DETECTOR (RT): A device that determines the presence of ionizing radiation.
DETERGENT REMOVER (PT): A penetrant remover that is a solution of a detergent in water.
DEUTERIUM: The isotope of hydrogen having one proton, one neutron, one electron, and an AMU of two.
DEVELOPER DRY (PT): A light fluffy dry absorbent powder, applied to the part being penetrant inspected after the
excess surface penetrant has been removed and the part has been dried. The Dry developer adheres primarily to the
flaw openings wetted by the penetrant liquid, to obtain increased bleed out of the penetrant and provide sharp flaw
DEVELOPER (PT): Material, wet or dry, which will draw or absorb penetrant from a surface crack or defect to the
extent the defect will be visible under natural, artificial, or black light, as applicable. Developers also control the
background of the high contrast penetrant color system.
DEVELOPER (RT): A chemical solution that reduces exposed silver halide crystals to metallic silver.
DEVELOPER, NON.AQUEOUS (PT): Absorbent powdered materials suspended in a non-aqueous liquid, used to
provide a white background for maximum color contrast, and to enhance the bleed out of the penetrant from the flaw
cavity to obtain increased accuracy of penetrant inspection.
DEVELOPER, SOLUBLE (PT): A developer completely soluble in its carrier, not a suspension of powder in a liquid,
which dries to an absorptive coating.
DEVELOPER, SOLVENT: A developer consisting of fine particles suspended in a volatile solvent. The volatile
solvent helps dissolve the penetrant out of the discontinuity and bring it to the surface.
DEVELOPER, WET (PT): An absorbent powder supplied in the dry form to be mixed and suspended in water for
application to the part being penetrant inspected, after the excess surface penetrant has been removed. The Wet
developer, on drying, provides an absorbent white background to the part for maximum color contrast, and enhances
the bleed out of the penetrant from the flaw cavity to obtain increased inspection accuracy.
DEVELOPING AGENT (RT): The constituent of a developer that reduces sufficiently exposed silver halide grains to
metallic silver at a greater rate than unexposed or insufficiently exposed grains.
DEVELOPING TIME (PT): The elapsed time necessary for the applied developer to bring out indications from
penetrant entrapments. Usually one-half the penetrant dwell time.
DEVELOPMENT (RT): The conversion of a latent image into a visible image by treatment of the film emulsion with a
suitable chemical solution (developer).
DEZINCIFICATION: Corrosion of some copper-zinc alloys involving loss of zinc and formation of a spongy porous
DIAMAGNETIC: A material that has less magnetic permeability than a vacuum. Although diamagnetic materials
have relative magnetic permeabilities slightly less than 1, the amount of difference is insignificant in eddy current
testing and diamagnetic material are classified as nonmagnetic with a relative permeability of 1.
DICHROIC FOG (RT): Fog caused by the deposition of a very thin layer of finely divided silver on an emulsion, which
when examined in white light, appears in two colors, red by transmission and green by reflection.
DIE: Various tools used to impart shape to material primarily because of the shape of the tool itself. Examples are
blanking dies, cutting dies, drawing dies, forging dies, punching dies, and threading dies.