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SHIP CAMOUFLAGE INSTRUCTIONS     UNITED STATES NAVY       SHIPS - 2   FIRST REVISION     Bureau of Ships   September 1941

1   TABLE OF CONTENTS Revised        September 1941       Chapter 1. INTRODUCTION Definition of Ship Camouflage Scope of These Instructions First Revision Further Revision         Chapter 2. CAMOUFLAGE MEASURES Camouflage Paint General Directions Common to All Measures Measure 9.  Black System Measure 11.  Sea Blue System   Measure 12.  Graded System Measure 13.  Haze Gray System Measure 14.  Ocean Gray System Wood Decks Aircraft Carrier Decks Canvas Covers White Uniforms Course Deception by Painted Splotches Course Deception by Train Visibility of Wakes All Ships not Painted Alike Flexibility of Choice of Camouflage 454229

2 Revised        September 1941         Chapter 3. DISCUSSION OF SHIP CAMOUFLAGE. References Results of Surface Ship Camouflage Experiments Discussion of Measures 11, 12, 13 and 14 Discussion of Splotch Pattern Discussion of Measure 9 for Submarines Discussion of Visibility of a Surface Ship at Sea Camouflage Paint Color Reflectivity Gloss

3 Revised        September 1941 INDEX TO PLATE NUMBERS   Camouflage Colors ...................... Plate 12 Measure 12 on Battleships ..................     "   13 Measure 12 on Carriers   ...................     "   14 Measure 12 on Heavy Cruiser .................     "   15 Measure 12 on Light Cruisers .................     "   16 Measure 12 on Destroyers ...................     "   17 Measure 12 on Auxiliaries ..................     "   18 Splotch Patterns .......................     "   19 Ship Viewed from Altitude of 20 Feet .............     "   20 Ship Viewed from Altitude of 60 Feet .............     "   21 Ship Viewed from Altitude of 180 Feet ............     "   22 Ship Viewed from Altitude of 1000 Feet ............     "   23 Ship Viewed from Altitude of 5000 Feet ............     "   24 Light and Dark Ship at Various Bearings ...........     "   25

4 Revised        September 1941 CHAPTER 1  INTRODUCTION  DEFINITION OF SHIP CAMOUFLAGE.       Ship camouflage mean painting a ship for the purpose of low visibility and of deception in course and range estimation. Low visibility is secured by reduction of contrast with the background. Course estimation is rendered difficult by using dark colors, which make shadows less conspicuous, or by a pattern of confusing spots. SCOPE OF THESE INSTRUCTIONS       Chapter 2 gives specific and detailed measures for the painting of surface ships and submarines for the purpose of low visibility and deception. In order to give a reader unfamiliar with the subject a clear understanding of developments up to the present time, there is included in Chapter 3 a brief but fairly complete survey of information resulting from experiments on which the measures are based. FIRST REVISION       This is the first revision of the publication "Ship Camouflage Instructions United States Navy. Ships-2. January 1941." It supplants the original edition in its entirety. Experimentation consequent upon the issuance of that publication has led to changes in the colors and minor modifications have been made in the measures themselves. Certain measures were found to be ineffective. This caused Measures 1, 2, 3, 4, 5, 6, 7 and 8 to become obsolete, and left Measure 9 unchanged. The present revision presents the old Measure 9 and new Measures 11, 12, 13 and 14. There has been no Measure 10.

5 Revised        September 1941 FURTHER REVISION.       This booklet is assembled in loose leaf form with the object of facilitating revision as further information becomes available. It is requested that pertinent comments be submitted via the chain of command and that instances of notably effective or ineffective camouflage be noted with particular care taken to evaluate all the circumstances.

