Inventions of the Great War - A. Russell Bond

It was the eyes of the submarines that brought a hurry call for the artists, and up to them was put the problem of hiding ships in plain sight. A new name was coined for these warriors of the paint-brush: camoufleurs they were called, and their work was known as camouflage.

MATCHING THE SKY

Of course, no paint will make a ship absolutely invisible at a short distance, but a large vessel may be made to disappear completely from view at a distance of six or seven miles if it is properly painted.

To be invisible, a ship must reflect as much light and the same shade of light as do its surroundings. If it is seen against the background of the sea, it must be of a bluish or a greenish tint, but a submarine lies so low in the water that any object seen at a distance is silhouetted against the sky, and so the ship must have a coat of paint that will reflect the same colors as does the sky. Now, the sky may be of almost any color of the rainbow, depending upon the position of the sun and the amount of vapor or dust in the air. Fortunately in the North Sea and the waters about the British Isles, where most of the submarine attacks took place, the weather is hazy most of the time, and the ship had to be painted of such a color that it would reflect the same light as that reflected by a hazy sky. With a background of haze and more or less haze between the ship and the periscope of the U-boat, it was not a very difficult matter to paint a ship so that it would be invisible six or seven miles away. One shade of gray was used to conceal a ship in the North Sea and an entirely different shade was used for the brighter skies of the Mediterranean.

A Giant Gun Concealed Among Trees Behind the French Lines

In this way, the artists made it possible for ships to sail in safety much nearer the pursuer who was trying to find them, and by just so much they reduced his powers of destruction. But still the odds were too heavy against the merchantman. Something must be done for him when he found himself within the seven-mile danger-zone. Here again the artists came to the rescue.