California Cosmetology Written ExamHaircoloringHard
A client mentions she has been using a home 'progressive' gray coverage product for several months. Before applying a professional permanent color with peroxide, the cosmetologist should perform which test to check for metallic salts that could cause dangerous reactions such as excessive heat, smoking, discoloration, or hair breakage?
- AAn elasticity test by stretching a wet strand
- BA simple visual inspection of the hair's shine and color
- CA metallic salt test, placing a strand in a solution of 20-volume peroxide and 28 parts ammonia and observing for bubbling, smoking, discoloration, or heat
- DA predisposition (patch) test on the skin
Show answer & explanationAnswer & explanation
Correct answer: C. A metallic salt test, placing a strand in a solution of 20-volume peroxide and 28 parts ammonia and observing for bubbling, smoking, discoloration, or heat
Metallic salts found in progressive/color-restoring products can react violently with peroxide-based professional color, causing heat, smoking, breakage, or unpredictable color results. A metallic salt test using peroxide and ammonia identifies their presence before proceeding.
Why the other options are wrong
- A. Elasticity testing checks hair strength and stretch, not chemical compatibility.
- B. Visual inspection alone cannot reliably detect metallic salts.
- D. A patch test checks for allergic skin reactions, not metallic salt presence.
Metallic Salt Incompatibility Test
A chemical test where a hair strand is placed in a peroxide/ammonia solution to detect metallic salts, which can react dangerously with professional permanent color.
- Metallic salts are found in some progressive/home color-restoring products
- Reaction with peroxide can cause smoking, heat, breakage, or discoloration
- Test must be performed before applying peroxide-based professional tint
Memory trick: Metal + peroxide = fireworks—test before you tint.