Pigments in paint can come from rocks, plants, insects or synthetic sources

The history of iconic pigments used in seven famous paintings

While art paints can be bought by the bucket at any craft store today, pigments throughout history have been difficult to come by. Art historian Kelly Grovier traces the fascinating history of pigments that make up hidden layers in masterpieces from Picasso and Hokusai’s Prussian Blue to Vermeer’s shade of red.

Scientists used mass spectrometry to determine the materials in a 1690 painting

Previously used to map the distribution of molecules on biological tissue samples, researchers combined the technique with machine learning to uncover six layers of pigments, binders, and a thin gold leaf layer within *The Marriage of the Virgin*, from a collection in the Metropolitan Museum of Art. The technique may help identify and track artists' material use to learn about pieces of unknown provenance. (Some readers may experience a paywall.)

Explore the chemical compounds found in fireworks

Besides the various salts and metals used to produce fireworks colors, shells are also filled with gunpowder and oxidizers to help fuel and accelerate reactions. Chlorates help strengthen colors, while dextrin, a starch, helps hold mixtures together.

The pharmaceutical industry evolved, in part, from the discovery of synthetic dyes

In 1856, a chemist accidentally discovered mauveine, the world's first synthetic dye, while trying to make quinine to treat malaria. The synthetic dyes that followed helped reveal germs under microscopes, paving the way for modern imaging techniques and breakthrough treatments, such as antibiotics.

What techniques did cave painters use to create their work?

Cave paintings long predate local craft stores and premade paints, so what techniques and tools did cave artists use to create such long-lasting works? This video gallery details how ancient artists inscribed and painted their work on cave walls, specifically the Chauvet cave in France.

The agricultural origins of paintball guns

The paintball field industry—where players compete in pseudo-battle using the (minimally) harmless guns—is worth over $1 billion annually, and it continues to grow. This fun piece breaks down the relatively recent history of the industry by...

Ancient Greek and Roman sculptures were likely colorful, not white

Archaeologists stumbling upon statues from ancient Greece often found weathered creatures, their faces and figures marred by age and conflict. But evidence of polychromy—painting sculptures with color—has continued to mount.

How the pigments that absorb light for photosynthesis contribute to plants' green color

Although light energy is captured to power the reactions that produce the building blocks of starch, cellulose, glucose, and other sugars, chlorophyll a and b are most sensitive to violet, blue, orange, and red light, leaving green light mostly unabsorbed. This green light is instead reflected, giving most plants this color appearance.

What is the rarest color in nature?

Plants, animals, or minerals found in nature bear almost every color imaginable. There are two factors that influence what hues you see in the wild: physics and evolution. So, which colors are you least likely to see in the natural world? Victoria Hwang explores one of nature's rarest spectacles.

Monks and peasants once used cobwebs as canvases for painting

The tradition goes back to the 16th century, when the delicate canvases were hung in churches and cloisters. The difficulty in painting on the cobwebs was intended to illustrate one's devotion to their faith.

Color originates from the brain processing light of varying wavelengths

Various geometric models, including Newton's color circle of hue and saturation and the horseshoe-shaped XYZ space for mixing colors via vector mathematics, have been proposed to describe colors accurately. However, these models do not encapsulate the variety of psychological effects that cause perceived colors to differ from mathematical representations.

Blood has evolved many times over hundreds of millions of years, resulting in different blood colors and compositions—and there are even some organisms that don't need blood at all.

View a sample of objects surprisingly derived from crude oil, including chewing gum and lipstick

Crude oil processing produces a variety of fuels and the building blocks for plastics, but it also distills out the hydrocarbons used to make aspirin, Teflon, vinyl, crayons, candles, Tupperware, roofing shingles, asphalt pavement, hair dye, anesthetics, food-grade lubricants, polyester, synthetic rubber, and resins for items like dentures.

Flamingos get their pink coloring from carotenoids—pigments of yellow, orange, and red—in their food, but they cannot take on other colorations because their bodies cannot process other pigments.

Concrete is made of water, a fine aggregate such as sand, a coarse aggregate such as gravel, and cement, which is a fine binding powder composed of limestone, clay, shells, and silica sand.

The history of soap and how it forms bathtub scum and white spots in old oil paintings

Soap has been produced since at least 2,200 BCE via a chemical reaction between fats or oils and a base. This creates salts that act as molecular bridges, helping water lift dirt and grease from surfaces. The same chemistry produces scum when metals in hard water bind to soap molecules, as well as white spots in paintings when metal ions in pigments react with fatty acids in the oil binder.

