Hey as I am sure you're aware there is a preview page batman eternal. Anyway in the picture Tim has red lenses DUN DUN DA!
For those of you who don't understand the significance of red lenses red lens in batman symbolize evil. Don't believe me check out the picture of all the batmen all the evil ones have red eyes while all the good ones have white eyes.
In the entire Batman eternal picture tim is the only one with red eyes while everyone else has white eyes. not to mention that tim is in teen titans has white lenses