Gold chloride is used for what in certain staining sequences?

• A. Toning
• B. Staining
• C. Differentiation
• D. Dehydration

Answer: (A)

Gold chloride is used for toning in silver staining sequences. After silver is deposited and developed, this toning step with gold chloride converts the metallic silver into a gold-toned, more stable image. It enhances contrast and greatly improves permanence, helping prevent fading over time. This reagent isn’t a primary stain, a dehydration step, or a differentiation step; its purpose is specifically to modify and stabilize the silver deposit to produce a clearer, more durable final image.