The Evaluation Criteria And Methods of Hair Dye

The evaluation criteria and methods of healthy hair dye: disassemble the 5 core dimensions and evaluate the product value scientifically,

Component safety: Double verification from regulations to actual measurement

Evaluation indicators

✅ Hazardous substances screening: detection of ammonia, PPD (p-phenylenediamine), isophenone and other allergenic/carcinogenic substances (refer to EU EC 1223/2009, China's "Technical Code for Safety of Cosmetics").

✅ Allergy risk: Potential allergens such as preservatives (e.g., methylisothiazolinone) and fragrances are analyzed and labeled with "suitable for sensitive muscles" certification (e.g., EcoCert, CRUELt-free).

✅ Proportion of natural ingredients: content of mild ingredients such as plant extracts (such as indigo, henna) and amino acid epigenetics (example: a brand containing 95% organic ingredients certified by COSMOS).

2.Hiar color rendering: accurate measurement from color cards to digitalization

Evaluation indicators

✅ Color number reproduction: Compare the official color card with the actual hair color effect (such as whether the target color "Aoki flax gray" is reddened).

✅ Color level: gloss feeling under strong light, multi-dimensional color development (example: indoor deep brown/red brown dual effect performance under sunlight).

✅ Background color compatibility: the color difference between different primary hair colors (black, brown, yellow) (example: black hair should be faded before light gold is dyed, test the fading agent matching scheme).

3.The degree of hair damage: the dual dimension of physical index + user experience

Evaluation indicators

✅ Physical damage: integrity of hair scales (electron microscope scanning), hair breaking strength (tensile testing machine).

✅ Chemical damage: Moisture loss (Karl Fischer titration), protein loss (amino acid analysis).

✅ Touch after use: smoothness, resilience recovery (user rating 1-5).

4.Color holding time: comprehensive consideration of environmental factors + nursing programs

Evaluation indicators

✅ Natural fading rate: color retention rate within 4 weeks (example: red color usually fades faster, test the effect of color locking technology).

✅ Anti-environmental interference: sun protection (UV accelerated fading test), anti-washing times (simulate washing twice a week, record fading cycle).

✅ Complementary convenience: the effect of color superposition during supplementary dyeing (to avoid embarrassment of "two sections of color")

5. Ease of use: Optimize the whole process from operation to experience

Evaluation indicators

✅ Operation complexity: number of steps (e.g. "1 dose mixing" vs. "3 steps mixing"), time cost (30 minutes vs. 60 minutes).

✅ Tool design: comb tooth spacing (anti-knotting), glove fit, dye fluidity (avoid dripping).

✅ Sensory experience: odor (intensity of ammonia smell), ease of washing after dyeing (whether there is residual sticky sensation).