Ship Camouflage Instructions
United States Navy
Ships - 2 
Revision 2
Bureau of Ships
June 1942



Protective Coloration

The first American camouflage systems approved by the Bureau of War Risk Insurance during the first World War all used some form of pattern, but it was used in the expectation that it would aid in reducing visibility at a distance.  The desirability of an individual ship was conceded and the split in policy resulted from the fact that complete concealment either with pattern or with uniform color, has proved so difficult of attainment.

The first American camouflaged ship to cross the Atlantic was the S.S. St. Paul, painted in the winter of 1917 utilizing "counter-shading" in an effort to reduce visibility of shadows.  This method was based on the research of Abbott H. Thayer a celebrated American painter of a past generation, who was a pioneer student of the protective coloration of birds and animals.  He was the earliest advocate of a white ship, and unsuccessfully labored to secure its adoption both in the U.S. Navy and by the British Admiralty.  When, a quarter of a century later a British artist and naval officer, Lt. Pter Scott, R.N.V.R., again proposed the white if very light ship its great value at night or in overcast weather was beginning to be recognized, and it is now coming into favor for certain areas.  Measure 16, the American equivalent of the British Western Approaches System, has been named the Thayer System.

Limitations in the Use of Protective Coloration

In protective Coloration in Nature there is always some "cover" or fixed background which may be matched.  The background of a ship at sea is constantly changing and the problem is very much more complex.  An inherent difficulty with camouflage for reduced visibility lies in the fact that the color or shade which is best for one time will inevitably be the worst possible color at another time.  Some persons have laboriously attempted to average all the possible backgrounds against which a ship may be seen throughout the day - throughout the year.  Such an average color is merely a "service paint". It is not camouflage, because it is not aimed at the period of greatest danger.  To have a reasonable chance of success o more limited objective must be selected.

The requirements of the situation are:

"Pick the particular circumstances under which a successful camouflage would be of the greatest tactical value.  Use the method of camouflage best suited to accomplish the maximum reduction of visibility in these circumstances, accepting what increases in visibility may ensue in other conditions."

Generally speaking light ships are best against surface observation and dark ships against observation from the air, but it is necessary to make closer distinctions than we have been  in the habit of doing.  The very dark ship will be best at the bombing angle, but at very long ranges or to low flying planes a lighter ship may be better.  For night or overcast weather the pure white ship will often not be quite white enough for invisibility, but in bright sunshine it will be extremely visible when seen sun-down.  However, the advent of very light ships is making it necessary for us to revise the generally accepted dictum that no paint if effective when the ship is seen up-sun.  White or light ships often prove quite successful when seen up-sun, which in some measure compensates for their very bad performance when seen down-sun on a bright day.

It is necessary to select the color best suited to the period of greatest danger, irrespective of high visibility at less critical times.

In reaching conclusions on systems of camouflage aimed at surface attack, it is desirable to avoid judgments based on observations of vessels at close ranges.  Except at night or in a thick fog, no one expects a vessel to disappear at close range, and in clear weather the color which is deemed satisfactory at that range is almost certain to be too dark when the vessel begins to reach those ranges where invisibility might be reasonably expected.  Light ships behave better than dark ships at long ranges, and pure white even in bright sunshine will be better than medium gray when applied to small area such as masts.  In tests made in 1919 on the U.S.S. Ohio, range finder readings ceased on the masts (painted pure white) several thousand yards before they stopped on the next ship in the column where the masts were painted the battleship gray in use at that period.

There is some evidence to show that a vessel correctly painted to disappear against a horizon sky on a bright day must inevitably appear very conspicuous when seen close at hand.  Invisibility occurs when a ship presents no contrast with its background, and the customary approach which has been to match the paint to the sky, can never completely succeed because it ignores the shaded areas of the ship which we now call contained shadow.

It is obvious that the invisible ship must be the sum of two reflectances--that of the contained shadow and that of the camouflage Paint.  Since the shadow is almost invariably much darker than the sky, it is necessary to make the paint lighter than the sky in order that the visual mixture of the two, which occurs at a distance, shall exactly equal the sky background.  Large areas of light paint on the superstructure, appearing as strong contrast close at hand, may well prove to be the only way by which the shadow can be obliterated.

The situation is quite different when the vessel is seen from the air against the water.  In this case the shadows are not very different from the color of the water, and the dark colors such as Navy Blue and Deck Blue will serve to conceal the vessel very effectively.

The menace of air attack caused a general revision of ideas about camouflage, and complicated the situation for protective coloration camouflage even more than it did for deceptive camouflage  The very dark ship proved best against aerial observation, and the very light ship was best from the surface viewpoint.  A compromise color was not very good for either situation.  This dilemma has made a deliberate choice necessary, a choice dictated by the chief source of danger in any given area.  The belief that one average color could serve as a universal panacea was always untenable, but the advent of aerial attack made it obvious.

An average sky, spoken of as the "weather coefficient", may be a matter of interest, but it is a matter of no real importance, unless it can be shown that such an average sky matches the typical sky of the period of greatest danger.  The methods used in seeking to attain reduced visibility remain much the same as they have always been, but there is a new understanding  of their proper use, which should insure more effective results.  Our use of Measure 21 in Pacific areas, and the British use of their Western Approaches System in Northern waters, are good examples of a tactical use of paint whereby high visibility under certain conditions is accepted as an essential cancomitant of reduced visibility for more critical periods.