An online database of camouflage used by 
United State Naval Warships during WWII

The Pearl Harbor Experiments 
(Thanks to Alan Raven for these documents)

It appears that there was considerable experimentation at Pearl Harbor in 1941 with different colors and measures. The documents below tell a great deal on what was discovered and how it applied to  USN camouflage thinking during the war. 

Here are 9 pages of documents that discuss these experiments conducted at Pearl Harbor in 1941

From:             BUSHIPS
Released By:  T. K. WYNKOPF
Date:              13 FEB 1942







Destroyers, Battle Force


U.S.S. DOBBIN (AD3), Flagship,
c/o Fleet Post Office,
Pearl Harbor, T.H.,

Jan 18 1942

From:               Commander Destroyers, Battle Force
To:                   Commander in Chief, U.S. Pacific Fleet
Via:                  Commander Battle Force

Subject:            Visibility of Ships – Camouflage Experiments

Reference:    (a) Cincpac ltr S19/(50) Serial 01391 of September 8, 1941

(b) Cincpac desp. 220033 of November, 1941.

                    (c) Cincpac ltr A2-11/FF12(2) S19/(50) Serial 01594 of October 6, 1941.

                    (d) Comdesbatfor ltr S19 Serial 01496 of November 5, 1941.

                    (e) Comdesbatfor ltr S19 Serial 01112 of August 12, 1941.

                    (f ) Comdesbatfor ltr. S19 Serial 047 of January 15, 1942.

1. In accordance with instructions contained in references (a) and (b), five destroyers of Destroyer Squadron FIVE were painted as follows:


Formula 5-S was applied to all  vertical and horizontal surfaces.

U.S.S. FLUSSER (DD368) Formula 5-N was applied to all vertical and horizontal surfaces.
U.S.S. DRAYTON (DD366) Sapphire blue paint was applied to all horizontal and vertical surfaces except that 5-S was applied to the decks.
U.S.S. MAHAN (DD364) Formula 5-S was applied to all vertical surfaces up to the main deck sheer line and to all horizontal surfaces; Formula 5-O was applied to all remaining vertical surfaces except pole masts which were painted with Formula 5-H.
 U.S.S. LAMSON (DD367) The ship was painted in accordance with Measure 2 of Ships-2 (First Edition) substituting Formulae 5-H, 5-O, and 5-S for Formulae 5-L, 5-O, and 5-D respectively.

2. In order to obtain the information necessary for the report required by reference (c), Commander Destroyers, Battle Force, published reference (d). In this letter observers were asked to compare the above ships with each other and with any other ship in the vicinity painted with Formula 5-D. Because of the relatively few times the above ships were at sea and available for observation prior to the outbreak of war, and because more urgent matters have occupied personnel since, relatively few reports have been received. The reports received, however, do warrant the drawing of certain conclusions.

(a)  When ships are silhouetted against the source of light, or when the vessel is between the source of light and the observer, color has no effect. All vessels are equally visible.

(b) In clear weather in daylight and at night time in starlight the darker colored ships are more visible. The various paint shades in order of their relative visibility are: (1) Formula 5-D, (2) Formula 5-N, (3) Formula 5-S, (4) Sapphire Blue, (5) the Graded System (MAHAN), and (6) the Graded System (LAMSON). At long ranges the Sapphire Blue appears to be almost the same as the ships painted with the lighter colors.

(c) The ships painted with the Graded System are the first to become invisible in hazy weather. In this condition of lighting the ship painted with Sapphire Blue becomes invisible before those painted with Formulae 5-N and 5-S.

(d) The ships painted with Formulae 5-N, 5-D, 5-S, and Sapphire Blue give the best target angle deception at all ranges.

(e) The Graded Systems offer some range deception when the ships are sighted at or near the horizon.

(f) None of the painting schemes give any camouflage of type.

