5 Things Indian Women Must Do Before Colouring Their Hair That Most Salons Will Skip

The allergen in permanent hair colour is paraphenylenediamine, or PPD. It is present in almost every box and salon colour that promises full grey coverage, and it is the reason some women end up with a swollen scalp, weeping skin, or a trip to the emergency room after a routine appointment. The Contact Dermatitis Society of India has flagged PPD sensitivity as one of the most underreported cosmetic reactions in the country, partly because women assume that tolerating a colour once means they can tolerate it forever. They cannot. Sensitisation builds over repeated exposures. A patch test done 48 hours before your appointment, a small amount of the mixed colour applied behind the ear or inside the elbow, is the only reliable screen. Most salons skip it because it adds a day to the booking cycle. Do it yourself at home before you go in.

A strand test is not about whether you like the shade. It tells you how long your hair needs to process before the colour sets, whether your strands will hold the pigment or bleed it out within two washes, and whether the particular formula will cause breakage on your specific hair. Cut a small section from an inconspicuous area, near the nape works, and apply the colour mixture to it. Time it. Rinse it. Let it dry. What you see on that strand is what you will see on your whole head. Indian women with hair that has been repeatedly treated with chemical straightening, keratin, or bleach often find that the strand test reveals extreme porosity: the colour grabs fast, goes darker than intended, and fades within weeks. Knowing this before the full application lets you adjust the developer strength or processing time. Salons rarely do this because it costs them time on a busy floor.

Colour applied to an irritated, flaking, or sunburned scalp causes a level of discomfort that most women describe as burning rather than the mild tingling that is normal. Beyond comfort, an already-compromised scalp barrier absorbs more of the chemical formula into the skin, which increases the risk of a systemic reaction. Check your scalp under good light three to four days before your appointment. If you see active dandruff, redness, or open scratches from recent itching, postpone the colour by at least a week. Use a gentle salicylic acid shampoo in the interim if dandruff is the issue, but stop two days before colouring, salicylic acid thins the scalp barrier and makes it more permeable to PPD. Indian climates, particularly in cities like Mumbai and Chennai where humidity is high year-round, make fungal scalp conditions more common than women realise. A clean, calm scalp takes colour more evenly and holds it longer.

Dry hair is porous hair, and porous hair does two things during colouring that you do not want: it absorbs colour unevenly, producing patchy results, and it loses structural integrity faster under the alkaline developer. A deep conditioning treatment applied three days before, not the night before, gives the moisture time to settle into the cortex rather than sitting on the surface. Coconut oil left on overnight works well for this because its low molecular weight lets it penetrate the hair shaft rather than coat it. Almond oil is a reasonable alternative for women whose scalp tends to break out under coconut oil. Rinse thoroughly before the colour appointment. Going in with oily hair is not the goal, going in with hydrated hair is. The distinction matters because oil left on the hair can act as a barrier and affect how evenly the colour deposits.

Porosity determines how open your hair cuticle is, and it directly controls how fast colour enters the shaft and how quickly it escapes after washing. The float test is the simplest check: drop a few clean, dry strands into a glass of water and wait four minutes. Strands that sink quickly have high porosity. Strands that float have low porosity. High-porosity hair, common in Indian women who have used hard water from borewells or municipal supplies with high mineral content, or who have heat-styled frequently, needs a lower-volume developer, typically 10 or 20 volume, to prevent over-processing. Low-porosity hair needs slightly more processing time and a slightly higher developer to lift the cuticle enough for the pigment to enter. Walking into a salon without knowing your porosity means the colourist is making a guess. Most of them make the same guess for every client because they don't have time to do otherwise. Knowing your own number gives you the information to push back if the formula doesn't seem right for your hair type.

The five steps above look like preparation, but they are actually diagnosis. A patch test tells you whether your immune system will cooperate. A strand test tells you what the colour will actually do on your specific hair. The scalp check, the deep conditioning, the porosity test, each one answers a question the colour formula cannot answer for itself. Salons skip them because they are running a production line. You are not.