Ship Camouflage
Instructions
United States Navy
Ships - 2
Bureau of Ships
January 1941
Chapter 1
Introduction
Scope of These Instructions.
The instructions give 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 4
a brief but fairly complete
survey of information resulting from experiments on which the measures are
based. Other considerations on which additional information is desired are
brought to attention.
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.
Definition of Ship Camouflage.
Ship camouflage means painting a ship for
the purpose of producing effects of low visibility and of deception in course
and range estimation.
Camouflage Colors.
Four colors are employed in camouflage
painting; these are three shades of gray, also black. the three gray
colors are called "Dark Gray", "Ocean Gray", and
"Light Gray" designated by formula numbers 5-D, 5-O, and 5-L
respectively. The "Light Gray" color is the same as that designated
in Appendix 6, "Instructions for Painting and Cementing Vessels of the
U.S. Navy," Edition 1939 as formula #5 "Standard Navy Gray."
The black color is the same as designated by formula 82, in this
publication. The four colors are shown in Plate
1. The percentage
diffuse reflectance of each color for white lights is also given in Plate
1.
This is the standard method of specifying the brightness or darkness of
a gray color. The gloss value or shininess is also given.
The colors of Plate 1 MUST NOT be used as standards from which to mix
paint.
Light Reflection.
Lightness in color means the ability of a surface to
reflect light DIFUSELY. It is usually thought of as varying in degree
from white through gray down to black. It is commonly expressed in
percentage reflection where the standard surface, reflecting 100%, is a
surface of pure magnesium oxide.
A low reflectance is considered the characteristic
most to be desired in camouflage paints for low visibility, and the paints
which have been developed have had other qualities sacrificed as necessary in
order to obtain this feature.
Gloss.
Gloss is the ability of a surface to reflect light
SPECULARLY which means regularly or like a mirror. Qualitatively the
results are reported as glossy or mat. Five types of gloss are
recognized, but for this discussion only two are important. OBJECTIVE
gloss is reported in terms of an arbitrary scale by which the amount of light
reflected specularly from the surface in question is compared to the amount
reflected specularly from a standard gloss surface of polished black
glass. Six percent reflection is called 60, 4% called 40, etc.
COMPARATIVE gloss is a ratio between the amount reflected in the mirror
direction and that reflected in another specific direction ( usually normal )
. It is a measure of the amount of so-called high lights a rounded
surface will show.
A low gloss is desirable in camouflage paints to
avoid distinct reflections from flat or curved surfaces in sun or searchlight
beams. It is distinctly a difference characteristic from reflectance and
is relatively less important.
To distinguish between reflectance and gloss, compare
a shiny new white refrigerator and a shiny new black automobile. Both
may have the same objective gloss value (about 60), but the reflectance of the
white refrigerator would be 88% whereas the reflectance of the automobile
would only be 4%.
The old Navy Standard light gray paint formula #5 had
a gloss value of 44 which weathers down to about 28 after 30 days
exposure. The reflectance of this color is about 44%. A marked
reduction in gloss has been obtained in the new formulas as noted in Plate 1,
and due to the darker color of formula 5-D, reflectance is much less.
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