TM55-1500-345-23
Table 8-5. Definitions of Common Painting Terms -- Continued
Definitions
Common Painting Terms
The numerical expression used to describe the hydrogen ion con-
PH Value
centration. The PH value denotes the degree of acidity or alkalinity.
A class of resins produced as the condensation product of phenol
Phenolic Resins
or substituted phenol and formaldehyde or derivatives.
A finely divided, insoluble substance which imparts color to the
Pigment
material to which it is added.
The ratio of the total volume of pigment to the total volume of non-
Pigment Volume Concentration
volatile matter in a paint.
The appearance of fine, pimply elevations or tiny holes on a
Pinholing
coating.
Materials which are added to resins to soften and improve flexibili-
Plasticizers
ty.
A large molecule formed when many molecules are linked together
Polymer
by polymerization.
In theory, those colors from which all other colors and white may be
Primary Colors
made. The primary colors in visible light are red, green, and blue.
The so-called pigment primaries, each absorbing a light primary,
would then be blue green or cyan (minus red), majenta (minus
green), and yellow (minus blue). Because of deficiencies in the
available cyan and majenta colorants, confusion developed, so that
red, yellow and blue are now often referred to as the pigment
primaries.
A volatile compound which is employed to bring coatings to the
Reducer
proper consistency. Also called thinner.
A measure of the deviation from normal that a beam of light
Reflective Index
undergoes upon passing through a given substance.
A method for expressing the amount of moisture in the air. It is ex-
Relative Humidity
pressed in per cent of saturation and is an indication of the propor-
tional amount of moisture that could be absorbed or held at that
temperature.
An organic polymer in the form of a crystalline or amorphous solid,
Resin
or viscous liquid, of either natural or synthetic origin.
The tendency of a wet paint film to flow downward and become
Sagging
thicker on vertical surfaces.
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