Camouflage
The late Sir Peter Scott was camouflage officer in the Royal Navy in World War 2. His camouflage schemes were so effective at hiding ships that they sometimes collided!
"By May 1941, all ships in the Western Approaches (the North Atlantic) were ordered to be painted in Scott's camouflage scheme. The scheme was said to be so effective that several British ships including HMS Broke collided with each other. The effectiveness of Scott's and Thayer's ideas was demonstrated experimentally by the Leamington Camouflage Centre in 1941. Under a cloudy overcast sky, the tests showed that a white ship could approach six miles (9.6 km) closer than a black-painted ship before being seen"
https://en.wikipedia.org/wiki/Peter_Scott