Have you ever seen someone with a lace front wig on and it looks like little black dots along the hairline?
It almost looks like little tiny bugs on the scalp along the hairline doesn't it? Those little black dots are actually the knots used to tie the hair to the lace.
Well bleached knots give the illusion that the hair is actually coming from the scalp. The area where the hair is tied to the lace, is lightened or "bleached." This reduces the color of the actual knot, or the appearance of the little black dots.
On off black or dark brown hair, the knots are typically lightened to a light brown color while blonde, light brown, and lighter shades of hair do not need bleaching. It is almost impossible to bleach the knots on jet black hair, for obvious reasons.
Another thing to keep in mind is bleached knots make the hair weaker than the rest of the hair, so there may be more shedding. However, if you care for your wig like you do your own hair, this shouldn't be too much of a problem.
The lower priced wigs normally do not have bleached knots, while the more expensive higher end wigs do. So remember when you make your next wig purchase, check to see the color of the knots. Don't pay more for less the next time you go wig shopping.