Developer

A developer is a powdered or suspended absorbent material applied after penetrant removal that draws trapped penetrant out of surface defects by reverse capillary action, producing visible indications.

Definition

Five developer forms are recognized: Form a (dry), Form b (water-soluble), Form c (water-suspendable), Form d (nonaqueous wet), and Form e (specific application).

Related terms

  • Form a Developer (Dry Powder) — Form a developer is a fine dry powder applied to fluorescent penetrant systems by dust cloud, electrostatic spray, or fluidized bed, valued for ease of post-inspection cleaning in production environments.
  • Form b Developer (Water-Soluble) — Form b developer is a water-soluble compound dissolved in water and applied by immersion or spray, drying to a thin uniform film that develops indications during dwell.
  • Form c Developer (Water-Suspendable) — Form c developer is a water-suspendable powder that must be agitated continuously and applied by spray or immersion, forming a chalky coating that absorbs penetrant from defects.
  • Form d Developer (Nonaqueous Wet) — Form d is a nonaqueous wet developer in which fine powder is suspended in a quick-evaporating solvent and applied by aerosol spray, producing the highest sensitivity of any developer form.
  • Form e Developer (Special) — Form e is a special-application developer such as plastic film or strippable polymer used when an inspection record must be permanently retained on the part.
  • Dwell Time — Dwell time is the duration that penetrant is allowed to remain on the test surface before excess removal, allowing capillary action to draw the dye into surface-breaking discontinuities.

More equipment terms

Calibration Block · Transducer · Dual-Element Probe · Angle-Beam Probe · Normal-Beam Probe · Couplant · Reference Reflector · Side-Drilled Hole · Flat-Bottom Hole · Notch Reference

Where this comes up in practice

Terms like this one appear in three places that matter commercially: the written practice that governs how your personnel are qualified, the procedures and technique sheets that define how an examination is actually performed, and the evidence an auditor or client asks for when they want to know why an inspection was accepted. Getting the terminology right is the easy part; being able to produce the qualification record, the calibration traceability and the procedure revision that applied on the day of the inspection is the part that decides audits.

Atlantis NDT provides NDT training and certification against ASNT SNT-TC-1A and ISO 9712, ASNT Level III consulting for written practices and procedure approval, inspection management software that holds qualification, calibration and procedure-revision evidence in recoverable form, and an asset integrity platform that binds inspection results to the asset they describe. Browse the full NDT glossary or ask a Level III directly.