A Guide to Acidic Demi-Permanent Glazes

Acidic demi-permanent glazes are used primarily to adjust tone, enhance shine, and blend demarcation lines. Unlike permanent hair colour, which relies on high alkalinity to swell the cuticle, acidic formulas maintain the structural integrity of the hair shaft.

Correct application relies on the specific mixing ratio of the colour component to the dedicated developer. Mastery of these variables ensures predictable outcomes and longevity.

1. Measure the ratio. Begin by measuring your chosen shade in a non-metallic bowl. The standard industry ratio for acidic glazes is one part colour to one part dedicated processing solution. Do not deviate from this ratio, as it is calibrated to ensure the correct pH balance upon contact with the hair.
2. Prepare for application. Section the hair into four equal quadrants to ensure even coverage. Using a tint brush, begin at the roots and work through to the ends. Ensure the hair is slightly damp, as moisture assists in the distribution of the product without diluting the pigment.
3. Monitor processing. Apply the mixture consistently, starting from the roots and pulling through to the mid-lengths and ends. Process at room temperature without the addition of heat. Heat accelerates the reaction prematurely, which can lead to uneven results or unintended darkening.
4. Emulsify and rinse. Before rinsing, add a small amount of warm water to the hair and emulsify the product by massaging it gently. This step ensures that any residue is loosened from the cuticle. Rinse thoroughly with cool water until the stream runs completely clear.
5. Seal the cuticle. Apply a pH-balanced conditioner to close the hair cuticle. Allow it to sit for three minutes before a final rinse. Proper sealing prevents the pigment from washing out prematurely and enhances the light-reflective qualities of the glaze.

Consistency in ratio prevents oxidation errors and preserves the structural integrity of the hair.