What test is typically performed before applying an aniline derivative tint?

The test that is typically performed before applying an aniline derivative tint is the patch test. This test is crucial for determining whether the client may have an allergic reaction to the hair dye. Aniline derivatives can contain chemicals that some individuals may be sensitive to, potentially leading to adverse skin reactions, such as itching, redness, or swelling. By performing a patch test, you apply a small amount of the product to a discreet area of the skin, usually behind the ear or on the inner elbow, and wait for a specified amount of time—often 24 to 48 hours—to observe for any signs of irritation or allergy. This step is essential to ensure the safety and comfort of the client during the coloring process.

While other tests such as strand tests, color matching tests, and pH tests have their specific purposes in the hair coloring and treatment process, they do not serve the same function as the patch test when it comes to assessing allergy risk associated with aniline derivatives. The strand test is used to evaluate the final color result and how the hair reacts to the dye, color matching ensures the right shade is chosen, and pH testing evaluates the acidity or alkalinity of hair products—all of which are important but do not directly address potential allergic