The condition has been visualised using thermal infrared which allows us to see thermal energy or radiation more commonly referred to as heat. The image shows the hand of a person experiencing symptoms of Raynaud's against that of a person who is unaffected The hand affected with Raynaud's is on the right, the other hand is unaffected. This image shows both hands after exposure to cold water for 2 minutes, both hands appear to emit low levels of radiation. This image illustrates how the unaffected hand warms considerably quicker and begins to emit higher levels of radiation (heat) soon after exposure whilst the affected hand continues to emit lower levels. Thermal Infrared is found within the Infrared region on the electromagnetic spectrum. The different colours in the images represent different levels of thermal energy being emitted from the skin's surface. In this image the yellow and orange colours show a high level of thermal energy and the blue a lower level. Raynaud's phenomenon (also referred to as Raynaud's syndrome or Raynaud's disease) affects the bodily extremities, most commonly the hands and feet. On exposure to cold or stress, the blood vessels at the extremities constrict or narrow restricting the flow of blood, this is called vasoconstriction. When this happens in the hands then the fingers will often change colour becoming very pale as less blood reaches the surface of the skin, this means there is also less radiation of heat from the affected area.