The yellow color that you may or may not see when your hair is highlighted is the color of keratin which is the structural protein in your hair.

Eumelanin is the brown or black pigment in your hair (and skin) and pheomelanin is a red or yellow pigment. The abundance of one type of melanin over the other is what determines your hair (and skin) color.

Hair bleach reacts more readily with eumelanin (dark) rather than pheomelanin, which is why you see red or gold residual tones in the hair after bleaching. Bleach reacts with the melanin in the hair by removing the color in an irreversible chemical reaction.

To understand fully, you must understand the natural remaining pigment or NRP; which is the tone that contributes to the end color result.

For example, if you were going from a level 6 (light-medium brown) to a level 10 platinum blonde, you would need to go through 5 levels of NRP. You must also decide the developer needed to achieve this- developer is the oxidizing agent mixed with hair color or bleach. You can think of developer-like blinds on a window- when you open the blinds a little you are only exposing minimal light into your room, but when you open them more, lighter, and when they are fully open you have exposed maximum light. Use this comparison to imagine light as the warmth in the hair- when using a higher-level developer during the hair color process it causes the blinds to open more and in exchange exposes more of the natural remaining pigment. While bleaching hair you are either enriching or canceling out warm tones- this is contingent on your desired outcome.

Dark hair has red or copper undertones, light brown hair usually has soft golden tones.

The darker your hair color is, the more contributing pigment is required to “lift through” .

This is why hair coloring and bleaching should be left to the professionals, as there is much more science involved than most people realize. No, it’s not rocket science but understanding the chemical process that occurs is pertinent to achieving the best results.

Also, because bleaching is altering the chemical composition of hair, its essential to replace proteins removed in order to maintain the health of your hair. Porosity is the measurement of the hair’s ability to hold and absorb moisture. It is also an indication of how easily moisture can penetrate the hair shaft. It is determined initially by genetics but can be altered through heat and chemical processing.