Bluing shampoo contains optical brighteners that make a dog's coat appear whiter.

• A. False
• B. It is true
• C. True
• D. It is brand dependent

Answer: (C)

Optical brighteners in bluing shampoos work by adding a blue, fluorescent tint that counteracts yellow or dingy tones in a dog's coat. This blue hue on the coat visually cancels the warm yellow cast because blue is opposite yellow on the color wheel, making the coat appear whiter and cleaner after rinsing. That’s why the statement is true. As a practical note, use bluing shampoos sparingly to avoid a noticeable blue tint, and check product labels since formulations can vary between brands.