|René Bache, "What Is 'Camouflage'?" (1918)|
An excerpt pertaining to ship camouflage from the same article—
Up to now the warpaint of fighting ships has been slate gray, which was supposed to harmonize with the sea, but henceforth (though the problem has not been worked out satisfactorily yet) they will be "camouflaged" in schemes of colors. In the American navy this idea is being tried out on destroyers; and not long ago one of Uncle Sam's submarines, while taking part in maneuvers, actually got lost from the fleet because (being adorned in this way) the other ships lost sight of it.
The United States government now requires that all of its merchant ships shall be similarly treated, information for the purpose being furnished to owners and ship masters by the Bureau of War Risk Insurance. They are at liberty to choose their own painting scheme from several "recipes" supplied. Of these the simplest consists in painting the vessel in such a way as to eliminate highlights and shadows [called countershading]. The under part of the "overhang" Is made white, and the super structure dark, the result being a blend with sea and sky.
Other schemes consist in arrangements of the primary colors In various patterns, the effect sought being a blend that will produce visually the impression of gray. But this gray has to the eye much more "deadness" than gray paint. It is misty. Optically speaking, the same principle applies as in the case of the zebra, whose black and white stripes, vivid enough when seen close at hand, are meant by nature as a protective coloration—in other words, to make tho animal less visible. Seen from a distance on its native desert, its stripes blend into a gray that is much less conspicuous than a mule's "all-over" gray.
One of these arrangements is of wavy stripes, green, blue and white. Stripes of curvilinear and scroll forms, it is found, have a confusing effect to the eye, the outlines of a hull thus adorned being lost to view at any considerable distance. Incidentally they make difficult the focusing of a telescope or binocular upon the ship, rendering it harder to see the craft distinctly.
Some of those schemes, curiously enough, seem to split up the ship's hull and superstructure into several parts, visually, with an appearance as if sea and sky showed between. The whole puzzle is very difficult to analyze, but when it has been thoroughly worked out, and its elements reduced to a scientific basis, it may be possible to make a vessel actually invisible at a distance of a mile.
Meanwhile, and for present purposes, the object sought is to render ships less easy to see. The sea is blue. The sea is green. The sea is mottled gray. Its color depends upon that of the day, which it reflects. Take a bucketful of water from the ocean, and it has no color. In reality the sea has no color of its own. How, then, shall it be successfully imitated?
One expert [William Andrew Mackay], who has made long study of the subject, declares that the color effect of the sea is a mixture of violet and green. If, therefore, a ship be painted with these two colors in a suitable pattern (stripes wavy or in scrolls), it will be made relatively invisible, because at a distance the light rays will mingle and so affect the optic nerve as to produce a color impression like that of the sea.