One of the contributing factor to skin color is blood. Blood is responsible for the rosy color of skin. It is influenced by how much blood flows in the capillaries, how much hemoglobin there is in the blood and the degree of oxygenation of arterial blood.
When blood is well-oxygenated the skin gives off a more reddish color or rosy color. When oxygenation is poor the skin becomes bluish, which is cyanosis.