In an effort to better protect ships from attack, especially from the threat of submarines, British artist and Royal Navy Lieutenant Commander Norman Wilkinson devised a camouflage scheme for warships at sea. The idea was to use a pattern of angular, geometric shapes and lines in bold, contrasting colors. The scheme became known variously as Razzle Dazzle, Dazzle camouflage or Dazzle painting. It was used a great deal on the ships of the Royal Navy and others in WWI. It was used as late as the end of WWII on some American Navy ships.
About this time, after viewing the above picture, you may be thinking that artist/camouflage designer Norman Wilkinson perhaps became confused and drank a glass of turpentine while he was working. That might explain trying to conceal a 600 foot long, 11,000 ton ship by painting it in purple star bursts. But the point was never really to hide the ships from view. Rather, the aim was to make ships trying to fire on the ship confused about the direction, speed, size, and range of their target. So the point was really to confuse the rangefinders and gunners of the enemy, not to hide from their lookouts and scouts. The hope was the Dazzle camo would make the enemy unable to identify the ship, or to tell whether they were looking at the bow or stern, or even if it was approaching or sailing away. Rangefinders of the early 20th Century operated on the co-incidence principal. The idea is that the ship is targeted with the rangefinder and the operator sees two half-images of the ship. He adjusts the knobs until the images meet up and finds the range based on tables and such. The camouflage was supposed to hinder this by making a pattern that seemed to not match up correctly at any range. Also, the dazzle patterns usually had a false bow wave to throw off accurate estimation of the ships' speed.
In a 1919 lecture, Norman Wilkinson explained:
The primary object of this scheme was not so much to cause the enemy to miss his shot when actually in firing position, but to mislead him, when the ship was first sighted, as to the correct position to take up. [Dazzle was a] method to produce an effect by paint in such a way that all accepted forms of a ship are broken up by masses of strongly contrasted colour, consequently making it a matter of difficulty for a submarine to decide on the exact course of the vessel to be attacked.... The colours mostly in use were black, white, blue and green.... When making a design for a vessel, vertical lines were largely avoided. Sloping lines, curves and stripes are by far the best and give greater distortion.
Whether or not the idea working in WWI, by the end of WWII it was close to completely obsolete. The amazing jump in effectiveness of naval based reconnaissance planes made many of its features useless, and the technology of visual rangefinders got better as well. With the advent of radar and radar range finders, Dazzle camouflage was done. There are however, some people who stated that it was still effective against submarines, which at the time usually needed to stalk their prey from underwater and their only view of the target was from tiny periscopes just inches off the surface.
HMS Belfast with the camouflaged paint scheme it had during WWII