4. Observations of aerial observers substantiate former reports in that the darker colors are move effective in camouflage of ships from the air. The various paint shades in order of their effectiveness in concealing ships from aerial observers are (1) Sapphire Blue, (2) Formula 5-D, (3) Formula 5-N, and (4) Formula5-S. The lighter shades are not effective in this respect. It was also noted that the paints made up from the present Formulae 5-U and 5-TM had considerably more gloss than did the Formula 5-D. In bright sunlight the gloss of the paint effectively nullified its camouflage value.

5. Commander Destroyers, Battle Force believes that the present standard paint shades, Formula 5-N and 5-S, are too light and too glossy for effective camouflage from aerial observers and too dark if the painting scheme is to offer the maximum deception to surface observers. The Sapphire Blue Paint appears to be the best all around shade for camouflage from both surface and aerial observers, but it lacks the properties of good adherence. A separate report on this Sapphire Blue Paint was forwarded in reference (f).


Copy to: Buships





Pearl Harbor, T.H.,

January 10, 1942

From:               Commanding Officer

To:                   Commander Patrol Wing TWO

Subject:            Visibility of Ships – Camouflage Experiments

Reference:        (a) ComPatWing TWO conf. ltr. PW2/S19 0727 of 4 November 1941.

                        (b) Pacific Fleet Conf. Notice No. 15CN-41.

                        (c) ComScoFor Conf. ltr. S19/(50) Serial 0835 of Oct. 21, 1941.

                        (d) CinCPac Mailgram 220033 of 23 Nov. 1941.

                        (e) Conf. ltr. PW2/S19/0814 of Dec. 1, 1941.

                        (f) Conf. ltr. PW2/S19/(0749) of Nov. 10, 1941.

                        (g) Pacific Fleet Conf. Notice No. 21CN-41 of Dec. 16, 1941.


1.         In accordance with references the following report is submitted:

(a) Measure 1A – Considered to be somewhat too light in color; gives insufficient target angle deception and less range deception than darker colors. Deck paint increases difficulty of identifying ships from the air.

                                                (b) Measure 2A – This is considered to be an effective method of camouflaging that fits into all weather conditions. Range and course deception are considered larger than is realized. However, the gradients of shading are considered to abrupt for best effectiveness. It is believed all colors should be of the same basic color and shaded to approach about half the present (Measure 2A) differences in effect.

  (c) Measure 12A – MAHAN not seen. Believe remarks under (b) above apply here also.

  (d) Measure 1B – DRAYTON was compared at sea with ships painted Measure 11 and latter were considered to be more effectively camouflaged for range deception and target angle under most conditions. In bright moonlight DRAYTON appeared to offer greater deception, in sunlight the opposite effect was felt.

  (e) Measure 11 (or 1-c) – This is considered to be an excellent compromise color for different weather conditions. At distance some difficulty was noted in distinguishing DL’s from the 10,000 ton CL’s. Definite range deception was noted and also some difficulty in determining target angle especially at considerable distance. This color under some conditions of moonlight appeared phosphorescent but only for short periods or intermittently.

  (f) Measure – Suppression of “sun-glint” – An effective and excellent means of avoiding detection to some extent. Requires considerable supervision to overcome years of painting training contrary to end sought. Ships should be air-inspected for results but preferably some time after complete ship’s inspections as paint is sometimes worn off, “sun-glint” places missed at first, and etc.

  (g) Suggestions for improvement:

  (1) It is recommended that a “graded” experiment be conducted using three shades of the same color. Navy Blue for the darker color is suggested.

  (2) Unobtrusive (non-specular) dazzle camouflage is recommended for experiment. Ships daubed with black, navy blue and rust required a longer look to determine identity. This measure may prove effective for merchantmen.

  (3) No white clothes worn by men on upper decks.

  (4) Paint all steel helmets the same color as the ship. 

  Measure 11 (1-c) has been completed on the McFARLAND as has also the “Suppression of ‘Sun-glint’” measure.






Cincpac File No. Pearl Harbor, T.H.

S19/(50) DEC 19 1941

Serial 02062


From:    Commander-in-chief, United States Pacific Fleet.

To: The Chief of the Bureau of Ships.

Subject: Camouflage of Ships by Painting – Program for Further Studies.

References: (a) Pac. Flt. CONF. Notice No. 21 CN-41.

