What is absorption?

• A. The process by which developer enters a surface opening increasing the volume of penetrant
• B. A chemical bonding between developer and substrate
• C. The adhesion of developer molecules to the part surface creating a film
• D. The dissolution of developer in surface moisture

Answer: (C)

Absorption in this context means the developer molecules adhere to the part surface and form a thin film. That film serves to attract or wick penetrant that is held in any surface flaws up to the surface, making indications visible by enhancing contrast. It’s a physical, surface-film action rather than chemical bonding or dissolution. The alternative descriptions don’t fit because they describe penetrant entering openings, chemical bonding, or dissolving in moisture, none of which capture the surface film formation that defines absorption here.