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LuxeSci Show Notes: S2E7 - Brown and Pink Pigments

Welcome to LuxeSci, a podcast to re-ignite your wonder by exploring the science behind luxury items.  We are still in our series on pigments, surprisingly.  We’ve gone through the staples of black and white all the colors of the rainbow so what could possibly be next?  Well…I didn’t think we’d find any else but it turns out that there are two other pigments that are very interesting.  This is what I love about science is that you can find some unexpected, fascinating things hiding under rocks if you look.


So today we’re talking about brown and pink, two very different colors with different connotations but equally fascinating in terms of their history and science. 


History of Brown,

Before we start I just want to warn our listeners that I am biased towards this color including having owned a brown car. Any student of trivia (i am obviously not included) will have heard that some paints were made with corpses… more on that later


Lets talk about the definition of Brown…

From wikipedia we learn that brown can be considered a composite color, but it is mainly a darker shade of orange. In the CMYK color model used in printing and painting, brown is usually made by combining the colors orange and black.[1][2][3] In the RGB color model used to project colors onto television screens and computer monitors, brown combines red and green.


According to public opinion surveys brown has ranked lowest in the USA and Europe. Some positive associations however include antiques roadshow, autumn, log cabins, and banana bread.


Brown has been used in art since prehistoric times. Paintings using umber, a natural clay pigment composed of iron oxide and manganese oxide, have been dated to 40,000 BC.[10] Paintings of brown horses and other animals have been found on the walls of the Lascaux cave dating back about 17,300 years. The female figures in ancient Egyptian tomb paintings have brown skin, painted with umber. Light tan was often used on painted Greek amphorae and vases, either as a background for black figures, or the reverse.

Umber is a general designation for a sedimentary mineral substance containing between 5 to 20% manganese oxides and hydroxides and a larger percentage of iron oxides. The higher content of manganese oxides compared to ochres is responsible for the brownish color.

Another ancient color source is iron:

The main color giving component of natural brown ochre (ocher) is limonite which is not a single mineral but a mixture of several iron-containing minerals among them goethite, akageneite, lepidocrocite, and jarosite, goethite (iron oxide hydroxide α-FeOOH) being the main component. The brown color may be at least partly caused by small amounts of manganese.


SEPIA

The Ancient Greeks and Romans produced a fine reddish-brown ink, of a color called sepia, made from the ink of cuttlefish. Sepia ink was commonly used for writing in Greco-Roman civilization. It remained in common use as an artist's drawing material until the 19th century.[2] Grisaille (see example below) is a painting technique developed in the 14th century in which a painting is rendered solely in tones of gray, sepia, or dark green.[4] In the last quarter of the 18th century, Professor Jacob Seydelmann of Dresden developed a process to extract and produce a concentrated form of sepia for use in watercolors and oil paints.[5]



Russet was a coarse homespun cloth made of wool and dyed with woad and madder to give it a subdued grey or brown shade. By the statute of 1363, poor English people were required to wear russet.

By the way…Woad is another source of the color blue….

satis tinctoria, also called woad (/ˈwoʊd/), dyer's woad, or glastum, is a flowering plant in the family Brassicaceae (the mustard family) with a documented history of use as a blue dye and medicinal plant. Its genus name, Isatis, derives from the ancient Greek word for the plant, ἰσάτις. Its use has been medicinal as well as for color and was used for healing wounds in Greece. It is probably why medicinal alcohol is dyed blue (beyond the safety reasons) to denote some relation to healing.


POPULARITY of Brown

In the Middle Ages dark brown pigments were rarely used in art; painters and book illuminators artists of that period preferred bright, distinct colors such as red, blue and green, rather than dark colors. The umbers were not widely used in Europe before the end of the fifteenth century; 

Artists began using far greater use of browns when oil painting arrived in the late fifteenth century. During the Renaissance, artists generally used four different browns including:

Mummy brown 

originally made in the 16th and 17th centuries from white pitch, myrrh, and the ground-up remains of ancient Egyptian mummies (both human and feline)

Historically, demand for mummy brown sometimes outstripped the available supply of true Egyptian mummies, leading to occasional substitution of contemporary corpses of slaves or criminals.[1] 

Mummy brown began to fall from popularity during the late 19th century when its composition became more generally known to artists.[9] The Pre-Raphaelite artist Edward Burne-Jones was reported to have ceremonially buried his tube of mummy brown in his garden when he discovered its true origins.[1][7] By the start of the 20th century, mummy brown had largely ceased production in its traditional form, owing to a continued decline in the supply of available mummies as well as a significant drop in demand.[1][2]

An Example of Mummy Brown…Martin Drolling..Interior of Kitchen



Asphalt?