(b) Buships CONF. ltr. C-S19-7 (341) dated November 26, 1941.

(c) Ship Camouflage Instructions (Ships-2) – revised.

With reference to the questions of paragraph 2 of reference (b), the following opinions are offered:-

The instructions contained in reference (c) appear satisfactory with the following exceptions:-

"Sea Blue", 5-S, prescribed in Measure 11 appears too light in color. "Navy Blue", 5-N, which is darker, will be more effective. The suitability of Deck Blue, 20-B, for use on the flight decks of carriers is questionable.

The substitution, when developed, of a durable dark blue paint for the black formula 82 now prescribed in indicated.

Ships being send on special missions should, in some instances, have special camouflage.

It is desirable that the Bureau train officers in the principles of camouflage and make them available to the forces afloat upon request.

2. Current instructions for the painting of ships of the Pacific Fleet are contained in reference (a).


Chief of Staff





CONFIDENTIAL 29 July, 1941

My dear Chadwick:

I understand from Commander Low that you are the officer on CinClant’s staff charged with the camouflage developments. I had occasion to talk with Admiral King in the Navy Department in connection with these developments. A misunderstanding has arisen in regard thereto which I would like to have you explain to the Admiral. Your letter which proposed Measure 12 commented on the fact that the present dark gray (5-D) was too dark and the light gray (5-L) was too light. This confirms some other reports which we had received unofficially as to the experience of the vessels in the Pacific. In order to conform to this comment, we have slightly modified the provisions for tinting the basic paint (Formula 5-U) to produce a blue-gray which we have termed sea blue (Formula 5-S) and which will supplant 5-D; also a slightly darker gray which we have termed haze gray (Formula 5-H) intended to supplant light gray (Formula 5-L).

Atlantic Fleet confidential letter 4CL-41 mentions these prospective new colors under these names.

We are directing the paint manufacturing Yards to make the necessary modifications in the tinting material, Formula 5-TM, for the purpose of having a single tinter which is used in increasing quantities to get the three shades 5-H, 5-O, and 5-S as follows:

To five gallons of 5-U

Add 2 pints of 5-TM to get haze gray, 5-H.

Add 5 pints to get ocean gray, 5-O.

Add 10 pints to get sea blue, 5-S.

This is a relatively simple modification to the paint manufacturing now in progress. The tinting material (5-TM) will be supplied in completely filled cans, which will be used as described above, instead of in partially filled cans which have, in the past, contained just enough to make the 5-L and the 5-O.

The revision of the camouflage book, which is now underway and which should be issued within a month, contemplates the use of these three prospective colors. Pending receipt of the revised book, I may say that we are paralleling the measures of the old book as closely as possible by making the all dark system Measure No. 11 instead of No. 1; the graded system, according to year letter 4CL-41, Measure No. 12 instead of No. 2; the light system, using haze gray instead of light gray, Measure No. 13 instead of No. 3, and the ocean gray system Measure No. 14, replacing the old black system Measure No. 4. Until the revised book and the new paints are received, the old book is a fairly satisfactory approximation if the new colors are substituted as indicated in 4CL-41. Our 221416 was sent out to obtain your opinion as to the new shades proposed for the darkest and lightest colors.

Your 261900 has been a trifle confusing. I left a memorandum for Admiral King dated 24 July, 1941, with some samples of an intense blue color to which we are giving the name "sapphire blue". This color is a new experiment and has no relation to the standing camouflage instructions. It includes some new pigments which are, for the moment, available only in very limited quantities. One hundred gallons of this paint will be manufactured at Norfolk and shipped to the AUGUSTA as soon as possible for a special experiment which Admiral King intimated he would be interested in observing himself. This experiment is entirely independent of the provisions we are making to provide quantity production of camouflage paints for the Fleets. I will initiate on the basis of your 261900 similar experiments on a "haze green". I would like to emphasize, however, that this experimentation does not directly refer to our 221416 which was concerned with going into production on the new shades of paint for general issue.

