Done more then a few with a sharpie and never have seen any fading issues.
Most of these repairs are at corners where all it needs is a little bit of black color to cover a little nick.
Also a little dab of glamor II helps blend the the blacks.
I use the Faber markers as mentioned above,but they do not have a black.
Ken,
Archival,are you serious? We are talking dabbing a little black ink on a damaged corner of a family dog picture.