Rocks, crystals, and gemstones are all made of minerals—solids that form from natural processes, such as evaporated water leaving salt behind or lava rapidly cooling into a solid.

The centuries-old history of titanium white goes back to the Inca

Titanium white can be found in items ranging from paint to pills. Though it was created in New York in 1908, the pigment was first used hundreds of years earlier by the Inca, according to this article.

Tattoo inks are largely unregulated by the FDA

With hundreds of ink manufacturers, all unregulated by the FDA, it’s hard to determine the exact ingredients in tattoo inks. Some pigments may contain carcinogenic chemicals, such as heavy metals and aromatic hydrocarbons, or even bacterial contaminants. Red ink often causes allergic reactions and may even contain lead or mercury.

When processing light, the brain can perceive colors with no natural wavelength

While some animals are sensitive to many forms of light, humans possess receptors that are sensitive to red, green, and blue wavelengths. These receptors send signals to the brain, which are processed and mixed to produce the array of colors we observe, including magenta, pink, and "supercolors" that lack a corresponding natural wavelength in the visible spectrum.

Discover the chemistry behind smoking foods, including the types of smoking and the source of smoking flavors and colors.

How did ancient cave painters manage to see what they were doing?

As ancient artists made their way deep into caves and created massive works of art that continue to inspire awe today, they would've required light sources to see what they were doing. This gallery details some of the light sources that cave artists...

From glands beneath their skin, hippos produce their own sunscreen in the form of a fluid containing hipposudoric and norhipposudoric acids, which absorb sunlight in the ultraviolet and visible range.

Water is naturally tinted with a slight blue, but sediments and organics can alter its color

The innate coloration comes from water absorbing red light in the visible spectrum more than green or blue, giving shallow waters in some parts of the Caribbean their turquoise hue. If sand is light, it can be churned up by turbulent water, clouding its appearance. Plankton and other organisms can color water by affecting how the rest of the spectrum is absorbed or reflected.

Tannins contribute to a wine's composition

Tannins are compounds found in many different types of food, including grape skins. When consumed, they produce a noticeable drying effect in the mouth. Because of the difference in production methods, red wines typically have tannins while white wines do not.

Instead of consuming water and carbon dioxide to produce oxygen and sugar, anoxygenic photosynthesis involves alternative reactants and products.

Jackson Pollock and others developed 'action painting,' highlighting the creative process

A subcategory of performance art, action painting emerged in 1945 as a way to capture a moment-by-moment view of the creative process through painting. For these pieces, the physical act of painting is as important as the finished product. This short explainer video covers the philosophy behind action painting, as well as exploring the works of several well-known action painters, including Jackson Pollock, Franz Kline, and Mark Rothko.

The five most common chemicals found in modern food

Most modern processed foods rely on a number of preservatives to stay fresh from production to our plates. The most common include citric acid (preservative and flavor), sodium benzoate (preservative), xanthan gum (thickening and stabilizing), carrageenan (thickening), and red dyes 3 and 4 (for color).

Molecules derived from algae can be found in foods such as ice cream, salad dressings, brownie mix, and gravies, as well as in products such as toothpaste, multivitamins, and egg substitutes.

By separating light with tools such as prisms, scientists can reveal the presence and composition of celestial matter by identifying color fingerprints unique to specific elements and molecules.

Fireworks' chemical composition and internal layout produce their unique displays

The burning of different metal compounds, facilitated by combining fuel with oxidizers, results in explosions of varying colors. The timing and pattern are engineered through the arrangement of pellets and fuses.

'Some painters transform the sun into a yellow spot, others transform a yellow spot into the sun.'

- Legendary artist Picasso (1881–1973)

Psychedelic compounds: a visual library

However psychedelic experiences manifest, they all begin with the presence of psychoactive compounds. Learn about their various chemical compositions in this structural library of psychedelic compounds. Clicking on an entry will take readers to a new page where they can learn about the chemistry and pharmacology of each compound, as well as the drug's possible applications.

Synchrotron radiation has revealed the fur color of creatures millions of years old

When electrons are accelerated in the loop, they produce intense X-rays that can reveal properties of a sample struck by them, just as X-rays can be used to show bone structure in humans. Studying the reflected light from fossils can uncover the presence of known pigmentation compounds.

