Making colour last past the third wash

Fresh colour is at its most fragile immediately after it is done. The outer layer of the hair has been opened to let pigment in and has not fully closed again. Almost everything that protects colour is about that first week and a half.

The first seventy-two hours

Leave it alone. No washing for three days if you can manage it, and when you do wash, use water that is cooler than feels pleasant. Heat opens the cuticle; every hot wash lets a little more pigment leave. In Ahmedabad's summer that is a genuinely unpopular instruction, and it is still the one that matters most.

Shampoo does more damage than sun

• Sulphate-free, always. Sulphates are detergents; they lift colour along with oil.
• Wash less often than you think you need to. Two or three times a week holds colour far better than daily.
• Concentrate shampoo at the roots and let the run-off clean the lengths.

Heat, chlorine and sun

A straightener at maximum temperature will strip tone faster than a fortnight of sunlight. Turn it down. Chlorine is worse again, and lightened hair takes on a green cast from pool water — wet your hair with clean water before swimming so it absorbs less.

Cool tones fade first, which is why an ash finish drifts warm before it drifts light. If yours is warming up sooner than you would like, a toning appointment between colours costs a fraction of a full correction.