6 Revised        September 1941 CHAPTER 2  INTRODUCTION       The following camouflage measures for combatant and merchant ships are to be placed in effect when ordered by competent authority. CAMOUFLAGE PAINT       Five colors are employed in camouflage painting, black and four shades of Blue-Gray, Black being used exclusively on submarines. The Blue-Gray colors are called "Sea Blue", "Ocean Gray", "Haze Gray", and "Deck Blue", designated by formulas 5-S, 5-O, 5-H and 20-B, respectively. They are shown approximately in Plate 12, but the colors of Plate 12 must not be used as standards from which to mix paint.      The three topside paints 5-H, 5-O, and 5-S are made from untinted white base paint formula 5-U by adding certain amounts of a Dark Blue-Black tinting material, formula 5-TM, as follows:      To five gallons of 5-U,         add 2 pints of 5-TM to get Haze Gray 5-H,         add 5 pints of 5-TM to get ocean Gray 5-O,         add 10 pints of 5-TM to get Sea Blue 5-S.      The Deck Blue paint 20-B is made from untinted deck paint formula 20-U by adding a tinting material 20-TM in the proportions 20 pints of 20-TM to 5 gallons of 20-U.      The tinting materials 5-TM and 20-TM will be supplied in completely filled cans.

7 Revised        September 1941 GENERAL DIRECTIONS COMMON TO ALL MEASURES.       The camouflage painting need not be exact or carried into corners. Small gear, wires, rigging and areas permanently in shadow, as under boats, etc., need not be painted with the camouflage colors. There is no objection to exact or careful painting which may be desired for the sake of good appearance at close range.      All pole masts and their yards, and slender upper works above approximately the top of the superstructure masses shall be painted Haze gray 5-H and measures 12, 13 and 14.      All horizontal surfaces shall be colored Deck Blue 20-B in all the systems. The systems only differ in the painting of the vertical surfaces. In cases of doubt, as on sloping surfaces and the top semi circumference of guns, use Deck Blue.      All bright or shiny objects visible from the outside of the vessel no matte how insignificant, shall not be polished and shall be painted, covered, removed, or have rust preventive compound applied as necessary to avoid a shiny surface.      Glass windows shall be covered or removed, especially during the day in sunny weather, and at night when anticipating searchlight discovery. Insofar as conditions permit, similar precautions shall be taken on airport lenses.      Raised characters, such as ships names and draft marks shall be retained and painted the same color as the hull in that vicinity. Distinguishing numbers to designate the ship to friendly aircraft may be painted as heretofore on tops of turrets or as prescribed by the Commanders-in-Chief of the fleets. Provision should be made to make them invisible

8 Revised        September 1941 except when definite identification is desired.      On surface ships which have designation numbers on the bow and stern, the size and locations shall be in accordance with the following plans, and shall be painted white, without shading. Type of Ship  Height  Inches  Bureau of Ships   Plan Number     1200 Ton Destroyers      Bow      Stern 24 15 or 25    469497    113671   Forecastle Deck Destroyers and 2100 Ton Destroyers      Bow      Ster 24 24    469497    235824      Plan No. 469497 is a new plan just being issued. It provides for numerals of the same general shape and spacing as those shown on Plan 235824 but without shadows. The smaller numbers are located about in the center of the area where the larger numbers were displayed and are on a line parallel to the base line. Type of Ship  Height  Inches  Bureau of Ships   Plan Number     Mine Sweepers      Bow Only 72    260232   Submarine Rescue Vessels      Bow Only 72    260232   Small Seaplane Tenders      Bow Only 72    260232   Patrol Vessels      Bow Only 72    260232      For patrol vessels the distinguishing number shall be preceded by "PC" and letters and numerals shall be spaced 8-1/2 inches apart, the figures shall follow the sheer lines, the forward figure being 3 feet

9 Revised        September 1941 from the bow and the tops of figures 1 foot below the deck at edge.      Special squadron insignia for mine-sweepers, submarine rescue vessels and small seaplane tenders shall be as shown on Bureau of Ships Plan No. 260232.

10 Revised        September 1941 MEASURE 9.  BLACK SYSTEM FOR SUBMARINES.      Effectiveness. Lowest visibility when submerged. When on surface low visibility to aerial observers in all types of weather. When on surface low visibility to surface observers in all types of weather.      Painting Instructions. Paint entire submarine above the waterline Black, formula 82. The painting shall be carried over all parts which are visible from the air including the numbers, capstan, running light boards and bridge rails. Radio insulators shall be dark. There shall be no boot topping. The underbody shall be painted with current issues of black antifouling paints.

