ISO hair color is a standardized system for classifying permanent hair dyes by level and tone. It ensures consistency in salon applications.
The ISO system uses numbers and letters to define hair color properties. Levels range from 1 (black) to 10 (lightest blonde), while tones are designated by letters (N for natural, G for gold, V for violet, etc.). This classification helps stylists select the right dye for desired results.
| Level | Color | Example |
|---|---|---|
| 1 | Black | Deep black shades |
| 5 | Dark Brown | Common base for brunettes |
| 7 | Light Brown | Used for subtle highlights |
| 10 | Lightest Blonde | Platinum blonde |
Tones modify the base level. For example, a 7N is a natural light brown, while a 7G adds golden highlights. This precision is important for achieving the exact shade a client wants.
Salons use ISO hair color to ensure consistent results across different brands and formulations. The system helps stylists communicate effectively with clients and other professionals. For instance, a stylist in New York can recommend a 6G shade to a colleague in Los Angeles, knowing the result will match expectations.
ISO hair color is particularly useful for correcting mistakes. If a client's hair turns out too dark, a stylist can use the ISO system to determine the exact lift needed for the desired outcome. This precision reduces the risk of further errors.
Many people confuse ISO hair color with semi-permanent dyes. Unlike semi-permanent dyes, which fade over time, ISO colors are permanent and require a developer to penetrate the hair shaft fully. Semi-permanent dyes deposit color on the hair's surface, making them easier to remove.
Another misconception is that ISO hair color is only for darkening hair. However, the system includes levels for lifting hair to lighter shades. For example, a 7N can be lifted to a 9N for a brighter result.
When I worked as a stylist, a client wanted to go from a 5N (dark brown) to a 7G (light brown with golden tones). Using the ISO system, I selected a dye that would lift the hair two levels and add the golden undertone. The result was a natural-looking light brown with subtle highlights, exactly what the client wanted.