Writing and Reading

      The red barn is certainly an iconic image, but why are so many barns this particular color? The practice started in the late 18th century with New England farmers applying a protective varnish to barn surfaces. The varnish usually contained some mixture of linseed oil, lime, or iron oxide, which, under the sun, would then turn to the red ochre hue that we have become so familiar with. Eventually, as red paint became available, many people stuck to the color tradition. It helps that red paint is one of the cheapest colors available for purchase due to the plentiful nature of the iron and oxygen compounds that give the paint its hue.

Which choice most effectively sets up the discussion that follows?