Asphalt is an exceedingly complex mixture of organic (bitumen) and inorganic components which cannot be characterized by a single chemical formula. Bitumen is a mixture of organic compounds with high molecular mass and consists mainly of hydrocarbons. The mineral components also vary according to the location where the mineral was found and not many examples exist in the art world of its use except by…. 

Gerrit Dou in 1658 “Young Mother”


Manganese brown

It is considered to be mostly the mixed oxide of manganese with the formula Mn3O4. The name was sometimes used for organic brown pigments or for umber. The pigment is not affected by light.

Dead Head and Worthless Remains:

Caput Mortem…

Caput mortuum (Latin, meaning "dead head", and variously spelled caput mortum or caput mortem), also known as cardinal purple, is the name given to a purple variety of haematite iron oxide pigment, used in oil paintsand paper dyes. Due to the cultural significance of its deep purple colour, it was a very popular for painting the robes of religious figures and important personages (e.g. art patrons), with its popularity peaking in the 18th and 19th centuries.[1][2]

The name for this pigment may have come from the alchemical usage, since iron oxide (rust) is the useless residue (caput mortuum) of oxidation. And no..it did not come from mummies.



Wood Soot ( Bister) 

Used mainly for sketches…also referred to as soot brown. Popular in France, typical use was in postage stamps



A pigment named after the artist:

Vandyke brown is an organic natural pigment consisting of materials found in brown coal, peat or generally in soil. Considerable confusion can be found in the older mentions of this pigment. It had been considered an inorganic iron pigment mainly in France and its name had also been used for various earth pigments such as umber and ochres.

The main deposits of Vandyke brown are in Germany in the region of Cologne. The pigment is prepared from the raw material by drying and grounding.


Example of Van Dyk brown in Rembrant van Rijn…Flora 1641

Burnt Sienna…the road to modern pigments

The name comes from clay soil near Siena, Italy, This color is called raw sienna.


The main color giving component of burnt sienna is iron oxide. The pigment contains around 50% iron oxide and varying amounts of clay and quartz. It is chemically not distinguishable from yellow ochres, the only significant difference being the color. Burnt sienna shows usually darker and warmer tint than the yellow ochres.


Neat Tidbits………………………

Why is UPS’s color brown?

1913 two partners in Seattle started what is now UPS but the color was yellow. As the company grew, a founding member in1916 decided that a less conspicuous color was needed that was not as hard to maintain as black. The brown of the Pullman cars was an inspiration because of their clear relationship with luxury and speed.Pullman sleeping cars were all the rage between 1867 and 1929, built to cater to high-end railway travelers by providing accommodations befitting a luxury hotel. Eventually the color made it to all uniforms and communications. Incidentally UPS was the third company in the US to trademark a color. Any idea which was the first? It was owens-corning, the glass company registering pink as its trademark color. Tiffany and T-mobile are two others with color trademarks.


Pink

  • So let’s start at the beginning with what is pink.

  • Optically - pink is “any of the pale shades of colors between bluish red to red, of medium to high lightness and low to moderate saturation.

  • While pink is generally considered a red, most tints of pink are slightly bluish with the exception of some leaning toward orange (salmon pink)

  •  the name pink was first used in the late 17th century and it comes from flowers called pinks (genus Dianthus), which are pale red (pink)

  • Most European languages pink = rose after the rose flower

  • The pink color in plants often comes from a group of compounds called anthocyanins

  • Water-soluable vacuolar pigments - means that they are contained in vacuoles in the plants, which are enclosed compartments filled with water and inorganic and organic molecules

  • Red, purple, blue or black depending on their pH

  • Present in all tissues of higher plants

  • Pink as a pigment was not in fashion for a long time since making red was so expensive, the darker the red, the wealthier you were and so the fashion was for bright crimsons and other deep reds.

