Red flags and dating
In modern color theory, also known as the RGB color model, red, green and blue are additive primary colors.
Red lac, also called red lake, crimson lake or carmine lake, was an important red pigment in Renaissance and Baroque art.
This is the principle that is used to make all of the colors on your computer screen and your television.
For example, purple on a computer screen is made by a similar formula to that used by Cennino Cennini in the Renaissance to make violet, but using additive colors and light instead of pigment: it is created by combining red and blue light at equal intensity on a black screen.
The red sky at sunset results from Rayleigh scattering, while the red color of the Grand Canyon and other geological features is caused by hematite or red ochre, both forms of iron oxide.
Iron oxide also gives the red color to the planet Mars.
Modern surveys in the United States and Europe show red is also the color most commonly associated with heat, activity, passion, sexuality, anger, love and joy.