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Category: iron oxide

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Human skin tones

We come in an amazing array of colors, but they can all be mixed with the same narrow array of pigments. Why is that?

When Brazilian photographer Angélica Dass was six, her teacher told her to use the skin-tone crayon for a drawing. “I looked at that pink and thought, how can I tell her this is not my skin color?” That night, she prayed to wake up white, she toldNina Strochlic of National Geographic.

If you have close friendships with non-white Americans, you have heard variations on this riff. That’s particularly true if you’re of an age when blacks were invisible in commercial culture. When I was a kid, there were no African-American dolls in the stores, and few children’s books with black protagonists.
Iron oxide yellow, courtesy Wikimedia Commons
There is no underlying biological construct of race. The idea of separate races was the brainchild of a 19th century physician and scientist, Samuel Morton. He rejected the Creation Story in Genesis and argued, instead, that each of the five different races in the world was created as a separate species. (Remember that the next time someone tells you that believing in the Bible is somehow anti-science.)
Morton claimed that he could define the intellectual ability of a race by its skull capacity. Caucasians were, naturally, at the top of his chart. Negroes were at the bottom. His theories carried a certain amount of weight in American culture until they were shredded by the late paleontologist Stephen Jay Gould in The Mismeasure of Man.
Burnt sienna pigment, courtesy Wikimedia Commons
But back to Angélica Dass. She married a Spaniard, and she began to wonder about the question of human skin color. In 2012, she started photographing members of her and her spouse’s families. She then matched a strip of pixels from their noses to a Pantone color card. Humanae arose from this. It now includes 4,000 portraits from 18 different countries.
“So-o-o-o-o many colors of skin, not just black, white, red, or yellow,” the reader who sent this to me commented. That’s true, but it’s also true that all human skin colors can be made with just a few pigments.
There’s really no such thing as white skin color, black skin color, or Asian skin color. They are mixed with the same array of paints; we just control how much white paint we add to the mix. My guide to mixing skin tones can be found here, but it’s also possible to mix all human skin tones with just iron oxide pigments. These range in tone from yellow through orange and red to black.
Iron oxide pigment, courtesy Wikimedia Commons
Iron is the most common element on earth, comprising almost a third of our planet’s total bulk. The second most-common element is oxygen. Iron oxides are chemical compounds of those two elements. They are extremely widespread in nature, appearing as rust and hemoglobin, among many other things. Humans use them in the form of iron ore, from which much of modern civilization was built. Iron oxide also gave us mankind’s first pigments, in the form of ochre, in use for 100,000 years. The iron oxide pigments are not only plentiful, they’re very safe.
Iron oxide powder, courtesy Wikimedia Commons
Our coloration is intimately related to our planet. We are creatures of the earth, tied to the earth, and created here. Our pigmentation points not only to that, but to the universality of mankind, despite the artificial and abusive construct of skin color.
It’s about time for you to consider your summer workshop plans. Join me on the American Eagle, at Acadia National Park, at Rye Art Center, or at Genesee Valley this summer.
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A pigment that’s older than modern man himself

In life and in death, our ancestors covered themselves with iron oxide.
Image of a horse colored with yellow ochre from Lascaux cave, France, c 17,300 BC
“What is the oldest pigment?” a reader asked me this week. That’s one of the few questions that archeology can answer definitively.
It’s ochre, one of the iron-oxide pigments. These minerals are common and easy to manipulate. Primitive man needed only to find suitable rocks and scratch or grind them. Adding water, he had paint. Adding milk, he had paint with a protein binder.
Ochre’s history is far older than modern man. A quartzite hammerstone found near the Danube shows a 500,000-year-old partial handprint of ochre. The earliest known cache of milled ochre comes from a Homo erectus site that’s about 285,000 years old. By 250,000 years ago, Neanderthals were using ochre at the Maastricht BelvĂ©dère site in The Netherlands. By 40,000 years ago, ochre was being manufactured in an ongoing process in an Ethiopian cave. That workshop lasted 4500 years.
Image of a human hand created with red ochre in Pech Merle cave, France, c.  25,000 BC
All that makes the Upper Paleolithic cave art at Lascauxseem downright modern.
Sienna, umber and red oxide are other iron-oxide pigments from antiquity, but none are as venerable as ochre. In ancient practice, different hues might have come from different rocks, or they could have been ochre that was heated or treated to change its structure.
The easiest way to manipulate ochre was to toss it in the fire. Burned, it turns red. Evidence of this dates from 100,000 to 70,000 years ago in deposits in Blombos Cave in South Africa.
Ochre filled a large niche in the prehistoric world. In addition to its obvious uses as a paint, it was a medicine, cosmetic, tanning agent and mastic.
Paintings in the Tomb of Nakht in ancient Egypt, c. 15th century BC
“[It] is not unusual to find a layer of the cave floor impregnated with a purplish red to a depth of eight inches. The size of these ochre deposits raises a problem not yet solved. The colouring is so intense that practically all the loose ground seems to consist of ochre,” wrote archeologist André Leroi-Gourhan of prehistoric Europeans. “One can imagine that the Aurignacians regularly painted their bodies red, dyed their animal skins, coated their weapons, and sprinkled the ground of their dwellings, and that a paste of ochre was used for decorative purposes in every phase of their domestic life. We must assume no less, if we are to account for the veritable mines of ochre on which some of them lived.”
Red ochre is closely associated with prehistoric burial rites. The so-called Red Lady of Pavilandwas a male skeleton dyed with red ochre about 33,000 years ago. 
Remains of the Red Lady of Paviland, Wales, c. 35,000 BC
“I found the skeleton enveloped by a coating of a kind of ruddle … which stained the earth, and in some parts extended itself to the distance of about half an inch around the surface of the bones … Close to that part of the thigh bone where the pocket is usually worn surrounded also by ruddle [were] about two handfuls of the Nerita littoralis. At another part of the skeleton, viz in contact with the ribs [were] forty or fifty fragments of ivory rods [also] some small fragments of rings made of the same ivory and found with the rods … Both rods and rings, as well as the Nerite shells, were stained superficially with red, and lay in the same red substance that enveloped the bones,” wrote its discoverer, the Rev. William Buckland.
Some prehistoric graves used cinnabar in place of ochre. That would have been a costly trade item. Even in death, society has always been divided between the haves and have-nots. Ironically, what they had in this instance was toxic.