What is used in staining techniques to increase the intensity and selectivity or affinity of dyes for certain tissues (example: phenol in carbol fuchsin)?

• A. Accentuator
• B. Mordant
• C. Fixative
• D. Dehydrant

Answer: (A)

Accentuator is used to boost how strongly a dye colors tissues and to influence the tissue's affinity for the dye. It changes how the dye penetrates and binds, making the stain more intense and often more selective for certain tissue components. In carbol fuchsin, phenol acts as an accentuator by helping the dye penetrate waxy, lipid-rich cell walls and by enhancing retention of the dye during subsequent steps, which produces a stronger, more persistent stain. A mordant, by contrast, forms a dye-tissue complex to lock color in, but that isn’t the mechanism highlighted by the example with phenol. Fixatives preserve structure, and dehydrants remove water; neither primarily serve to increase dye intensity or selective affinity in the way an accentuator does.