If you will be so kind as to explain this matter to the Admiral and to make the distinction clear between the new camouflage paints now going into production and the prospective experiments on "sapphire blue" and the contemplated experiments on "haze green", I think we may be saved some further misunderstandings.

With best regards, I am

Sincerely yours,

Henry A. Ingram

Commander J.H. Chadwick, U.S.N.

Staff, Commander-in-Chief, Atlantic Fleet


c/o Postmaster

New York City

Copies to:

Commander H.N. Wallin, U.S.N.

Dr. E. O. Hulburt

Mr. D. P. Graham



Brief; Program for Further Studies for Camouflage of Ships by Painting

Date Written Date Received Serial Number Received From

12/19 12/24/41 719473 CinC Pac

Section Code Date Data Required or Information Obtained

341 12/24th copies made AHB

348 12/26th Please recommend a setup for Paragraph 1C

340 12/27th It would save a great deal of time to get men who had experience in camouflage in the last war—a list of names will be submitted. These men could be brought up to the present state of the art in two or three weeks.

341 5/21/42 There is another man (other than Warner) that Bettenger has in mind & recommends highly whom we might consider getting. Has he (?) to you about?

340 5/21/42 The other man to whom Capt Nelson referred is Eric Gugler—who had experince and training—painting ships—and the theoretical side at the naval Research Laboratory at Rochester Kodak Park—it is recommended that Mr. Gugler be given a commission in the USNR in view of his training in the late war—and his high standing in his civilian activities

Paragraph 1(a)(1)—Navy Blue 5-N was substituted for Sea Blue 5-S on 4 Nov 1941 for Atlantic Fleet by A.F. Conf. Let. 13CL-41 and on 16 Dec 1941 by P.F. Conf. Notice 21CN41. Deck Blue 20-B was affirmed for Atlantic carriers on 12 Dec 1941 and was directed by Cominch by reply to BuShips query C-S19-7(341) of 28 Jan 1942.

Paragraph 1(a)(2)—Comsubslant andComsubsPac both have decided preference for black. Experiments with dark blue underway at Pearl Harbor & Panama.

1(b)—Comment is too vague for guiding definite action. Several new measures will be included in May revision of Ships-2, notably Measure 16—a light colored system for anti-submarine vessels in low visibility areas.

300 5/22 1(c)—Cominch letter FF1/S19-7/FN-1 Serial 0506 of 1 Apr 1942 states "Experienced seagoing officers cannot be spared…for training in camouflage. Present available personnel plus…reserve officers must be relied upon for supervision of camouflage."

340 5/28 The next revision of camouflage instructions will be in sufficient detail to permit forces in the field to apply measures prescribed without officer supervision. Recommend commissioning of Mr. Everett Warner now a contract employer, but that no other officers be obtained at this time for training.




U.S.S. MARYLAND, Flagship


CONFIDENTIAL Pearl Harbor, T.H.,

CLIPPER/ MAIL December 6, 1941

(pencilled note: Rec 15 Dec via Clipper Airmail)

Dear Commander,

This will give you some early information on the progress of our current experiments in camouflage painting in this Fleet, and perhaps enable you to act in advance of receipt of the official report, which will not be forwarded until late in January 1942.

The sapphire blue apparently will do all that is claimed for it, and is color fast. However, adherence is only fair to poor, and some slight gloss has developed upon weathering. If these two defects could be overcome, it might be the answer, at least as far as air observation is concerned.

The graded systems are definitely out. They are as visible from the air as light gray, as was expected from previous tests.

Indications to date are that Measure 11 of Ships 2, utilizing formula 5S, is too light. Cinclant’s "Navy blue" looks like a step in the right direction, and we are directing that one ship of each type be painted "Navy blue" to permit comparative service tests.

We have one destroyer painted "Navy blue", and from observations made thus far, it is possible that a color underway [sic] between "navy blue" and formula 5D might be required. If so, do you know of any objections to mixing 5TM and 5U in the proportions of 20 pints of the former to 5 gallons of the latter? It is possible that such a large proportion of tinting paste to untinted base may be detrimental to the adherence, resistance to weathering and other qualities of the mixed paint.

