Which description best matches the physical characteristics of dry powder used as a developer?

• A. Dry powder is heavy and clumps
• B. Dry powder is light and fluffy and clings to the surface in a fine film
• C. Dry powder dissolves in moisture
• D. Dry powder forms a hard crust

Answer: (B)

In dry powder developer, the goal is to create a light, uniform coating that clings to the surface and forms a fine film. This thin film provides a clean, even background for the penetrant to be drawn to defects, making indications visible without obscuring them. A powder that is light and fluffy can be dispersed evenly and will adhere lightly to the surface, often aided by static charge, leaving a film that can be left in place during development.

If the powder were heavy and clumped, it would create an uneven, bulky layer that could mask small indications and distort the development process. If it dissolved in moisture, it wouldn’t stay as a surface film to attract the penetrant. If it formed a hard crust, the film would be too rigid and could prevent the penetrant from migrating properly to reveal defects. The description of a light, fluffy powder that clings to the surface in a fine film best matches how a dry powder developer is intended to behave.