Color blindness (color vision deficiency or CVD) is not actually blindness, rather it is a deficiency in the way some people perceive color. According to colourblindawareness.org, 1 in 12 men and 1 in 200 women are colorblind. These numbers suggest that there is at least one color blind participant in each training class!
Color blindness is not the same for everyone; there are different forms and degrees of color deficiency. One person may find it difficult to distinguish shades of color and another may have an extreme case where they cannot see any colors at all. The most common form of color blindness is known as red/green color blindness, a less common form is blue color blindness, and seeing just black and white (monochromacy) is very rare.
People who are color blind can typically see things just as clearly as others but they have a harder time differentiating between colors, which can depend on the darkness, lightness, or shading of the coloration. For example, a red/green color blind person will often confuse blue and purple because they can’t ‘see’ the red tones of the color purple.