Aswin, the animation you want to do is mostly done in Adobe After Effects rather than Vegas. In Vegas you could look for a change to color text animation and keyframe the color of the text when the ink is covering the text, then leave the final keyframe in the color you want. If you see the video carefully that what they did, the ink goes over the text and the text is colorized by itself, not by the ink. The text color animation could go from top to bottom colorizing the text at the same time the ink goes down.
