Slides developed during World War II as a training tool, for top-side battle-station personnel on board ship and for all aircraft personnel, by the US Navy.
In 1942 a Recognition School was established by the Navy at Ohio State University where the method of identification was developed. In 1943 the school was taken over by the US Navy. The importance of training in visual recognition of ships and aircraft became even more evident during World War II. Mistakes resulting in costly errors and loss of life led to an increased emphasis on recognition as a vital skill.