The story of the Radium Girls, who exposed the dangers of radioactive paint

After radium was discovered in 1898, companies began using radium-based paints on watch and clock dials to create a glow-in-the-dark effect. Women who worked to apply the paint were encouraged to use their lips and tongues to help create the fine point needed to draw small numbers, unknowingly poisoning themselves.

Natural toxins produced on plants or consumed by animals may cause food poisoning

When humans eat plants with certain natural toxins on them—including a family of toxins called aflatoxins that fungi produce on crops like peanuts and corn— they can become ill with food poisoning. Toxins can still harm humans even if animals or plants appear fine to the human eye. The World Health Organization advises that we should throw away moldy or discolored foods, refrain from eating wild plants or mushrooms that aren’t definitively nonpoisonous, and remember that just because something is “natural” it’s not always safe to eat.

Collagen supplements typically come from animal sources like fish, pigs, or cattle

Eating collagen-rich foods won't lead to more collagen in the body because your digestive system breaks down consumed collagen into amino acids. Instead, eating a healthy diet of proteins and greens helps your body to produce collagen. Collagen supplements derived from animal skin and bones are typically sold in a prebroken-down peptide formulation called hydrolyzed collagen so they can be absorbed through the gut into the bloodstream.

Japanese artwork often incorporates bold colors, clean lines, and natural subjects

While Japanese art is diverse and continues to adopt new styles and techniques, the Japanese approach to painting nature inspired Georgia O’Keeffe, who was known for depicting the environment in a detailed yet realistic manner. Below is "The Great Wave off Kanagawa," from 1931, by Hokusai.

Poison ivy was sent to Europe in the 1600s as an exotic, ornamental oddity.

The scientists trying to prove Jackson Pollock's symbolism

Jackson Pollock is one of the most famous American artists in history. He is well-known for his Abstract Expressionist "drip paintings," which seemed to defy interpretation. But following the artist's posthumous bipolar diagnosis, a team of scientists attempted to prove that his symptoms, including mania and psychosis, caused Pollock to embed images under his thrown paint.

Atmospheric composition and temperature impact the color of lightning

Just as fire ranges from red to blue with increasing temperature, lightning's blueish-white comes from the superheating of air. The emission of light from the predominantly nitrogen- and oxygen-rich atmosphere produces a purple tint, with additional color caused by light scattering from humidity, hail, dust, and ash.

Paleontologists apply rules about rock layering, fossilization, and radioactivity to date geological samples

Concepts such as the understanding that older rock layers will form beneath newer ones allow scientists to compare the ages of samples from various layers. Although no geological site preserves evidence across all time, samples can be combined with fossils of known age, such as those dated by analyzing the decay of their radioactive isotopes, to reconstruct Earth's timeline.

The ancient uses of asphalt

Asphalt is derived from bitumen, a naturally occurring byproduct of decomposed organic materials. As one of the thickest forms of petroleum, the substance has been in use by humans and their ancestors for at least 40,000 years for various purposes, including as a sealant, an adhesive, decoration, and more. Learn more about this ancient material here.

Tattoos are made by injecting pigments into the skin

Tattoo ink is injected under the skin, which can leave the body open to infections and allergic reactions. While many tattoo artists are licensed professionals who follow sanitary guidelines, that’s not always the case.

Picasso had several distinct periods

Picasso was known for his ever-evolving style, which art historians have often divided into his artistic periods. Warmer color palettes and subjects characterized his Pink Period (sometimes called the Rose Period). Other phases focused on neoclassical, surrealist, and mythological art and subjects. Below is Family of Saltimbanques from the Pink Period.

Although vinegar was first discovered when wine was left to sour after exposure to air, the fermentation of different base ingredients contributes to the variety of vinegars seen today.

From the surface, Mars can appear butterscotch, golden brown, and even green

Images from orbiters, landers, and rovers show that Mars has a mix of surface colors resulting from variations in the mineral compositions of different regions. The reddish tint when viewed from Earth comes from kicked up particles of rusted iron.

Rockwell based many of his paintings on staged photographs

Rockwell’s work was often noted for its realism. His paintings' near-photographic precision was no accident. Early in his career, he painted from live models. Later, he’d conceived a scene, staged it, photographed it, and then used the photos as the foundation for his paintings.

'If you hear a voice within you say 'you cannot paint,' then by all means paint, and that voice will be silenced.'

- Vincent van Gogh (1853-1890)

See how fireworks are made and which metals are responsible for different colors.