Which of the following is a Dye Lake dye?

• A. Titan Yellow
• B. Clayton Yellow
• C. Thiazole Yellow
• D. Calmagite

Answer: (A)

Dye lakes are water-insoluble pigments formed when a soluble dye is precipitated with a metal salt (such as aluminum or calcium). This transformation from a soluble dye to an insoluble lake pigment is what gives lakes their pigment properties and allows them to be used in solid‑state applications. Titan Yellow is known to form such a lake pigment, so it serves as an example of a Dye Lake. The other dyes listed are typically used in soluble forms: Clayton Yellow and Thiazole Yellow are usually soluble dyes, and Calmagite is a metallochromic indicator used in complexometric titrations, which remains soluble rather than forming a lake pigment.