Lace Tint
The reason as to why a lace may require tinting is because the colour of it may not necessarily match the colour of your scalp such; in which will make it obvious that you're wearing a wig, this could be because the lace may have not tinted whilst bleaching, the lace maybe a transparent lace and would require tinting or simply because the colour of the lace is too light for your skin tone.
Different ways to tint lace includes:
Tint spray; this can be found at your local beauty supply or online, and this is used by applying the tint spray on the back of a dry lace and blow drying it on a cold.
Using makeup; foundation or concealer; either on the back of the lace or a little on the parting line.
Or even actually dying the lace using hair dye to a tone that best suits your scalp.