section_path: Optimal colors/Maximum chroma colors, semichromes, or full colors
section_name: Maximum chroma colors, semichromes, or full colors
paragraph_text: Maximum chroma colors, semichromes, or full colors
  
  Each hue has a maximum chroma color, also known as maximum chroma point, semichrome, or full color; there are no colors of that hue with a higher chroma. They are the most chromatic, vibrant optimal colors. Although we are, for now, unable to produce them, these are the colors that would be located in an ideal color wheel. They were called semichromes or full colors by the German chemist and philosopher Wilhelm Ostwald in the early 20th century.
  
  If B is the complementary wavelength of wavelength A, then the straight line that connects A and B passes through the achromatic axis in a linear color space, such as LMS or CIE 1931 XYZ. If the emission or reflection spectrum of a color is 1 (100%) for all the wavelengths between A and B, and 0 for all the wavelengths on the other half of the color space, then that color is a maximum chroma color, semichrome, or full color (this is the explanation to why they were called semi chromes). So maximum chroma colors are a type of optimal colors.
  
  As explained, full colors are far from being monochromatic. If the spectral purity of a maximum chroma color is increased, its chroma will decrease, because it will approach the visible spectrum, ergo, it will approach black.
  
  In perceptually uniform color spaces, the lightness of the full colors varies from around 30% in the violetish blue hues, to around 90% in the yellowish hues. The chroma of each maximum chroma point also varies depending on the hue; in optimal color solids plotted in perceptually uniform color spaces, semichromes like red, green, blue, violet, and magenta have a high chroma, while semichromes like yellow, orange, and cyan have a slightly lower chroma.
  
  In color spaces, such as the HSL color space, the maximum chroma colors are located around the equator at the periphery of the color sphere. This makes color solids with a spherical shape inherently non- perceptually uniform, since they imply that all full colors have a lightness of 50%, when, as humans perceive them, there are full colors with a lightness from around 30% to around 90%. A perceptually uniform color solid has an irregular shape.