Why are barns red?

When driving through farm country, we notice that many barns are
painted red. Why red? Wouldn't any other color be just as effective?
The answer stems from one of the original ingredients of paint - iron
oxide.

Late in the 1700's, farmers in New England, Wisconsin, and Minnesota
began using a mixture of iron oxide (readily available from the soil),
lime, linseed oil, and skim milk to produce a superior paint that
quickly hardened into a bright red, plastic-like coating. The paint
adhered well and lasted for years. Iron oxide, a rust-related
compound, gave red paint its distinctive pigment, one more durable
than any other natural pigment. As an added benefit, red paint
absorbed the sun's rays in winter, keeping the barn warm. Red paint
became the traditional color for barns.

Recently, though, with the advent of prepainted metal structures,
farmers have begun to use color to fine-tune internal temperature. In
cold regions, dark colors besides red, such as brown, green, and blue,
are common now. In warmer regions, white, cream, yellow, and other
light hues are more prevalent.

The following 1835 recipe (from a farmer's periodical) makes about a
gallon of iron-oxide paint. A medium-sized barn will require about 10
gallons:

4 lbs. skim milk
8 oz. lime
6 oz. linseed oil
1.5 lbs. iron oxide (available in solution at
most paint stores
2 oz turpentine

James Callow comment: cf. Puckett, Ohio, no. 1029: "A pregnant woman should never look
at a red barn, or the baby will be born with strawberry marks."

cf. Puckett, Ohio, no. 33147: "Paint the barn red to frighten away
evil spirits."

Where learned: MICHIGAN ; LINCOLN PARK