What Is Color?

Steven Weinberg, an artist and illustrator, poses a deceptively simple question in this children's nonfiction book: What is color? Organized around the color wheel, the book blends science, history, and cultural stories from across the globe to argue that color touches every dimension of human experience. Weinberg warns that his investigation became "stinky, messy, even a little bit dangerous" (1) and defines three foundational terms: pigment, the substance that provides color; vehicle, the substance that carries pigment without adding color; and medium, the combination of pigment and vehicle that constitutes an art material like crayons or oil paint.

The opening chapter establishes color's scientific basis. White light contains all colors, as demonstrated when a prism splits a beam into a rainbow, a principle Weinberg credits to English scientist Isaac Newton. Visible light occupies a narrow band of the electromagnetic spectrum, each color corresponding to a different wavelength. Color perception depends on absorption and reflection: A red apple absorbs every wavelength except red, which bounces to the viewer's eye. Weinberg introduces the color wheel as a tool showing how colors relate to one another, then turns to the pigment titanium white, made from the mineral rutile and used industrially since the 1920s as a safe replacement for toxic lead whites. He notes that Inca cultures in South America painted ceremonial cups called qeros with titanium white centuries before its modern invention.

The red chapter frames color as a recipe, opening with Japanese artist Yayoi Kusama, whose dot-based art grew from a childhood vision of a flower field dissolving into dots. Weinberg traces red pigments through history: vermilion, made by alchemists (early experimenters who blended science with secrecy) combining mercury and sulfur; dragon's blood, whose fantastical recipe concealed that the pigment comes from tree resin in Yemen; and cochineal, a bright red produced from tens of thousands of tiny bugs farmed on cacti by Mesoamerican cultures like the Aztec and Maya. When the Spanish conquered Mesoamerica in the 1500s, they seized cochineal production and kept its insect source secret to protect their monopoly. The chapter pushes art's origins back to cave paintings made 40,000 to 50,000 years ago, noting that the oldest known examples, roughly 64,000 years old, were likely made by Neanderthals.

Orange proposes that color is feeling, opening with Georges Seurat's Pointillism technique, in which tiny dots of color placed side by side create a scene like pixels on a screen. New chromium and cadmium pigments discovered in the 1800s gave painters like Claude Monet brilliantly bright, affordable colors that helped inspire Impressionism, a movement focused on capturing the feel of a scene rather than precise detail. The chapter explores saffron, traditionally used to dye Buddhist monks' robes, and henna, a plant paste that produces intricate orange designs on skin, used in wedding rituals across Muslim, Jewish, Hindu, and Sikh traditions.

Yellow asserts that color is everywhere. Weinberg describes piuri (also called Indian yellow), a vibrant pigment reportedly made from the urine of mango-fed cows, and discusses gold as both material and pigment, profiling Mansa Musa, king of the Malian Empire in the early 1300s and arguably the richest person in history. The chapter introduces ochre, a family of iron-rich earth pigments used in art and ceremonies for tens of thousands of years, and profiles Emily Kame Kngwarreye, a First Nations Australian (Anmatyerre) artist who created cultural art with natural ochre for most of her life before producing internationally celebrated work for outside audiences in her 70s.

Green argues that color is everyone, comparing the Colossus of Rhodes (built around 282 BCE) to the Statue of Liberty (1886), both of which turned green through oxidation and symbolized liberty. Weinberg profiles Charles Edenshaw, a 19th-century Haida artist and tribal leader's descendant who served as an ambassador for Indigenous Pacific Northwest art. The chapter warns about Scheele's green, a vivid 1775 pigment combining copper with toxic arsenic that became fashionable in European clothing and wallpaper despite causing fatal poisoning; some historians believe French emperor Napoleon Bonaparte died from arsenic exposure in a room covered with the wallpaper. Weinberg also recounts the Radium Girls, early 20th-century factory workers who painted watch dials with radioactive radium, became gravely ill, and won a landmark court case establishing protections for future workers.