11 Revised        September 1941 MEASURE 11.  SEA BLUE SYSTEM.      Effectiveness. Lowest visibility to aerial observers day and night in all types of weather. Lowest visibility under searchlight. High visibility to surface observers in all types of weather. Considerable course deception to surface observers in all types of weather.      Painting Instructions. Vertical surfaces from boot-topping to top of superstructure masses, pole masts, yards, slender upper works above level of top superstructure masses, Sea Blue, 5-S. Horizontal surfaces, Deck Blue, 20-B.

12 Revised        September 1941 MEASURE 12.  GRADED SYSTEM.      Effectiveness. A compromise. Moderately low visibility to aerial observers and surface observers in all types of weather. Some course deception. Usually makes ship appear more remote when the height of the observer is such as to align the division between the colors approximately with the horizon.      Painting Instructions. Vertical surfaces from boot-topping to level of main deck or highest sheer line, continuous for full length, on all vessels except carriers, Sea Blue 5-S. On carriers, including Lexington and Saratoga, from waterline to level of hanger deck, Sea Blue, 5-S. Vertical surfaces above main deck level, (hanger deck of carriers) to level of the top of the highest superstructure masses, Ocean Gray 5-O.

13 Revised        September 1941 Pole masts, yards, slender upper works above level of top superstructure masses, Haze Gray 5-H. Horizontal surfaces, Deck Blue, 20-B. Plates Nos. 13 to 18 indicate the approximate extent of the different colors for typical vessels.     NOTE: The Commanding Officer of the ship being painted is at liberty to use his judgement in slight modification to the width of these strata of color to conform to structural characteristics of the vessel, such as the sheer and deck lines.

14 Revised        September 1941 MEASURE 13.  HAZE GRAY SYSTEM.      Effectiveness. Lowest visibility to surface observers hazy and foggy weather. High visibility under searchlight. High visibility to aerial observers in all types of weather. High visibility to surface observers when lighted by sun or moon. No particular course or range deception.      Painting Instructions. Vertical surfaces from boot-topping to top of superstructure masses, pole masts, yards, slender upper works above level of top superstructure masses, Haze Gray, 5-H. Horizontal surfaces, Deck Blue, 20-B.

15 Revised        September 1941 MEASURE 14.  OCEAN GRAY SYSTEM.      Effectiveness. Lowest visibility to surface observers in bright sunny weather and on moonlight nights. Increased visibility to aerial observers. No particular course or range deception.      Painting Instructions. Vertical surfaces from boot-topping to top of superstructure masses, Ocean Gray 5-O. Pole masts, yards, slender upper works above level of top superstructure masses, Haze Gray, 5-H. Horizontal surfaces, Deck Blue, 20-B. (Note, the original text doesn't call out for Deck Blue on horizontal surfaces at this point, but the first paragraph of the next page does in general)

16 Revised        September 1941 WOOD DECKS.       Wood decks except on submarines and carriers shall be darkened to the color Deck Blue. Deck Blue paint shall be used in lieu of stain for this purpose. AIRCRAFT CARRIER DECKS.       The question as to the degree that the flight decks of aircraft carriers should be colored for low visibility to aerial observers compared to adequate visibility for operation of their own aircraft is under investigation on the USS Ranger. Deck markings should be discontinued and as narrow as will serve the purpose in order that they may not be used by enemy bombers to estimate the vessel's course. CANVAS COVERS.       Canvas covers visible from the outside vessel are to be dyed a color corresponding to Deck Blue. WHITE UNIFORMS       Men in ranks clothed in white uniforms are conspicuous up to moderate distances on a ship painted for low visibility. COURSE DECEPTION BY PAINTED BLOTCHES.       Surfaces and corners of surfaces useful in estimating course angles may be broken-up by means of large splotches of paint. These should not be smaller than the resolving power of the eye at the ranges at which it is desired to create confusion. The resolving power of the human eye by day is about two to three minutes of arc depending on the color contrast. Very small blotches are ineffective. The total area covered by the pattern should not be more than about 1/3 of the area of the surface in question. The splotches may be regular or irregular. The color of

