Lieutenant-Colonel Charles Hamilton Smith, KH (26 December 1776 in East Flanders, Belgium – 21 September 1859 in Plymouth) was an English artist, naturalist, antiquary, illustrator, soldier, and spy.
His military career began in 1787, when he studied at the Austrian academy for artillery and engineers at Mechelen and Leuven in Belgium. Although his military service, which ended in 1820 and included the Napoleonic Wars, saw him travel extensively (including the West Indies, Canada, and United States), much of his time was spent at a desk job in Britain. One of his noteworthy achievements was an 1800 experiment to determine which colour should be used for military uniforms. The increasing accuracy of firearms, especially rifles, brought advantages to shades which offer a less distinctive target – by testing the accuracy of a rifle company against grey, green, and red targets, he showed scientifically the advantages of grey (and to a lesser extent, green) uniforms over red ones common at the time, and recommended that grey be adopted for riflemen and light infantry. The British army did not heed his advice, with green becoming the colour associated with light infantry. Initially commissioned into the 60th Foot, Smith later transferred to the 6th Foot.