Evolution of human colour vision that are found between 450 and 625. Individuals with various forms of colour blindness such as deuteranopia and protanopia are missing human middle wavelength sensitive or long wavelength sensitive opsins. Their minimum wavelength differences are <5 but only at around 500. Protanopes, who are missing long wavelength sensitive cones, are unable to distinguish between colours in the green-yellow-red section of the electromagnetic spectrum. They find yellow, red and orange colours to have much lower brightness when compared to a trichromat. The dimming of these colours can result in confusion in many cases, such as when attempting to identify red traffic
Orange (colour) Winslow Homer brightened his palette with vivid oranges. In France painters took orange in an entirely different direction. In 1872 Claude Monet painted "Impression, Sunrise", a tiny orange sun and some orange light reflected on the clouds and water in the centre of a hazy blue landscape. This painting gave its name to the impressionist movement. Orange became an important colour for all the impressionist painters. They all had studied the recent books on colour theory, and they know that orange placed next to azure blue made both colours much brighter. Auguste Renoir painted boats with stripes of chrome orange