Hair dye for surgery?

[surgen]

I am scheduled for surgery in August and have a couple questions regarding the necessity to dye my salt 'n pepper hair prior to surgery:

- I assume the reason for this is to increase the visibility of each follicle during surgery?

- Is it just the donor area hair that is most important to be colored?

- What type of dye should be used? Is a gradual type, like Grecian Formula OK? How about a Semi-permanent dye?

- How long before surgery should I apply it?

Thanks.