Coxswain W. S. Gephart to Captain Charles B. McVay, Commander. New Jersey
U.S.S. New Jersey,
April 4th, 1918.
From: W.S. Gephart, (Cox) N.N.V.
To: Commanding Officer.
Subject: Principles of low visibility, camouflage.
1. Camouflage, another term for protective coloration, in relation to low visibility, involves the same principles as in the Animal Kingdom; that is, the object to be protected must take on as much as possible the character, color, etc., of the habitat.
2. A ship at sea is seen as a dark object against a light back ground; it obstructs from the vision as much light as it occupies in area. Therefore, that area, i.e. the ship must try to return to the eye the color of the light it obstructs.
3. We know that light sends to the eye countless atoms of different colors which are mixed on the retina of the eye and transmitted to the brain and we have the sensation of light. The spectroscope demonstrates that the three primary sensations of light are red, green and violet, coming to the eye in the order named. Hence, Mr. Wm. Andrew Mackay evolved the idea, and put into practice, the system of using these three colors in broken areas which blend into a soft gray at distances relative to varying atmospheric conditions. A logical question might arise: Why not mix the three colors together, since at a distance it blends, and apply the resulting gray to the ships?
4. Such a mixture would be opaque and non vibrating, and have little atmospheric quality. The effectiveness of the gray of the low visibility system is due to the fact that the mixture takes place not on the ship’s surface but on the retina of the eye.
5. In the cool light of the early dawn the cool colors on the ships predominate sympathetically and merge into a cool gray, and in a warm light the red color influences the other two and the result is a warm gray.
6. In instances of exceptionally overcast or thick weather, ships so painted have reported passing and firing on enemy submarines running on the surface before being sighted.
7. No one system of camouflage can possibly be effective in different zones when opposite weather conditions prevail. The U.S.S. New Jersey has been painted to represent a ship operating in a zone with conditions six days gray and one day bright.
8. The system employed has been most effective against enemy submarines, and given favorable weather conditions should also make ranging more difficult from surface fighting ships.
W. S. Gephart Cox.