Videomaker – Learn video production and editing, camera reviews › Forums › Technique › Miscellaneous Techniques › Sin City Coloring Effects? (how can I…) › If you want the whole thin
If you want the whole thing to be in color, but just have the antagonist to have red eyes, you could look into colored contacts. This is a common thing used in TV (the Sci-Fi show from a few years ago called Invisible Man used red contacts).
That might be the fastest solution you could do. Of course, it’s more expensive, so weight the costs of your time to do color correction.