was used in 1942 for secret trials of a Canadian invention, diffused lighting camouflage
. This used dimmable lamps for counter-illumination, camouflage by bringing the brightness of the ship's superstructure to the same as the night sky. The system of 60 lamps reduced the distance at which a ship could be seen
from a surfaced submarine by 25% using binoculars, or by 33% using the naked eye. It worked best on clear moonless nights, at best preventing Largs from being seen until it closed to 2,250 yards (2,060 m) when counter-illuminated, compared to 5,250 yards (4,800 m) unlighted, a 57% reduction in range. However, with the development of marine radar, the system was not put into service
https://en.wikipedia.org/wiki/HMS_Largs ... e_research
https://en.wikipedia.org/wiki/Diffused_ ... Royal_Navy
PS Jag tror det är tvärtom: de närmast
e är inaktiva. "Bulwark of HMS Largs showing four Diffused Lighting Camouflage fittings, two lifted inboard, 2 deployed, for trials in the Clyde Approaches, 1942." "HMS Largs bulwark with diffused lighting camouflage fittings, 2 retracted (up), 2 deployed."