In closing, it is our opinion that it is very desirable that we undertake further tests of sapphire blue on at least one ship of each type at as early a date as the paint can be made available here by the Bureau.

Yours sincerely,

Copy: Comdr. D.H. Clark

Cincpac Material Officer. Richard Mandelkorn

Lt.Comdr. H. A. Ingram

Bureau of Ships,

Navy Department,

Washington, D.C.


By confidential pilot letter C-S19-7(341)/C-EN28/A2-11 of September 27, 1941, the Bureau of Ships informed all Naval Districts, Navy Yards, District Materiel Officers, and Supervisors of Shipbuilding of the following selections of camouflage by Fleet Commanders:

Pacific Fleet (by CinCPac confidential letter S19/50, Serial 01445 of September 13, 1941)

All vertical surfaces above top of boot topping, including topmasts: 5-S

All horizontal surfaces, both wood and metal, 20-D [sic] Deck Blue, except carrier flight decks for which special instructions would be forthcoming.

Canvas covers visible from outside to be dyed to match Deck Blue.

Atlantic Fleet (by CinCLant confidential letter A2-11/S19/FF13/(0722) of July 19, 1941, as modified by CinCLant Despatch 260110 of July 1941)

Boot-topping to first continuous sheer line: Sea Blue 5-S

Superstructure masses Ocean Gray 5-O

Above superstructure masses Haze Gray 5-H

All horizontal surfaces, wood and metal, 20-D [sic] Deck Blue [handwritten correction: 20-B], except carrier flight decks.

Canvas covers visible outside dyed Deck Blue.

3. CNO

Vessels under direct CNO control to be as Atlantic Fleet.

Naval Districts

District craft not to be camouflaged yet [presumably to conserve limited supplies of new paint for forward forces??].

New LANT camouflage to be in new Ships-2 Revision as Ms. 12.

New PAC camouflage to be in new Ships-2 revision as Ms. 11




On July 21, 1941, Daniel Graham of the Bureau of Ships (BuShips) sent a confidential memo to the Head of the Design Division reporting on developments in Sapphire Blue paint:

On 27 June 1941 the Bureau of Ships (BuShips) invited the Krebs Pigment Corporation to suggest formulations for the Sapphire Blue manufactured on the same alkyd resin base vehicle just introduced for the "second series" camouflage paints, but having improved durability and non-fading properties via substitution of other blues for ultramarine.

On 18 July, BuShips representatives visited Krebs to view the results: two formulations, one being an extremely close match to ultramarine Sapphire Blue, the other being not so close a match, but having even better durability. The first utilized a copper phthalocyanine blue, brand designation Monastral Blue – BP173-D, and a vat dye indanthrene blue, brand designation BP174. The second was made with Monastral Blue and Monastral Violet (copper phthalocyanine violet), brand designation BP214.

These pigments were recommended by Krebs as the most permanent, free from chemical fading, that were then available.

Manufacturing capacity could be a problem, with no stocks on hand and an existing back order of 6,000 pounds of Monastral Blue for use in Army camouflage.

It was suggested that some be issued to the Atlantic Fleet for personal observation by Admiral King, "who has shown a keen personal interest in the development of low visibility paints and painting systems."

Krebs’ formulae for the alternative Sapphire Blues were as follows:

Formula No. 1 (extremely close match to ultramarine-based Sapphire Blue)

Ingredient Pounds/100 gallons

Nonchalking Titanium Dioxide 17.2

Acicular Zinc Oxide 46.0

Magnesium Silicate, high oil absorption type 188.9

Copper Phthalocyanine Blue (Krebs Monastral Blue BP173-D) 40.5

Indanthrene Blue 52.7

Dipentine 5.7

Alkyd Resin 144.3

Petroleum Spirits 442.9

Lead Napthenate 1.0

Manganese Napthenate 0.4

Cobalt Napthenate 0.4


Formula No.2 (not an exact match to ultramarine-based Sapphire Blue, but more durable)

