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
Colour sergeant Marines retained the rank throughout. Historically, colour sergeants of British line regiments protected ensigns, the most junior officers who were responsible for carrying their battalions' colours to rally troops in battles. For this reason, to reach the rank of colour sergeant was considered a prestigious attainment, granted normally to those sergeants who had displayed courage on the field of battle. This tradition continues today as colour sergeants form part of a colour party in military parades. Colour sergeants are referred to and addressed as "Colour Sergeant" or "Colour" ("Colour Sergeant Hewitt" or "Colour Hewitt", for instance) in the Army, or