High Quality Content by WIKIPEDIA articles! In 1935, the United States Navy Naval Research Laboratory began studies and tests on low visibility ship camouflage. Research continued through World War II to (1) reduce visibility by painting vertical surfaces to harmonize with the horizon and horizontal surfaces to blend with the sea, or (2) confuse identity and course by painting obtrusive patterns on vertical surfaces. Some camouflage methods served both purposes. Horizontal decks were uniformly a blue gray shade, except as noted for measures 11 and 21. Commonwealth captains executed Admiralty camouflage schemes with greater variation than was customary with these American measures.