17 Revised        September 1941 the splotch should be chosen from the three Blue Gray colors if Plate 12 to contrast with the color of the surface. Thus if the surface is Sea Blue the splotches are Haze Gray, and vice versa; if the surface is Ocean Gray the splotches are Sea Blue. the edges of the splotches may either be left sharp, or blurred into the surface color, or partially sharp and partially blurred. No exact form of spots can be specified. Some examples are given in Plate 19. It is probable that almost any spot pattern devised at random, within the above restrictions of size, relative area, and color contrast, will on the average be as effective as any other pattern. COURSE DECEPTION BY TRAIN.       Guns, boats, rangefinders and any object susceptible to training should be trained at various to aid in course deception, but to be effective for this purpose guns should not be elevated above about 10 degrees to the horizontal. VISIBILITY OF WAKES.       When a ship has been painted to achieve low visibility the visibility of the wake become important. For the dark colored ships the speed at which the wake is visible further than the ship is 10 to 15 knots during daylight. The exact value varies with the type of ship, the weather and the conditions of illumination and observation. Light Gray ships are sighted from the air long before the wake regardless of speed. At a given speed smaller ships produce a more visible wake then larger ships. Overcast skies and choppy seas reduce the wake visibility. At night the wake of a destroyer at speed 10 knots is visible one mile, at 25 knots 2 miles. In general for a dark colored ship making sufficient

18 Revised        September 1941 speed for submarine evasion, the wake will reveal the vessel to aircraft observers day and night, and under searchlight, before the vessel itself is sighted. ALL SHIPS NOT PAINTED ALIKE.       Since it is impossible to hide completely all ships all of the time it may be desirable to paint ships in the same formation differently so that their number cannot be definitely determined unless the formation is approached very closely. Thus, information gained by a scout at long range would be inaccurate as to numbers and also as to positive type identification. FLEXIBILITY OF CHOICE OF CAMOUFLAGE.       Task force commanders should be given flexibility as to which system they use, and should extend this flexibility to Commanding Officers and detached groups having special problems. The following conditions indicate a need for flexibility:       (a)   A ship equipped with "radar" has a different problem than one not so equipped.       (b)   Ships operating in areas susceptible to submarine attacks require different treatments than ships in areas where air attacks are the major consideration.       (c)   Large ships with wooden decks and relatively insignificant wakes at low speed require a different treatment than ships with prominent wakes at high speed.       (d)   Ships with flat athwartship surfaces need them broken-up by splotch painting for course deception.

19 Revised        September 1941       (e)   Ships operating in area frequently overcast and exposed to oblique sunlight, need different colors than those in tropical and blue sky areas.       (d)   Battleships whose major threat is from underwater damage should be painted against submarine detection (sky background) if operating in areas where submarines are the major threat.

20 Revised        September 1941 CHAPTER 3  DISCUSSION OF SHIP CAMOUFLAGE   REFERENCES   Reference 1:   Bureau of Construction and Repair Confidential Publication - "Handbook on Ship Camouflage" (Short Title - C. and R. 4) 1937.  Reference 2:   Naval Research Laboratory Report H-1585, January 12, 1940, "Naval Camouflage, Tests at Sea, June to September, 1939," and references therein.  Reference 3:   Comdesbatfor Conf. Ltr. to Buships, 25 October 1940, S19 - Ser. 4888, "Camouflage of Destroyers - Low Visibility Paint."  Reference 4:   Comdesdiv. 17 Conf. Ltr. S19/FB17, 7 March 1941; FB17/S19/A16-3, 13 may 1941.  Reference 5:   Comdr. Lexington Air Group Conf. Ltr. CLAG/S19/(ts) (231) 6 June 1941.  Reference 6:   CinClant Ltr. S19/0581, 26 June 1941; 4Cl-41, 19 July 1941.  Reference 7:   CinCpac Ltr. S19/(50) Serial 01445, 13 September 1941.  Reference 8:   Naval Research Laboratory Report H-1598, March 14, 1940, "tests at Sea of February, 1940, in the Key West Area of the Visibility of Submarines and Transparency Measurements of Navigable Waters." Comsubfor. Ltr. to Buships, FF4/A4-3/S19, 3 September 1940.

