Indian yellow was historically made by collecting the urine of cows fed an exclusive diet of mango leaves, then processing the urine through heating, filtering, and drying into concentrated balls of pigment. The process was confined to a tiny community in Bihar, India, and the original method is no longer practiced. Today, “Indian yellow” on paint tubes refers to synthetic pigments designed to match the original’s warm, transparent tone.
The Traditional Process in Bihar
Nearly everything we know about the original manufacturing process comes from a single investigative account. In the late 19th century, a man named T. N. Mukharji traveled from Calcutta to the town of Monghyr (now Munger) in Bihar, following a request from the Royal Botanic Gardens at Kew to track down the pigment’s origin. In a small suburb called Mirzapur, he found a community of gwalas (milkmen) who were reportedly the only people in the world manufacturing the pigment, known locally as “piuri.”
The process started with the cows. The gwalas fed them almost nothing but mango leaves and water, which dramatically increased bile pigments in the animals’ systems and turned their urine a vivid yellow. Mukharji noted the cows looked “very unhealthy,” though some had survived six or seven years on this diet. The milkmen occasionally allowed grass and other fodder to keep the animals alive, but this diluted the coloring power of the urine, so they kept supplementation to a minimum.
Because the restricted diet produced only small amounts of highly concentrated urine, it had to be collected in small pots. The liquid was then heated over a fire to reduce it further, filtered through cloth to separate the sediment, and the resulting paste was shaped into balls. These balls were dried using a combination of fire and sunlight until they hardened into the raw pigment that would eventually be shipped to artists across Europe and Asia.
Why Production Stopped
The cow is sacred in Hindu culture, and deliberately malnourishing cattle was deeply controversial even within India. This is likely why piuri production remained confined to such a small, isolated group rather than becoming a widespread industry. The pigment was allegedly banned in 1908 on animal cruelty grounds, though no official record of that specific law has ever been found. Researchers have suggested the ban may have been enforced under pre-existing Bengal acts for the prevention of animal cruelty dating to 1869. A 1912 Calcutta High Court case, Misri Gope v. Abdul Latif, did directly address whether depriving cows of water and feeding them only mango leaves to produce a dye constituted cruelty.
The historian Victoria Finlay later tried to verify the entire origin story. She traveled to Mirzapur and found no oral tradition, no local memory of pigment production, and no legal records of the supposed ban. The only printed source she could locate describing the practice was Mukharji’s single letter. Whether the account is fully accurate or somewhat embellished remains an open question, but laboratory analysis of surviving piuri samples has confirmed they do contain the expected chemical compounds from mango-leaf metabolism, lending credibility to the core claim.
What Makes the Pigment Chemically Unique
The active coloring compound in genuine Indian yellow is euxanthic acid, a substance formed when cows metabolize compounds found in mango leaves. The pigment exists as a magnesium salt of this acid. What made it so prized by painters is that euxanthic acid and its related compound, euxanthone, are chemically quite stable, giving the pigment strong resistance to fading. Samples from the 19th century held at the Royal Botanic Gardens at Kew still retain vivid color.
This chemical stability also makes the pigment nearly impossible to synthesize in a lab through simple reactions. The two building blocks, euxanthone and glucuronic acid (a sugar acid), don’t combine easily under normal conditions. Researchers at SUNY Buffalo State have attempted to produce synthetic euxanthic acid and found the process extremely difficult, which is one reason no one has successfully recreated the original pigment through chemistry alone.
Why Artists Valued It
Indian yellow occupied a niche that few other pigments could fill. It was deeply transparent, making it ideal for glazing, a technique where thin layers of color are built up over one another to create luminous depth. It had a warm, slightly brownish golden tone distinct from cooler yellows like cadmium or lemon yellow. Its lightfastness was excellent, meaning paintings made with it held their color over centuries. It was also low-staining and non-granulating, so it spread smoothly and could be lifted or adjusted on paper. These qualities made it a favorite for watercolor painters and miniaturists, particularly in Indian and Persian manuscript painting.
Art conservators can now identify genuine Indian yellow on historical paintings and manuscripts using Raman spectroscopy, a technique that bounces laser light off a surface to reveal the chemical fingerprint of pigments without touching or damaging the artwork. This has proven useful for detecting forgeries: if a painting claimed to be from the 18th century contains modern synthetic yellows instead of euxanthic acid, the dates don’t add up.
Modern Indian Yellow Paints
Every tube of paint labeled “Indian Yellow” sold today is a synthetic substitute. The most common replacement pigment is PY 150, also called nickel azo yellow. It’s a hybrid pigment where a nickel ion is bonded to an organic molecule from the azo dye family. Kremer Pigments, a well-known supplier of historical and specialty pigments, sells PY 150 specifically as an Indian yellow substitute because it closely matches the original’s brownish golden undertone.
Some manufacturers use other pigment combinations to approximate the color, often blending transparent yellow oxides or quinacridone golds. If you’re trying to match the qualities that made the original pigment distinctive, look for paints that are transparent, have high lightfastness ratings, and carry that characteristic warm, amber-leaning yellow. Checking the pigment code on the tube (listed as “PY” followed by a number on most artist-grade paints) will tell you exactly what you’re getting. PY 150 is the closest single-pigment match to the historical color.
Can You Recreate the Color at Home?
You cannot recreate genuine Indian yellow pigment at home. Even setting aside the ethical and legal problems with the traditional method, the chemistry is too complex to replicate outside a specialized lab. The specific metabolic pathway that converts mango leaf compounds into euxanthic acid happens inside a living cow’s digestive system, and no simple chemical process duplicates it.
What you can do is mix a convincing approximation using widely available artist pigments. A transparent yellow oxide tinted with a small amount of transparent orange or quinacridone gold will get you into the right color range. The goal is a golden yellow that leans slightly toward orange, with enough transparency to function as a glaze. If you’re working in watercolor, several manufacturers offer pre-mixed “Indian Yellow Hue” paints that perform well and maintain the transparency and lightfastness the original was known for.