Nonchalking Titanium Dioxide 20.3

Acicular Zinc Oxide 54.3

Magnesium Silicate, high oil absorption type 207.3

Copper Phthalocyanine Blue (Krebs Monastral Blue BP173-D) 45.8

Copper Phthalocyanine Violet (Krebs Monastral Violet BP174) 22.9

Dipentine 6.8

Alkyd Resin 165.5

Petroleum Spirits 429.9

Lead Napthenate 1.2

Manganese Napthenate 0.5

Cobalt Napthenate 0.5

NOTE: These Sapphire Blues were formulated by adding Monastral Blue, Monastral Violet, and/or Indanthrene Blue to standard White 5-U; therefor the 5-U formula can be extracted b y eliminating these ingredients from the above formulae.

By confidential letter C-S19-7 (341) of July 14, 1941 to OpNav, BuShips informed CNO that Norfolk and Mare Island, the paint manufacturing yards, were already issuing 5-D, 5-U, and 5-TM, and that contracts had been placed for delivery of the appropriate raw materials to Cavite Navy Yard.

BuShips also informed CNO of the recent proposals by CinCPac to replace 5-D and 5-L by 5-S Sea Blue and 5-H Haze Gray, respectively. BuShips forwarded samples of all five paints for information and comment.




By letter IV-3/Tp/43S-2/41 of October 16, 1941, "Report on the Spectral Apparent Reflectance Relative to MgO, and the Munsell Notation, of Ten Camouflage Paints", the National Bureau of Standards provided BuShips with Munsell data on ten more paint samples:

Paint Munsell Reference Reflectance

White Base 5-U 10Y 8.8/0.3 70

Light Gray 5-L 2PB 6.7/0.4 40

Haze Green (CinCLant) 7G 5.9/2.5 18.1

Ocean Gray 5-O 3PB 4.3/1.4 15.5

Dark Gray 5-D, one coat 5PB 2.7/0.8 6.0

Dark Gray 5-D, two coats 5PB 2.8/0.8 6.6

Submarine Blue, Formula #1 3PB 0.8/0.8 1.6

Submarine Blue, Formula #2 3PB 1.6/0.7 3.0

Submarine Blue, Formula #3 5PB 1.0/0.4 2.0

Sapphire Blue 5.5PB 2.4/6.5 5.5

Ultramarine Blue in Spar Varnish 8PB 2.9/12.0 7.2

By Restricted Mailgram dated November 27, 1941, CinCPac informed the Pacific Fleet of an experiment involving Measure 1C (Experimental Measure 21), requesting COMDESBATFOR (Commander, Destroyers, Battle Force) to designate one destroyer to be painted in accordance with a new "Measure 1C." This was to be consistent with Measure 11, but substituting 5-N Navy Blue for 5-S Sea Blue, and the experiment was to be carried out in addition to those listed in paragraph 3 of Pacific Fleet Confidential Notice 15CN-41.





7 FEB 1942


From:               The Commander Patrol Wing TWO
To:                   The Commander-in-Chief, U.S. Pacific Fleet
Via:                  The Commander Scouting Force

Subject:            Visibility of Ships – Camouflage Experiments

Reference:        (a) Pacific Fleet conf. Notice No. 15CN-41

                        (b) Comscofor conf. Ltr. S19/(50) serial 0835 of October 21, 1941

Enclosure:         (A) CO USS MC FARLAND conf. Ltr. AVD14/S19/serial 03 of
                         January 10, 1942


  1. No distinction was found between ships painted with graded colors except that the bluish gray surfaces were less visible than others and that the light gray surfaces were most conspicuous.

  2. The following comments were made by pilots of the Wing:

  1. Ships having glass eliminated and retained glass covered, effectively suppressed sun glint and reduced reflections.

  2. Decks painted with blue-gray paint were less visible than other ships.

  3. Ships with upper structure painted light gray were very conspicuous compared with ships painted completely with blue-gray.

      It is recommended that both decks and other horizontal or nearly horizontal surfaces be painted the same color as the bluish gray decks to further reduce visibility.

Enclosure (A) is forwarded as representing observations made from surface vessels of this command.



Copy to:     Comairscofor