21 Revised        September 1941 RESULTS OF SURFACE SHIP CAMOUFLAGE EXPERIMENTS.      The results from earlier investigations of many aspects of surface ship camouflage by the Bureau of Construction and Repair were summarized in reference 1. Investigations continued since that time are described in references 2 to 8. The tests of references 2 and 3 culminated in the preparation of the First Edition of this booklet in January 1941. Some of the more important facts on which the measures of the First Edition were used are:        (a)   That a darker color is of low visibility to aerial observers in all type of weather because of sea background, but is relatively visible to surface observers because of sky background, and yields some course deception to surface observers because shadows are not prominent. (b)   That a light color is of low visibility to surface observers in hazy and foggy weather. (c)   That a graded system produces some range deception. (d)   That bold dazzle camouflage was undesirable because of enhanced visibility. (e)   That unobtrusive dazzle camouflage yielded some deception without too great enhancement of visibility, but was limited in its application. (f)   That all camouflage is ineffective against the sun or other concentrated source of illumination. (g)   That camouflage for low visibility is more successful on small ships than on large ships.

22 Revised        September 1941        (h)   That wakes and smoke may neutralize any advantage gained by paint.      The measures of the First Edition employed three shades of gray, a Dark Gray, a Medium Gray, and a Light Gray (Standard Navy Gray of 1928 - 1940). Subsequent experiments, references 4, 5, 6 and 7 led to the conclusion that the Dark Gray was too dark and the Light Gray too light., and that Blue Gray colors would be better than pure Gray colors. The Blue Gray colors were selected, those of Plate 12, and Measures 11 to 14 are based on them. Another change was made based upon reference 6. In the First Edition, Measure 2 was a graded system in which the hull of the ship was painted with three stripes, of Dark Gray at the waterline, Ocean Gray next above, and Light Gray above that. This measure has been replaced by Measure 12 in which the dark color Sea Blue is carried from the waterline to the main deck, with Ocean Gray above this on the Superstructure masses and haze Gray on pole masts and small projections. Measure 12 departed considerably from the original conception of a "graded" system, in which grading was carried out entirely on the hull.      Experiment showed, references 5, 6 and 7, that certain measures of the First Edition were ineffective, namely, Measure 5, painted bow waves for speed deception, and Measures 6, 7 and 8, artifices of painting a ship to look like another ship of another class or type. Accordingly, these measures have been omitted in the present revision.

23 Revised        September 1941 DISCUSSION OF MEASURES 11, 12, 13, AND 14.       Based on the preceding section the following remarks may be made concerning Measures 11, 12, 13 and 14.      Measure 11, Sea Blue, has not been tested. However, its effectiveness may be said to be known approximately, and to be about the same as, or perhaps better than, the darker pure gray system which has been tested.      Measure 12, graded, has not been tested. However, its effectiveness may be said to be known approximately and to be about the same as, or perhaps better than, a system not greatly different which has been tested by the Commander-in-Chief, Atlantic Fleet. The system consisted of Sea Blue to the sheer line, Ocean Gray to the top of the high turrets including stacks and Haze Gray above, (reference 6).      Measure 13, Haze Gray, has not been tested, but inasmuch as it is intermediate in brightness between Ocean Gray and Standard Navy Gray of 1928 - 1940, its effectiveness may be said to be known approximately.      Measure 14, Ocean Gray, has been tested and its effectiveness is known.      Table 1 gives the approximate effectiveness of the various systems. In fact, Table 1 gives about the only clear-cut conclusions which can be drawn in the light of present knowledge.

