaminated with blood.  What was created by this accident is the chemical compound of iron ferrocyanide.  Frisch, Diesbach’s supervisor, improved the original formula to make the pigment more stable.

Through Frisch’s active promotion, Prussian Blue became widely used in Europe by 1710.  He named the new color, “Prussian Blue”.  As the use of the pigment spread across Europe, it became also known as “Berlin Blue” and “Parisian Blue”.  Since different manufacturers used local supplies, slightly different hues of this pigment came into being.  Some of these hues were known as “Celestial Blue”, “Haarlem Blue”, and “Hamburg Blue”.  However, the generic name for Prussian Blue is “iron blue”.

The exploration of color in the 18th Century was more than simply an artistic pursuit.  It was also a scientific and philosophical one as well.  The examination of “color” was the junction of practical and aesthetic pursuits during this time.  For example, the invention of Prussian Blue crossed many disciplines.  Manufacturing the pigment involved colormakers, apothecaries, drysalters, and chemists.  No one group had total control over the process of making the paint.  Conflicts arose prompting the eventual breakdown of traditional guilds, and the rise of modern manufacturing methods.

Friday, November 25, 2011

NIMRAVID (Hyena-Cats) FAMILY: Questioning

Neither Hyenas nor Cats, Nimravid Family, an ancient carnivore group, preceded both.  Flourishing during the Oligocene epoch (34 million years ago (mya) to 21 mya), Nimravids roamed throughout Eurasia and North America.  Known as “False Saber-toothed Cats”, They are an example of parallel evolution.
            Only paleontologists can tell the skulls of Nimravids and Saber-toothed Cats apart.  Nimravids had similar life styles to these Cats such as seizing their prey with their claws.  In addition, Nimvarids had saber teeth like many Cats.  Because of these characteristics, at one time They were included in the Cat Family.  Now, Nimravids are considered a separate group of carnivores.
            Nimravids point to the diversity of life.  They first appeared in the late Eocene epoch (37 mya).  Living in the woodlands, They survived until nine mya (the late Miocene).  Only when the forests became grasslands did Nimravids become extinct.  (During this time, Cats emerged as well as Hyenas.)
            Saber-toothed design for carnivores is more common than most people know.  The Gorgonopsids of the Permian Period (290 – 248 mya) were the first to have it.  Then during the Eocene epoch, Creodonts (ancient carnivores) developed saber teeth.  Moreover, Barbourofelids (close relatives to Cats) and Thylacosmilidae (marsupials from South America) also had them.  What this means is that saber teeth alone do not a Cat make.  It takes more.
            Nimravids take you back into the murkiness of time.  What you may think is so, may not be.  Allow your doubts to surface, and be ambivalent as you ponder your sureties.  Asking questions will lead you onto paths of new discoveries.  Question first instructs Nimravids, before you decide.

Wednesday, November 23, 2011

DINOFELIS (“Terrible Cat”): Nightmares

As a member of the Machairodontinae (Saber-Toothed Cats) Subfamily, Dinofelis is an ancient cousin to the more famous Smilodon (Saber-toothed Cat).  Referred to as a “False Saber-toothed Cat”, his canines, that were short and blunt, resembled small sabers.  Similar to a modern Jaguar, Dinofelis climbed trees and ambushed his prey.
            Living about eight million years ago (mya) to one and half mya (during the Pliocene epoch), Dinofelis roamed throughout Africa, Eurasia, and North America.  Living in densely forested areas, He stalked his prey through undercover of the brush.  However the world became colder, the forests shrank, and thus Dinofelis’ range became more and more restricted.
            Early Man’s worst nightmare was Dinofelis, since his favorite food was Australopithecus (early ancestor of modern Humans).  Some paleontologists theorized that Dinofelis may have forced Hominids out from their forest homes.  Once out in the savannah, Australopithecus, who walked upright, could see Dinofelis prowling about in the tall grass.
            Dinofelis stalks us in our dreams and menaces our spirits.  He can still be our worst nightmare, since our response to Him determines how we live our present life.  We can choose to face the terror and find a new way to live.  Or we can choose to run away and risk being eaten by Him.  Once we face our terror that Dinofelis presents, He will cease to frighten us.

Tuesday, November 22, 2011

THYLACOSMILUS (“POUCHED KNIFE” (Marsupial Cat): Hidden Biases

An example of convergent evolution, Thylacosmilus of South America resembled Smilodon (Saber-toothed Cat) of North America.  The size of a modern Jaguar, He had a stout muscular body to stalk his prey.  Living during the Miocene epoch (eight million years ago (mya) to two mya), this marsupial carnivore was the top predator of South America until the coming of Smilodon.
            The most notable feature of Thylacosmilus was his two upper canines which looked like sabers.  Unlike Saber-toothed Cat, his teeth were firmly set in his jaw.  Growing continuously throughout his life, these special teeth wore down through use.  However Thylacosmilus had extensions of his lower jaw which protected these teeth much like scabbards protect swords.
            Thylacosmilus often preyed on animals larger than Himself.  Since He had heavily muscled shoulders and neck, Thylacosmilus would often pounce on his prey.  Then by holding his victim down, He would kill Them by stabbing downwards with his teeth.
            Although He resembled a Cat, Thylacosmilus was not one.  Moreover, He was not the marsupial equivalent of the placental Saber-toothed Cats.  Instead, Thylacosmilus was a member of the Sparassodonts, an ancient family of marsupial predators.
            When the two continents of the New World connected, the Great American Faunal Interchange occurred.  Smilodon went south to invade Thylacosmilus’ territory.  Because He was too specialized in his hunting, Thylacosmilus went extinct.  The more flexible Smilodon completely took over his territory.
            Thylacosmilus highlights our hidden biases.  We assume that because He looked like a Saber-toothed Cat, that Thylacosmilus was one.  Also because He was a close relative of the Marsupials, we assumed that He was doomed.  What we may not understand that during the Interchange, many unique Mammals of both continents went extinct.  Moreover the Opossum Family (Didelphis) who are Marsupials expanded their range from South America to North America, and is still successful today.
            We all have biases that we may not be aware of.  Through his aggressive manner, Thylacosmilus forces us to face them.  He is nothing what we thought He was.  By respecting Him, we can discover what an amazing world lies beyond our perceptions. Let Thylacosmilus challenge your beliefs.