What was the whiting made with?

• A. calcium carbonate in water
• B. chalk-like powder suspended in alcohol
• C. graphite powder in oil
• D. starch in water

Answer: (B)

In liquid penetrant inspection, whiting is the dry developer that creates a contrasting background and helps pull penetrant out of surface flaws so indications become visible. The traditional whiting is a chalk-like powder, specifically calcium carbonate, suspended in alcohol. The fine chalk particles provide a white coating, and the alcohol carrier allows even application and quick drying, leaving a uniform white deposit that highlights defects when viewed under normal or UV lighting.

Other mixtures wouldn’t give that dry, white, uniform background: a calcium carbonate powder in water would stay wet and not provide the same quick-drying film; graphite in oil would create a dark, not white, layer; starch in water would form a paste rather than a fine, dry powder coating.