24 Revised        September 1941

25 Revised        September 1941 DISCUSSION OF SPLOTCH PATTERNS       A pattern of splotches for disturbing course estimation is completely ineffective in shadow. Its effectiveness, if any, depends on the illumination and condition of observation. These factors are so variable that no particular pattern can claim an advantage over any other pattern. This is the reason that the directions in Chapter 3 for painting the spots are indefinite. In general it is better to paint the lighter colors on areas which are usually in a shadow and the darker splotches on areas usually in the light. The splotch patterns of Plate 19 have not been tested. Finally, it is true that although patterns of spots have been painted frequently on ships, there is no first hand information concerning their effectiveness. DISCUSSION OF MEASURE 9 FOR SUBMARINES.       Experiments off Key West, in the Canal Zone, and in Hawaiian waters with submerged submarines observed from the air, reference 8, showed in general that a dark color was the color of lowest visibility, and in particular that a dark blue was slightly less visible than black. The experiments were not sufficiently extensive to decide whether the slight difference was of essential importance. It turned out that the earlier formulations of the dark blue paint, called "Pearl Harbor Blue", deteriorated and turned milky in a few weeks, whereas the black paint remained serviceable for several months. Therefore, black paint is specified in Measure 9. Improved formulas of Blue are being tested extensively in the fleet at present. A special kind of colloidal painting for the purpose of reducing the visibility of the vertical surfaces (conning tower) of a submarine on the surface is being investigated by Comsublant

26 Revised        September 1941 and the Commandant First Naval District. DISCUSSION OF VISIBILITY OF A SURFACE SHIP AT SEA       The infinite variety of background against which ships are seen as a result of varying light and cloud effects will always make camouflage a controversial subject until a means is found to color a ship at will. All that can be expected is the color which is effective most often against the observer whom it is most important to evade. It is of interest to discuss a few well known general facts about the visibility of a ship at sea; a complete discussion of all cases would be tedious. The visibility of a ship at sea depends on its contrast with the background, and this in turn depends on its contrast with the background, and this in turn depends on a number of factors, the more important of which are the color of the ship and the background, the distance from the observer, the height of the observer above sea level and on the amount and character of the illumination.      Some of factors are illustrated in Plates 20 to 25, which give the appearance of a ship at various ranges to an observer at various altitudes above sea level. Plates 20 to 24 are drawn to scale, and if looked at from a distance of about 30 feet are true to size.      As shown in Plate 20, to an observer not more than about 20 feet above sea level as on a submarine, practically the entire ship appears against the sky for all ranges above a few miles. Hence for low visibility the ship should in general be a light color; a dark colored ship will be most visible but may give course deception because of the indistinctness of shadows.      Plates 20, 21 and 22 for altitudes of the observer of 20, 60 and 180 feet, respectively, illustrate the case of the observer on a surface

27 Revised        September 1941 ship and show that the ship appears against either a background of sea and sky, or of sky alone. In this case a ship painted with some type of graded system may occasionally be less visible than a ship painted a solid color. In addition a graded system may confuse the position of the waterline relative to the horizon and may yield range deception.      Plates 23 and 24 for altitudes of 1000 and 5000 feet, respectively, illustrate the case of the observer in the air. He views the ship against the sea at all ranges. Since the sea is fairly dark, except toward the sun and in the rare condition of mirror calm, the ship should be painted a dark color for the lowest visibility.      The effect of the relative bearing of the sun on the visibility of a light color ship and a dark color ship is illustrated in Plate 25. The observer is at the center of the circle, and the altitude of the sun is taken to be between 20 degrees and 40 degrees. The ships are assumed to be always broadside to the observer; this is a simple case. The outside circle of ships appears against the horizon sky and hence refers to an observer near sea level. The inside circle of ships appears against the water and hence refers to an observer in the air. Toward, the sun both the light ship and dark ship are always darker than the background, whether the background is sky or water.      In the case of the sky background the dark ship is too dark at all bearings from the sun. Opposite the sun the light color ship may be too light, and if so, there is an intermediate sector in which the light ship may approximate the sky background in brightness and be of low visibility. The width and position of this sector depends on the reflectivity (brightness) of the paint of the light color ship.

