When a full lace wig is made, hair is inserted or ventilated , one at a time into the
lace cap selected.
The finished appearance of this process shows all of the knotted hairs near the scalp area.
If the hair color is close to, or the same as the lace cap base, these knots are not noticeable upon close scrutiny.
However, if the hair color is dark and the lace color is light, the
knots are then more noticeable upon close scrutiny.

The technique used to minimize the appearance of the knots is called bleaching. Bleaching
the knots of a full lace wig lighten the knots so that each hair strand, blend with the lace and look
like natural hair growing from the scalp.

Below is a picture up close of bleached knots on a full lace wig.

NOTE:
How much bleached knots get lighten up, depends on the hair color and the lace color of the full lace wig. Also, when knots are bleached too light, hair will shed excessively from the hair unit.