Final answer:
The last step of a "Primo Shampoo" regarding hair dyeing is the oxidation of the dye to its final color. Regular shampooing is simply a hair cleaning process with different product formulations for various benefits.
Step-by-step explanation:
The last step of a "Primo Shampoo" in the context of hair dyeing involves the oxidation of the product formed from the quinonediimine-coupler reaction.
Once the dyed hair is exposed to the air, the dye oxidizes to create the final hair color. Regular shampooing, a hair care routine, is different and involves cleaning hair using a shampoo, which could be in liquid or bar form, applying it to wet hair, massaging the scalp, and then rinsing it out.
Some shampoos are pearlescent and may contain glycol distearate or silicone for additional conditioning benefits.