28 Revised        September 1941      In the case of the sea background, in the sector away from the sun the dark ship may approximate the background brightness and be less visible than the light color ship. There is another smaller sector, however, more or less toward the sun in which the dark ship is too dark and the light ship is the least visible.      More complex cases arise if the ship is not broadside to the observer. Such cases being perfectly obvious would be tiresome to consider in detail, and similarly for cases of a partly cloudy sky. CAMOUFLAGE PAINT       All camouflage paint must be mat or dull, not glossy, and specification must be made of the maximum allowable amount of gloss. Other optical qualities of the paint which require specification are its color and reflectivity. COLOR.       A practical method of recording the color is by means of the Munsell Book of Color.* The specification that a certain is "Munsell PB 5/2" means that under daylight illumination the paint matches color and brightness the colored rectangle in the Munsell Book of Color on page "Purple Blue", row 5, column 2. The spectrophotometric curves of all the color samples of the Munsell Book have been determined by the United States National Bureau of Standards, and the colors are therefore reproducible at any future time. The Munsell notations of the camouflage colors are given in Table 2. * Abridged Edition, 1929, Munsell Color Company, Inc., Baltimore, Maryland. The Munsell color charts provide the best working standard available at present.

29 Revised        September 1941 Start on 30 Table 2. Data of Camouflage Colors    Name Formula Munsell Reflectivity Gloss   Deck Blue 20-B PB 3/4 7 Percent 14   Sea Blue 5-S PB 4/4 11 Percent 17.5   Ocean Gray 5-O PB 5/2 17 Percent 12   Haze Gray 5-H PB 6/2 28 Percent 12   REFLECTIVITY       The diffuse reflectivity of a painted surface for white light is a convenient and often used method of describing the lightness or darkness of the surface. The reflectivity is the ratio of the total amount of white light diffusely reflected by the surface to the amount falling on the surface. The reflectivity of a black surface is zero and of a white surface is 100 percent. Magnesium carbonate has a reflectivity of about 98 percent and and is a practical standard of a non-glossy white. The reflectivities of all the Munsell colors are tabulated on the unabridged edition and therefore if a color is specified on the Munsell system its reflectivity is known automatically. But in order to avoid looking up the Munsell table it is often desirable to give the reflectivities in addition to the Munsell notation. The reflectivities of Deck Blue, Sea Blue, Ocean Gray and Haze Gray are listed in Table 2. The reflectivity of a surface does not of course specify its color; for example on may have a red surface and a blue surface of the same reflectivity. However, in dealing with a series of different shades of approximately the same color, as in the case of the camouflage colors, the reflectivity gives a fairly satisfactory numerical description of

30 Revised        September 1941 their lightness or darkness. It is of interest to recall that Navy Standard Light Gray paint of the years 1928 - 1940 had a reflectivity of about 40 percent, and this was considerably lighter than the present Haze Gray. GLOSS       A low gloss is desirable in camouflage paints to avoid highlights or bright reflections from the surfaces in sunlight or the beam of a searchlight. Gloss is the property of a surface to reflect light SPECULARLY, which means like a mirror. A surface which is not glossy is said to be MAT. There is no accepted definition or scale of gloss; several arbitrary scales are available which depend upon the particular instrument selected to measure the gloss. A convenient scale is based on the ratio of the amount of light reflected at an angle of 45 degrees from the surface in question to the amount reflected at the same angle from a surface of polished black glass. On this scale the gloss values of the camouflage paints, freshly painted, are entered in Table 2. The gloss value of a camouflage paint should be below about 20 percent to avoid undesirable bright reflections or "Highlight". The Navy Standard Light Gray paint of 1928 - 1940 had a gloss of about 44 percent which weathered to about 28 after thirty days exposure.

Transcribed by RESEARCHER @ LARGE. Formatting & Comments Copyright R@L.

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