Blue proposes that color is language, noting that some languages lack a dedicated word for blue and some combine it with green, a concept linguists call "grue." Weinberg traces "ultramarine" to Latin for "beyond the sea," reflecting the distance between Rome and the lapis lazuli mines of modern-day Afghanistan. He explains indigo, a plant-based dye used for at least 6,200 years, and woad, a European cousin made famous by Celtic warriors; Roman general Julius Caesar wrote that the Celts dyed themselves blue to look terrifying, and the Romans called them "pretani" (painted), from which the name Britain derives. French artist Yves Klein, who at age 19 claimed the blue sky as his personal color, later trademarked his own shade. The chapter asks why some art becomes famous and answers through the Dutch painter Vincent van Gogh: Largely unsuccessful in his lifetime, van Gogh's reputation was built after his death by his sister-in-law Jo van Gogh-Bonger, who organized exhibitions and published books that established his work.

Purple proposes that color is time, revealing that the ancient world was more colorful than its surviving white marble suggests. Modern analysis has shown that Greek and Roman sculptures were once covered in bright paint that faded over centuries. Weinberg details sea snail purple, made from the ink glands of Mediterranean murex snails and so expensive that at times only the Roman emperor could wear it. He describes a modern project that extracts iron oxides from coal-polluted rivers to produce pigments while returning clean water to the environment. He recounts how William Henry Perkin, a young English experimenter trying to synthesize quinine (a malaria treatment) from coal soot, accidentally discovered a purple pigment in 1856 at age 18, inspiring the development of synthetic pigments. A sidebar profiles Italian Renaissance artist Michelangelo, who began his career forging an ancient Cupid statue; when the deception was uncovered, his skill earned him legitimate commissions.

Pink proposes that color is change, opening with American painter Georgia O'Keeffe, who painted Cerro Pedernal mountain from her New Mexico studio repeatedly because its colors shifted constantly with the light. Weinberg traces the arbitrary history of gendered colors: In the 1800s, American babies wore white regardless of sex; by the 1920s, pink was prescribed for boys; by the 1940s, the assignment inexplicably flipped. The chapter recounts the pink triangle's transformation from a Nazi persecution symbol forced onto LGBTQ+ prisoners, alongside yellow stars for Jewish people and other colored patches for targeted groups, into a modern emblem of LGBTQ+ pride. Weinberg credits survivor Josef Kohout, whose 1972 book The Men with the Pink Triangle helped spark ongoing conversations about LGBTQ+ rights. A section on Land Art, a movement in which artists create works directly in or with natural landscapes, highlights Agnes Denes planting wheat in a Manhattan landfill and Jeanne-Claude and Christo surrounding islands in Miami's Biscayne Bay in pink plastic.

The final chapter, on black, proposes that color is beautiful. Contemporary artist Kerry James Marshall uses layered colors to paint dark skin, centering his work on the experience and beauty of Black American life. Weinberg explains carbon black, a pigment made from burnt organic matter used since the age of cave art, and describes the Chinese and Japanese tradition of ink painting with inksticks made from soot and animal glues. A grimmer history follows: mummy brown, a pigment made from ground-up decomposed human remains, was sold at a Paris shop called À la Momie beginning in 1712, and the last tubes were produced about a century ago. From Mali, Weinberg describes bogolan, an ancient textile art using specially aged Niger River mud to create permanent blacks and browns rich with cultural symbols. The chapter covers Vantablack, a 2014 material that absorbs 99.96% of light using forests of atom-thick nanotubes, and the controversy when British-Indian artist Anish Kapoor purchased exclusive artistic rights, prompting British artist Stuart Semple to crowdfund a rival ultra-black paint available to everyone except Kapoor. Weinberg discusses tattoos as ancient carbon-black art, citing Ötzi the Iceman, a 5,300-year-old body preserved in the Italian Alps with at least 61 tattoos.

In a brief conclusion, Weinberg synthesizes the book's accumulating answers: Color is art, science, a recipe, feeling, everywhere, everyone, language, time, change, and beautiful. He reflects that the book became a story about humanity and everything people have figured out over roughly 60,000 years, and invites readers to make their own discoveries. Back matter provides hands-on recipes for grape purple ink and avocado pink dye, a pigment garden diagram, a global color map, an annotated periodic table, a bibliography, a glossary, and an index.