Color
Color Wheel
The Color Wheel is the basis of Color Theory. It shows relationships between primary, secondary, tertiary, complementary and analogous colors.
Issac Newton created the first color wheel that had seven colors (1666). He also:
investigated the refraction of light, demonstrating that a prism could decompose white light into a spectrum of colours, and that a lens and a second prism could recompose the multicoloured spectrum into white light.Isaac Newton
A hundred years later Moses Harris (c1766) produced the first color wheel that classified yellow, blue and red as the three primary colors and the secondary colors as orange purple and green.
Johann Wolfgang von Goethe (1749-1832) created the first systematic study of the physiological effects of color study. His studies and observations lead to most modern color concepts.
RYB Wheel
When the RYB color wheel was first introduced it was for mixing colors for painting. The RGB colors are used for colors for a screen, and the CMYK colors are used for printing.