Evolution of human colour vision lights, which appear to be clear. Other colour perception issues include having trouble distinguishing yellows from reds and violet, lavender and purple from blue. In other cases, objects that reflect both red and blue light may appear to just be blue to these individuals. Deuteranopes, who are missing medium wavelength sensitive cones, are similar to protanopes in that they cannot distinguish between colours in the green-yellow-red part of the electromagnetic spectrum. However, deuteranopes do not suffer from dimming issues. For example, purple colors are not seen as being opposite to other colours in the spectrum but instead appear to be
Yellow-billed amazon work, "Systema Naturae". The yellow-billed amazon is long. Its plumage is mostly green with pink over the throat, upper breast and sides of neck, and blue in the larger wing feathers. Feathers over the ears are dark blue-green. The bare white eye-rings are surrounded by a narrow rim of white plumage, which continues as a narrow band of white over the forehead. Plumage over the lores is pale blue and the fore-crown is blue. A barred appearance over the back and sides of neck arises from the green feathers having black tips and edges. The tail feathers are green with