Hi Marhkimov,
This info is mainly based on some of the chapters on this subject in the "Navi Italian" series of books, the Vitochart number 25 for Axis and Japanese Warship Camouflage Colors, information from some other publications, and a study of a lot of photos. Working thus from secondary sources it can only be a first approach to the subject but hopefully it will be useful to the modder.
Like other navies of the time the Italian navy experimented with camouflage painting towards the end of WW I. After the war the Regia Marina returned to a standard light gray paint. Only torpedo boats had a dark gray over-all scheme into the late twenties. From the early thirties onwards the standard scheme for all Italian combatant ships was as follows.
Hull and upperworks - Grigio Azzuro Chiaro, (Light Blue-Gray)
Waterline - Nero, (Black).
Underwater hull - Rossa Mattone, (Brick Red), or - Verde Scuro, (Dark Green).
Decks, (steel), - Grigio Ferro, (Iron Gray) also known as, - Grigio Ponte, (Bridge Gray).
Decks, (wood), - Unpainted. (After the war began wood decks were painted over in Grigio Ferro).
Boats - Grigio Azzuro Chiaro with the lower hull Nero.
Interior walls - Verde Chiaro, (Light Green).
Command bridges - Blu Scuro, (Dark Blue).
Interior walls of gun turrets - Blu Scuro.
Anchors & chains - Nero.
After the Battle of Punta Stilo in the late summer of 1940, (when Italian warships came under attack from their own air forces), all Italian warships recieved oblique red and white stripes painted on the forecastie forward of the breakwater as a recognition marking for "friendly" aircraft. Some ships also had these stripes painted on the after deck. Shipboard biplanes had their top wings painted this way also. The angle of the stripes was either 45 degrees or, (more often), 60 degrees to the axis of the ship. This marking system was in use through the end of 1943.
In 1940 the Italians began testing camouflage designs based initially on patterns from previous experience in WWI. A few small auxiliaries were used for this purpose. The first major fleet units to receive camouflage patterns were the BB LITTORIO, CA FIUME, and the submarine MILLO in the spring of 1941. These were followed by the BB DUIUO, CL ATTENDOLO, and BB VITTORIO VENETO, all in early-to-mid 1941. The ATTENDOLO pattern was designed by the famous naval artist Claudus. It was a multi-colored scheme, a variation of which was adapted to the battleships ANDREA DORIA and GIULIO CESARE in late 1941. Colors were Azzuro Opaco, Grigio Chiaro Opaco, and Nero. CONTE DI CAVOUR in late 1941 also used this scheme with another panel of Bianco Sporco Opaca added to the pattern. By the end of 1941 camouflage became usual for the ships of the Regia Marina. It would seem that all warship types from destroyers upwards carried a camouflage pattern at one time or another. At first there was an experimental phase, (late 1941 - early 1942), where many colors were used. These were:
Bianco Sporco Opaco - (Foul Flat White).
Grigio Chiaro - (Light Gray).
Gregio Cenerino - (Ash Gray).
Gregio Scuro - (Dark Gray).
Grigio Molto Scuro - (Very Dark Gray).
Nero - (Black).
Bianco Vedastro Opaco - (Flat Greenish White) = Verde Chiarissimo.
Verde Chiaro - (Light Green).
Verde Scuro - (Dark Green). Giallo Verde - (Yellow-Green).
Giallo - (Yellow). Azzuro - (Blue).
Then, in the summer of 1942, the first standard painting instructions appeared. These consisted of 3-color design schemes using: Bianco Sporco Opaco - Grigio Chiaro - Grigio Scuro. They consisted of areas of light and dark gray with dull white areas at the bow and stern to make the ship appear to be shorter. Usually port and starboard sides had different patterns. With some ships the light areas at bow and stern were first painted in Bianco Vedastro Opaco, later being painted over in Bianco Sporco Opaco. Many ships also had false bow waves in Bianco Sporco Opaco. Late in this phase of camouflage development most ships had the white portions at bow and stern repainted in light gray and integrated into the camouflage pattern.
In 1943 a second generation of official paint standards appeared. These were generally of 2-tone patterns using Grigio Chiaro and Grigio Scuro. The identification letters on destroyers and torpedo boats generally remained in place even after the ship was camouflaged. In some cases the color was changed to Grigio Chiaro or Bianco, (White), to allow them to blend into the camouflage scheme.
During 1944, (cobelligerency period), those Italian ships that fought for the allies were painted in a standard scheme in accord with the USN Measure 22 or Royal Navy Admiralty Standard design. The hull was in Grigio Scuro, upperworks in Grigio Chiaro. Those ships under German control initially retained their Italian camouflage paint. Later many were repainted overall with Gregio Scuro or other dark grays.
After the war many of the surviving units retained their wartime painting into 1948. Light gray upperworks and dark gray hull was a common scheme as was light or dark gray overall. In 1948 the Italian Navy returned to the pre-war standard of Grigio Azzuro Chiaro overall with Red identification letters. The I.D. letters were replaced by NATO pennant numbers after 1953.
The Italian names for the colors used in this article are from Italian publications dealing with this subject. I do not know if these are the official designations. The Vitocharts in part use other names for some of the colors but the names used here are consistent with all the other sources I consulted. It seems that there were also systems using letters and numbers identifying the paints. The numbers in these listings give the year of introduction. I found indications for listing for the years (19)10, 17, 24, 29, 37, 38, 40, and 42. It seems very unlikely that the colors really differed or changed from one listing to the next. Probably every change in adminstrative instructions brought a change in the numbers on the color lists. The color itself was designated by a letter. Unfortunately there appears to have been no logical system for the letter designations. Some colors had a prefix, SP, which indicated that they were experimental. For example, LITTORIO and FlUME received an experimental scheme consisting of SP 4213, (a blue/green), SP 42C, (a gray/green named Grigio Ferro), and SP 42F, (a olive color named Verde Oliva Minetico). The 37B color, (Gregio Ponto), later became 42G and seems to be the standard color used for decks and bridges, which was also known as Grigio Ferro (iron gray). It is all very confusing. From 1943 there was a designation system in use consisting of the letter prefix CL and the combination of a cypher and a letter. In this area there is need for much additional research.
The chart shows 10 colors covering those mainly used by the Italian Navy during World War II. Colors include:
Grigio Scuro (Dark Gray),
Girgio Chiaro (Light Gray),
Blu Scuro (Dark Blue),
Azzuro (Light Blue),
Marrone Verdastro (Greenish Dark Brown),
Grigio-Azzuro Chiaro (Light Blue-Gray),
Verde Chiaro (Light Green),
Giallo Verde (Light Yellow-Green),
Bianco Sporco Opaco (Matt Foul White),
Rosso (Red).