It is important that the donor hair follicles and the transplantation area have matching hair colors. That way the result will be natural.
If both areas have gray hair, this is good for the transplantation.
In order to make things more simple, it is possible to dye the hair follicles in the back of the head. This dye is temporary, and because the hair is short, this look will not last long. It is fairly easy to transplant gray hair just like non-gray hair.