If metallic salts are suspected, which test should be performed before proceeding with a chemical service?

• A. 1-20 Test: 1 oz 20 vol + 20 drops of ammonia + immersing 20 strands for 30 minutes.
• B. Patch test with a strand of hair dyed with color product
• C. A general porosity test
• D. A moisture retention test

Answer: (A)

Testing for metallic salts before a chemical service is essential because metals in the hair can react with peroxide-based products, causing dangerous heat buildup, unpredictable color results, or even hair damage. The 1-20 test does this directly by simulating the service environment: using a small amount of developer (20-volume) with ammonia and immersing a set of strands for about 30 minutes. If metallic salts are present, this combination often triggers a visible reaction—heat, fizzing, discoloration, or other changes—alerting you to avoid proceeding with that chemical process. Patch testing for allergy, porosity, or moisture retention addresses different concerns (allergic reaction to ingredients, physical structure, or hydration) and doesn’t reveal how metals will interact with oxidizers. So this test provides the specific safety check needed when metallic salts are suspected.