  • It was however, used in paintings for flesh color of faces and handstand sometimes in religious art

  • During the Renaissance, the pink pigment was light cinabrese - a mixture of sinopia (Venetian Red) and lime white

  • Pink really took off in the 18th century where it became the height of fashion in European courts due to its popularity with Louis XV of France’s mistress, Madame de Pompadour

  • Since then, pink has gone through many evolutions, but continues to be a main stay of fashion and art (think Maryln Monroe’s iconic pink dress in Gentlemen Prefer Blondes) and shocking pink as the signature color of fashion designer Elsa Schiaparelli

  • This is going to be a slightly different description since pink is usually made by either combining pigments (such as red and white) or by using a less concentrated red dye.

  • One example that we discussed on our red and green podcast is madder

  • Madder (Rubia tinctorum) contains two organic red dyes, alizarin and purpurin and can be a dull violet red or dull magenta red

  • With the isolation and synthesis of alizarin especially, synthetic pink pigments are now available such as light alizarin crimson

  • However, there is some cool science around the color pink

  • Sunsets and sunrises

  • Rayleigh scattering - named after the 19th century British physicist Lord Rayleigh

  • Elastic scattering of light (or other electromagnetic radiation) by particles much smaller than the wavelength of the radiation

  • There is a wavelength dependence of the scattering which means that the shorter (blue) wavelengths are scattered more strongly than the longer (red) wavelengths and this partially accounts for the sky being blue

  • Beam of light coming from the sun scatters off molecules of gas and other small particles in the atmosphere

  • Blue color is a mix of blue and green, with violet wavelengths being absorbed by the oxygen in the atmosphere\

  • But we’re here to talk about pink.  At sunset and sunrise, the path of the light to our eyes is the longest

  • This long path removes the short blue wavelengths and leaves the longer, orange, red and pink light to reach our eyes and produce the colors we see

  • This remaining light can also be further scattered by cloud droplets to give the sky above the horizon a pink or reddish glow

  • Pink in biology

  • What if I told you that the color of the oldest life on earth was pink?

  • Oldest organic color yet discovered and the research was published in the Proceedings of the National Academy of Sciences in 2018

  • Found in 1.1. Billion year old rocks

  • A PhD student at Australian National University, Nur Gueneli,  was doing what grad students do - she pulverized some rock from oil shale deposits in Mauritania.  She wanted to extract molecules from any ancient organisms trapped inside

  • So you pulverized the rock, mix the powder with an organic solvent to begin the extraction procedure and then….the mixture turns a very bright pink

  • The pigment comes from a fossilized cyanobacteria and its chlorophyll

  • Cyanobacteria is a blue-green algae

  • The pigment is pink when diluted but the molecules are red and purple in their concentrated form

  • World’s pinkest pink

  • We mentioned vantablack in our episode on black, the black so dark that it looks like a hole

  • Apparently the creator of vantablack, Anish Kapoor, declared exclusive rights to the color and that didn’t sit well with some of the art community, including artist Stuart Semple. 

  • Semple then created the “pinkest pink” which is quite a vibrant, neon, vivid pink, which is available to everyone except Anish Kapoor (if you go on the website, you have to verify that you’re not Anish Kapoor)

  • The feud continued and Semple has since taken to creating more pigments (not available to Kapoor) including 3 new blacks, the Glitteriest Glitter and “whitest white paint” 

  • This has worked out well for Semple as he’s earned quite a following and the title of “Robin Hood of the Rainbow”


Glossary

  • Anthocyanins - pigments found in plant vacuoles that lead to deep red, purple, blue colors

  • Rayleigh scattering - scattering of electromagnetic radiation (light) by particles that are smaller than the radiation

  • Cyanobacteria - blue-green algae

Cocktail party facts

  • What phenomenon is responsible for the sky being blue - Rayleigh scattering

  • What organisms produce a bright pink pigment and were found 1.1 billion years ago - cyanobacteria

  • What color was made in response to a licensing disagreement amongst artists - Pinkest Pink


Thank you for listening to this episode of LuxeSci.  Please rate and review us on Apple Podcasts, Spotify or wherever you listen.  This is the best way to help us get noticed and find new listeners.  A special thanks as always to my audio engineer Dimos.  Our theme music is Harlequin Mood by Burdy



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