Coloring hair – whether you are lightening the hair or simply adding color - requires that you take many things into consideration. Two of the more important things to take into consideration are the texture and the
density of the hair you are dealing with. These two factors make up how “full” a head of hair appears to be.
As you know, texture refers to the diameter of the individual hairs on the head, while density is a measure of the number of hairs on the head. We’ve all heard people described as having “thick” hair. This expression
is generally a factor of the density of the hair and the texture combined. The fact that anyone can have any range of measure in these two traits of the hair means that there are countless combinations. Perhaps the
hair is very dense, but very fine in texture. In this case, the hair would still be thick, while if the hair is very coarse it doesn’t take as many hairs to give the same effect of fullness.
One thing to note about hair density is that it can actually be categorized by hair color. Blondes tend to have the densest hair with around 27-30% more hairs per inch than would be found in brown or black shades.
Those individuals with red hair tend to have lowest density with an average of 70-72% as many hairs on the head as are found in brown and black shades. You should also be aware that the density and texture of the
hair can vary on the same scalp from area to area. This can become an issue when dealing with hair coloring, and can require very close monitoring of the color – especially when the hair is being lightened.
Most haircolor packaging – especially that found in haircolor kits in supermarkets and drugstores – is designed to color a head of hair that is of average density, average texture and around-or-less-than shoulder
length. This means that when the texture and density are greater than average you may need more color in order to deal with the amount of hair you have.
There’s also the fact that the instructions for applying hair color are generally designed for hair that is of average density and texture. Coarse hair may require a longer processing time because it typically has
a stronger structure and can often be resistant (which indicates low porosity, a measure of the ease with which the hair absorbs moisture). Conversely, fine hair must be monitored carefully when coloring –
particularly when lightening the hair – since it tends to process faster and could be damaged by lightening processes if you leave it too long.
Density affects hair color as well, as hair that is very dense may tend to process faster near the scalp than at the ends, since the denseness of the hair can hold in the heat of the head, speeding up color
processing and lightening especially. In cases of very dense hair, it may be necessary to apply the color to the hair at least a half-inch from the scalp first, then after ten minutes apply the color to the scalp
area and work the color through the ends.
If you’re dealing with hair that has noticeably different texture and density in differing areas of the head, then you probably want to apply your color to the coarsest or densest areas first, and then apply color
to the less coarse or dense areas after giving those areas a head start on processing. Even in these situations, be sure to carefully watch the less dense, and finer textured areas of the hair to make sure the
processing doesn’t result in damage.