Red is widely considered to be the first colour used by early humans, in the form of iron oxide-rich ochres dug from the earth. It is connected with strong emotions and signals danger, an association shared across cultures – around the world, red is the most common colour used for warning and stop signs. Throughout history, artists have used red pigments gleaned from a variety of sources. Modern developments in organic and inorganic chemistry have now seen the red pigment family become one of th

Here's Why Your Face Gets Red After Working Out—and How to Prevent It