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
Blue–green distinction in language plant hues, and grey (like the sea); other shades of green would be referred to in Modern Irish as "uaine" or "uaithne", while "liath" is grey proper (like a stone). Scottish Gaelic uses the term "uaine" for "green". However, the dividing line between it and "gorm" is somewhat different than between the English "green" and "blue", with "uaine" signifying a light green or yellow-green, and "gorm" extending from dark blue (what in English might be navy blue) to include the dark green or blue-green of vegetation. Grass, for instance, is "gorm", rather than "uaine". In addition, "liath" covers a range