US Patent 7290896 Blood tracking system

A blood tracking system, comprising a light source comprising a first LED configured to emit light of a first color and a second LED configured to emit light of a second color is disclosed. The light of the first color and the light of the second color are mixed to appear as light of a third color when the first LED and the second LED are activated; and wherein the light of a third color is effective for highlighting blood. A method of highlighting a red material comprising illuminating the red material with both red and blue light is also disclosed.