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
Trooping the Colour (and, once they have collected their colour during the ceremony, as 'Escort to the Colour'). At the outset, the colour is held by the Colour Party - a colour sergeant and two other guardsmen of No. 1 Guards, standing well-spaced on the northern side of Horse Guards Parade. Once obtained by the Regimental Sergeant Major of No. 1 Guard, the colour is borne through the ranks of Nos 2-6 Guards by an Ensign of No. 1 Guard. It is a great honour for a young officer to carry the colour in this ceremony, as historically only the most courageous Ensigns